Source: Wiley Online Library
Authors: Jaime B. Palter & David S. Trossman
DOI: 10.1002/2017GB005777

Abstract

"A decline in global ocean oxygen concentrations has been observed over the twentieth century and is predicted to continue under future climate change. We use a unique modeling framework to understand how the perturbed ocean circulation may influence the rate of ocean deoxygenation in response to a doubling of atmospheric CO₂ and associated global warming. [...]."

Read the full article here.

Source: Wiley Online Library
Authors: T. Klenz et al. 
DOI: 10.1029/2018JC014264

Abstract

"Extensive field campaigns in the Mauritanian upwelling region between 2005 and 2016 provide the database for analyzing the seasonal variability of the eastern boundary circulation (EBC) and associated water mass distribution at 18°N. The data set includes shipboard upper ocean current, hydrographic, and oxygen measurements from nine research cruises conducted during upwelling (December to April) and relaxation (May to July) seasons. [...]."

Read the full article here.

Source: Frontiers in Marine Science
Authors: Kirk N. Sato et al.
DOI: 10.3389/fmars.2018.00258

Abstract

"Marine calcifiers are considered to be among the most vulnerable taxa to climate-forced environmental changes occurring on continental margins with effects hypothesized to occur on microstructural, biomechanical, and geochemical properties of carbonate structures. Natural gradients in temperature, salinity, oxygen, and pH on an upwelling margin combined with the broad depth distribution (100–1,100 m) of the pink fragile sea urchin, Strongylocentrotus (formerly Allocentrotus) fragilis, along the southern California shelf and slope provide an ideal system to evaluate potential effects of multiple climate variables on carbonate structures in situ. [...]."

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Source: IOP Science
Authors: Karin F. Kvale et al.
DOI: 10.1088/1748-9326/aaedc3

Abstract

"Warm periods in Earth's history tend to cool more slowly than cool periods warm. Here we explore initial differences in how the global ocean takes up and gives up heat and carbon in forced rapid warming and cooling climate scenarios. We force an intermediate-complexity earth system model using two atmospheric CO₂ scenarios. A ramp-up (1% per year increase in atmospheric CO₂ for 150 years) starts from an average global CO₂ concentration of 285 ppm to represent warming of an icehouse climate. [...]."

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Source: Wiley Online Library
Authors: Renato Salvatteci et al.
DOI: 10.1029/2018GL080634

Abstract

"The response of the Humboldt Current System to future global warming is uncertain. Here we reconstruct alkenone‐derived near‐surface temperatures from multiple cores along the Peruvian coast to infer the driving mechanisms of upwelling changes for the last 20 kyr. Our records show a deglacial warming consistent with Antarctic ice‐core temperatures and a Mid‐Holocene cooling, which, in combination with other paleoceanographic records, suggest a strengthening of upwelling conditions. [...]."

Read the full article here.

Source: Oxford University Press
Authors: Chuanlun Zhang et al.
DOI: 10.1093/nsr/nwy074

Abstract

"Carbon is a keystone element in global biogeochemical cycles. It plays a fundamental role in biotic and abiotic processes in the ocean, which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere. The interactions between abiotic and biogenic carbon (e.g. CO₂, CaCO₃, organic matter) in the ocean are complex, and there is a half-century-old enigma about the existence of a huge reservoir of recalcitrant dissolved organic carbon (RDOC) that equates to the magnitude of the pool of atmospheric CO₂. The concepts of the biological carbon pump (BCP) and the microbial loop (ML) shaped our understanding of the marine carbon cycle. [...]."

Read the full article here.

Source: Oxford University Press
Authors: Jane M. Caffrey et al. 
DOI: 10.1093/femsle/fny288

Abstract

"Increased organic loading to sediments from eutrophication often results in hypoxia, reduced nitrification and increased production of hydrogen sulfide, altering the balance between nitrogen removal and retention. We examined the effect of short-term exposure to various oxygen and sulfide concentrations on sediment nitrification, denitrification and DNRA from a chronically hypoxic basin in Roskilde Fjord, Denmark. Surprisingly, nitrification rates were highest in the hypoxic and anoxic treatments (about 5 μmol cm⁻³ d⁻¹) and the high sulfide treatment was not significantly different than the oxic treatment. [...]."

Read the full article here.

Source: Science
Authors: K. F. Wishner et al.
DOI: 10.1126/sciadv.aau5180

Abstract

"Oxygen minimum zones (OMZs), large midwater regions of very low oxygen, are expected to expand as a result of climate change. While oxygen is known to be important in structuring midwater ecosystems, a precise and mechanistic understanding of the effects of oxygen on zooplankton is lacking. Zooplankton are important components of midwater food webs and biogeochemical cycles. Here, we show that, in the eastern tropical North Pacific OMZ, previously undescribed submesoscale oxygen variability has a direct effect on the distribution of many major zooplankton groups. Despite extraordinary hypoxia tolerance, many zooplankton live near their physiological limits and respond to slight (≤1%) changes in oxygen. [...]."

Read the full article here.

Source: What's Up Newp
Author: Ryan Belmore

"Oceanographers at the University of Rhode Island have found that even slight levels of ocean oxygen loss, or deoxygenation, have big consequences for tiny marine organisms called zooplankton. Zooplankton are important components of the food web in the expanse of deep, open ocean called the midwater. Within this slice of ocean below the surface and above the seafloor are oxygen minimum zones (OMZs), large regions of very low oxygen. Unlike coastal “dead zones” where oxygen levels can suddenly plummet and kill marine life not acclimated to the conditions, zooplankton in OMZs are specially adapted to live where other organisms – especially predators – cannot. [...]."

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Source: Wiley Online Library
Authors: Natalya D. Gallo et al.
DOI: 10.1002/ecy.2539

"Extremophiles – organisms that live in extreme environments – invite us to question our assumptions about the requirements for life. Fish, as a group, are thought to be relatively hypoxia intolerant due to their high metabolic requirements (Vaquer‐Sunyer and Duarte 2008); however, the cusk‐eel, Cherublemma emmelas, and the catshark, Cephalurus cephalus, appear to thrive in one of the most extreme low oxygen marine habitats in the world – the Gulf of California. Here, we describe the behavior and habitat of these extraordinary species that live under conditions commonly thought to be uninhabitable by fish. [...]."

Read the full article here.

Source: EOS
Authors: Andrea Fassbender et al.

"Sea level rise, heat transport, ocean acidification, these ocean processes, well known in the public sphere, play out on a regional to global scale. But less well known are more localized processes that bring some ecological niches together, keep others separated, and help sustain ocean life by circulating nutrients. Physical processes in the ocean that take place over intermediate and small scales of space and time play a key role in vertical seawater exchange. They also have significant effects on chemical, biological, and ecological processes in the upper ocean. [...]."

Read the full article here.

Source: Biogeosciences
Authors: Neus Garcias-Bonet et al.
DOI: 10.5194/bg-15-7333-2018

Abstract

"Nitrogen loads in coastal areas have increased dramatically, with detrimental consequences for coastal ecosystems. Shallow sediments and seagrass meadows are hotspots for denitrification, favoring N loss. However, atmospheric dinitrogen (N₂) fixation has been reported to support seagrass growth. Therefore, the role of coastal marine systems dominated by seagrasses in the net N₂ flux remains unclear. Here, we measured denitrification, anaerobic ammonium oxidation (anammox), and N₂ fixation in a tropical seagrass (Enhalus acoroides) meadow and the adjacent bare sediment in a coastal lagoon in the central Red Sea. [...]."

Read the full article here.

Source: Phys.org
Author: Evan Bush

"More than two-thirds of life on Earth died off some 252 million years ago, in the largest mass extinction event in Earth's history. Researchers have long suspected that volcanic eruptions triggered "the Great Dying," as the end of the Permian geologic period is sometimes called, but exactly how so many creatures died has been something of a mystery. Now scientists at the University of Washington and Stanford believe their models reveal how so many animals were killed, and they see frightening parallels in the path our planet is on today. Models of the effects of volcanic greenhouse gas releases showed the Earth warming dramatically and oxygen disappearing from its oceans, leaving many marine animals unable to breathe, according to a study published Thursday in the peer-reviewed journal Science. By the time temperatures peaked, about 80 percent of the oceans' oxygen, on average, had been depleted. Most marine animals went extinct. [...]."

Read the full article here.

Source: Science
Authors: Justin L. Penn et al.
DOI: 10.1126/science.aat1327

Abstract

"Climate change triggered by volcanic greenhouse gases is hypothesized to have caused the largest mass extinction in Earth’s history at the end of the Permian Period (~252 million years ago). Geochemical evidence provides strong support for rapid global warming and accompanying ocean oxygen (O₂) loss, but a quantitative link among climate, species’ traits, and extinction is lacking. To test whether warming and O₂ loss can mechanistically account for the marine mass extinction, we combined climate model simulations with an established ecophysiological framework to predict the biogeographic patterns and severity of extinction. Those predictions were confirmed by a spatially explicit analysis of the marine fossil record. [...]."

Read the full article here.

Source: ACS Publications 
Authors: V. Rohith Reddy Matli et al.
DOI: 10.1021/acs.est.8b03474

Abstract

"Nearly every summer, a large hypoxic zone forms in the northern Gulf of Mexico. Research on the causes and consequences of hypoxia requires reliable estimates of hypoxic extent, which can vary at submonthly time scales due to hydro-meteorological variability. Here, we use an innovative space-time geostatistical model and data collected by multiple research organizations to estimate bottom-water dissolved oxygen (BWDO) concentrations and hypoxic area across summers from 1985 to 2016. [...]."

Read the full article here.

Source: Frontiers in Marine Science
Authors: Carlos Neira et al.
DOI: 10.3389/fmars.2018.00448

Abstract

"Ocean deoxygenation has become a topic of increasing concern because of its potential impacts on marine ecosystems, including oxygen minimum zone (OMZ) expansion and subsequent benthic effects. We investigated the influence of oxygen concentration and organic matter (OM) availability on metazoan meiofauna within and below an OMZ in bathyal sediments off Costa Rica, testing the hypothesis that oxygen and OM levels are reflected in meiofaunal community structures and distribution. Mean total densities in our sampling cores (400–1800 m water depth) were highest with 3688 ind. 10 cm⁻² at the OMZ core at 400 m water depth, decreasing rapidly downslope. [...]."

Read the full article here.

Source: Springer Link
Authors: Phillip Westbrook et al.
DOI: 10.1007/s00227-018-3449-1

Abstract

"The eastern oyster (Crassostrea virginica) and the reefs they create provide significant ecosystem services. This study measured their possible role in nutrient mitigation through bioassimilation, burial, and oyster-mediated sediment denitrification in near-shore shallow water (< 1 m water depth) and deep-water (> 1 m water depth) oyster reefs in Louisiana. Nitrogen (N) and carbon (C) in shell and tissue differed by oyster reproductive status, size, and habitat type. [...]."

Read the full article here.

Source: Biogeosciences
Authors: Olaf Duteil et al. 
DOI: 10.5194/bg-15-7111-2018

Abstract

"The impact of the positive and negative phases of the Pacific Decadal Oscillation (PDO) on the extension of the poorly oxygenated regions of the eastern Pacific Ocean was assessed using a coupled ocean circulation–biogeochemical model. We show that during a “typical” PDO-positive phase the volume of the suboxic regions expands by 7 % over 50 years due to a slowdown of the large-scale circulation related to the decrease in the intensity of the trade winds. Changes in oxygen levels are mostly controlled by advective processes between 10∘ N and 10∘ S, whereas diffusive processes are dominant poleward of 10∘: in a “typical” PDO-positive phase the sluggish equatorial current system provides less oxygen to the eastern equatorial part of the basin while the oxygen transport by diffusive processes significantly decreases south of 10∘ S. [...]."

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Source: NOAA
Author: Yaamini Venkataraman

"Not every marine scientist has the same origin story. Some are instantly enthralled by the ocean and its many inhabitants at a ripe young age. For others, a lightbulb goes off while sitting in an undergraduate class. Dr. Nancy Foster Scholar Kate Hewett grew up on the islands of Micronesia, but did not consider a career in marine sciences until graduate school. While working as an environmental engineer in Boston, Massachusetts, she decided to go back to school to develop a deeper understanding of the environmental problems she encountered at work. In her classes, the complicated physics associated with coastal zones pulled at Hewett’s engineering heartstrings. [...]."

Read the full article here.

Source: EOS
Author: Sarah Stanley

"Upwelling hinders an efficient method to estimate a key measure of biological productivity in coastal waters, but accounting for surface temperatures could boost accuracy.
Although coastal waters make up only about 10% of the surface area of the ocean, they harbor most of its life. Measuring biological activity in these regions can reveal their impact on fisheries, low-oxygen dead zones, and the global carbon cycle, but coastal zones remain understudied. Now new research by Teeter et al. suggests how to improve the accuracy of a method that uses oxygen and argon measurements to quickly estimate marine biological activity. [...]."

Read the full article here.

Source: Nature
Authors: S. J. Batenburg et al.
DOI: 10.1038/s41467-018-07457-7

Abstract

"During the Late Cretaceous and early Cenozoic the Earth experienced prolonged climatic cooling most likely caused by decreasing volcanic activity and atmospheric CO2 levels. However, the causes and mechanisms of subsequent major global warming culminating in the late Paleocene to Eocene greenhouse climate remain enigmatic. We present deep and intermediate water Nd-isotope records from the North and South Atlantic to decipher the control of the opening Atlantic Ocean on ocean circulation and its linkages to the evolution of global climate. [...]."

Read the full article here.

Source: PNAS
Authors: Theodore R. Them et al.
DOI: 10.1073/pnas.1803478115

Abstract

"For this study, we generated thallium (Tl) isotope records from two anoxic basins to track the earliest changes in global bottom water oxygen contents over the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma) of the Early Jurassic. The T-OAE, like other Mesozoic OAEs, has been interpreted as an expansion of marine oxygen depletion based on indirect methods such as organic-rich facies, carbon isotope excursions, and biological turnover. Our Tl isotope data, however, reveal explicit evidence for earlier global marine deoxygenation of ocean water, some 600 ka before the classically defined T-OAE. [...]."

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Source: Oxford University Press
Authors: J. Anthony Koslow et al.
DOI: 10.1093/icesjms/fsy154

Abstract

"Declining oxygen concentrations in the deep ocean, particularly in areas with pronounced oxygen minimum zones (OMZs), are a growing global concern related to global climate change. Its potential impacts on marine life remain poorly understood. A previous study suggested that the abundance of a diverse suite of mesopelagic fishes off southern California was closely linked to trends in midwater oxygen concentration. [...]."

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Source: EOS
Author: L. Poppick

"The Gulf of Maine’s location at the meeting point of two major currents, as well as its shallow depth and shape, makes it especially susceptible to warming.
Late last month, four endangered sea turtles washed ashore in northern Cape Cod, marking an early onset to what has now become a yearly event: the sea turtle stranding season. These turtles—in last month’s case, Kemp’s ridley sea turtles—venture into the Gulf of Maine during warm months, but they can become hypothermic and slow moving when colder winter waters abruptly arrive, making it hard to escape. “They are enjoying the warm water, and then all of a sudden the cold comes, and they can’t get out fast enough,” said Andrew Pershing, an oceanographer at the Gulf of Maine Research Institute in Portland, Maine. [...]."

Read the full article here.

Source: The Conversation
Authors: Jeremy D. Owens & Theodore R. Them II

"All animals, whether they live on land or in the water, require oxygen to breathe. But today the world’s oceans are losing oxygen, due to a combination of rising temperatures and changing ocean currents. Both factors are driven by human-induced climate change. This process has the potential to disrupt marine food chains. We already know that large hypoxic, or low-oxygen, zones can be deadly. If hypoxia expands in both size and duration, it is possible to cause widespread extinction of marine life, which has happened previously in Earth’s history. [...]."

Read the full article here.

Source: Frontiers in Marine Science
Authors: Carlos Neira et al.
DOI: 10.3389/fmars.2018.00448

Abstract

"Ocean deoxygenation has become a topic of increasing concern because of its potential impacts on marine ecosystems, including oxygen minimum zone (OMZ) expansion and subsequent benthic effects. We investigated the influence of oxygen concentration and organic matter (OM) availability on metazoan meiofauna within and below an OMZ in bathyal sediments off Costa Rica, testing the hypothesis that oxygen and OM levels are reflected in meiofaunal community structures and distribution. [...]."

Read the full article here.

Source: EurekAlert

"Coastal regions with low dissolved oxygen (known as hypoxia) can lead to poor water quality and harm regional fisheries. These areas of low dissolved oxygen are expanding and expected to continue growing in coming years due to human impacts on the environment. A recent article published in Continental Shelf Research explores aspects of the environmental conditions that can potentially lead to hypoxia in the Mississippi Bight region of the northern Gulf of Mexico. This area extends from Apalachicola in Florida to the Mississippi River Delta. [...]."

Read the full article here.

Source: Science Direct
Authors: Brian Dzwonkowski et al.
DOI: 10.1016/j.csr.2018.09.009

Abstract

"River discharge, and its resulting region of freshwater influence (ROFI) in the coastal ocean, has a critical influence on physical and biogeochemical processes in seasonally stratified shelf ecosystems. Multi-year (2010–2016) observations of satellite-derived sea surface salinity (SSS) and in situ water column hydrographic data during summer 2016 were used to investigate physical aspects of the ROFI east of the Mississippi River Delta to better assess regional susceptibility to hypoxia in the summer months. [...]."

Read the full article here.

Source: Springer Link
Authors: Catherine V. Davis et al.
DOI: 10.1007/s12237-018-0372-0

Abstract

"Ocean acidification is a global phenomenon with highly regional spatial and temporal patterns. In order to address the challenges of future ocean acidification at a regional scale, it is necessary to increase the resolution of spatial and temporal monitoring of the inorganic carbon system beyond what is currently available. One approach is to develop empirical regional models that enable aragonite saturation state to be estimated from existing hydrographic measurements, for which greater spatial coverage and longer time series exist in addition to higher spatial and temporal resolution. [...]."

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Source: Forbes
Author: Priya Shukla

"The oceans have long been considered our planet's heat sponge - a 2014 report from the Intergovernmental Panel on Climate Change (IPCC) stated that the oceans had absorbed 93% of the excess heat that greenhouse gases have trapped within the Earth's atmosphere. However, a recent study shows that the world's oceans have absorbed 60% more heat over the past 25 years than initially thought. [...]."

Read the full article here.

Source: Wiley Online Library
Authors: Svenja Christiansen et al.
DOI: 10.1002/lno.10926

Abstract

"Gelatinous zooplankton hold key functions in the ocean and have been shown to significantly influence the transport of organic carbon to the deep sea. We discovered a gelatinous, flux‐feeding polychaete of the genus Poeobius in very high abundances in a mesoscale eddy in the tropical Atlantic Ocean, where it co‐occurred with extremely low particle concentrations. Subsequent analysis of an extensive in situ imaging dataset revealed that Poeobius sp. occurred sporadically between 5°S–20°N and 16°W–46°W in the upper 1000 m. [...]."

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Source: Wiley Online Library
Authors: Nicolas Kolodziejczyk et al.
DOI: 10.1029/2018JC014135

Abstract

"Glider measurements acquired along four transects between Cap‐Vert Peninsula and the Cape Verde archipelago in the eastern tropical North Atlantic during March–April 2014 were used to investigate fine‐scale stirring in an anticyclonic eddy. The anticyclone was formed near 12°N off the continental shelf and propagated northwest toward the Cape Verde islands. At depth, between 100 and –400 m, the isolated anticyclone core contained relatively oxygenated, low‐salinity South Atlantic Central Water, while the surrounding water masses were saltier and poorly oxygenated. [...]."

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Source: Frontiers in Marine Science
Authors: Vincent Echevin et al.
DOI: 10.3389/fmars.2018.00367

Abstract

"El Niño events, in particular the eastern Pacific type, have a tremendous impact on the marine ecosystem and climate conditions in the eastern South Pacific. During such events, the accumulation of anomalously warm waters along the coast favors intense rainfall. The upwelling of nutrient-replete waters is stopped and the marine ecosystem is strongly impacted. These events are generally associated with positive surface temperature anomalies in the central and eastern equatorial Pacific. [...]."

Read the full article here.

Source: Nature
Authors: L. Resplandy et al.
DOI: 10.1038/s41586-018-0651-8

Abstract

"The ocean is the main source of thermal inertia in the climate system. During recent decades, ocean heat uptake has been quantified by using hydrographic temperature measurements and data from the Argo float program, which expanded its coverage after 2007. However, these estimates all use the same imperfect ocean dataset and share additional uncertainties resulting from sparse coverage, especially before 2007. [...]."

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Source: Spektrum.de

"In den tropischen und subtropischen Meeren existieren in mittleren Tiefen riesige sauerstoffarme Zonen. Im Zuge des Klimawandels dehnen sie sich immer stärker aus. Auch in Küstenregionen entstehen durch Stickstoffbelastung aus der Landwirtschaft lebensfeindliche Zonen ohne Sauerstoff – mit verheerenden Folgen für das marine Ökosystem. [...]."

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Source: IOP Science
Authors: Yoann Thomas et al.
DOI: 10.1088/1748-9326/aae254

Abstract

"Beyond key ecological services, marine resources are crucial for human food security and socio-economical sustainability. Among them, shellfish aquaculture and fishing are of primary importance but become more vulnerable under anthropogenic pressure, as evidenced by reported mass mortality events linked to global changes such as ocean warming and acidification, chemical contamination, and diseases. Understanding climate-related risks is a vital objective for conservation strategies, ecosystems management and human health. [...]."

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The german Internet and TV channel HYPERRAUM.TV published two reports in collaboration with the SFB754 experts Martin Visbeck and Andreas Oschlies.

German speaking users may find the videos online by using one of the two links:

Report 1: Fische in Atemnot

Report 2: Sauerstoff-Transporte

Source: Annual Review of Marine Science
Author: Lisa A. Levin
DOI: 10.1146/annurev-marine-121916-063359

Abstract

"Oxygen loss in the ocean, termed deoxygenation, is a major consequence of climate change and is exacerbated by other aspects of global change. An average global loss of 2% or more has been recorded in the open ocean over the past 50–100 years, but with greater oxygen declines in intermediate waters (100–600 m) of the North Pacific, the East Pacific, tropical waters, and the Southern Ocean. Although ocean warming contributions to oxygen declines through a reduction in oxygen solubility and stratification effects on ventilation are reasonably well understood, it has been a major challenge to identify drivers and modifying factors that explain different regional patterns, especially in the tropical oceans. [...]."

Read the full article here.

Source: PLOS
Authors: Grant Dickey et al.
DOI: 10.1371/journal.pone.0205908

Abstract

"Blue mussel (Mytilus edulis) produce byssal threads to anchor themselves to the substrate. These threads are always exposed to the surrounding environmental conditions. Understanding how environmental pH affects these threads is crucial in understanding how climate change can affect mussels. This work examines three factors (load at failure, thread extensibility, and total thread counts) that indicate the performance of byssal threads as well as condition index to assess impacts on the physiological condition of mussels held in artificial seawater acidified by the addition of CO₂. [...]."

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Source: Nature
Authors: Babette A. A. Hoogakker et al.
DOI: 10.1038/s41586-018-0589-x

Abstract

"Increased storage of carbon in the oceans has been proposed as a mechanism to explain lower concentrations of atmospheric carbon dioxide during ice ages; however, unequivocal signatures of this storage have not been found. In seawater, the dissolved gases oxygen and carbon dioxide are linked via the production and decay of organic material, with reconstructions of low oxygen concentrations in the past indicating an increase in biologically mediated carbon storage. [...]."

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Source: PNAS
Authors: Wang Zheng et al.
DOI: 10.1073/pnas.1721733115

Abstract

"Photic zone euxinia (PZE) is a condition where anoxic, H₂S-rich waters occur in the photic zone (PZ). PZE has been invoked as an impediment to the evolution of complex life on early Earth and as a kill mechanism for Phanerozoic mass extinctions. Here, we investigate the potential application of mercury (Hg) stable isotopes in marine sedimentary rocks as a proxy for PZE by measuring Hg isotope compositions in late Mesoproterozoic (∼1.1 Ga) shales that have independent evidence of PZE during discrete intervals. [...]."

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Source: Science Direct
Authors: S. Krause et al.
DOI: 10.1016/j.gca.2018.09.018

Abstract

"During Earth’s history, precipitation of calcium carbonate by heterotrophic microbes has substantially contributed to the genesis of copious amounts of carbonate sediment and its subsequent lithification. Previous work identified the microbial sulfur and nitrogen cycle as principal pathways involved in the formation of marine calcium carbonate deposits. While substantial knowledge exists for the importance of the sulfur cycle, specifically sulfate reduction, with regard to carbonate formation, information about carbonate genesis connected to the microbial nitrogen cycle is dissatisfactory. [...]."

Read the full article here.

Source: Nature
Authors: Francisco Ramírez et al.
DOI: 10.1038/s41598-018-33237-w

Abstract

"Climate impacts on marine ecosystems may be exacerbated by other, more local stressors interacting synergistically, such as pollution and overexploitation of marine resources. The reduction of these human stressors has been proposed as an achievable way of retaining ecosystems within a “safe operating space” (SOS), where they remain resilient to ongoing climate change. However, the operability of an SOS requires a thorough understanding of the spatial distribution of these climate and human impacts. [...]."

Read the full article here.

Source: Springer Link
Authors: N.P. Lukashina
DOI: 10.1134/S0001

Abstract

"In the subpolar North Atlantic, four sediment cores were taken. All of them were suitable for reconstructing the dynamics of the meridional overturning circulation in the late Quaternary. Stratigraphy of the cores was performed by carbonate analyses, study of planktonic foraminifera, and oxygen isotopic composition in Neogloboquadrina pachyderma sin. Study of benthonic foraminifera assemblages has shown significant differences in the deep-water dynamics in the late Quaternary related to water exchange between the North Atlantic and Arctic seas. [...]."

Read the full article here.

Source: PLOS 
Authors: Simon E. Freeman et al.
DOI: 10.1371/journal.pone.0201766

Abstract

"We have observed that marine macroalgae produce sound during photosynthesis. The resultant soundscapes correlate with benthic macroalgal cover across shallow Hawaiian coral reefs during the day, despite the presence of other biological noise. Likely ubiquitous but previously overlooked, this source of ambient biological noise in the coastal ocean is driven by local supersaturation of oxygen near the surface of macroalgal filaments, and the resultant formation and release of oxygen-containing bubbles into the water column. During release, relaxation of the bubble to a spherical shape creates a monopole sound source that ‘rings’ at the Minnaert frequency. [...]."

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Source: Climate of the Past
Authors: Anastasia Zhuravleva & Henning A. Bauch
DOI: 10.5194/cp-14-1361-2018

Abstract

"Paleorecords and modeling studies suggest that instabilities in the Atlantic Meridional Overturning Circulation (AMOC) strongly affect the low-latitude climate, namely via feedbacks on the Atlantic Intertropical Convergence Zone (ITCZ). Despite the pronounced millennial-scale overturning and climatic variability documented in the subpolar North Atlantic during the last interglacial period (MIS 5e), studies on cross-latitudinal teleconnections remain very limited. This precludes a full understanding of the mechanisms controlling subtropical climate evolution across the last warm cycle. [...]."

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Source: Science Direct
Authors: Wataru Fujisaki et al.
DOI: 10.1016/j.gloplacha.2018.09.015

Abstract

"To constrain the redox conditions and related nitrogen cycles during the Middle Permian (Guadalupian) to latest Late Permian (Lopingian) deep mid-Panthalassa, we determined the abundances of major, trace, and rare earth elements along with the carbon and nitrogen isotope ratios in shales interbedded with deep-sea cherts that are well-exposed at the Gujo-Hachiman section in the Mino-Tanba belt, SW Japan. [...]."

Read the full article here.

Source: Wiley Online Library
Authors: Yohei Takano et al.
DOI: 10.1029/2018GB005939

Abstract

"We explore centennial changes in tropical Pacific oxygen (O₂) using numerical models to illustrate the dominant patterns and mechanisms under centennial climate change. Future projections from state‐of‐the‐art Earth System Models exhibit significant model to model differences, but decreased solubility and weakened ventilation together deplete thermocline O₂ in middle to high latitudes. In contrast, the tropical thermocline O₂undergoes much smaller changes or even a slight increase. [...]."

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Source: Nature 
Authors: Anthony D. Bertagnolli & Frank J. Stewart
DOI: 10.1038/s41579-018-0087-z

Abstract

"In the ocean’s major oxygen minimum zones (OMZs), oxygen is effectively absent from sea water and life is dominated by microorganisms that use chemicals other than oxygen for respiration. Recent studies that combine advanced genomic and chemical detection methods are delineating the different metabolic niches that microorganisms can occupy in OMZs. Understanding these niches, the microorganisms that inhabit them, and their influence on marine biogeochemical cycles is crucial as OMZs expand with increasing seawater temperatures."

Read the full article here.

Source: Wiley Online Library
Authors: Hongjie Wang et al.
DOI: 10.1029/2018GL078571

Abstract

"We examined the stable carbon isotopic composition of remineralized organic carbon (δ¹³C_OCx) in the northern Gulf of Mexico (nGoM) using incubations (sediment and water) and a three end‐member mixing model. δ¹³C_OCx in incubating sediments was ‐18.1±1.3‰, and δ¹³C_OCx in incubating near‐surface and near‐bottom waters varied with salinity, ranging from ‐30.4‰ to ‐16.2‰ from brackish water to full strength Gulf water. The average δ¹³C_OCx was ‐18.6 ±1.8‰ at salinity >23. A three end‐member mixing model based on a multi‐year dataset collected in previous summer hypoxia cruises (2011, 2012, 2014, 2015 and 2016) suggested that δ¹³C_OCx in near‐bottom waters across the nGoM (5‐50 m) was ‐18.1±0.6‰. [...]." 

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Source: University of Washington
Author: Hannah Hickey

"The Gulf of St. Lawrence has warmed and lost oxygen faster than almost anywhere else in the global oceans. The broad, biologically rich waterway in Eastern Canada drains North America’s Great Lakes and is popular with fishing boats, whales and tourists. A new study led by the University of Washington looks at the causes of this rapid deoxygenation and links it to two of the ocean’s most powerful currents: the Gulf Stream and the Labrador Current. The study, published Sept. 17 in Nature Climate Change, explains how large-scale climate change already is causing oxygen levels to drop in the deeper parts of this waterway."

Read the full article here.

Source: Nature
Auhors: Mariona Claret et al.
DOI: 10.1038/s41558-018-0263-1

Abstract

"Global observations show that the ocean lost approximately 2% of its oxygen inventory over the past five decades, with important implications for marine ecosystems. The rate of change varies regionally, with northwest Atlantic coastal waters showing a long-term drop that vastly outpaces the global and North Atlantic basin mean deoxygenation rates. However, past work has been unable to differentiate the role of large-scale climate forcing from that of local processes. [...]."

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Source: Nature
Authors: Morgan Reed Raven et al.
DOI: 10.1038/s41467-018-05943-6

Abstract

"Ocean Anoxic Event 2 (OAE2) was a period of dramatic disruption to the global carbon cycle when massive amounts of organic matter (OM) were buried in marine sediments via complex and controversial mechanisms. Here we investigate the role of OM sulfurization, which makes OM less available for microbial respiration, in driving variable OM preservation in OAE2 sedimentary strata from Pont d’Issole (France). We find correlations between the concentration, S:C ratio, S-isotope composition, and sulfur speciation of OM suggesting that sulfurization facilitated changes in carbon burial at this site as the chemocline moved in and out of the sediments during deposition. [...]."

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Source: Nature 
Authors: Mark G. Lawrence et al.
DOI: 10.1038/s41467-018-05938-3

Abstract

"Current mitigation efforts and existing future commitments are inadequate to accomplish the Paris Agreement temperature goals. In light of this, research and debate are intensifying on the possibilities of additionally employing proposed climate geoengineering technologies, either through atmospheric carbon dioxide removal or farther-reaching interventions altering the Earth’s radiative energy budget. Although research indicates that several techniques may eventually have the physical potential to contribute to limiting climate change, all are in early stages of development, involve substantial uncertainties and risks, and raise ethical and governance dilemmas. [...]."

Read the full article here.

Source: Nature
Authors: Juan José Alava et al.
DOI: 10.1038/s41598-018-31824-5

Abstract

"Climate change increases exposure and bioaccumulation of pollutants in marine organisms, posing substantial ecophysiological and ecotoxicological risks. Here, we applied a trophodynamic ecosystem model to examine the bioaccumulation of organic mercury (MeHg) and polychlorinated biphenyls (PCBs) in a Northeastern Pacific marine food web under climate change. We found largely heterogeneous sensitivity in climate-pollution impacts between chemicals and trophic groups. Concentration of MeHg and PCBs in top predators, including resident killer whales, is projected to be amplified by 8 and 3%, respectively, by 2100 under a high carbon emission scenario (Representative Concentration Pathway 8.5) relative to a no-climate change control scenario. [...]."

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Source: Philosophical Transactions of the Royal Society A
Author: Hugh C. Jenkyns
DOI: 10.1098/rsta.2017.0073

Abstract

"The two major oceanic anoxic events of the Cretaceous, those of the Early Aptian (OAE 1a) and the Cenomanian–Turonian boundary (OAE 2), registered some of the highest temperatures reconstructed for the Cretaceous Period, and are thought to be related to the input of volcanically derived carbon dioxide from one or more Large Igneous Provinces. Widely distributed deposition of marine organic matter, the hallmark of OAEs, and intensified silicate weathering in response to a globally accelerated hydrological cycle and/or reaction of seawater with freshly extruded basalt, are both potential mechanisms whereby the content of atmospheric carbon dioxide could have been drawn down to promote cooling, on the assumption that this potential effect was not offset by increased addition of this volcanically derived greenhouse gas. [...]."

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Source: Phys.org

"A carbon cycle anomaly discovered in carbonate rocks of the Neoproterozoic Hüttenberg Formation of north-eastern Namibia follows a pattern similar to that found right after the Great Oxygenation Event, hinting at new evidence for how Earth's atmosphere became fully oxygenated. [...]."

Read the full article here.

Source: Utrecht University Repository
Author: Martina Sollai

"Nitrogen (N) cycling influences primary production in the ocean and, hence, the global climate. It is performed by a variety of microorganisms, including eukaryotes, bacteria and archaea in oxic, suboxic, and anoxic waters. Our knowledge of the reactions involved in marine N cycling and its associated microorganisms has greatly increased in the last decade due to the development of multiple culture-independent methods. Among them are gene and lipid biomarkers, which hold taxonomic potential and can be successfully applied in modern day and paleoenvironmental studies. However, many aspects of N cycling and their long-term implications for the marine environment and the global climate still require more study, especially in suboxic and anoxic waters, including the oxygen-deficient zones (ODZs), which are expanding in the modern oceans. [...]."

Read the full article here.

Source: Science Direct
Author: Florian Scholz
DOI: 10.1016/j.earscirev.2018.08.002

Abstract

"Because of anthropogenic global warming, the world ocean is currently losing oxygen. This trend called ocean deoxygenation is particularly pronounced in low-latitude upwelling-related oxygen minimum zones (OMZs). In these areas, the temperature-related oxygen drawdown is additionally modulated by biogeochemical feedback mechanisms between sedimentary iron (Fe) and phosphorus release, water column nitrogen cycling and primary productivity. Similar feedbacks were likely active during past periods of global warming and oceandeoxygenation. However, their integrated role in amplifying or mitigating climate change-driven ocean anoxia has not been evaluated in a systematic fashion. [...]."

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Source: Biogeosciences
Authors: Marine Bretagnon et al.
DOI: 10.5194/bg-15-5093-2018

Abstract

"The fate of the organic matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth's system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive eastern boundary upwelling systems (EBUSs) associated with oxygen minimum zones (OMZs) would be expected to foster OM preservation due to low O₂ conditions. But their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru. [...]."

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Source: Nature 
Authors: Christian Schlosser et al. 
DOI: 10.1038/s41598-018-30580-w

Abstract

"Dissolved iron (DFe) concentrations in oxygen minimum zones (OMZs) of Eastern Boundary Upwelling Systems are enhanced as a result of high supply rates from anoxic sediments. However, pronounced variations in DFe concentrations in anoxic coastal waters of the Peruvian OMZ indicate that there are factors in addition to dissolved oxygen concentrations (O₂) that control Fe cycling. [...]."

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Source: Science
Authors: Weiqi Yao et al. 
DOI: 10.1126/science.aar8658

Abstract

"The consequences of global warming for fisheries are not well understood, but the geological record demonstrates that carbon cycle perturbations are frequently associated with ocean deoxygenation. Of particular interest is the Paleocene-Eocene Thermal Maximum (PETM), where the carbon dioxide input into the atmosphere was similar to the IPCC RCP8.5 emission scenario. Here we present sulfur-isotope data that record a positive 1 per mil excursion during the PETM. Modeling suggests that large parts of the ocean must have become sulfidic. [...]."

Read the full article here.

Source: The Royal Society
Authors: Tomoya Dobashi et al. 
DOI: 10.1098/rsos.180707

Abstract

"Body-size relationships between predators and their prey are important in ecological studies because they reflect the structure and function of food webs. Inspired by studies on the impact of global warming on food webs, the effects of temperature on body-size relationships have been widely investigated; however, the impact of environmental factors on body-size relationships has not been fully evaluated because climate warming affects various ocean environments. Thus, here, we comprehensively investigated the effects of ocean environments and predator–prey body-size relationships by integrating a large-scale dataset of predator–prey body-size relationships in marine food webs with global oceanographic data. We showed that various oceanographic parameters influence prey size selection. [...]."

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Source: Phys.org

"Scientists have shown that coastal waters and river estuaries can exhibit unique vulnerabilities to acidification than offshore waters. This acidification, detected in waters off the United States West Coast and the Gulf of Mexico, can lead to disorientation and cognitive problems in some marine fish species, such as salmon, sharks, and cod. This work is presented at the Goldschmidt Conference in Boston. Scientists have recently discovered that marine creatures can be adversely affected by hypercapnia, a condition of too much dissolved CO₂ in seawater (CO₂ partial pressure, or pCO₂). When this level rises above 1000 micro atmospheres (1000 μatm), some fish species suffer cognitive problems and disorientation, such as losing their way or even swimming towards predators. Surface ocean CO₂ partial pressures tend to be around 400 μatm, so until now scientists have thought that hypercapnia was a problem which would only become apparent over time in subsurface waters. [...]."

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Source: Science Direct
Authors: Florian Scholz et al.
DOI: j.chemgeo.2018.04.031

Abstract

"Molybdenum (Mo) concentrations and isotope compositions in sediments and shalesare commonly used as proxies for anoxic and sulfidic (i.e., euxinic) conditions in the water column of paleo-marine systems. A basic assumption underlying this practice is that the proxy signal extracted from the geological record is controlled by long-term (order of decades to millennia) Mo scavenging in the euxinic water column rather than Mo deposition during brief episodes or events (order of weeks to months). [...]."

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Source: Wiley Online Library
Authors: Alison R. Gray et al.
DOI: 10.1029/2018GL078013

Abstract

"Although the Southern Ocean is thought to account for a significant portion of the contemporary oceanic uptake of carbon dioxide (CO₂), flux estimates in this region are based on sparse observations that are strongly biased towards summer. Here we present new estimates of Southern Ocean air‐sea CO₂ fluxes calculated with measurements from biogeochemical profiling floats deployed by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project during 2014‐2017. Compared to ship‐based CO₂ flux estimates, the float‐based fluxes find significantly stronger outgassing in the zone around Antarctica where carbon‐rich deep waters upwell to the surface ocean. [...]."

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Source: Ocean Science
Authors: Rena Czeschel et al.
DOI: 10.5194/os-14-731-2018

Abstract

"The influence of mesoscale eddies on the flow field and the water masses, especially the oxygen distribution of the eastern tropical South Pacific, is investigated from a mooring, float, and satellite data set. Two anticyclonic (ACE1/2), one mode-water (MWE), and one cyclonic eddy (CE) are identified and followed in detail with satellite data on their westward transition with velocities of 3.2 to 6.0cms⁻¹ from their generation region, the shelf of the Peruvian and Chilean upwelling regime, across the Stratus Ocean Reference Station (ORS;  ∼ 20°S, 85°W) to their decaying region far west in the oligotrophic open ocean. [...]."

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Source: Science Daily

"Researchers are looking to the geologic past to make future projections about climate change. Their research focuses on the ancient Tethys Ocean (site of the present-day Mediterranean Sea) and provides a benchmark for present and future climate and ocean models."

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Source: Nature
Authors: Christopher K. Junium et al.
DOI: 10.1038/s41467-018-05486-w

Abstract

"The degree to which ocean deoxygenation will alter the function of marine communities remains unclear but may be best constrained by detailed study of intervals of rapid warming in the geologic past. The Paleocene–Eocene Thermal Maximum (PETM) was an interval of rapid warming that was the result of increasing contents of greenhouse gases in the atmosphere that had wide ranging effects on ecosystems globally. Here, we present stable nitrogen isotope data from the Eastern Peri-Tethys Ocean that record a significant transition in the nitrogen cycle. [...]."

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Source: Nature
Authors: Alyssa G. Kent et al.
DOI: 10.1038/s41564-018-0213-8

Abstract

"Ocean temperatures will increase significantly over the next 100 years due to global climate change. As temperatures increase beyond current ranges, it is unclear how adaptation will impact the distribution and ecological role of marine microorganisms. To address this major unknown, we imposed a stressful high-temperature regime for 500 generations on a strain from the abundant marine Roseobacter clade. High-temperature-adapted isolates significantly improved their fitness but also increased biofilm formation at the air–liquid interface. [...]."

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Source: Science Direct
Authors: Christian Woehle et al.
DOI: 10.1016/j.cub.2018.06.027

Abstract

"Benthic foraminifera are unicellular eukaryotes inhabiting sediments of aquatic environments. Several species were shown to store and use nitrate for complete denitrification, a unique energy metabolism among eukaryotes. The population of benthic foraminifera reaches high densities in oxygen-depleted marine habitats, where they play a key role in the marine nitrogen cycle. However, the mechanisms of denitrification in foraminifera are still unknown, and the possibility of a contribution of associated bacteria is debated. Here, we present evidence for a novel eukaryotic denitrification pathway that is encoded in foraminiferal genomes. [...]."

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Source: Science Daily (University of Toronto)

"Earth scientists exploring how ocean chemistry has evolved found similarities between an event 55 million years ago and current predicted trajectories of planet temperatures, with regards to inputs of CO2 into the atmosphere and oxygen levels in the oceans. As the oceans warm, oxygen decreases while hydrogen sulfide increases, making the oceans toxic and putting marine species at risk."

Read the full article here.

Source: Nature
Authors: Sylvain Agostini et al.
DOI: 10.1038/s41598-018-29251-7

Abstract

"Rising atmospheric concentrations of carbon dioxide are causing surface seawater pH and carbonate ion concentrations to fall in a process known as ocean acidification. To assess the likely ecological effects of ocean acidification we compared intertidal and subtidal marine communities at increasing levels of pCO₂ at recently discovered volcanic seeps off the Pacific coast of Japan (34° N). This study region is of particular interest for ocean acidification research as it has naturally low levels of surface seawater pCO₂ (280–320 µatm) and is located at a transition zone between temperate and sub-tropical communities. [...]."

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Source: Wiley Online Library
Authors: Allison K. Barner et al.
DOI: 10.1111/gcb.14372

Abstract

"Decades of research have demonstrated that many calcifying species are negatively affected by ocean acidification, a major anthropogenic threat in marine ecosystems. However, even closely related species may exhibit different responses to ocean acidification and less is known about the drivers that shape such variation in different species. Here, we examine the drivers of physiological performance under ocean acidification in a group of five species of turf‐forming coralline algae. [...]."

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Source: Nature
Authors: Mark John Costello et al.
DOI: 10.1038/s41598-018-29419-1

Abstract

"With increasing depth, the ocean is less sampled for physical, chemical and biological variables. Using the Global Marine Environmental Datasets (GMED) and Ecological Marine Units (EMUs), we show that spatial variation in environmental variables decreases with depth. This is also the case over temporal scales because seasonal change, surface weather conditions, and biological activity are highest in shallow depths. [...]."

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Source: Nature
Authors: Robin van der Ploeg et al.
DOI: 10.1038/s41467-018-05104-9

Abstract

"The Middle Eocene Climatic Optimum (MECO) represents a ~500-kyr period of global warming ~40 million years ago and is associated with a rise in atmospheric CO₂ concentrations, but the cause of this CO₂ rise remains enigmatic. Here we show, based on osmium isotope ratios (¹⁸⁷Os/¹⁸⁸Os) of marine sediments and published records of the carbonate compensation depth (CCD), that the continental silicate weathering response to the inferred CO₂ rise and warming was strongly diminished during the MECO—in contrast to expectations from the silicate weathering thermostat hypothesis. [...]."

Read the full article here.

Source: Science  
Authors: Weiqi Yao et al. 
DOI: 10.1126/science.aar8658

Abstract

"The consequences of global warming for fisheries are not well understood, but the geological record demonstrates that carbon cycle perturbations are frequently associated with ocean deoxygenation. Of particular interest is the Paleocene-Eocene Thermal Maximum (PETM) where the CO₂ input into the atmosphere was similar to the IPCC RCP8.5 emission scenario. Here we present sulfur-isotope data which record a positive 1 ‰ excursion during the PETM. Modeling suggests that significant parts of the ocean must have become sulfidic. The toxicity of hydrogen sulfide will render two of the largest and least explored ecosystems on Earth, the mesopelagic and bathypelagic zones, uninhabitable by multi-cellular organisms. This will affect many marine species whose eco-zones stretch into the deep ocean. [...]."

Read the full article here.

Source: PLOS
Authors: Maritza Fajardo et al.
DOI: 10.1371/journal.pone.0200349

Abstract

"Hypoxia is one of the most important stressors affecting the health conditions of coastal ecosystems. In highly productive ecosystems such as the Humboldt Current ecosystem, the oxygen minimum zone is an important abiotic factor modulating the structure of benthic communities over the continental shelf. Herein, we study soft-bottom macrobenthic communities along a depth gradient–at 10, 20, 30 and 50 m–for two years to understand how hypoxia affects the structure of shallow communities at two sites in Mejillones Bay (23°S) in northern Chile. [...]."

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Source: Phys.org

"In the waters of the Arabian Sea, a vast "dead zone" the size of Scotland is expanding and scientists say climate change may be to blame. In his lab in Abu Dhabi, Zouhair Lachkar is labouring over a colourful computer model of the Gulf of Oman, showing changing temperatures, sea levels and oxygen concentrations.His models and new research unveiled earlier this year show a worrying trend.Dead zones are areas of the sea where the lack of oxygen makes it difficult for fish to survive and the one in the Arabian Sea is "is the most intense in the world," says Lachkar, a senior scientist at NYU Abu Dhabi in the capital of the United Arab Emirates. [...]."

Read the full articlere here.

Source: Science Daily

"The melting of glaciers on one side of the globe can trigger disintegration of glaciers on the other side of the globe, as has been presented by scientists, who investigated marine microalgae preserved in glacial deposits and subsequently used their findings to perform climate simulations."

Read the full article here.

Source: Nature
Authors: E. Maier et al.
DOI: 10.1038/s41586-018-0276-y

Abstract

"There is compelling evidence that episodic deposition of large volumes of freshwater into the oceans strongly influenced global ocean circulation and climate variability during glacial periods. In the North Atlantic region, episodes of massive freshwater discharge to the North Atlantic Ocean were related to distinct cold periods known as Heinrich Stadials. [...]."

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Source: Nature
Authors: Sangita Ganesh et al.
DOI: 10.1038/s41396-018-0223-9

Abstract

"Anaerobic ammonium oxidation (anammox) contributes substantially to ocean nitrogen loss, particularly in anoxic marine zones (AMZs). Ammonium is scarce in AMZs, raising the hypothesis that organic nitrogen compounds may be ammonium sources for anammox. Biochemical measurements suggest that the organic compounds urea and cyanate can support anammox in AMZs. [...]."

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Source: Nature
Authors: Dan Wang et al.
DOI: 10.1038/s41467-018-04980-5

Abstract

"The late Ediacaran to early Cambrian interval witnessed extraordinary radiations of metazoan life. The role of the physical environment in this biological revolution, such as changes to oxygen levels and nutrient availability, has been the focus of longstanding debate. Seemingly contradictory data from geochemical redox proxies help to fuel this controversy. As an essential nutrient, nitrogen can help to resolve this impasse by establishing linkages between nutrient supply, ocean redox, and biological changes. [...]."

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Source: Geochemical Perspectives Letters 
Authors: R. Guilbaud et al.
DOI: 10.7185/geochemlet.1806

Abstract

"The relationship between the evolution of early animal communities and oceanic oxygen levels remains unclear. In particular, uncertainty persists in reconstructions of redox conditions during the pivotal early Cambrian (541-510 million years ago, Ma), where conflicting datasets from deeper marine settings suggest either ocean anoxia or fully oxygenated conditions. By coupling geochemical palaeoredox proxies with a record of organic-walled fossils from exceptionally well-defined successions of the early Cambrian Baltic Basin, we provide evidence for the early establishment of modern-type oxygen minimum zones (OMZs). [...]."

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Source: Nature 
Authors: William D. Orsi
DOI: 10.1038/s41579-018-0046-8

Abstract

"Vast regions of the dark ocean have ultra-slow rates of organic matter sedimentation, and their sediments are oxygenated to great depths yet have low levels of organic matter and cells. Primary production in the oxic seabed is supported by ammonia-oxidizing archaea, whereas in anoxic sediments, novel, uncultivated groups have the potential to produce H₂ and CH₄, which fuel anaerobic carbon fixation. [...]."

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Source: Nature 
Authors: Sebastiaan van de Velde et al.
DOI: 10.1038/s41467-018-04973-4

Abstract

"The evolution of burrowing animals forms a defining event in the history of the Earth. It has been hypothesised that the expansion of seafloor burrowing during the Palaeozoic altered the biogeochemistry of the oceans and atmosphere. However, whilst potential impacts of bioturbation on the individual phosphorus, oxygen and sulphur cycles have been considered, combined effects have not been investigated, leading to major uncertainty over the timing and magnitude of the Earth system response to the evolution of bioturbation. [...]."

Read the full article here.

Source: United Nations Development Programme
Author: Andrew Hudson

"Tremendous – and deserved - attention has been paid for the last few years to the scourge of ocean plastics pollution, which we now know reaches the farthest depths of the ocean and can have impacts on ocean life from the smallest plankton to the largest whales.  We know (Jambeck et al., 2015) that some 4.8 million to 12.7 million metric tonnes of plastic enter the ocean each year. UN Environment has estimated the socio-economic costs of ocean plastics pollution at about US$13 billion per year.  We are only beginning to explore and understand the potential human health impacts of plastics in the oceanic food chain. [...]."

Read the full article here.

Source: PeerJ
Authors: Susana Agusti et al. 
DOI: 10.7717/peerj.5081

Abstract

"The planktonic metabolic balance that is the balance between gross primary production (GPP) and community respiration (CR) was determined in Matilda Bay (estuarine) and Woodman Point (coastal) in Perth, Western Australia. The rates of net community production (NCP = GPP – CR) and the ratio between GPP and CR (P/R) were assessed to evaluate whether the metabolic balance in the two coastal locations tends to be net autotrophic (production exceeding community respiration) or net heterotrophic (respiration exceeding production). [...]."

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Source: Nature
Authors: Nigel C. Sainsbury et al.
DOI: 10.1038/s41558-018-0206-x

"Climate change-driven alterations in storminess pose a significant threat to global capture fisheries. Understanding how storms interact with fishery social-ecological systems can inform adaptive action and help to reduce the vulnerability of those dependent on fisheries for life and livelihood."

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Source: Wiley Online Library
Authors: Lianna Teeter et al.
DOI: 10.1029/2017GB005874

Abstract

"Under physically isolated conditions, net community production (NCP) can be accurately estimated from the rate of oxygen evasion to the atmosphere derived from local mixed layer oxygen/argon measurements. We use a simple box model to demonstrate that, when physical inputs are negligible, the sea‐to‐air flux of biological oxygen (bioflux) represents the average NCP exponentially weighted over the past several residence times of oxygen in the mixed layer. This new weighting scheme shows that there is no apparent lag between bioflux and exponentially‐weighted time‐averaged NCP. [...]."

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Source: Science 
Authors: Feifei Zhang et al.
DOI: 10.1126/sciadv.aan8983

Abstract

"The terminal Ediacaran Period witnessed the decline of the Ediacara biota (which may have included many stem-group animals). To test whether oceanic anoxia might have played a role in this evolutionary event, we measured U isotope compositions (δ²³⁸U) in sedimentary carbonates from the Dengying Formation of South China to obtain new constraints on the extent of global redox change during the terminal Ediacaran. [...]."

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Source: Phys.org

"Ecologists from the University of Michigan and the University of Maryland Center for Environmental Science are forecasting a larger-than-average Chesapeake Bay "dead zone" in 2018, due to increased rainfall in the watershed this spring. This summer's Chesapeake Bay hypoxic or dead zone, an area of low to no oxygen that can kill fish and other aquatic life, is expected to be about 1.9 cubic miles (7.9 cubic kilometers), according to the forecast released today by the two universities. [...]."

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Source: Biogeosciences
Authors: Sarah Eggleston & Eric D. Galbraith
DOI: 10.5194/bg-15-3761-2018

Abstract

"The complexity of dissolved gas cycling in the ocean presents a challenge for mechanistic understanding and can hinder model intercomparison. One helpful approach is the conceptualization of dissolved gases as the sum of multiple, strictly defined components. Here we decompose dissolved inorganic carbon (DIC) into four components: saturation (DIC_sat), disequilibrium (DIC_dis), carbonate (DIC_carb), and soft tissue (DIC_soft). The cycling of dissolved oxygen is simpler, but can still be aided by considering O₂, O_2sat, and O_2dis. [...]."

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Source: Biogeosciences
Authors: V. V. S. S. Sarma & T. V. S. Udaya Bhaskar
DOI: 10.1029/2018JG004447

Abstract

"Intense oxygen minimum zone (OMZ) occurs in the mid‐depth of the Eastern Tropical Pacific (ETP), Arabian Sea (AS), and Bay of Bengal (BoB). However, the occurrence of anammox/denitrification was reported only in the ETP and AS and its absence in the BoB is attributed to presence of traces of dissolved oxygen (DO). Anticyclonic Eddies (ACE) supply high nutrient, organic‐rich and oxygen poor waters from the coastal upwelling regions leading to strengthening of OMZ in the offshore of AS and ETP. [...]."

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Source: Earth System Dynamics
Authors: Gianna Battaglia & Fortunat Joos
DOI: 10.5194/esd-9-797-2018

Abstract

"Ocean deoxygenation is recognized as key ecosystem stressor of the future ocean and associated climate-related ocean risks are relevant for current policy decisions. In particular, benefits of reaching the ambitious 1.5 °C warming target mentioned by the Paris Agreement compared to higher temperature targets are of high interest. Here, we model oceanic oxygen, warming and their compound hazard in terms of metabolic conditions on multi-millennial timescales for a range of equilibrium temperature targets. [...]."

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Source: Nature 
Authors: Andreas Oschlies et al.
DOI: 10.1038/s41561-018-0152-2

Abstract

"Direct observations indicate that the global ocean oxygen inventory is decreasing. Climate models consistently confirm this decline and predict continuing and accelerating ocean deoxygenation. However, current models (1) do not reproduce observed patterns for oxygen changes in the ocean’s thermocline; (2) underestimate the temporal variability of oxygen concentrations and air–sea fluxes inferred from time-series observations; and (3) generally simulate only about half the oceanic oxygen loss inferred from observations. [...]."

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Source: Nature
Authors: Svetlana Fernandes et al.
DOI: 10.1038/s41598-018-27002-2

Abstract

"Biogeochemistry of oxygen minimum zone (OMZ) sediments, which are characterized by high input of labile organic matter, have crucial bearings on the benthic biota, gas and metal fluxes across the sediment-water interface, and carbon-sulfur cycling. Here we couple pore-fluid chemistry and comprehensive microbial diversity data to reveal the sedimentary carbon-sulfur cycle across a water-depth transect covering the entire thickness of eastern Arabian Sea OMZ, off the west coast of India. [...]."

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Source: Phys.org

"Scientists have predicted the dead zone, or area with little to no oxygen in the northern Gulf of Mexico, will become larger than the state of Connecticut by the end of July. The dead zone will cover about 6,620 square miles of the bottom of the continental shelf off Louisiana and Texas. While there are more than 500 dead zones around the world, the northern Gulf of Mexico dead zone is the second largest human-caused coastal hypoxic area in the world. [...]."

Read the full article here.

Source: GeoScienceWorld
Authors: Guang-Yi Wei et al.
DOI: 10.1130/G40150.1

Abstract

The diversification of metazoans during the latest Neoproterozoic and early Cambrian has been attributed to, among other factors, a progressive rise in surface oxygen levels. However, recent results have also questioned the idea of a prominent rise in atmospheric oxygen levels or a major or unidirectional shift in the marine redox landscape across this interval. Here, we present new carbonate-associated uranium isotope data from upper Ediacaran to lower Cambrian marine carbonate successions. [...]."

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Source: Biogeosciences
Authors: Joachim Segschneider et al. 
DOI: 10.5194/bg-15-3243-2018

Abstract

"Climate and marine biogeochemistry changes over the Holocene are investigated based on transient global climate and biogeochemistry model simulations over the last 9500 years. The simulations are forced by accelerated and non-accelerated orbital parameters, respectively, and atmospheric pCO₂, CH₄, and N₂O. The analysis focusses on key climatic parameters of relevance to the marine biogeochemistry, and on the physical and biogeochemical processes that drive atmosphere–ocean carbon fluxes and changes in the oxygen minimum zones (OMZs). [...]."

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Source: Frontiers in Marine Science
Authors: Mar Benavides et al.
DOI: 10.3389/fmars.2018.00089

Abstract

"Specialized prokaryotes performing biological dinitrogen (N₂) fixation (“diazotrophs”) provide an important source of fixed nitrogen in oligotrophic marine ecosystems such as tropical and subtropical oceans. In these waters, cyanobacterial photosynthetic diazotrophs are well known to be abundant and active, yet the role and contribution of non-cyanobacterial diazotrophs are currently unclear. The latter are not photosynthetic (here called “heterotrophic”) and hence require external sources of organic matter to sustain N₂ fixation. [...]."

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Source: Wiley Online Library
Authors: P. J. Llanillo et al.
DOI: 10.1002/2017JC013509

Abstract 

"Ventilation of the eastern South Pacific Oxygen Minimum Zone (ESP‐OMZ) is quantified using climatological Argo and dissolved oxygen data, combined with reanalysis wind stress data. We (1) estimate all oxygen fluxes (advection and turbulent diffusion) ventilating this OMZ, (2) quantify for the first time the oxygen contribution from the subtropical versus the traditionally studied tropical‐equatorial pathway, and (3) derive a refined annual‐mean oxygen budget for the ESP‐OMZ. In the upper OMZ layer, net oxygen supply is dominated by tropical‐equatorial advection, with more than one‐third of this supply upwelling into the Ekman layer through previously unevaluated vertical advection, within the overturning component of the regional Subtropical Cell (STC). [...]."

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Source: Science Direct
Authors: Carmen Grados et al.
DOI: 10.1016/j.pocean.2018.05.005

Abstract

"Since the 1960’s, the Instituto del Mar del Perú (IMARPE) collected tens of thousands of in-situ temperature and salinity profiles in the Northern Humboldt Current System (NHCS). In this study, we blend this unique database with the historical in-situ profiles available from the World Ocean Database for the period 1960-2014 and apply a four-dimensional interpolation scheme to construct a seasonal climatology of temperature and salinity of the NHCS [...]."

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Source: Nature
Authors: Laure Resplandy
DOI: 10.1038/d41586-018-05034-y

"Computer simulations show that areas of the ocean that have low levels of dissolved oxygen will expand, but then shrink, in response to global warming — adding to an emerging picture of the finely balanced processes involved."

Read the full article here.

Source: Wiley Online Library
Authors: Weiwei Fu et al.
DOI: 10.1002/2017GB005788

Abstract

"Dissolved oxygen (O₂) is essential for the survival of marine animals. Climate change impacts on future oxygen distributions could modify species biogeography, trophic interactions, biodiversity, and biogeochemistry. The Coupled Model Intercomparison Project Phase 5 models predict a decreasing trend in marine O₂ over the 21st century. [...]."

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Source: EurekAlert

"New research sheds light on first of five major mass extinctions.
For decades, scientists have conducted research centered around the five major mass extinctions that have shaped the world we live in. The extinctions date back more than 450 million years with the Late Ordovician Mass Extinction to the deadliest extinction, the Late Permian extinction 250 million years ago that wiped out over 90 percent of species. [...]."

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Source: Science Direct
Authors: Xiangkuan Zhao et al.
DOI: 10.1016/j.palaeo.2018.05.009

Abstract

"The Ediacaran–Cambrian transition is a critical period in Earth history, during which both marine environment and life experienced drastic changes. It was suggested that pervasive oxygenation and associated chemical changes in the ocean have potentially triggered the rapid diversification of early Cambrian metazoans. The timing and process of ocean oxygenation, however, have not been well constrained. [...]."

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Source: Nature 
Authors: Cameron M. Callbeck et al.
DOI: 10.1038/s41467-018-04041-x

Abstract

"Members of the gammaproteobacterial clade SUP05 couple water column sulfide oxidation to nitrate reduction in sulfidic oxygen minimum zones (OMZs). Their abundance in offshore OMZ waters devoid of detectable sulfide has led to the suggestion that local sulfate reduction fuels SUP05-mediated sulfide oxidation in a so-called “cryptic sulfur cycle”. [...]."

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Source: The New Humanitarian
Author: Jessica Leber

"At the Ocean Risk Summit in Bermuda, experts gathered to advance a new model for how insurance and reinsurance companies can leverage their products and balance sheets to restore marine ecosystems and slow climate change impacts. [...]."

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Source: Science 
Authors: Thorsten B. H. Reusch et al.
DOI: 10.1126/sciadv.aar8195

Abstract

"Coastal global oceans are expected to undergo drastic changes driven by climate change and increasing anthropogenic pressures in coming decades. Predicting specific future conditions and assessing the best management strategies to maintain ecosystem integrity and sustainable resource use are difficult, because of multiple interacting pressures, uncertain projections, and a lack of test cases for management. [...]."

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Source: Nature
Author: Laure Resplandy

"Computer simulations show that areas of the ocean that have low levels of dissolved oxygen will expand, but then shrink, in response to global warming — adding to an emerging picture of the finely balanced processes involved.

Global warming has reduced the amount of dissolved oxygen in the ocean by 2% since 1960. A major concern is that the rate of loss of dissolved oxygen has already increased by up to 20% in tropical waters, expanding the volume of regions called oxygen minimum zones (OMZs), where levels of dissolved oxygen are already very low. [...]."

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Source: Nature
Authors: Alice S. Ren et al.
DOI: 10.1038/s41598-018-25341-8

Abstract

"A potential consequence of climate change is global decrease in dissolved oxygen at depth in the oceans due to changes in the balance of ventilation, mixing, respiration, and photosynthesis. We present hydrographic cruise observations of declining dissolved oxygen collected along CalCOFI Line 66.7 (Line 67) off of Monterey Bay, in the Central California Current region, and investigate likely mechanisms. [...]."

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Source: Biogeosciences
Authors: Isaac D. Irby et al.
DOI: 10.5194/bg-15-2649-2018

Abstract

"The Chesapeake Bay region is projected to experience changes in temperature, sea level, and precipitation as a result of climate change. This research uses an estuarine-watershed hydrodynamic–biogeochemical modeling system along with projected mid-21st-century changes in temperature, freshwater flow, and sea level rise to explore the impact climate change may have on future Chesapeake Bay dissolved-oxygen (DO) concentrations and the potential success of nutrient reductions in attaining mandated estuarine water quality improvements. [...]."

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Source: Nature 
Authors: Nicolaas Glock et al.
DOI: 10.1038/s41467-018-03647-5

Abstract

"Anthropogenic impacts are perturbing the global nitrogen cycle via warming effects and pollutant sources such as chemical fertilizers and burning of fossil fuels. Understanding controls on past nitrogen inventories might improve predictions for future global biogeochemical cycling. Here we show the quantitative reconstruction of deglacial bottom water nitrate concentrations from intermediate depths of the Peruvian upwelling region, using foraminiferal pore density. [...]."

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Source: Wiley Online Library
Authors: Mitchell K. Wolf et al.
DOI: 10.1002/2017GB005829

Abstract

"Deep water formation supplies oxygen‐rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during wintertime convection are scarce, and the controls over the extent of these disequilibria are poorly quantified. [...]."

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Source: Science Direct
Authors: Sebastian Beil et al.
DOI: 10.1016/j.cretres.2017.11.006

Abstract

"A 325 m long continuous succession of uppermost Albian to lower Turonian pelagic (outer shelf) deposits was recovered from a new drill site in the central part of the Tarfaya Basin (southern Morocco). Natural gamma ray wireline logging, carbonate and organic carboncontent, bulk carbonate and organic carbon stable isotopes and X-ray fluorescence (XRF)-scanner derived elemental distribution data in combination with planktonic foraminiferal biostratigraphy indicate complete recovery of the Cenomanian Stage. [...]."

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Source: Wiley Online Library
Authors: B. Y. Queste et al.
DOI: 10.1029/2017GL076666

Abstract

"At suboxic oxygen concentrations, key biogeochemical cycles change and denitrification becomes the dominant remineralization pathway. Earth system models predict oxygen loss across most ocean basins in the next century; oxygen minimum zones near suboxia may become suboxic and therefore denitrifying. Using an ocean glider survey and historical data, we show oxygen loss in the Gulf of Oman (from 6‐12 to < 2 μmol kg^‐1) not represented in climatologies. [...]."

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Source: Science Daily

"New research reveals a growing 'dead zone' in the Gulf of Oman. Little data has been collected in the area for almost 50 years because of piracy and geopolitical tensions. The area devoid of oxygen was confirmed by underwater robots. Reasearchers found an area larger than Scotland with almost no oxygen left. The environmental disaster is worse than expected with dire consequences for fish and marine plants, plus humans who rely on the oceans for food and employment."

Read the full article here.

Source: Nature 
Authors: William R. Gray et al.
DOI: 10.1038/s41561-018-0108-6

Abstract

"The interplay between ocean circulation and biological productivity affects atmospheric CO₂ levels and marine oxygen concentrations. During the warming of the last deglaciation, the North Pacific experienced a peak in productivity and widespread hypoxia, with changes in circulation, iron supply and light limitation all proposed as potential drivers. [...]."

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Source: Nature
Authors: Kan Zhang et al.
DOI: 10.1038/s41561-018-0111-y

Abstract

"The Mesoproterozoic era (1,600–1,000 million years ago (Ma)) has long been considered a period of relative environmental stasis, with persistently low levels of atmospheric oxygen. There remains much uncertainty, however, over the evolution of ocean chemistry during this period, which may have been of profound significance for the early evolution of eukaryotic life. [...]."

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Source: EurekAlert

"Nitrogen is essential to marine life and cycles throughout the ocean in a delicately balanced system. Living organisms--especially marine plants called phytoplankton--require nitrogen in processes such as photosynthesis. In turn, phytoplankton growth takes up carbon dioxide from the atmosphere and helps regulate global climate. [...]."

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Source: Nature
Authors: Lea Steinle et al.
DOI: 10.1038/s41396-018-0107-z

Abstract

"The Kryos Basin is a deep-sea hypersaline anoxic basin (DHAB) located in the Eastern Mediterranean Sea (34.98°N 22.04°E). It is filled with brine of re-dissolved Messinian evaporites and is nearly saturated with MgCl₂-equivalents, which makes this habitat extremely challenging for life. The strong density difference between the anoxic brine and the overlying oxic Mediterranean seawater impedes mixing, giving rise to a narrow chemocline. [...]."

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Source: Science 
Authors: Feifei Zhang et al.
DOI:10.1126/sciadv.1602921

Abstract

"Explaining the ~5-million-year delay in marine biotic recovery following the latest Permian mass extinction, the largest biotic crisis of the Phanerozoic, is a fundamental challenge for both geological and biological sciences. Ocean redox perturbations may have played a critical role in this delayed recovery. However, the lack of quantitative constraints on the details of Early Triassic oceanic anoxia (for example, time, duration, and extent) leaves the links between oceanic conditions and the delayed biotic recovery ambiguous. [...]."

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Source: Geological Society of America
Authors: Caineng Zou et al.
DOI: 10.1130/G40121.1

Abstract

"The Late Ordovician mass extinction (LOME, ca. 445 Ma) was the first of the "Big Five" Phanerozoic extinction events and comprised two extinction pulses. Proposed kill mechanisms include glacially induced global cooling and the expansion of water-column anoxia and/or euxinia (sulfidic conditions), but no general consensus has been reached with regard to the precise role of these mechanisms. [...]."

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Source: Science Direct
Authors: Alex I. Sheen et al.
DOI: 10.1016/j.gca.2018.01.036

Abstract

"Emerging geochemical evidence suggests that the atmosphere-ocean system underwent a significant decrease in O₂ content following the Great Oxidation Event (GOE), leading to a mid-Proterozoic ocean (ca. 2.0–0.8 Ga) with oxygenated surface waters and predominantly anoxic deep waters. The extent of mid-Proterozoic seafloor anoxia has been recently estimated using mass-balance models based on molybdenum (Mo), uranium (U), and chromium (Cr) enrichments in organic-rich mudrocks (ORM). [...]."

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Source: Oxford University Press 
Authors: Michiel H in ‘t Zandt et al.
DOI: 10.1093/femsec/fiy064

Abstract

"Microorganisms are the drivers of biogeochemical methane and nitrogen cycles. Essential roles of chemolithoautotrophic microorganisms in these cycles were predicted long before their identification. Dedicated enrichment procedures, metagenomics surveys and single-cell technologies have enabled the identification of several new groups of most-wanted spookmicrobes, including novel methoxydotrophic methanogens that produce methane from methylated coal compounds and acetoclastic ‘Candidatus Methanothrix paradoxum’, which is active in oxic soils. [...]."

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Source: University of Miami
Author: Diana Udel

"Scientists are studying the oxygen-deprived waters of the Black Sea to help answer questions about the deepest parts of the ocean and Earth’s climate. A new study led by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science found that even in the absence of oxygen, the chemical and biological processes occurring in the Black Sea resemble those in the oxygenated deep ocean. [...]."

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Source: Nature
Authors: C.A. Boch et al.
DOI: 10.1038/s41598-018-23746-z

Abstract

"Climate change is causing warming, deoxygenation, and acidification of the global ocean. However, manifestation of climate change may vary at local scales due to oceanographic conditions. Variation in stressors, such as high temperature and low oxygen, at local scales may lead to variable biological responses and spatial refuges from climate impacts. We conducted outplant experiments at two locations separated by ~2.5 km and two sites at each location separated by ~200 m in the nearshore of Isla Natividad, Mexico to assess how local ocean conditions (warming and hypoxia) may affect juvenile abalone performance. [...]."

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Source: Science
Authors: Sylvia A. Earle et al.
DOI: 10.1126/science.aat0167

Abstract

"In their Review "Declining oxygen in the global ocean and coastal waters" [...] D. Breitburg et al. summarize evidence showing that oxygen has declined in the open ocean and in coastal waters over the past 50 years as a result of increased greenhouse gas emissions and nutrient discharges to coastal waters. We also urgently need more data on the role and speed of microbial engagement, including how deoxygenation is altering microbial pathways and rates of processes within the water column and the deep ocean. [...]." 

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Source: Wiley Online Library
Authors: Arnaud Laurent et al.
DOI: 10.1002/2017JC013583

Abstract

"The continental shelf in the northern Gulf of Mexico experiences expansive seasonal hypoxic conditions and eutrophication‐driven acidification in bottom waters. Rising surface ocean temperatures, freshwater and nutrient inputs, and atmospheric CO₂ will further exacerbate these conditions. Using a high‐resolution, regional circulation‐biogeochemical model, we simulated the spatio‐temporal dynamics of oxygen and inorganic carbon in the northern Gulf of Mexico under present and a projected future (2100) climate state. [...]."

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Source: National Centers for Coastal Ocean Science (NCCOS)
Author: Alan Lewitus

"NCCOS is working with the Northern Gulf Institute (NGI) and Gulf of Mexico State partners to develop a robust and sustainable Gulf of Mexico-wide monitoring program for hypoxia. At the 7th Annual Hypoxia Research Coordination Workshop, planning continued for a Cooperative Hypoxia Assessment and Monitoring Program. The Cooperative Hypoxia Assessment and Monitoring Program (CHAMP) is a bottom-up effort comprised of State (LA, AL/MS, TX) and issue-based workgroups. Eight workgroups (Fisheries, Louisiana-Mississippi/Alabama-Texas state monitoring, autonomous vehicles, Hypoxia Task Force, Oil/Gas and Ocean Acidification, and Gulf Restoration) identify and pursue leveraging and support opportunities within their local focus areas, benefiting the entire Gulf region. [...]."

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Source: Phys.org

"Achieving water quality goals for the Gulf of Mexico may take decades, according to findings by researchers at the University of Waterloo. The results, which appear in Science, suggest that policy goals for reducing the size of the northern Gulf of Mexico's dead zone may be unrealistic, and that major changes in agricultural and river management practices may be necessary to achieve the desired improvements in water quality. The transport of large quantities of nitrogen from rivers and streams across the North American corn belt has been linked to the development of a large  dead zone in the northern Gulf of Mexico, where massive algal blooms lead to oxygen depletion, making it difficult for marine life to survive. [...]."

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Source: Nature 
Authors: Daniele Bianchi et al.
DOI: 10.1038/s41561-018-0081-0

Abstract

"In ocean waters, anaerobic microbial respiration should be confined to the anoxic waters found in coastal regions and tropical oxygen minimum zones, where it is energetically favourable. However, recent molecular and geochemical evidence has pointed to a much broader distribution of denitrifying and sulfate-reducing microbes. [...]."

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Source: Science Daily

"Scientists have shown that creatures which develop in hypoxic (low oxygen) conditions in the marine environment could experience previously unseen hindered development, and become compromised as adults. [...] The prevalence of hypoxic (low oxygen) areas in coastal waters is predicted to increase in the future, both in terms of their scale and duration. And while the adults of many estuarine invertebrates can cope with short periods of hypoxia, it has previously been unclear whether that ability is present if animals are bred and reared under chronic hypoxia. [...]."

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Source: Nature
Authors: Manuela Truebano et al.
DOI: 10.1038/s41598-018-21490-y

Abstract

"The prevalence of hypoxic areas in coastal waters is predicted to increase and lead to reduced biodiversity. While the adult stages of many estuarine invertebrates can cope with short periods of hypoxia, it remains unclear whether that ability is present if animals are bred and reared under chronic hypoxia. We firstly investigated the effect of moderate, short-term environmental hypoxia (40% air saturation for one week) on metabolic performance in adults of an estuarine amphipod, and the fitness consequences of prolonged exposure. [...]."

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Source: Nature 
Authors: Christien P. Laber et al.
DOI: 10.1038/s41564-018-0128-4

Abstract

"Marine phytoplankton account for approximately half of global primary productivity, making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon, which can stimulate nutrient regeneration, primary production and upper ocean respiration2 via lytic infection and the ‘virus shunt’. [...]."

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Source: Nature
Authors: Elizabeth D. Swanner et al. 
DOI: 10.1038/s41598-018-22694-y

Abstract

"Many marine Precambrian iron formations (IF) record deep anoxic seawater enriched in Fe(II) (i.e. ferruginous) overlain by mildly oxygenated surface water. This is reflected by iron-rich sediments forming in deep basins, and relatively iron-poor sediments forming in shallow, sunlit waters. Such an iron gradient is often interpreted as a redox interface where dissolved Fe(II) was oxidized and precipitated as Fe(III)-bearing minerals. As such, sedimentary iron enrichments are proxy to the progressive oxidation of the oceans through geological time. [...]."

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Source: Biogeosciences
Authors: Malin Ödalen et al.
DOI: 10.5194/bg-15-1367-2018

Abstract

"During the four most recent glacial cycles, atmospheric CO₂ during glacial maxima has been lowered by about 90–100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. [...]."

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Source: Science 
Author: Paul Voosen

"Two 7-meter-long sailboats are set to return next month to California, after nearly 8 months tacking across the Pacific Ocean. Puttering along at half-speed, they will be heavy with barnacles and other growth. No captains will be at their helms. That is not because of a mutiny. These sailboats, outfitted with sensors to probe the ocean, are semiautonomous drones, developed by Saildrone, a marine tech startup based in Alameda, California, in close collaboration with the National Oceanic and Atmospheric Administration (NOAA) in Washington, D.C. The voyage is the longest test for the drones and also the first science test in the Pacific—an important step in showing that they could replace an aging and expensive array of buoys that are the main way scientists sniff out signs of climate-disrupting El Niño events. [...]."

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Source: Nature 
Authors: Genming Luo et al.
DOI: 10.1038/s41467-018-03361-2

Abstract

"The marine nitrogen cycle is dominated by redox-controlled biogeochemical processes and, therefore, is likely to have been revolutionised in response to Earth-surface oxygenation. The details, timing, and trajectory of nitrogen cycle evolution, however, remain elusive. Here we couple nitrogen and carbon isotope records from multiple drillcores through the Rooihoogte–Timeball Hill Formations from across the Carletonville area of the Kaapvaal Craton where the Great Oxygenation Event (GOE) and its aftermath are recorded. [...]."

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Source: PNAS
Authors: Matthew O. Clarkson et al.
DOI: 10.1073/pnas.1715278115

Abstract

"Oceanic Anoxic Event 2 (OAE 2), occurring ∼94 million years ago, was one of the most extreme carbon cycle and climatic perturbations of the Phanerozoic Eon. It was typified by a rapid rise in atmospheric CO₂, global warming, and marine anoxia, leading to the widespread devastation of marine ecosystems. However, the precise timing and extent to which oceanic anoxic conditions expanded during OAE 2 remains unresolved. [...]."

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Source: University of Exeter

"A major study into an ancient climate change event that affected a significant percentage of Earth’s oceans has brought into sharp focus a lesser-known villain in global warming: oxygen depletion. The study, just published in the prestigious Proceedings of the National Academy of Sciences (PNAS), examined a past period of global warming around 94 million years ago, when oceans became de-oxygenated. This famous period in Earth’s geological history, known as an Oceanic Anoxic Event (OAE), was more severe and on much longer timescales than the current changes. But it has given the scientists studying this period an extreme case-study to help understand how the oceans are effected by high atmospheric CO₂ emissions. [...]."

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Source: Nature
Authors: Weijing Zhu et al.
DOI: 10.1038/s41598-018-20688-4

Abstract

"In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus on suspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world. [...]."

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Source: Frontiers in Marine Science
Authors: Henry C. Bittig et al.
DOI: 10.3389/fmars.2017.00429

Abstract

"Recently, measurements of oxygen concentration in the ocean—one of the most classical parameters in chemical oceanography—are experiencing a revival. This is not surprising, given the key role of oxygen for assessing the status of the marine carbon cycle and feeling the pulse of the biological pump. The revival, however, has to a large extent been driven by the availability of robust optical oxygen sensors and their painstakingly thorough characterization. For autonomous observations, oxygen optodes are the sensors of choice: They are used abundantly on Biogeochemical-Argo floats, gliders and other autonomous oceanographic observation platforms. [...]."

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Source: Wiley Online Library
Authors: Ivy Frenger et al.
DOI: 10.1002/2017GB005743

Abstract

"Subsurface eddies are known features of ocean circulation, but the sparsity of observations prevents an assessment of their importance for biogeochemistry. Here we use a global eddying (0.1°) ocean-biogeochemical model to carry out a census of subsurface coherent eddies originating from eastern boundary upwelling systems (EBUS) and quantify their biogeochemical effects as they propagate westward into the subtropical gyres. [...]."

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Source: National Oceanic and Atmospheric Administration (NOAA)
Author: Troy Kitch

"When water runs off of farmland and urban centers and flows into our streams and rivers, it is often chock-full of fertilizers and other nutrients. These massive loads of nutrients eventually end up in our coastal ocean, fueling a chain of events that can lead to hypoxic "dead zones" — areas along the sea floor where oxygen is so low it can no longer sustain marine life. In this episode, we're joined by NOAA scientist Alan Lewitus to explore why dead zones form, how the problem of hypoxia is growing worse, and what we're doing about it. [...]."

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Source: Science 
Authors: R. Dietmar Müller & Adriana Dutkiewicz
DOI: 10.1126/sciadv.aaq0500

Abstract

"Atmospheric carbon dioxide (CO₂) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. [...]."

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Source: Nature 
Author: Martin Visbeck
DOI: 10.1038/s41467-018-03158-3

Abstract

"Human activity has already affected all parts of the ocean, with pollution increasing and fish-stocks plummeting. The UN’s recent announcement of a Decade of Ocean Science provides a glimmer of hope, but scientists will need to work closely with decision-makers and society at large to get the ocean back on track. [...]."

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Source: Science Direct
Authors: Turki Al-Said et al.
DOI: 10.1016/j.marpolbul.2018.02.013

Abstract

"Measurements of total organic carbon (TOC) for two years in Kuwaiti waters showed high TOC levels (101.0–318.4, mean 161.2 μM) with maximal concentrations occurring within the polluted Kuwait Bay and decreasing offshore, indicating substantial anthropogenic component. Analysis of winter-time data revealed a large increase in density over the past four decades due to decrease in Shatt Al-Arab runoff, implying that the dissolved/suspended organic matter in surface waters of the northern Gulf could be quickly injected into the Gulf Deep Water (GDW). [...]."

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Source: Nature
Authors: Fiz F. Perez et al.
DOI: 10.1038/nature25493

Abstract

"Since the Industrial Revolution, the North Atlantic Ocean has been accumulating anthropogenic carbon dioxide (CO₂) and experiencing ocean acidification, that is, an increase in the concentration of hydrogen ions (a reduction in pH) and a reduction in the concentration of carbonate ions. The latter causes the ‘aragonite saturation horizon’—below which waters are undersaturated with respect to a particular calcium carbonate, aragonite—to move to shallower depths (to shoal), exposing corals to corrosive waters. [...]."

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Source: Nature
Authors: J. S. Stark et al.
DOI: 10.1038/s41598-018-21029-1

Abstract

"Free-ocean CO2 enrichment (FOCE) experiments have been deployed in marine ecosystems to manipulate carbonate system conditions to those predicted in future oceans. We investigated whether the pH/carbonate chemistry of extremely cold polar waters can be manipulated in an ecologically relevant way, to represent conditions under future atmospheric CO2 levels, in an in-situ FOCE experiment in Antarctica. [...]."

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Source: Environmental Monitor
Author: Karla Lant

"A new research study from a Global Ocean Oxygen Network (GO2NE) team of scientists reveals that the number of low- and zero oxygen sites in the world’s oceans have increased dramatically in the past 50 years. The Intergovernmental Oceanographic Commission of the United Nations created the GO2NE working group to provide a multidisciplinary, global view of deoxygenation, with the end goal of advising policymakers on preserving marine resources by countering low oxygen. [...]."

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Source: PLOS
Authors: Luis G. Egea et al.
DOI: 10.1371/journal.pone.0192402

Abstract

"Global change has been acknowledged as one of the main threats to the biosphere and its provision of ecosystem services, especially in marine ecosystems. Seagrasses play a critical ecological role in coastal ecosystems, but their responses to ocean acidification (OA) and climate change are not well understood. There have been previous studies focused on the effects of OA, but the outcome of interactions with co-factors predicted to alter during climate change still needs to be addressed. [...]."

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Source: Ocean Science
Authors: Iván Pérez-Santos et al.
DOI: 10.5194/os-14-1185-2018

Abstract

"Abstract. The Puyuhuapi Fjord is an atypical fjord, with two mouths, located in northern Patagonia (44.7° S). One mouth lies to the south, close to the Pacific Ocean, whilst the second connects with the Jacaf Channel to the north where a shallow sill inhibits deep water ventilation contributing to the hypoxic conditions below ~ 100 m depth. Acoustic Doppler Current Profiler moorings, scientific echo sounder transects, and in-situ abundance measurements were used to study zooplankton assemblages and migration patterns along Puyuhuapi Fjord and Jacaf Channel. […]."

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Source: Earth System Science Data 
Authors: Vincent Taillandier et al.
DOI: 10.5194/essd-10-627-2018

Abstract

"We report on data from an oceanographic cruise, covering western, central and eastern parts of the Mediterranean Sea, on the French research vessel Tethys 2 in May 2015. This cruise was fully dedicated to the maintenance and the metrological verification of a biogeochemical observing system based on a fleet of BGC-Argo floats. During the cruise, a comprehensive data set of parameters sensed by the autonomous network was collected. [...]."

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Source: Biogeosciences
Authors: Birgit Gaye et al.
DOI: 10.5194/bg-15-507-2018

Abstract

"At present, the Arabian Sea has a permanent oxygen minimum zone (OMZ) at water depths between about 100 and 1200 m. Active denitrification in the upper part of the OMZ is recorded by enhanced δ¹⁵N values in the sediments. Sediment cores show a δ¹⁵N increase during the middle and late Holocene, which is contrary to the trend in the other two regions of water column denitrification in the eastern tropical North and South Pacific. [...]."

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"The distribution of oxygen in the ocean is controlled by physical, biogeochemical and biological processes. Both the supply and consumption of oxygen are sensitive to climate change in ways that are not fully understood. Recent observations suggest that the oxygen content of the ocean is declining (ocean deoxygenation) and that oxygen minimum zones and coastal hypoxia sites are expanding with tremendous effects on the ocean’s ecosystems and living organisms.

This conference:

• focused on the past, present and future state of oxygen
  in the ocean on global, regional and local scales 
• analysed mechanisms and feedbacks critical to identify natural
  and anthropogenic causes of oxygen variability
• determined impacts on biogeochemical cycles and ecosystems [...]."

More information: www.sfb754.de/o2conference2018

Source: Biogeosciences 
Authors: Richard J. Matear & Andrew Lenton
DOI: 10.5194/bg-15-1721-2018

Abstract

"Carbon–climate feedbacks have the potential to significantly impact the future climate by altering atmospheric CO₂ concentrations (Zaehle et al., 2010). By modifying the future atmospheric CO₂ concentrations, the carbon–climate feedbacks will also influence the future ocean acidification trajectory. Here, we use the CO₂ emissions scenarios from four representative concentration pathways (RCPs) with an Earth system model to project the future trajectories of ocean acidification with the inclusion of carbon–climate feedbacks. [...]."

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Source: Biogeosciences 
Authors: Zouhair Lachkar et al. 
DOI: 10.5194/bg-2017-146

Abstract

"The decline in oxygen supply to the ocean associated with global warming is expected to expand oxygen minimum zones (OMZs). This global trend can be attenuated or amplified by regional processes. In the Arabian Sea, the World’s thickest OMZ is highly vulnerable to changes in the Indian monsoon wind. Evidence from paleo records and future climate projections indicate strong variations of the Indian monsoon wind intensity over climatic timescales. Yet, the response of the OMZ to these wind changes remains poorly understood and its amplitude and timescale unexplored. Here, we investigate the impacts of perturbations in Indian monsoon wind intensity (from −50 % to +50 %) on the size and intensity of the Arabian Sea OMZ, and examine the biogeochemical and ecological implications of these changes. [...]."

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Source: Biogeosciences
Authors: Thomas W. Trull et al.
DOI: 10.5194/bg-15-31-2018

Abstract

"The Southern Ocean provides a vital service by absorbing about one-sixth of humankind's annual emissions of CO₂. This comes with a cost – an increase in ocean acidity that is expected to have negative impacts on ocean ecosystems. The reduced ability of phytoplankton and zooplankton to precipitate carbonate shells is a clearly identified risk. The impact depends on the significance of these organisms in Southern Ocean ecosystems, but there is very little information on their abundance or distribution. [...]."

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Source: Science
Authors: Denise Breitburg et al.
DOI: 10.1126/science.aam7240

Abstract

"Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. [...]."

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Source: The Guardian
Author: Damian Carrington

"Areas starved of oxygen in open ocean and by coasts have soared in recent decades, risking dire consequences for marine life and humanity.
Ocean dead zones with zero oxygen have quadrupled in size since 1950, scientists have warned, while the number of very low oxygen sites near coasts have multiplied tenfold. Most sea creatures cannot survive in these zones and current trends would lead to mass extinction in the long run, risking dire consequences for the hundreds of millions of people who depend on the sea. [...]."

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Source: Nature
Authors: Daniel A. Stolper & C. Brenhin Keller 
DOI: 10.1038/nature25009

Abstract

"The oxygenation of the deep ocean in the geological past has been associated with a rise in the partial pressure of atmospheric molecular oxygen (O₂) to near-present levels and the emergence of modern marine biogeochemical cycles. It has also been linked to the origination and diversification of early animals. [...]."

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Source: Biogeosciences
Authors: Zouhair Lachkar et al.
DOI: 10.5194/bg-15-159-2018

Abstract

"The decline in oxygen supply to the ocean associated with global warming is expected to expand oxygen minimum zones (OMZs). This global trend can be attenuated or amplified by regional processes. In the Arabian Sea, the world's thickest OMZ is highly vulnerable to changes in the Indian monsoon wind. Evidence from paleo-records and future climate projections indicates strong variations of the Indian monsoon wind intensity over climatic timescales. [...]."

Read the full article here.

Source: Nature Middle East
Author: Lakshini Mendis
DOI: 10.1038/nmiddleeast.2018.2

"A new review highlights the impact of declining oxygen levels in the open ocean and coastal waters due to increasing temperatures and nutrient discharge. Half of the world’s oxygen originates from the ocean. Yet, worldwide, the amount of open ocean without any oxygen has quadrupled over the past 50 years. Oxygen-minimum zones have expanded by several million square kilometres, increasing by more than 10-fold since 1950. [...]."

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Source: Climate of the Past
Authors: Joost Frieling et al.
DOI: 10.5194/cp-14-39-2018

Abstract

"The Paleocene–Eocene Thermal Maximum (PETM, 56 Ma) was a phase of rapid global warming associated with massive carbon input into the ocean–atmosphere system from a C-depleted reservoir. Many midlatitude and high-latitude sections have been studied and document changes in salinity, hydrology and sedimentation, deoxygenation, biotic overturning, and migrations, but detailed records from tropical regions are lacking. [...]."

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Source: Biogeosciences
Authors: Jassin Petersen et al.
DOI: 10.5194/bg-15-331-2018

Abstract

"The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn²⁺) and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. [...]."

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Source: Science Direct
Authors: Hannah E. Lutterbeck et al.
DOI: 10.1016/j.dsr2.2017.12.023

Abstract

"Nitric oxide (NO) is a short-lived compound of the marine nitrogen cycle. However, measurements of NO in seawater are analytically challenging and our knowledge about its oceanic distribution is, therefore, rudimentary. NO was measured in the oxygen minimum zone (OMZ) of the eastern tropical South Pacific Ocean (ETSP) off Peru during R/V Meteor cruise M93 in February/March 2013. [...]."

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Source: Science Daily

"Nitrogen monoxide (NO) belongs to the group of nitrogen oxides which are infamous as toxic emissions in urban agglomerations. But NO is also produced in nature and plays a role in the nitrogen cycle. However, from earth's largest ecosystem, the ocean, we have hardly any NO measurements. [...]."

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Source: Biogeosciences
Authors: Birgit Gaye et al.
DOI: 10.5194/bg-15-507-2018

Abstract

"At present, the Arabian Sea has a permanent oxygen minimum zone (OMZ) at water depths between about 100 and 1200 m. Active denitrification in the upper part of the OMZ is recorded by enhanced δ¹⁵N values in the sediments. Sediment cores show a δ¹⁵N increase during the middle and late Holocene, which is contrary to the trend in the other two regions of water column denitrification in the eastern tropical North and South Pacific. [...]."

Read the full article here.

Source: Wiley Online Library
Authors: Ivy Frenger et al.
DOI: 10.1002/2017GB005743

Abstract

"Subsurface coherent eddies are well-known features of ocean circulation, but the sparsity of observations prevents an assessment of their importance for biogeochemistry. Here, we use a global eddying (0.1° ) ocean-biogeochemical model to carry out a census of subsurface coherent eddies originating from eastern boundary upwelling systems (EBUS), and quantify their biogeochemical effects as they propagate westward into the subtropical gyres. [...]."

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Source: Ocean Science 
Authors: Rena Czeschel et al.
DOI: 10.5194/os-2018-5

Abstract

"The influence of mesoscale eddies on the flow field and the water masses, especially the oxygen distribution of the eastern tropical South Pacific is investigated from a mooring, float and satellite data set. Two anticyclonic (ACE1/2), one mode water (MWE) and one cyclonic eddy (CE) are identified and followed in detail with satellite data on their westward transition with velocities of 3.2 to 6.0 cm/s from their generation region, the shelf of the Peruvian and Chilean upwelling regime, across the Stratus Ocean Reference Station (ORS) (~ 20° S, 85° W) to their decaying region far west in the oligotrophic open ocean. [...]."

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Source: Scripps Institution of Oceanography

"Several dozen of the world’s top oceanographers were at Scripps Institution of Oceanography at the University of California San Diego last week to showcase advances in the technology used to observe the oceans. At the 19th annual meeting of the Partnership for Observation of the Global Oceans (POGO), which Scripps Oceanography co-founded in 1999, leaders said that the organization has evolved from setting up scientific observation networks in the global oceans to encouraging the spread of oceanographic expertise worldwide. Now, said POGO Chair Karen Wiltshire, the organization seeks to create consensus among scientists to create a global voice calling attention to issues ranging from ocean acidification to deoxygenation and sustainable fishing. [...]."

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Source: Ocean Science
Authors:  Giuliana Turi et al.
DOI: 10.5194/os-14-69-2018

Abstract

"Coastal upwelling systems, such as the California Current System (CalCS), naturally experience a wide range of O₂ concentrations and pH values due to the seasonality of upwelling. Nonetheless, changes in the El Niño–Southern Oscillation (ENSO) have been shown to measurably affect the biogeochemical and physical properties of coastal upwelling regions. In this study, we use a novel, high-resolution global climate model (GFDL-ESM2.6) to investigate the influence of warm and cold ENSO events on variations in the O₂ concentration and the pH of the CalCS coastal waters. [...]."

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Source: Nature 
Authors: Marcel M. M. Kuypers et al.
DOI: 10.1038/nrmicro.2018.9

Abstract

"Nitrogen is an essential component of all living organisms and the main nutrient limiting life on our planet. By far, the largest inventory of freely accessible nitrogen is atmospheric dinitrogen, but most organisms rely on more bioavailable forms of nitrogen, such as ammonium and nitrate, for growth. [...]."

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Source: PLOS
Authors: Maryam Yazdani Foshtomi et al.
DOI: 10.1371/journal.pone.0192391

Abstract

"The presence of large densities of the piston-pumping polychaete Lanice conchilega can have important consequences for the functioning of marine sediments. It is considered both an allogenic and an autogenic ecosystem engineer, affecting spatial and temporal biogeochemical gradients (oxygen concentrations, oxygen penetration depth and nutrient concentrations) and physical properties (grain size) of marine sediments, which could affect functional properties of sediment-inhabiting microbial communities. [...]."

Read the full article here.