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Response of N2O production rate to ocean acidification in the western North Pacific

Abstract.

"Ocean acidification, induced by the increase in anthropogenic CO2 emissions, has a profound impact on marine organisms and biogeochemical processes1. The response of marine microbial activities to ocean acidification might play a crucial role in the future evolution of air–sea fluxes of biogenic gases such as nitrous oxide (N2O), a strong GHG and the dominant stratospheric ozone-depleting substance2. Here, we examine the response of N2O production from nitrification to acidification in a series of incubation experiments conducted in subtropical and subarctic western North Pacific. [...]"

Source: Nature Climate Change
Authors: Florian Breider et al.
DOI: 10.1038/s41558-019-0605-7

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Meeting climate targets by direct CO2 injections: what price would the ocean have to pay?

Abstract.

"We investigate the climate mitigation potential and collateral effects of direct injections of captured CO2 into the deep ocean as a possible means to close the gap between an intermediate CO2 emissions scenario and a specific temperature target, such as the 1.5 C target aimed for by the Paris Agreement. For that purpose, a suite of approaches for controlling the amount of direct CO2 injections at 3000 m water depth are implemented in an Earth system model of intermediate complexity. [...]"

Source: Earth System Dynamics
Authors: Fabian Reith et al.
DOI: 10.5194/esd-10-711-2019

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Scenarios of Deoxygenation of the Eastern Tropical North Pacific During the Past Millennium as a Window Into the Future of Oxygen Minimum Zones

Abstract.

"Diverse studies predict global expansion of Oxygen Minimum Zones (OMZs) as a consequence of anthropogenic global warming. While the observed dissolved oxygen concentrations in many coastal regions are slowly decreasing, sediment core paleorecords often show contradictory trends. This is the case for numerous high-resolution reconstructions of oxygenation in the Eastern Tropical North Pacific (ETNP). [...]"

Source: Frontiers in Marine Science
Authors: Konstantin Choumiline et al.
DOI: 10.3389/feart.2019.00237

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A Synthesis of Opportunities for Applying the Telecoupling Framework to Marine Protected Areas

Abstract.

"The world’s oceans face unprecedented anthropogenic threats in the globalized era that originate from all over the world, including climate change, global trade and transportation, and pollution. Marine protected areas (MPAs) serve important roles in conservation of marine biodiversity and ecosystem resilience, but their success is increasingly challenged in the face of such large-scale threats. [...]"

Source: Sustainability
Authors: Vanessa Hull et al.
DOI: 10.3390/su11164450

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Organic Heterogeneities in Foraminiferal Calcite Traced Through the Distribution of N, S, and I Measured With NanoSIMS:

A New Challenge for Element-Ratio-Based Paleoproxies?

 

Abstract.

"Oceanic oxygen decline due to anthropogenic climate change is a matter of growing concern. A quantitative oxygen proxy is highly desirable in order to identify and monitor recent dynamics as well as to reconstruct pre-Anthropocene changes in amplitude and extension of oxygen depletion. Geochemical proxies like foraminiferal I/Ca ratios seem to be promising redox proxies. [...]"

Source: Frontiers in Earth Science
Authors: Nicolaas Glock et al.
DOI: 10.3389/feart.2019.00175

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Antarctic offshore polynyas linked to Southern Hemisphere climate anomalies

Abstract.

"Offshore Antarctic polynyas—large openings in the winter sea ice cover—are thought to be maintained by a rapid ventilation of deep-ocean heat through convective mixing. These rare phenomena may alter abyssal properties and circulation, yet their formation mechanisms are not well understood. Here we demonstrate that concurrent upper-ocean preconditioning and meteorological perturbations are responsible for the appearance of polynyas in the Weddell Sea region of the Southern Ocean. [...]"

Source: Nature
Authors: Ethan C. Campbell et al.
DOI: 10.1038/s41586-019-1294-0

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World Oceans Day: Scientists ‘taken aback by scale and speed of ocean changes’

"Armed with better data than ever before, scientists have in recent months sounded the alarm over the rising pace of global warming and the parlous state of Nature. But there is another area of concern, one that covers two thirds of the planet and plays a crucial role in absorbing dangerous greenhouse gases and regulating everything from food chains to weather patterns. Oceans are crucial to life on Earth, yet they frequently only feature in the environment debate when plastic pollution or fish-stock declines are discussed. But experts believe that might be changing. “We have an important opportunity over the next 18 months to do something for oceans,” said Dan Laffoley, from the International Union for the Conservation of Nature. [...]"

Source: France24

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Effects of ocean acidification on the respiration and feeding of juvenile red and blue king crabs (Paralithodes camtschaticus and P. platypus)

Abstract.

"Ocean acidification is a decrease in pH resulting from dissolution of anthropogenic CO2 in the oceans that has physiological effects on many marine organisms. Juvenile red and blue king crabs (Paralithodes camtschaticus and P. platypus) exhibit both increased mortality and decreased growth in acidified waters. In this study, we determined how ocean acidification affects oxygen consumption, feeding rates, and growth in both species. [...]"

Source: ICES Journal of Marine Science
Authors: William Christopher Long et al.
DOI: 10.1093/icesjms/fsz090

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Variations in ocean deoxygenation across Earth System Models: Isolating the role of parametrized lateral mixing

Abstract.

"Modern Earth System Models (ESMs) disagree on the impacts of anthropogenic global warming on the distribution of oxygen and associated low‐oxygen waters. A sensitivity study using the GFDL CM2Mc model points to the representation of lateral mesoscale eddy transport as a potentially important factor in such disagreement. Because mesoscale eddies are smaller than the spatial scale of ESM ocean grids, their impact must be parameterized using a lateral mixing coefficient AREDI. [...]"

Source: Global Biogeochemical Cycles
Authors: A. Bahl, A. Gnanadesikan and M.‐A. Pradal
DOI: 10.1029/2018GB006121

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Slaking the world’s thirst with seawater dumps toxic brine in oceans

"Growing populations and tightening water supplies have spurred people in many places—including the Middle East, Australia, California and China—to look to the oceans and other salty waters as a source of new drinking water. But desalination plants are energy intensive and create a potentially environment-harming waste called brine (made up of concentrated salt and chemical residues), which is dumped into the ocean, injected underground or spread on land.

Despite the ecological threats, “there was no comprehensive assessment about brine—how much we produce,” says Manzoor Qadir, assistant director of the United Nations University Institute on Water, Environment and Health. So he and his colleagues calculated that figure and found it is 50 percent greater than the desalination industry’s previous rough estimate. In fact, it is enough to cover Florida with 30 centimeters of brine every year. [...]"

Source: Scientific American

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