News

Large-scale ocean deoxygenation during the Paleocene-Eocene Thermal Maximum

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. [...]"

Source: Science  
Authors: Weiqi Yao, Adina Paytan, Ulrich G. Wortmann
DOI: 10.1126/science.aar8658

Read the full article here.


The Ocean is losing its breath: declining oxygen in the world's ocean and coastal waters; summary for policy makers

"Oxygen is critical to the health of the ocean. It structures aquatic ecosystems, impacts the biogeochemical cycling of carbon, nitrogen and other key elements, and is a fundamental requirement for marine life from the intertidal zone to the greatest depths of the ocean." [...]

Source: UNESCO (UNESDOC)
Authors: Denise Breitburg et al.

Get the full publication here.


Hazards of decreasing marine oxygen: the near-term and millennial-scale benefits of meeting the Paris climate targets

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. [...]"

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

Read the full article here.


Drivers and mechanisms of ocean deoxygenation

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. [...]"

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

Read the full article here.


Will ocean zones with low oxygen levels expand or shrink?

"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."

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

Read the full article here.


UNM scientists find widespread ocean anoxia as cause for past mass extinction

"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. [...]"

Source: EurekAlert!

Read the full article here.


Will ocean zones with low oxygen levels expand or shrink?

"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. [...]"

Source: nature.com

Read the full article here.


Oxygenation of the Mesoproterozoic ocean and the evolution of complex eukaryotes

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. [...]"

Source: Nature Geoscience
Authors: Kan Zhang
DOI: 10.1038/s41561-018-0111-y

Read the full article here.


Tiny microenvironments in the ocean hold clues to global nitrogen cycle

"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. [...]"

Source: EruekAlert

Read the full article here.

 


New Study in Oxygen-Deprived Black Sea Provides Insights on Future Carbon Budget

"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. [...]"

Source: University of Miami Rosenstiel School of Marine & Atmospheric Science

Read the full article here.


Showing 1 - 10 of 50 results.
Items per Page 10
of 5