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Coupling of oceanic carbon and nitrogen facilitates spatially resolved quantitative reconstruction of nitrate inventories

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. [...]"

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

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Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo‐O2 Data

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 [...]"

Source: Global Biogeochemical Cycles
Authors: Mitchell K. Wolf et al.
DOI: 10.1002/2017GB005829

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New insights into Cenomanian paleoceanography and climate evolution from the Tarfaya Basin, southern Morocco

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. [...]"

Source: Cretaceous Research
Authors: SebastianBeil et al.
DOI: 10.1016/j.cretres.2017.11.006

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Physical controls on oxygen distribution and denitrification potential in the north west Arabian Sea

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. [...]"

Source: Grophysical Research Letters
Authors: B. Y. Queste et al.
DOI: 10.1029/2017GL076666

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Growing 'dead zone' confirmed by underwater robots in the Gulf of Oman

"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. "

Source: Science Daily

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Nancy Rabalais - The "dead zone" of the Gulf of Mexico

"Ocean expert Nancy Rabalais tracks the ominously named "dead zone" in the Gulf of Mexico -- where there isn't enough oxygen in the water to support life. The Gulf has the second largest dead zone in the world; on top of killing fish and crustaceans, it's also killing fisheries in these waters. Rabalais tells us about what's causing it -- and how we can reverse its harmful effects and restore one of America's natural treasures."

Watch the full TED Talk here.


Deglacial upwelling, productivity and CO2 outgassing in the North Pacific Ocean

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. [...]"

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

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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

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Life on the edge: active microbial communities in the Kryos MgCl2-brine basin at very low water activity

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. [...]"

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

Read the full article here.


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