News

A Sixteen-year Decline in Dissolved Oxygen in the Central California Current

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.  [...]"

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

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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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Global niche of marine anaerobic metabolisms expanded by particle microenvironments

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. [...]"

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

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Nitrogen fixation sustained productivity in the wake of the Palaeoproterozoic Great Oxygenation Event

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. [...]"

Source: Nature Communications
Authors: Genming Luo
DOI: 10.1038/s41467-018-03361-2

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Persistent spatial structuring of coastal ocean acidification in the California Current System

Abstract.

"The near-term progression of ocean acidification (OA) is projected to bring about sharp changes in the chemistry of coastal upwelling ecosystems. The distribution of OA exposure across these early-impact systems, however, is highly uncertain and limits our understanding of whether and how spatial management actions can be deployed to ameliorate future impacts. Through a novel coastal OA observing network, we have uncovered a remarkably persistent spatial mosaic in the penetration of acidified waters into ecologically-important nearshore habitats across 1,000 km of the California Current Large Marine Ecosystem.  [...]"

Source: Scientific Reports
Authors: F. Chan et al.
DOI: 10.1038/s41598-017-02777-y

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