Abstract.

"We investigated anammox, denitrification and dissimilatory reduction of nitrite to ammonium (DNRA) activity in the Eastern Tropical South Pacific oxygen minimum zone (OMZ) off northern Chile, at high‐depth resolution through the oxycline into the anoxic OMZ core. This was accompanied by high‐resolution nutrient and oxygen profiles to link changes in nitrogen transformation rates to physicochemical characteristics of the water column. Denitrification was detected at most depths, but anammox was the most active N2‐producing process, while DNRA was not detectable. [...]"

Source: Environmental Microbiology
Authors: Loreto De Brabandere et al.
DOI: 10.1111/1462-2920.12255

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Abstract.

"The so-called secondary nitrite maximum (SNM) is a pronounced subsurface feature in many oxygen deficient zones of the ocean. A nitrite layer of up to several hundred meters thickness indicates high microbial activity and nitrogen loss from the system. To study the effects of primary and export production on the SNM, we have developed a one-dimensional ecosystem model for oxygen deficient zones. Our model couples the marine nitrogen and oxygen cycles with physical water column processes, includes euphotic, aphotic, aerobic and anaerobic processes and thereby dynamically describes source and sink processes for nitrite. [...]"

Source: Ecological Modelling
Authors: Aike Beckmann and Inga Hense
DOI: 10.1016/j.ecolmodel.2017.05.014

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Abstract.

"Oligotrophic and productive areas of the ocean differ in plankton community composition and biomass transfer efficiency. Here, we describe the plankton community along a latitudinal transect in the tropical and subtropical Atlantic Ocean. Prochlorococcus dominated the autotrophic community at the surface and mixed layer of oligotrophic stations, replaced by phototrophic picoeukaryotes and Synechococcus in productive waters. [...]"

Source: Scientific Reports
Authors: Laia Armengol et al.
DOI: 10.1038/s41598-019-38507-9

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Abstract.

"Benthic foraminifera populate a diverse range of marine habitats. Their ability to use alternative electron acceptors—nitrate (NO3−) or oxygen (O2)—makes them important mediators of benthic nitrogen cycling. Nevertheless, the metabolic scaling of the two alternative respiration pathways and the environmental determinants of foraminiferal denitrification rates are yet unknown. We measured denitrification and O2 respiration rates for 10 benthic foraminifer species sampled in the Peruvian oxygen minimum zone (OMZ). [...]"

Source: PNAS
Authors: Nicolaas Glock et al.
DOI: 10.1073/pnas.1813887116

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Abstract.

"The deglacial history of CO2 release from the deep North Pacific remains unresolved. This is due to conflicting indications about subarctic Pacific ventilation changes based on various marine proxies, especially for Heinrich Stadial 1 (HS-1) when a rapid atmospheric CO2 rise occurs. Here, we use a complex Earth System Model to investigate the deglacial North Pacific overturning and its control on ocean stratification. [...]"

Source: Nature Communications
Authors: X. Gong et al.
DOI: 10.1038/s41467-019-08606-2

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Abstract.

"The eastern Mediterranean Sea sedimentary record is characterised by intervals of organic rich sediment (sapropels), indicating periods of severe anoxia triggered by astronomical forcing. It has been hypothesized that nitrogen fixation was crucial in injecting the Mediterranean Sea with bioavailable nitrogen (N) during sapropel events. However, the evolution of the N biogeochemical cycle of sapropels is poorly understood. For example, the role of the complementary removal reaction, anaerobic ammonium oxidation (anammox), has not been investigated because the traditional lipid biomarkers for anammox, ladderane fatty acids, are not stable over long periods in the sedimentary record. [...]

Source: Biogeosciences
Authors: Darci Rush et al.
DOI: 10.5194/bg-2019-27

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Abstract.

"While the value of giant kelp (Macrocystis pyrifera) as a habitat-forming foundation species is well-understood, it is unclear how they impact the oxygen concentration and pH of the surrounding seawater, and further, how such a dynamic abiotic environment will affect eco-evolutionary dynamics in a context of global change. Here, we profiled the nearshore kelp forest environment in Southern California to understand changes in dissolved oxygen (DO) and pH with high spatiotemporal resolution. We then examined transgenerational effects using sea urchins (Strongylocentrotus purpuratus) as our study organism.  [...]"

Source: Frontiers in Marine Science
Authors: Umihiko Hoshijima and Gretchen Hofmann
DOI: 10.3389/fmars.2019.00062

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"Climate change is causing significant changes to phytoplankton in the world's oceans, and a new MIT study finds that over the coming decades these changes will affect the ocean's color, intensifying its blue regions and its green ones. Satellites should detect these changes in hue, providing early warning of wide-scale changes to marine ecosystems. [...]"

Source: ScienceDaily

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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. [...]"

Source: Nature Communications
Authors: Stephanie Dutkiewicz et al.
DOI: 10.1038/s41467-019-08457-x

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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. [...]"

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

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