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The effect of bio-irrigation by the polychaete Lanice conchilega on active denitrifiers: Distribution, diversity and composition of nosZ gene

Abstract.

"The presence of large densities of the piston-pumping polychaete Lanice conchilega can have important consequences for the functioning of marine sediments. It is considered both an allogenic and an autogenic ecosystem engineer, affecting spatial and temporal biogeochemical gradients (oxygen concentrations, oxygen penetration depth and nutrient concentrations) and physical properties (grain size) of marine sediments, which could affect functional properties of sediment-inhabiting microbial communities. [...]"

Source: PLOS
Authors: Maryam Yazdani Foshtomi et al.
DOI: 10.1371/journal.pone.0192391

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The microbial nitrogen-cycling network

Abstract.

"Nitrogen is an essential component of all living organisms and the main nutrient limiting life on our planet. By far, the largest inventory of freely accessible nitrogen is atmospheric dinitrogen, but most organisms rely on more bioavailable forms of nitrogen, such as ammonium and nitrate, for growth. [...]"

Source: Nature Reviews Microbiology
Authors: Marcel M. M. Kuypers, Hannah K. Marchant & Boran Kartal
DOI: 10.1038/nrmicro.2018.9

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Response of O2 and pH to ENSO in the California Current System in a high-resolution global climate model

Abstract.

"Coastal upwelling systems, such as the California Current System (CalCS), naturally experience a wide range of O2 concentrations and pH values due to the seasonality of upwelling. Nonetheless, changes in the El Niño–Southern Oscillation (ENSO) have been shown to measurably affect the biogeochemical and physical properties of coastal upwelling regions. In this study, we use a novel, high-resolution global climate model (GFDL-ESM2.6) to investigate the influence of warm and cold ENSO events on variations in the O2 concentration and the pH of the CalCS coastal waters. [...]"

Source: Ocean Science
Authors:  Giuliana Turi et al.
DOI: 10.5194/os-14-69-2018

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Top Ocean Research Organizations Develop Unified Voice at Scripps Meeting

Global research organization seeks to leverage technological advances to promote ocean protection

"Several dozen of the world’s top oceanographers were at Scripps Institution of Oceanography at the University of California San Diego last week to showcase advances in the technology used to observe the oceans.

At the 19th annual meeting of the Partnership for Observation of the Global Oceans (POGO), which Scripps Oceanography co-founded in 1999, leaders said that the organization has evolved from setting up scientific observation networks in the global oceans to encouraging the spread of oceanographic expertise worldwide. Now, said POGO Chair Karen Wiltshire, the organization seeks to create consensus among scientists to create a global voice calling attention to issues ranging from ocean acidification to deoxygenation and sustainable fishing. [...]"

Source: Scripps Institution of Oceanography

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Impact of mesoscale eddies on water mass and oxygen distribution in the eastern tropical South Pacific

Abstract.

"The influence of mesoscale eddies on the flow field and the water masses, especially the oxygen distribution of the eastern tropical South Pacific is investigated from a mooring, float and satellite data set. Two anticyclonic (ACE1/2), one mode water (MWE) and one cyclonic eddy (CE) are identified and followed in detail with satellite data on their westward transition with velocities of 3.2 to 6.0 cm/s from their generation region, the shelf of the Peruvian and Chilean upwelling regime, across the Stratus Ocean Reference Station (ORS) (~ 20° S, 85° W) to their decaying region far west in the oligotrophic open ocean. [...]"

Source: Ocean Science (under review)
Authors: Rena Czeschel et al.
DOI: 10.5194/os-2018-5

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Biogeochemical role of subsurface coherent eddies in the ocean: Tracer cannonballs, hypoxic storms, and microbial stewpots?

Abstract.

"Subsurface coherent eddies are well-known features of ocean circulation, but the sparsity of observations prevents an assessment of their importance for biogeochemistry. Here, we use a global eddying (0.1° ) ocean-biogeochemical model to carry out a census of subsurface coherent eddies originating from eastern boundary upwelling systems (EBUS), and quantify their biogeochemical effects as they propagate westward into the subtropical gyres.  [...]"

Source: Global Biogeochemical Cycles
Authors: Ivy Frenge et al.
DOI: 10.1002/2017GB005743


Glacial–interglacial changes and Holocene variations in Arabian Sea denitrification

Abstract.

"At present, the Arabian Sea has a permanent oxygen minimum zone (OMZ) at water depths between about 100 and 1200 m. Active denitrification in the upper part of the OMZ is recorded by enhanced δ15N values in the sediments. Sediment cores show a δ15N increase during the middle and late Holocene, which is contrary to the trend in the other two regions of water column denitrification in the eastern tropical North and South Pacific.  [...]"

Source: Biogeosciences
Authors: Birgit Gaye et al.
DOI: 10.5194/bg-15-507-2018

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New measurement technology helps to determine NO concentrations in the ocean

"Nitrogen monoxide (NO) belongs to the group of nitrogen oxides which are infamous as toxic emissions in urban agglomerations. But NO is also produced in nature and plays a role in the nitrogen cycle. However, from earth's largest ecosystem, the ocean, we have hardly any NO measurements."

Source: Science Daily

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Nitric oxide (NO) in the oxygen minimum zone off Peru

Abstract.

"Nitric oxide (NO) is a short-lived compound of the marine nitrogen cycle. However, measurements of NO in seawater are analytically challenging and our knowledge about its oceanic distribution is, therefore, rudimentary. NO was measured in the oxygen minimum zone (OMZ) of the eastern tropical South Pacific Ocean (ETSP) off Peru during R/V Meteor cruise M93 in February/March 2013. [...]"

Source: Deep Sea Research Part II: Topical Studies in Oceanography
Authors: Hannah E. Lutterbeck et al.
DOI: 10.1016/j.dsr2.2017.12.023

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Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen-depleted sediments

Abstract.

"Symbioses between anaerobic or microaerophilic protists and prokaryotes are common in anoxic and oxygen-depleted habitats ranging from marine sediments to gastrointestinal tracts. Nevertheless, little is known about the mechanisms of metabolic interaction between partners. In these putatively syntrophic associations, consumption of fermentative end products (e.g., hydrogen) by the prokaryotic symbionts is thought to facilitate protistan anaerobic metabolism.  [...]"

Source: Molecular Ecology
Authors: R. A. Beinart et al.
DOI: 10.1111/mec.14465

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