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Competing and accelerating effects of anthropogenic nutrient inputs on climate-driven changes in ocean carbon and oxygen cycles

Abstract. 

"Nutrient inputs from the atmosphere and rivers to the ocean are increased substantially by human activities. However, the effects of increased nutrient inputs are not included in the widely used CMIP5 Earth system models, which introduce bias into model simulations of ocean biogeochemistry. Here, using historical simulations by an Earth system model with perturbed atmospheric and riverine nutrient inputs, we show that the contribution of anthropogenic nutrient inputs to past global changes in ocean biogeochemistry is of similar magnitude to the effect of climate change. [...]". 

 

Source: Science Advances
Authors: Akitomo Yamamoto et al. 
DOI: 10.1126/sciadv.abl9207

Read the full article here.


Constraint on net primary productivity of the global ocean by Argo oxygen measurements

Abstract.

"The biological transformation of dissolved inorganic carbon to organic carbon during photosynthesis in the ocean, marine primary production, is a fundamental driver of biogeochemical cycling, ocean health and Earth’s climate system. The organic matter created supports oceanic food webs, including fisheries, and is an essential control on atmospheric carbon dioxide levels. Marine primary productivity is sensitive to changes due to climate forcing, but observing the response at the global scale[...]"

 

Source: Nature Geoscience 
Authors: Kenneth S. Johnson et al.
DOI: https://doi.org/10.1038/s41561-021-00807-z

Read the full article here.


Modeling the role of riverine organic matter in hypoxia formation within the coastal transition zone off the Pearl River Estuary

Abstract.

"Globally expanding hypoxia in estuaries and coastal oceans has largely been attributed to the elevated river nutrient inputs, whereas the role of river-delivered terrestrial organic matter (OMterr) in hypoxia formation has been less investigated. This study uses a coupled physical-biogeochemical model and observations to investigate how OMterr directly (via remineralization) and indirectly (via the nutrients released from OMterr remineralization) promotes hypoxia development in the coastal transition zone[...]"

 

Source: Association for the Sciences of Limnology and Oceanography
Authors: Liuqian Yu et al.
DOI: https://doi.org/10.1002/lno.11616

Read the full article here.


Oxygen Seasonality, Utilization Rate, and Impacts of Vertical Mixing in the Eighteen Degree Water Region of the Sargasso Sea as Observed by Profiling

Abstract.

"Seasonal oxygen structure and utilization in the Sargasso Sea are characterized using nine profiling floats with oxygen 2021 sensors (years 2005–2008), deployed in an Eighteen Degree Water (EDW) experiment (CLIMODE). During autumn-winter when the mixed layer is deepening, oxygen increases from the surface to the base of the EDW at 400 m. During spring-summer, oxygen decreases except between the seasonal pycnocline and compensation depth, creating the seasonal shallow oxygen maximum layer (SOMax) with oxygen production[...]"

 

Source: Advancing Earth and Space Science
Authors: Samuel J. Billheimer et al.
DOI: https://doi.org/10.1029/2020GB006824

Read the full article here.


Response of benthic nitrogen cycling to estuarine hypoxia

Abstract.

"The effects of bottom water oxygen concentration on sediment oxygen uptake, oxygen penetration depth, nitrate and ammonium fluxes, anammox, denitrification, dissimilatory nitrate reduction to ammonium, nitrification, and mineralization were investigated off the Changjiang estuary and its adjacent East China Sea, by combining a seasonal comparison[...]"

 

Source: ASLO- Association for the Sciences Limnology and Oceanography
Authors: Guodong Song et al.
DOI: https://doi.org/10.1002/lno.11630

Read the full article here.


A benthic oxygen oasis in the early Neoproterozoic ocean

Abstract.

"Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans[...]"

 

Source: Science Direct
Authors: Haiyang Wang et al.
DOI: https://doi.org/10.1016/j.precamres.2020.106085

Read the full article here.


Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean

Abstract.

"Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because of the logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation in echinoderm assemblages at these mesophotic systems, where this group is among the predominant fauna. We compiled data on echinoderm taxa at 91 sampling stations, from historical and recent surveys (between 1950 and 2019), covering a longitudinal gradient of approximately 3,700 km along with the Nazca, Salas y Gómez[...]"

 

Source: Frontiers in Marine Science
Authors: Ariadna Mecho et al.
DOI: 10.3389/fmars.2021.574780

Read the full article here.


A benthic oxygen oasis in the early Neoproterozoic ocean

Abstract.

"Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans. However, little research has been directed toward testing the benthic oxygen[...]"

 

Source: Science Direct
Authors:Haiyang Wang et al.
DOI: https://doi.org/10.1016/j.precamres.2020.106085

Read the full article here.


Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene

Abstract.

"A marked 120 My gap in the fossil record of vampire squids separates the only extant species (Vampyroteuthis infernalis) from its Early Cretaceous, morphologically-similar ancestors. While the extant species possesses unique physiological adaptations to bathyal environments with low oxygen concentrations, Mesozoic vampyromorphs inhabited epicontinental shelves. However, the timing of their retreat towards bathyal and oxygen-depleted habitats is poorly documented. Here, we document a first record of a post-Mesozoic vampire squid from the Oligocene of the Central Paratethys[...]"

Source: Nature - Communications Biology
Authors: Martin Košťák et al.
DOI: https://doi.org/10.1038/s42003-021-01714-0

Read the full article here.


Triple Oxygen Isotopes in Silica–Water and Carbonate–Water Systems

Abstract.

"The field of stable isotope geochemistry began with the recognition that the oxygen isotope composition of ancient carbonates could be used as a paleothermometer (Urey 1947; Urey et al. 1951). As stated by Urey (1947), “Accurate determinations of the Ol8 content of carbonate rocks could be used to determine the temperature at which they were formed”. This concept was based on the temperature dependence for the oxygen isotope fractionation between calcite and water. Urey realized that if a mass spectrometer with sufficient precision could be built, a method of reproducibly extracting oxygen from[...]"

 

Source: Reviews in Mineralogy and Geochemistry
Authors: Jordan A.G. Wostbrock et al.
DOI: https://doi.org/10.2138/rmg.2021.86.11

Read the full article here.

 

 

 


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