Abstract.

"Historically, sea ice loss in the Arctic Ocean has promoted increased phytoplankton primary production because of the greater open water area and a longer growing season. However, debate remains about whether primary production will continue to rise should sea ice decline further. Using an ocean color algorithm parameterized for the Arctic Ocean, we show that primary production increased by 57% between 1998 and 2018. Surprisingly, whereas increases were due to widespread sea ice loss during the first decade[...]"

Source: American Association For The Advancement Of Science 
Authors: K. M. Lewis et al.
DOI: 10.1126/science.aay8380 

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Abstract.

"The Mediterranean Sea is a small region of the global ocean but with a very active overturning circulation that allows surface perturbations to be transported to the interior ocean. Understanding of ventilation is important for understanding and predicting climate change and its impact on ocean ecosystems. To quantify changes of deep ventilation, we investigated the spatiotemporal variability of transient tracers (i.e., CFC-12 and SF6) observations combined with temporal evolution of hydrographic and oxygen observations in the Mediterranean Sea from 13 cruises conducted during 1987–2018, with emphasize on the update from 2011 to 2018. Spatially, both the Eastern and Western Mediterranean Deep Water (EMDW and WMDW) show a general west-to-east gradient[...]"

Source: Frontiers
Authors: Pingyang Li et al.
DOI: https://doi.org/10.3389/fmars.2020.00594

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Abstract.

"The marine chromium (Cr) cycle is still insufficiently understood, in particular the mechanisms modulating the spatial distribution of dissolved stable Cr isotopes in seawater. Redox transformations between its main oxidation states, Cr(VI) and Cr(III), have been held accountable for the observed tight inverse logarithmic relationship between the dissolved Cr concentration [Cr] and its isotopic composition (δ53Cr), whereby isotopically light Cr(III) is removed in surface waters and oxygen minimum zones[...]"

Source: Science Direct
Authors: Philipp Nasemann et al.
DOI: https://doi.org/10.1016/j.gca.2020.06.027

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Abstract.

"Understanding the role of benthic organisms in marine sediments is becoming increasingly important with the growing problem of eutrophication of marine ecosystems around the world, including the Baltic Sea. Therefore, we have conducted a series of incubation experiments on sediment cores collected from sites characterized by varying oxygen conditions and measured the influx (uptake by sediment) of oxygen as well as the sediment–water exchange of phosphate, ammonia and silicate.[...]"

Source: Science Direct
Authors: Halina Kendzierska et al.
Doi: https://doi.org/10.1016/j.jembe.2020.151439

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Abstract.

"Ocean deoxygenation is a threat to marine ecosystems. We evaluated the potential of two ocean intervention technologies, that is, “artificial downwelling (AD)” and “artificial upwelling (AU),” for remedying the expansion of Oxygen Deficient Zones (ODZs). The model‐based assessment simulated AD and AU implementations for 80 years along the eastern Pacific ODZ.[...]"

Source: Advancing Earth And Space Science 
Authors: Ellias Yuming Feng et al.
DOI: https://doi.org/10.1029/2020GL088263

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Abstract.

"Nearly every nation has signed the UNFCC Paris Agreement, committing to mitigate global anthropogenic carbon (C_ant) emissions and limit global mean temperature increase to 1.5 °C. A consequence of emission mitigation is reduced efficiency of ocean C_ant uptake, which is driven by mechanisms that have not been studied in detail. The historical pattern of continual increase in atmospheric CO₂ has resulted in a proportional increase in C_ant uptake. [...]"

Source: Biogeosciences
Authors: Sean Ridge and Galen McKinley
DOI: 10.5194/bg-2020-254

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Abstract.

"Human activities have altered the state of the ocean, leading to warming, acidification and deoxygenation. These changes impact ocean biogeochemistry and influence ecosystem functions and ocean health. The long-term global effects of these changes are difficult to predict using current satellite sensing and traditional in situ observation techniques. [...]"

Source: Nature Reviews Earth & Environment
Authors: Fei Chai et al.
DOI: 10.1038/s43017-020-0053-y

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Abstract.

"In the context of continuously increasing anthropogenic nitrogen inputs, knowledge of how ammonia oxidation (AO) in the ocean responds to warming is crucial to predicting future changes in marine nitrogen biogeochemistry. Here, we show divergent thermal response patterns for marine AO across a wide onshore/offshore trophic gradient. [...]"

Source: Nature Communications
Authors: Zhen-Zhen Zheng et al.
DOI: 10.1038/s41467-020-17366-3

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Abstract.

"Temporal variations in excess nitrate (DIN_xs) relative to dissolved inorganic phosphorus (DIP) were evaluated using datasets derived from repeated measurements along meridional and zonal transects in the upper (200–600 m) North Atlantic (NAtl) between the 1980s and 2010s. The analysis revealed that the DIN_xs trend in the western NAtl differed from that in the eastern NAtl. In the western NAtl, which has been subject to atmospheric nitrogen deposition (AND) from the USA, the subsurface DIN_xs concentrations have increased over the last 2 decades. [...]"

Source: Biogeosciences
Authors: Jin-Yu Terence Yang et al.
DOI: 10.5194/bg-17-3631-2020

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Abstract.

"Atmospheric fluxes of dissolved organic matter (DOM) were studied for the first time on the island of Lampedusa, a remote site in the central Mediterranean Sea (Med Sea), between 19 March 2015 and 1 April 2017. The main goals of this study were to quantify total atmospheric deposition of DOM in this area and to evaluate the impact of Saharan dust deposition on DOM dynamics in the surface waters of the Mediterranean Sea. Our data show high variability in DOM deposition rates without a clear seasonality and a dissolved organic carbon (DOC) input from the atmosphere of 120.7 mmol DOC m⁻² yr⁻¹. [...]"

Source: Biogeosciences
Authors: Yuri Galletti et al.
DOI: 10.5194/bg-17-3669-2020

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Abstract.

"The ongoing uptake of anthropogenic carbon by the ocean leads to ocean acidification, a process that results in a reduction in pH and in the saturation state of biogenic calcium carbonate minerals aragonite (Ω_arag) and calcite (Ω_calc). Because of its naturally low Ω_arag and Ω_calc (refs.), the Arctic Ocean is considered the region most susceptible to future acidification and associated ecosystem impacts. [...]"

Source: Nature
Authors: Jens Terhaar et al.
DOI: 10.1038/s41586-020-2360-3

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Abstract.

"Anthropogenic climate change is projected to lead to ocean warming, acidification, deoxygenation, reductions in near-surface nutrients, and changes to primary production, all of which are expected to affect marine ecosystems. Here we assess projections of these drivers of environmental change over the twenty-first century from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under the CMIP6 Shared Socioeconomic Pathways (SSPs). [...]"

Source: Biogeosciences
Authors: Lester Kwiatkowski et al.
DOI: 10.5194/bg-17-3439-2020

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Abstract.

"The Zero Emissions Commitment (ZEC) is the change in global mean temperature expected to occur following the cessation of net CO₂ emissions and as such is a critical parameter for calculating the remaining carbon budget. The Zero Emissions Commitment Model Intercomparison Project (ZECMIP) was established to gain a better understanding of the potential magnitude and sign of ZEC, in addition to the processes that underlie this metric. [...]"

Source: Biogeosciences
Authors: Andrew H. MacDougall et al.
DOI: 10.5194/bg-17-2987-2020

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A Story of the Collaborative Research Centre "Climate-Biogeochemistry Interactions in the Tropical Ocean"

After 12 years of intensive research, the Collaborative Research Centre 754 "Climate-Biogeochemical Interactions in the Tropical Ocean" ended in winter 2019 with a final symposium in Heiligenhafen.

More than 100 scientists involved in the large-scale project over its entire running time were able to gain numerous new insights into the processes of nutrient cycling, the interaction between ocean and atmosphere and the ecosystems in the tropical oceans. Above all, however, they drew attention to a phenomenon that affects the entire ocean: global oxygen loss and the spread of oxygen minimum zones in the ocean. With this video, the SFB 754 now draws a conclusion and at the same time points out the new research tasks that have resulted from its work. These include improved ocean observation and the question of how to prevent further oxygen loss.

For more information please look at www.sfb754.de

For a german version of the video please follow this link.

Abstract.

"Deoxygenation in coastal and open‐ocean ecosystems rarely exists in isolation but occurs concomitantly with acidification. Here, we first combine meta‐data of experimental assessments from across the globe to investigate the potential interactive impacts of deoxygenation and acidification on a broad range of marine taxa. [...]"

Source: Global Change Biology
Authors: Alexandra Steckbauer et al.
DOI: 10.1111/gcb.15252

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"A type of anaerobic bacteria responsible for more than 50 percent of nitrogen loss from marine environments has been shown to use solid-state matter present outside their cells for respiration. The finding by KAUST researchers adds to knowledge of the global nitrogen cycle and has important energy-saving potential for wastewater treatment. [...]"

Source: Phys.org

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