News

Impact of mid-glacial ice sheets on deep ocean circulation and global climate

Abstract.

"This study explores the effect of southward expansion of Northern Hemisphere (American) mid-glacial ice sheets on the global climate and the Atlantic Meridional Overturning Circulation (AMOC) as well as the processes by which the ice sheets modify the AMOC. For this purpose, simulations of Marine Isotope Stage (MIS) 3 (36 ka) and 5a (80 ka) are performed with an atmosphere–ocean general circulation model. In the MIS3 and MIS5a simulations, the global average temperature decreases by 5.0 and 2.2 ∘C, respectively, compared with the preindustrial climate simulation. The AMOC weakens by 3 % in MIS3, whereas it strengthens[...]"

 

Source: EGU-European Geosciences Union 
Authors: Sam Sherriff-Tadano et al.
DOI: https://doi.org/10.5194/cp-17-95-2021

Read the full article here.


Antarctic icebergs reorganize ocean circulation during Pleistocene glacials

Abstract.

"The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today1; in the Atlantic basin, deep waters of Southern Ocean origin increased in volume while above them the core of the North Atlantic Deep Water (NADW) shoaled2. An absence of evidence on the origin of this phenomenon means that the sequence of events leading to global glacial conditions remains unclear.[...]"

 

Source: Nature
Authors: Aidan Starr et al.
DOI: https://doi.org/10.1038/s41586-020-03094-7

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.

 

 

 


Ocean Optimism: Moving Beyond the Obituaries in Marine Conservation

Abstract.

"While the ocean has suffered many losses, there is increasing evidence that important progress is being made in marine conservation. Examples include striking recoveries of once-threatened species, increasing rates of protection of marine habitats, more sustainably managed fisheries and aquaculture, reductions in some forms of pollution, accelerating restoration of degraded habitats, and use of the ocean and its habitats to sequester carbon and provide clean energy. Many of these achievements have multiple benefits[...]"

 

Source: Annual Reviews
Authors: Nancy Knowlton
DOI: https://doi.org/10.1146/annurev-marine-040220-101608

Read the full article here.


Impacts of hypoxic events surpass those of future ocean warming and acidification

Abstract.

"Over the past decades, three major challenges to marine life have emerged as a consequence of anthropogenic emissions: ocean warming, acidification and oxygen loss. While most experimental research has targeted the first two stressors, the last remains comparatively neglected. Here, we implemented sequential hierarchical mixed-model meta-analyses (721 control–treatment comparisons) to compare the impacts of oxygen conditions associated with the current and continuously intensifying hypoxic[...]"

 

Source: Nature Ecology and Evolution
Authors: Eduardo Sampaio et al.
DOI: https://doi.org/10.1038/s41559-020-01370-3

Read the full article here.


Methane oxidation in the waters of a humics-rich boreal lake stimulated by photosynthesis, nitrite, Fe(III) and humics

Abstract.

"Small boreal lakes are known to contribute significantly to global methane emissions. Lake Lovojärvi is a eutrophic lake in Southern Finland with bottom water methane concentrations up to 2 mM. However, the surface water concentration, and thus the diffusive emission potential, was low (< 0.5 μM). We studied the biogeochemical processes involved in methane removal by chemical profiling and through incubation experiments. δ13C-CH4 profiling of the water column revealed methane-oxidation hotspots just below the oxycline and within the anoxic water column. In incubation experiments involving the addition of light and/or oxygen, methane oxidation rates in the anoxic hypolimnion were enhanced 3-fold, suggesting a major role for photosynthetically fueled aerobic methane oxidation. A distinct peak in methane concentration was observed at the chlorophyll a maximum[...]"

Source: Biogeoscience
Authors: Sigrid van Grinsven et al.
DOI: https://doi.org/10.5194/bg-2021-3

Read the full article here.


Around one third of current Arctic Ocean primary production sustained by rivers and coastal erosion

Abstract.
 

"Net primary production (NPP) is the foundation of the oceans’ ecosystems and the fisheries they support. In the Arctic Ocean, NPP is controlled by a complex interplay of light and nutrients supplied by upwelling as well as lateral inflows from adjacent oceans and land. But so far, the role of the input from land by rivers and coastal erosion has not been given much attention. Here, by upscaling observations from the six largest rivers and using measured coastal erosion rates, we construct a pan-Arctic[...]"

Source: Nature Communications
Authors: Jens Terhaar et al.
DOI: https://doi.org/10.1038/s41467-020-20470-z

Read the full article here.


The rise of angiosperms strengthened fire feedbacks and improved the regulation of atmospheric oxygen

Abstract.

"The source of oxygen to Earth’s atmosphere is organic carbon burial, whilst the main sink is oxidative weathering of fossil carbon. However, this sink is to insensitive to counteract oxygen rising above its current level of about 21%. Biogeochemical models suggest that wildfires provide an additional regulatory feedback mechanism. However, none have considered how the evolution of different plant groups through time have interacted with this feedback. The Cretaceous Period[...]"

 

Source: Nature Geoscience
Authors: Claire M. Belcher et al.
DOI: https://doi.org/10.1038/s41467-020-20772-2

Read the full article here.


Status and trends of Arctic Ocean environmental change and its impacts on marine biogeochemistry: Findings from the ArCS project

Abstract.

"Ocean observation research theme under ArCS project, “Theme 4: Observational research on Arctic Ocean environmental changes”, aimed to elucidate the status and trends of ongoing Arctic Ocean environmental changes and to evaluate their impacts on Arctic marine ecosystem and the global climate system. For these purposes, we conducted field observations, mooring observations, laboratory experiments, numerical modeling, and international collaborative research focusing on the Pacific Arctic[...]"

 

Source: Science Direct
Authors: Takashi Kikuchi et al.
DOI: https://doi.org/10.1016/j.polar.2021.100639

Read the full article here.


Assimilating synthetic Biogeochemical-Argo and ocean colour observations into a global ocean model to inform observing system design

Abstract.

"A set of observing system simulation experiments was performed. This assessed the impact on global ocean biogeochemical reanalyses of assimilating chlorophyll from remotely sensed ocean colour and in situ observations of chlorophyll, nitrate, oxygen, and pH from a proposed array of Biogeochemical-Argo (BGC-Argo) floats. Two potential BGC-Argo array distributions were tested: one for which biogeochemical sensors are placed on all current Argo floats and one for which biogeochemical sensors are placed on a quarter of current Argo floats. Assimilating BGC-Argo data greatly improved model results throughout the water column[...]"

 

Source: Biogeosciences
Authors: David Ford et al.
DOI: https://doi.org/10.5194/bg-18-509-2021

Read the full article here.


Showing 381 - 390 of 1,186 results.
Items per Page 10
of 119

Newsletter

It is possible to subscribe to our email newsletter list.

Depending on the amount of publications, we will summarize the activities on this blog in a newsletter for everyone not following the blog regularly.

If you want to subscribe to the email list to receive the newsletter, please send an email to sfb754@geomar.de with the header "subscribe".

If you want to unsubscribe from the newsletter, please send an email to sfb754@geomar.de with the header "unsubscribe".

You cannot forward any messages as a regular member to the list. If you want to suggest new articles or would like to contact us because of any other issue, please send an email to sfb754@geomar.de.

GOOD Social Media

To follow GOOD on LinkedIn, please visit here.
 

To follow GOOD on Twitter, please visit here.


To follow GOOD on Blue Sky, please visit here