News

Climatic Changes in North Atlantic O2 Amplified by Temperature Sensitivity of Phytoplankton Growth

Abstract.

"Ocean warming is associated with a decline in the global oxygen (O2) inventory, but the ratio of O2 loss to heat gain is poorly understood. We analyzed historical variability in temperature (T), O2, and nitrate (N⁢O3−) in hydrographic observations and model simulations of the North Atlantic, a relatively well-sampled region that is important for deep ocean ventilation. Multidecadal fluctuations of O2 concentrations in subpolar thermocline waters (100–700 m) are correlated with changes in their heat content, with a slope 35% steeper than that expected from thermal solubility. [...]".

 

Source: Wiley Online Library
Authors: Andrew J. Margolskee et al.
DOI: https://doi.org/10.1029/2023GB007930

Read the full article here.


Depth Variance of Organic Matter Respiration Stoichiometry in the Subtropical North Atlantic and the Implications for the Global Oxygen Cycle

Abstract.

"Climate warming likely drives ocean deoxygenation, but models still cannot fully explain observed declines in oxygen. One unconstrained parameter is the oxygen demand per carbon respired for complete remineralization of organic matter (i.e., the total respiration quotient, rΣ-O2:C). Here, we tested if rΣ-O2:C declined with depth by quantifying suspended concentrations of particulate organic carbon (POC), particulate organic nitrogen (PON), particulate organic phosphorus (POP), particulate chemical oxygen demand (PCOD), and total oxygen demand (Σ-O2 = PCOD + 2PON) down to a depth of 1,000 m in the Sargasso Sea. [...]".

 

Source: Wiley Online Library
Authors: Skylar D. Gerace et al. 
DOI: https://doi.org/10.1029/2023GB007814

Read the full article here.


Preprint: Hypoxia also occurs in small highly turbid estuaries: the example of the Charente (Bay of Biscay)

Abstract.

"The French coast facing the Bay of Biscay (north-east Atlantic) is characterised by the presence of small macrotidal and turbid estuaries, including the Charente, geographically located between the two large estuaries of the Gironde and the Loire (south-west France). Multi-year, multi-site, high-frequency water quality surveys have shown that the Loire, and to a lesser extent the Gironde, suffer from summer hypoxia. These observations raised the question of the possible occurrence of hypoxia, particularly in one of these small estuaries, the Charente, which flows into the Bay of Marennes-Oléron, the first oyster-producing area in France. [...]".

 

Source: Biogeosciences
Authors: Sabine Schmidt & Ibrahima I. Diallo
DOI: https://doi.org/10.5194/bg-2023-150

Read the full article here.


Subpolar gyre decadal variability explains the recent oxygenation in the Irminger Sea

Abstract. 

"Accurate monitoring of the long-term trend of oxygen content at global scale requires a better knowledge of the regional oxygen variability at interannual to decadal time scale. Here, we combined the Argo dataset and repeated ship-based sections to investigate the drivers of the oxygen variability in the North Atlantic Ocean, a key region for the oxygen supply into the deep ocean. We focus on the Labrador Sea Water in the Irminger Sea over the period 1991–2018 and we show that the oxygen solubility explains less than a third of the oxygen variability. [...]".

 

Source: Nature
Authors: Charlène Feucher et al.
DOI: https://doi.org/10.1038/s43247-022-00570-y

Read the full article here.


Authigenic uranium deposition in the glacial North Atlantic: Implications for changes in oxygenation, carbon storage, and deep water-mass geometry

Abstract.

"Oxygen in the ocean has essential ecological and climatic functions, and can be an important indicator of deep-ocean ventilation and carbon storage. Previous studies are divided on whether the subsurface North Atlantic, which today is well-oxygenated, had higher or lower oxygen levels during the Last Glacial Maximum (LGM). Crucially, the limited number of previous reconstructions precludes any conclusions regarding basin-wide patterns in past changes in oxygenation. [...]".

 

Source: Science Direct 
Authors: Yuxin Zhou & Jerry F. McManus
DOI: https://doi.org/10.1016/j.quascirev.2022.107914

Read the full article here.


A global viral oceanography database (gVOD)

Abstract.

"Virioplankton are a key component of the marine biosphere in maintaining diversity of microorganisms and stabilizing ecosystems. They also contribute greatly to nutrient cycles/cycling by releasing organic matter after lysis of hosts. In this study, we constructed the first global viral oceanography database (gVOD) by collecting 10 931 viral abundance (VA) data and 727 viral production (VP) data, along with host and relevant oceanographic parameters when available. Most VA data were obtained in the North Atlantic (32 %) and North Pacific (29 %) oceans, while the southeast Pacific[...]"

 

Source: Earth System Science Data 
Authors: Le Xie et al.
DOI: https://doi.org/10.5194/essd-13-1251-2021

Read the full article here.


Acceleration of ocean warming, salinification, deoxygenation and acidification in the surface subtropical North Atlantic Ocean

Abstract.

"Ocean chemical and physical conditions are changing. Here we show decadal variability and recent acceleration of surface warming, salinification, deoxygenation, carbon dioxide (CO2) and acidification in the subtropical North Atlantic Ocean (Bermuda Atlantic Time-series Study site; 1980s to present). Surface temperatures and salinity exhibited interdecadal variability, increased by ~0.85 °C (with recent warming of 1.2 °C) and 0.12, respectively, while dissolved oxygen levels decreased by ~8% (~2% per decade).[...]"

 

Source: Nature - Communications Earth and Environment
Authors: Nicholas Robert Bates et al.
DOI: https://doi.org/10.1038/s43247-020-00030-5

Read the full article here.


Contrasting decadal trends of subsurface excess nitrate in the western and eastern North Atlantic Ocean

Abstract.

"Temporal variations in excess nitrate (DINxs) 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 DINxs 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 DINxs concentrations have increased over the last 2 decades. [...]"

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

Read the full article here.


Modulation of the North Atlantic deoxygenation by the slowdown of the nutrient stream

Abstract.

"Western boundary currents act as transport pathways for nutrient-rich waters from low to high latitudes (nutrient streams) and are responsible for maintaining midlatitude and high-latitude productivity in the North Atlantic and North Pacific. This study investigates the centennial oxygen (O2) and nutrient changes over the Northern Hemisphere in the context of the projected warming and general weakening of the Atlantic Meridional Overturning Circulation (AMOC) in a subset of Earth system models included in the CMIP5 catalogue. In all models examined, the Atlantic warms faster than the Pacific Ocean, resulting in a greater basin-scale solubility decrease. [...]"

Source: Biogeosciences
Authors: Filippos Tagklis et al.
DOI: 10.5194/bg-17-231-2020

Read the full article here.


Deep-Water Dynamics in the Subpolar North Atlantic at the End of the Quaternary

Abstract.

"In the subpolar North Atlantic, four sediment cores were taken. All of them were suitable for reconstructing the dynamics of the meridional overturning circulation in the late Quaternary. Stratigraphy of the cores was performed by carbonate analyses, study of planktonic foraminifera, and oxygen isotopic composition in Neogloboquadrina pachyderma sin. Study of benthonic foraminifera assemblages has shown significant differences in the deep-water dynamics in the late Quaternary related to water exchange between the North Atlantic and Arctic seas. [...]"

Source: Oceanology
Authors: N.P. Lukashina
DOI: 10.1134/S0001

Read the full article here.


Showing 1 - 10 of 14 results.
Items per Page 10
of 2

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