News

Limited iodate reduction in shipboard seawater incubations from the Eastern Tropical North Pacific oxygen deficient zone

Abstract.

"The relative abundance of the inorganic iodine species, iodide and iodate, are applied to characterize both modern and ancient marine oxygen deficient zones (ODZs). However, the rates and mechanisms responsible for in situ iodine redox transformations are poorly characterized, rendering iodine-based redox reconstructions uncertain. Here, we provide constraints on the rates and mechanisms of iodate reduction in the Eastern Tropical North Pacific (ETNP) offshore ODZ using a shipboard tracer–incubation method. Observations of iodate reduction from incubations[...]"

 

Source: Science Direct
Authors: D.S. Hardisty et al.
DOI: https://doi.org/10.1016/j.epsl.2020.116676

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The role of environmental factors in the long-term evolution of the marine biological pump

Abstract.

"The biological pump—the transfer of atmospheric carbon dioxide to the ocean interior and marine sediments as organic carbon—plays a critical role in regulating the long-term carbon cycle, atmospheric composition and climate. Despite its centrality in the Earth system, the response of the biological pump to biotic innovation and climatic fluctuations through most stages of Earth’s history has been largely conjectural. Here we use a mechanistic model of the biological carbon pump to revisit the factors controlling the transfer efficiency of carbon from surface waters to the ocean interior and marine sediments[...]".

 

Source: Nature Geoscience 
Authours: Mojtaba Fakhraee et al.
DOI: https://doi.org/10.1038/s41561-020-00660-6

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Oceanographic processes control dissolved oxygen variability at a commercial Atlantic salmon farm: Application of a real-time sensor network

Abstract.

"Open ocean fish farming involves containment of cultured animals under environmental conditions influenced by seasonal variation and water quality. Recently, an important area of research focus has been on water quality monitoring to improve aquaculture management. The development of novel sensors that report in real-time is critical to improve the monitoring capacity of farms, while increasing the understanding of the dynamics of environmental variables. In this study, commercially available, real-time dissolved oxygen and temperature sensors were distributed in the center of 19 cages at a commercial[...]"

 

Source: Science Direct
Authors: Meredith Burke et al.
DOI: https://doi.org/10.1016/j.aquaculture.2020.736143

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Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment

Abstract.

"In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics – namely production, consumption, and net emissions – is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climate-active trace gases including methane (CH4) and nitrous oxide (N2O). The temporal and spatial distributions of CH4 and N2O are controlled by the interaction of complex biogeochemical and physical processes. To evaluate and quantify how these mechanisms affect marine CH4 and N2O cycling requires a combination of traditional scientific disciplines including oceanography, microbiology, and numerical modeling[...]"

Source: Biogeosciences
Authors: Samuel T. Wilson et al.
DOI: https://doi.org/10.5194/bg-17-5809-2020

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Early deglacial CO2 release from the Sub-Antarctic Atlantic and Pacific oceans

Abstract.

"Over the last deglaciation there were two transient intervals of pronounced atmospheric CO2 rise; Heinrich Stadial 1 (17.5-15 kyr) and the Younger Dryas (12.9-11.5 kyr). Leading hypotheses accounting for the increased accumulation of CO2 in the atmosphere at these times invoke deep ocean carbon being released from the Southern Ocean and an associated decline in the global efficiency of the biological carbon pump. Here we present new deglacial surface seawater pH and CO2sw records from the Sub-Antarctic regions of the Atlantic [...]"

 

Source: Science Direct
Autors: R. Shuttleworth et al.
DOI: https://doi.org/10.1016/j.epsl.2020.116649

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Seasonal variability of Air-Sea Fluxes in two contrasting basins of the north Indian Ocean

Abstract.

"Latent Heat Flux (LHF) and Sensible Heat Flux (SHF) are the two important parameters in air-sea interactions and hence have significant implications for any coupled ocean-atmospheric model. These two fluxes are conventionally computed from met-ocean parameters using bulk aerodynamic formulations; or the Coupled Ocean Atmosphere Response Experiment (COARE) bulk flux algorithms. Here COARE 3.5 algorithm is used to estimate the heat flux from two Ocean Moored Buoy Network for northern Indian Ocean[...]"

 

Source: Science Direct
Authors: Samar Kumar Ghose et al.
DOI: https://doi.org/10.1016/j.dynatmoce.2020.101183

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Organic matter composition and heterotrophic bacterial activity at declining summer sea ice in the central Arctic Ocean

Abstract.

"The Arctic Ocean is highly susceptible to climate change as evidenced by rapid warming and the drastic loss of sea ice during summer. The consequences of these environmental changes for the microbial cycling of organic matter are largely unexplored. Here, we investigated the distribution and composition of dissolved organic matter (DOM) along with heterotrophic bacterial activity in seawater and sea ice of the Eurasian Basin at the time of the record ice minimum in 2012. Bacteria in seawater were highly responsive to fresh organic matter and remineralized on average 55% of primary production in the upper mixed layer. Correlation analysis showed that the accumulation of dissolved combined carbohydrates (DCCHO) and dissolved[...]"

 

Source: Association for the Sciences Limnology and Oceanography
Authors: Judith Piontek et al.
DOI: https://doi.org/10.1002/lno.11639

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An ice–climate oscillatory framework for Dansgaard–Oeschger cycles

Abstract.

"Intermediate glacial states were characterized by large temperature changes in Greenland and the North Atlantic, referred to as Dansgaard–Oeschger (D–O) variability, with some transitions occurring over a few decades. D–O variability included changes in the strength of the Atlantic meridional overturning circulation (AMOC), temperature changes of opposite sign and asynchronous timing in each hemisphere, shifts in the mean position of the Intertropical Convergence Zone and variations in atmospheric CO2[...]"

 

Source: Nature Reviews Earth and Environment
Authors: Laurie C. Menviel et al.
DOI: https://doi.org/10.1038/s43017-020-00106-y

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New Webinar Series on Ocean Deoxygenation

New Webinar Series on Ocean Deoxygenation
Do you want to know more about deoxygenation in the ocean?
Join us for the upcoming webinar!

The Global Ocean Oxygen Network (IOC Expert Working Group GO2NE) starts a new series on ocean deoxygenation. The first webinar will take place 11 November 2020. The speakers will present latest science on the impacts of reduced oxygen in the open ocean and coastal zones. Each webinar will feature two presentations by a more senior and an earlier-career scientist, 20 minutes each followed by 10 minutes moderated discussion sessions.

When? Wednesday, 11th November 2020, 14:00 h – 15:00 h CET

To register please click here.