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Investigating ocean deoxygenation and the oxygen minimum zone in the Central Indo Pacific region based on the hindcast datasets

Abstract. 

"Deoxygenation is increasingly recognized as a significant environmental threat to the ocean following sea temperature rises due to global warming and climate change. Considering the cruciality of the deoxygenation impacts, it is important to assess the current status and predict the future possibility of ocean deoxygenation, for instance, within the Central Indo Pacific (CIP) regions represent climate-regulated marine areas. This study divided CIP into five regions then investigated the deoxygenation parameters (dissolved oxygen, temperature, salinity, and pH) collected from 1993 to 2021 sourced from in situ measurement and long-term hindcast data. [...]".

 

Source: Environmental Monitoring and Assessment
Authors: Karlina Triana et al.
DOI: https://doi.org/10.1007/s10661-022-10615-6

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Seasonal nearshore ocean acidification and deoxygenation in the Southern California Bight

Abstract. 

"The California Current System experiences seasonal ocean acidification and hypoxia (OAH) owing to wind-driven upwelling, but little is known about the intensity, frequency, and depth distribution of OAH in the shallow nearshore environment. Here we present observations of OAH and dissolved inorganic carbon and nutrient parameters based on monthly transects from March 2017 to September 2018 extending from the surf zone to the ~ 40 m depth contour in La Jolla, California. Biologically concerning OAH conditions were observed at depths as shallow as 10 m and as close as 700 m to the shoreline. [...]".

 

Source: Scientific Reports
Authors: Samuel A. H. Kekuewa et al. 
DOI: https://doi.org/10.1038/s41598-022-21831-y

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Physical-chemical factors influencing the vertical distribution of phototrophic pico-nanoplankton in the Oxygen Minimum Zone (OMZ) off Northern Chile

Abstract. 

"The vertical distribution of phytoplankton is of fundamental importance in the structure, dynamic, and biogeochemical pathways in marine ecosystems. Nevertheless, what are the main factors determining this distribution remains as an open question. Here, we evaluated the relative influence of environmental factors that might control the coexistence and vertical distribution of pico-nanoplankton associated with the OMZ off northern Chile. Our results showed that in the upper layer Synechococcus-like cells were numerically important at all sampling stations. [...]". 

 

Source: Science Direct 
Authors: Edson Piscoya et al.
DOI: https://doi.org/10.1016/j.marenvres.2022.105710

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A double-edged sword: The role of sulfate in anoxic marine phosphorus cycling through Earth history

Abstract. 

"Modern anoxic marine sediments release phosphorus (P) to seawater, driving feedbacks at multiple timescales. On sub-Myr timescales, anoxic P regeneration amplifies ocean deoxygenation; on multi-Myr timescales, it stabilizes atmospheric O2. Some authors have extended this thinking to the Precambrian: by analogy, widespread ocean anoxia would imply extensive P regeneration from sediments. However, this neglects the role of sulfate in P regeneration. [...]".

 

Source: Geophysical Research Letters
Authors: Michael A. Kipp
DOI: https://doi.org/10.1029/2022GL099817

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A Depth-Transect of Ocean Deoxygenation During the Paleocene-Eocene Thermal Maximum: Magnetofossils in Sediment Cores From the Southeast Atlantic

Abstract. 

"The Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma) presents a past analog for future global warming. Previous studies provided evidence for major loss of dissolved oxygen during the PETM, although understanding the degree and distribution of oxygen loss poses challenges. Magnetofossils produced by magnetotactic bacteria are sensitive to redox conditions in sediments and water columns, and have been used to reconstruct paleoredox conditions over a range of geological settings. [...]".

 

Source: JGR Solid Earth
Authors: Pengfei Xue et al.
DOI: https://doi.org/10.1029/2022JB024714

Read the full article here.


Ocean biogeochemical modelling

Abstract. 

"Ocean biogeochemical models describe the ocean’s circulation, physical properties, biogeochemical properties and their transformations using coupled differential equations. Numerically approximating these equations enables simulation of the dynamic evolution of the ocean state in realistic global or regional spatial domains, across time spans from years to centuries. This Primer explains the process of model construction and the main characteristics, advantages and drawbacks of different model types, from the simplest nutrient–phytoplankton–zooplankton–detritus model to the complex biogeochemical models used in Earth system modelling and climate prediction. [...]".

 

Source: Nature Reviews Methods Primers 
Authors: Katja Fennel et al.
DOI: https://doi.org/10.1038/s43586-022-00154-2 

Read the full article here.


Impact of warming and deoxygenation on the habitat distribution of Pacific halibut in the Northeast Pacific

Abstract. 

"Ocean warming and deoxygenation are already modifying the habitats of many aerobic organisms. Benthic habitat in the Northeast Pacific is sensitive to deoxygenation, as low oxygen concentrations occur naturally in continental shelf bottom waters. Here, we examine the potential impacts of deoxygenation and ocean warming on the habitat distribution of Pacific halibut (Hippoglossus stenolepis), one of the most commercially important groundfish in North America. [...]".

 

Source: Wiley Online Library  
Authors: Ana C. Franco et al.
DOI: https://doi.org/10.1111/fog.12610

Read the full article here.


Ventilation changes drive orbital-scale deoxygenation trends in the late Cretaceous ocean

Abstract. 

"Mechanisms that drive cyclicity in marine sediment deposits during hothouse climate periods in response to Earth’s orbit variations remain debated. Orbital cycles fingerprint in the oceanographic records results from the combined effect of terrestrial (e.g. weathering-derived nutrient supply, freshwater discharge) and oceanic (e.g. productivity, oxygenation) processes, whose respective contribution remains to be clarified. [...]".

 

Source: Geophysical Research Letters
Authors: Anta-Clarisse Sarr et al.
DOI: https://doi.org/10.1029/2022GL099830

Read the full article here.


Uranium isotope reconstruction of ocean deoxygenation during OAE 2 hampered by uncertainties in fractionation factors and local U-cycling

Abstract. 

"A δ238U record of changing ocean anoxia during OAE 2 is reconstructed using seawater derived U in pelagic marine sediments in the Portland #1 core in the south-central region of the Western Interior Seaway of North America. The peak negative excursion of 1.4‰ in authigenic sedimentary δ238U values is consistent with expansion of marine anoxia during the event, but the size of the shift is much larger than the negative excursions recorded in two other published records. [...]". 

 

Source: Science Direct 
Authors: Brayden S. McDonald et al.
DOI: https://doi.org/10.1016/j.gca.2022.05.010

Read the full article here.


Geochemical evidence from the Kioto Carbonate Platform (Tibet) reveals enhanced terrigenous input and deoxygenation during the early Toarcian

Abstract.

"The early Toarcian, as registered in a variety of sedimentary archives, was characterized by an abrupt negative carbon-isotope excursion (CIE) typically superimposed on a long-term positive trend, and was accompanied by significant climatic and environmental changes. However, the changes in continental weathering influx and oceanic deoxygenation in shallow waters and their possible role in causing carbonate-platform crises in low latitudes remains poorly constrained. [...]".

 

Source: Science Direct 
Authors: Zhong Han et al.
DOI: https://doi.org/10.1016/j.gloplacha.2022.103887

Read the full article here.


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