Abstract. 

"When an organism makes a long-distance transition to a new habitat, the associated environmental change is often marked and requires physiological plasticity of larvae, juveniles, or other migrant stages. Exposing shallow-water marine bivalves (Aequiyoldia cf. eightsii) from southern South America (SSA) and the West Antarctic Peninsula (WAP) to changes in temperature and oxygen availability, we investigated changes in gene expression in a simulated colonization experiment of the shores of a new continent after crossing of the Drake Passage, and in a warming scenario in the WAP. [...]".

Source: Frontiers
Authors: Mariano Martínez et al.
DOI: https://doi.org/10.3389/fphys.2023.1083240

Read the full article here.

Abstract. 

"Bottom waters of the northeast Pacific continental shelf naturally experience localized hypoxic conditions, with significant influences on food webs and biogeochemical cycling. In August 2021, extreme hypoxia was detected from several measurement platforms along the southern British Columbia continental shelf, with oxygen concentration <60 μmol kg⁻¹, and a difference from the seasonal climatology of more than 2 standard deviations. Early and intense remote upwelling and local density shifts were associated with an anomalously strong spring phytoplankton bloom, which likely stimulated localized respiration of subsurface organic matter. [...]".

Source: Wiley Online Library 
Authors: Ana C. Franco et al.
DOI: https://doi.org/10.1029/2022GL101857

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Abstract. 

"The prevalence and frequency of hypoxia events have increased worldwide over the past decade as a consequence of global climate change and coastal biological oxygen depletions. On the other hand, anthropogenic emissions of CO2 and consequent accumulation in the sea surface result in a perturbation of the seawater carbonate system, including a decrease in pH, known as ocean acidification. While the effect of decreases in pH and dissolved oxygen (DO) concentration is better understood, their combined effects are still poorly resolved. [...]". 

Source: Science Direct 
Authors: Murat Belivermiş et al.
DOI: https://doi.org/10.1016/j.marpolbul.2023.114602

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Abstract. 

"Benthic species are exposed to oxygen fluctuations that can affect their performance and survival. Physiological effects and ecological consequences of fluctuating oxygen are not well understood in marine bioturbators such as the soft-shell clam Mya arenaria. We explored the effects of different oxygen regimes (21 days of exposure to constant hypoxia (~4.1 kPa PO2), cyclic hypoxia (~2.1–~10.4 kPa PO2) or normoxia (~21 kPa PO2)) on energy metabolism, oxidative stress and ecological behaviors (bioirrigation and bioturbation) of M. arenaria. Constant hypoxia and post-hypoxic recovery in cyclic hypoxia led to oxidative injury of proteins and [...]".

Source: Science Direct 
Authors: Natascha Ouillon et al.
DOI: https://doi.org/10.1016/j.scitotenv.2022.160459

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Abstract.

"The continuous expansion of the oxygen minimum zone (OMZ) is a microcosm of marine hypoxia problem. Based on a survey in M4 seamount area of Tropical Western Pacific Ocean, the effects of thermodynamic parameters on OMZ were discussed. The study showed thermodynamic parameters mainly affect the upper oxycline of OMZ. The increase in temperature aggravates seawater stratification, which not only shallows oxycline but also increases the strength of DO stratification, promoting the expansion of OMZ. [...]".

Source: Science Direct 
Authors: Jun Ma et al. 
DOI: https://doi.org/10.1016/j.marpolbul.2023.114579

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Abstract. 

"Sedimentary molybdenum (Mo) and uranium (U) enrichments are widely used to reconstruct changes in bottom water oxygen conditions in aquatic environments. Until now, most studies using Mo and U have focused on restricted suboxic-euxinic basins and continental margin oxygen minimum zones (OMZs), leaving mildly reducing and oxic (but eutrophic) coastal depositional environments vastly understudied. Currently, it is unknown: (1) to what extent Mo and U enrichment factors (Mo- and U-EFs) can accurately reconstruct oxygen conditions in coastal sites experiencing mild deoxygenation, and (2) to what degree secondary [...]". 

Source: Science Direct 
Authors: K. Mareike Paul et al.
DOI: https://doi.org/10.1016/j.chemgeo.2022.121203

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Abstract.

"The deep-sea is rapidly losing oxygen, with profound implications for marine organisms. Within Eastern Boundary Upwelling Systems, such as the California and the Benguela Current Ecosystems, an important question is how the ongoing expansion, intensification and shoaling of Oxygen Minimum Zones (OMZs) will affect deep-sea fishes throughout their lifetimes. One of the first steps to filling this knowledge gap is through the development of tools and techniques to track fishes’ exposure to hypoxic (<45 μmol kg-1), low-temperature (∼4–10°C) and low-pH (∼7.5) waters when inhabiting OMZs. [...]".

Source: Science Direct 
Authors: Leticia Maria Cavole et al.
DOI: https://doi.org/10.1016/j.dsr.2022.103941

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Call for paper manuscripts

We would like to draw your attention to a new collection on ocean hypoxia in Scientific Reports.

The paper manuscript submission deadline is 4 April 2023.

For further information about the call, visit: https://www.nature.com/collections/bgdgcgahcf/. 

Abstract. 

"Ocean deoxygenation could potentially trigger substantial changes in the composition and reactivity of dissolved organic matter (DOM) pool, which plays an important role in the global carbon cycle. To evaluate links between DOM dynamics and oxygen availability, we investigated the DOM composition under varying levels of oxygen in a seasonally hypoxic fjord through a monthly time-series over two years. We used ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to characterize DOM on a molecular level. [...]".

Source: Science Direct 
Authors: Xiao Chen et al.
DOI: https://doi.org/10.1016/j.watres.2022.118690

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Abstract. 

"Coastal hypoxia—harmfully low levels of oxygen—is a mounting problem that jeopardizes coastal ecosystems and economies. The northern Indian Ocean is particularly susceptible due to human-induced impacts, vast naturally occurring oxygen minimum zones, and strong variability associated with the seasonal monsoons and interannual Indian Ocean Dipole (IOD). We assess how natural factors influence the risk of coastal hypoxia by combining a large set of oxygen measurements with satellite observations to examine how the IOD amplifies or suppresses seasonal hypoxia tied to the Asian Monsoon. We show that on both seasonal and interannual timescales hypoxia is controlled by wind- and coastal Kelvin wave-driven upwelling of oxygen-poor waters onto the continental shelf and reinforcing biological feedbacks (increased subsurface oxygen demand). [...]".

Source: Global Biogeochemical Cycles
Authors: Jenna Pearson et al.
DOI: https://doi.org/10.1029/2021GB007192

Read the full article here.