News
Whole transcriptome analysis of demersal fish eggs reveals complex responses to ocean deoxygenation and acidification
Abstract.
"Ocean acidification and deoxygenation co-occur in marine environments, causing deterioration of marine ecosystems. However, effects of compound stresses on marine organisms and their physiological coping mechanisms are largely unknown. Here, we show how high pCO2 and low dissolved oxygen (DO) cause transcriptomic changes in eggs of a demersal fish (Sillago japonica), which are fully exposed to such stresses in natural environment. Overall gene expression was affected more strongly by low DO than by high pCO2. Enrichment analysis detected significant stress responses such as glycolytic processes in response to low DO. [...]".
Source: Science Direct
Authors: Akira Iguchi et al.
DOI: https://doi.org/10.1016/j.scitotenv.2023.169484
Preprint: Reviews and syntheses: Abrupt ocean biogeochemical change under human-made climatic forcing – warming, acidification, and deoxygenation
Abstract.
"Abrupt changes in ocean biogeochemical variables occur as a result of human-induced climate forcing as well as those which are more gradual and occur over longer timescales. These abrupt changes have not yet been identified and quantified to the same extent as the more gradual ones. We review and synthesise abrupt changes in ocean biogeochemistry under human-induced climatic forcing. We specifically address the ocean carbon and oxygen cycles because the related processes of acidification and deoxygenation provide important ecosystem hazards. [...]".
Source: Biogeosciences
Authors: Christoph Heinze et al.
DOI: https://doi.org/10.5194/bg-2023-182
Marine anoxia initiates giant sulfur-oxidizing bacterial mat proliferation and associated changes in benthic nitrogen, sulfur, and iron cycling...
Full title: "Marine anoxia initiates giant sulfur-oxidizing bacterial mat proliferation and associated changes in benthic nitrogen, sulfur, and iron cycling in the Santa Barbara Basin, California Borderland"
Abstract.
"The Santa Barbara Basin naturally experiences transient deoxygenation due to its unique geological setting in the southern California Borderland and seasonal changes in ocean currents. Long-term measurements of the basin showed that anoxic events and subsequent nitrate exhaustion in the bottom waters have been occurring more frequently [...]".
Source: Biogeosciences
Authors: David J. Yousavich et al.
DOI: https://doi.org/10.5194/bg-21-789-2024
Enhanced ocean deoxygenation in the Bering Sea during MIS 11c
Abstract.
"Accelerated Arctic warming has raised concerns about future environmental conditions in the Bering Sea, one of the world's most productive marine ecosystems. Marine Isotope Stage (MIS) 11 (424–374 ka), a period with orbital parameters similar to those of the current interglacial (Holocene), is thought to be a suitable analog to predict future marine environments. Here, we reconstruct paleoredox changes in the Bering Sea over the last 800 kyr using high-resolution U/Th ratios from four sites, which were sampled by the Integrated Ocean Drilling Program (IODP) Expedition 323. [...]".
Source: Science Direct
Authors: Xuguang Feng et al.
DOI: https://doi.org/10.1016/j.palaeo.2023.111982
Climate, Oxygen, and the Future of Marine Biodiversity
Abstract.
"The ocean enabled the diversification of life on Earth by adding O2 to the atmosphere, yet marine species remain most subject to O2 limitation. Human industrialization is intensifying the aerobic challenges to marine ecosystems by depleting the ocean's O2 inventory through the global addition of heat and local addition of nutrients. Historical observations reveal an ∼2% decline in upper-ocean O2 and accelerating reports of coastal mass mortality events. The dynamic balance of O2 supply and demand provides a unifying framework for understanding these phenomena across scales from the global ocean to individual organisms. [...]".
Source: Annual Review of Marine Science
Authors: Curtis Deutsch et al.
DOI: https://doi.org/10.1146/annurev-marine-040323-095231
Highly active fish in low oxygen environments: vertical movements and behavioural responses of bigeye and yellowfin tunas to oxygen minimum zones...
Full title: "Highly active fish in low oxygen environments: vertical movements and behavioural responses of bigeye and yellowfin tunas to oxygen minimum zones in the eastern Pacific Ocean"
Abstract.
"Oxygen minimum zones in the open ocean are predicted to significantly increase in volume over the coming decades as a result of anthropogenic climatic warming. The resulting reduction in dissolved oxygen (DO) in the pelagic realm is likely to have detrimental impacts on water-breathing organisms, particularly those with higher metabolic rates, such as billfish, tunas, and sharks. [...]".
Source: Springer Nature
Authors: Nicolas E. Humphries et al.
DOI: https://doi.org/10.1007/s00227-023-04366-2
Divergent responses of the coral holobiont to deoxygenation and prior environmental stress
Abstract.
"Ocean deoxygenation is intensifying globally due to human activities – and is emerging as a grave threat to coral reef ecosystems where it can cause coral bleaching and mass mortality. However, deoxygenation is one of many threats to coral reefs, making it essential to understand how prior environmental stress may influence responses to deoxygenation. To address this question, we examined responses of the coral holobiont (i.e., the coral host, Symbiodiniaceae, and the microbiome) to deoxygenation in corals with different environmental stress backgrounds. [...]".
Source: Frontiers in Marine Science
Authors: Sara D. Swaminathan et al.
DOI: https://doi.org/10.3389/fmars.2023.1301474
Redox geochemical signatures in Mediterranean sapropels: Implications to constrain deoxygenation dynamics in deep-marine settings
Abstract.
"Global warming and anthropogenic activity are boosting marine deoxygenation in many regions around the globe. Deoxygenation is a critical ocean stressor with profound implications for marine ecosystems and biogeochemical cycles. Understanding the dynamics and evolution of past deoxygenation events can enhance our knowledge of present-day and future impacts of climate change and anthropogenic pressure on marine environments. Many studies have reconstructed the evolution redox conditions of past deoxygenation events using geochemical proxies. [...]".
Source: Science Direct
Authors: Ricardo D. Monedero-Contreras et al.
DOI: https://doi.org/10.1016/j.palaeo.2023.111953
The past to unravel the future: Deoxygenation events in the geological archive and the anthropocene oxygen crisis
Abstract.
"Despite the observation that we are witnessing a true oxygen crisis, the ocean deoxygenation theme is getting less attention from the media and population compared to other environmental stressors concerning climate change. The current ocean oxygen crisis is characterized by a complex interplay of climatic, biological, and oceanographic processes acting at different time scales. Earth system models offer insights into future deoxygenation events and their potential extent [...]".
Source: Science Direct
Authors: Alan Maria Mancini et al.
DOI: https://doi.org/10.1016/j.earscirev.2023.104664
Interactive effects of ocean deoxygenation and acidification on a coastal fish Sillago japonica in early life stages
Abstract.
"Acidification and deoxygenation are major threats to ocean environments. Despite the possibilities of their co-occurrence, little is known about their interactive effects on marine organisms. The effects of low pH and low dissolved oxygen (DO) on the early life stages of the coastal fish Sillago japonica were investigated. Twenty-five experimental treatments fully crossed in five levels of pH 7.6–8.1 and DO 50–230 μmol/kg (20–100 % saturation degree) were tested, and hatching rate of the embryos and survivability of the larvae after 24 h at 25 °C were investigated. [...]".
Source: Science Direct
Authors: Makiko Yorifuji et al.
DOI: https://doi.org/10.1016/j.marpolbul.2023.115896
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