News

Decreased oxygen levels could present hidden threat to marine species

"Scientists have shown that creatures which develop in hypoxic (low oxygen) conditions in the marine environment could experience previously unseen hindered development, and become compromised as adults. [...]

The prevalence of hypoxic (low oxygen) areas in coastal waters is predicted to increase in the future, both in terms of their scale and duration. And while the adults of many estuarine invertebrates can cope with short periods of hypoxia, it has previously been unclear whether that ability is present if animals are bred and reared under chronic hypoxia.[...]"

Source: Sciencedaily.com (University of Plymouth)

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Short-term acclimation in adults does not predict offspring acclimation potential to hypoxia

Abstract.

"The prevalence of hypoxic areas in coastal waters is predicted to increase and lead to reduced biodiversity. While the adult stages of many estuarine invertebrates can cope with short periods of hypoxia, it remains unclear whether that ability is present if animals are bred and reared under chronic hypoxia. We firstly investigated the effect of moderate, short-term environmental hypoxia (40% air saturation for one week) on metabolic performance in adults of an estuarine amphipod, and the fitness consequences of prolonged exposure. [...]"

Source: Scientific Reports
Authors: Manuela Truebano et al.
DOI: 10.1038/s41598-018-21490-y

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Fleet of sailboat drones could monitor climate change’s effect on oceans

"Two 7-meter-long sailboats are set to return next month to California, after nearly 8 months tacking across the Pacific Ocean. Puttering along at half-speed, they will be heavy with barnacles and other growth. No captains will be at their helms.

That is not because of a mutiny. These sailboats, outfitted with sensors to probe the ocean, are semiautonomous drones, developed by Saildrone, a marine tech startup based in Alameda, California, in close collaboration with the National Oceanic and Atmospheric Administration (NOAA) in Washington, D.C. The voyage is the longest test for the drones and also the first science test in the Pacific—an important step in showing that they could replace an aging and expensive array of buoys that are the main way scientists sniff out signs of climate-disrupting El Niño events. [...]"

Source: Science Magazine

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A missing link in the estuarine nitrogen cycle?: Coupled nitrification-denitrification mediated by suspended particulate matter

Abstract.

"In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus on suspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world. [...]"

Source: Scientific Reports
Authors: Weijing Zhu et al.
DOI: 10.1038/s41598-018-20688-4

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Distribution of planktonic biogenic carbonate organisms in the Southern Ocean south of Australia: a baseline for ocean acidification impact assessment

Abstract.

"The Southern Ocean provides a vital service by absorbing about one-sixth of humankind's annual emissions of CO2. This comes with a cost – an increase in ocean acidity that is expected to have negative impacts on ocean ecosystems. The reduced ability of phytoplankton and zooplankton to precipitate carbonate shells is a clearly identified risk. The impact depends on the significance of these organisms in Southern Ocean ecosystems, but there is very little information on their abundance or distribution."

Source: Biogeosciences
Authors: Thomas W. Trull et al.
DOI: 10.5194/bg-15-31-2018

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Community composition in mangrove ponds with pulsed hypoxic and acidified conditions

Abstract.

"The potential resilience of biological communities to accelerating rates of global change has received considerable attention. We suggest that some shallow aquatic ecosystems, where temperature, dissolved oxygen (DO), and pH can exhibit extreme variation on short timescales of hours or days, provide an opportunity to develop a mechanistic understanding of species persistence and community assembly under harsh environmental conditions.  [...]"

Source: Ecosphere (ESA journal)
Authors: Keryn B. Gedan et al.
DOI: 10.1002/ecs2.2053

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Physiological and ecological implications of ocean deoxygenation for vision in marine organisms

Abstract.

"Climate change has induced ocean deoxygenation and exacerbated eutrophication-driven hypoxia in recent decades, affecting the physiology, behaviour and ecology of marine organisms. The high oxygen demand of visual tissues and the known inhibitory effects of hypoxia on human vision raise the questions if and how ocean deoxygenation alters vision in marine organisms.  [...]"

Source: Philosophical Transactions of the Royal Society A
Authors: Lillian R. McCormick, Lisa A. Levin
DOI: 10.1098/rsta.2016.0322

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Oyster reproduction is compromised by acidification experienced seasonally in coastal regions

Abstract.

"Atmospheric carbon dioxide concentrations have been rising during the past century, leading to ocean acidification (OA). Coastal and estuarine habitats experience annual pH variability that vastly exceeds the magnitude of long-term projections in open ocean regions. Eastern oyster (Crassostrea virginica) reproduction season coincides with periods of low pH occurrence in estuaries, thus we investigated effects of moderate [...] and severe OA [...] on oyster gametogenesis, fertilization, and early larval development successes. [...]"

Source: Scientific Reports
Authors: Myrina Boulais et al.
DOI: 10.1038/s41598-017-13480-3

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Ocean Acidification More Rapid in Coastal Oceans

"New research under the joint NCCOS Competitive Research Program and NOAA Ocean Acidification Program finds the combined effects of anthropogenic and biological carbon dioxide (CO2) inputs may lead to more rapid acidification in Chesapeake Bay and other coastal water compared to the open ocean. The results indicate that eutrophication can exacerbate ocean acidification (OA) where animal and plant respiration contributes a far greater acidification in the coastal oceans relative to the open ocean. [...]"

Source: The National Centers for Ciastal Ocean Science

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Projections of climate-driven changes in tuna vertical habitat based on species-specific differences in blood oxygen affinity

Abstract.

"Oxygen concentrations are hypothesized to decrease in many areas of the ocean as a result of anthropogenically driven climate change, resulting in habitat compression for pelagic animals. The oxygen partial pressure, pO2, at which blood is 50% saturated (P50) is a measure of blood oxygen affinity and a gauge of the tolerance of animals for low ambient oxygen. Tuna species display a wide range of blood oxygen affinities (i.e., P50 values) and therefore may be differentially impacted by habitat compression as they make extensive vertical movements to forage on subdaily time scales. [...]"

Source: Global Change Biology
Authors: K. A. S. Mislan et al.
DOI: 10.1111/gcb.13799

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