Physical preconditioning of oxygen depletion in shelf seas
"The global ocean dissolved oxygen (DO) inventory is decreasing and the areal extent of DO deficiency is increasing. In the shelf sea BML, net DO removal can occur as a result of restricted ventilation due to seasonal thermal stratification, oxygen consumption via pelagic and benthic respiration of organic matter, and nitrification. DO decline is becoming evident in several shelf seas, with recent model studies estimating that large regions of the Northwest European continental shelf seas (325,000 to 400,000 km2) have the potential to become seasonally deficient in DO in late summer. It is therefore of vital importance that DO is monitored accurately and effectively in shelf seas. [...]"
Source: EGU General Assembly 2020
Authors: Charlotte Williams et al.
UK's lost sea meadows to be resurrected in climate fight
First seagrass restoration in Britain will capture carbon rapidly and offer habitat for lost marine life
“We think this whole bay was once carpeted with seagrass,” says Evie Furness, waving across the sparkling, sunlit waters of Dale Bay in Pembrokeshire, Wales. The underwater meadow is long gone though, a victim of past pollution and shipping. So from a boat half a mile from shore, Furness is feeding a long rope into the water, which carries a little hessian bag of seagrass seeds every metre. “We’ve passed the 800,000 seed mark now,” she says. [...]"
Source: The Guardian
Effects of hypoxia on the behavior and physiology of kelp forest fishes
"Forecasts from climate models and oceanographic observations indicate increasing deoxygenation in the global oceans and an elevated frequency and intensity of hypoxic events in the coastal zone, which have the potential to affect marine biodiversity and fisheries. Exposure to low dissolved oxygen (DO) conditions may have deleterious effects on early life stages in fishes. [...]"
Source: Global Change Biology
Authors: Evan G. Mattiasen et al.
Oceanic and atmospheric methane cycling in the cGENIE Earth system model
"The methane (CH4) cycle is a key component of the Earth system that links planetary climate, biological metabolism, and the global biogeochemical cycles of carbon, oxygen, sulfur, and hydrogen. However, currently lacking is a numerical model capable of simulating a diversity of environments in the ocean where CH4 can be produced and destroyed, and with the flexibility to be able to explore not only relatively recent perturbations to Earth’s CH4 cycle but also to probe CH4 cycling and associated climate impacts under the very low-O2 conditions characteristic of most of Earth history and likely widespread on other Earth-like planets. [...]"
Source: Geoscientific Model Development
Authors: Christopher T. Reinhard et al.
Intermediate water masses, a major supplier of oxygen for the eastern tropical Pacific ocean
"It is well known that Intermediate Water Masses (IWM) are sinking in high latitudes and ventilate the lower thermocline (500–1500 m depth). We here highlight how the IWM oxygen content and the IWM pathway along the Equatorial Intermediate Current System (EICS) towards the eastern tropical Pacific ocean are essential for the supply of oxygen to the lower thermocline and the Oxygen Minimum Zones (OMZs). [...]"
Source: Ocean Science
Authors: Olaf Duteil et al.
Effects of spatial variability on the exposure of fish to hypoxia: a modeling analysis for the Gulf of Mexico
"The hypoxic zone in the northern Gulf of Mexico varies spatially (area, location) and temporally (onset, duration) on multiple scales. Exposure to hypoxic dissolved oxygen (DO) concentrations (< 2 mg L−1) is often lethal and exposure to 2 to 4 mg L−1 often causes the sublethal effects of decreased growth and fecundity on individuals of many fish species. We simulated the movement of individual fish within a high-resolution 3-D coupled hydrodynamic-water quality model (FVCOM-WASP) configured for the northern Gulf of Mexico to examine how spatial variability in DO concentrations would affect fish exposure to hypoxic and sublethal DO concentrations. [...]"
Authors: Elizabeth D. LaBone et al.
Multi-agency report highlights increasing signs and impacts of climate change in atmosphere, land and oceans
"New York / Geneva, 10 March 2020 - The tell-tale physical signs of climate change such as increasing land and ocean heat, accelerating sea level rise and melting ice are highlighted in a new report compiled by the World Meteorological Organization and an extensive network of partners. It documents impacts of weather and climate events on socio-economic development, human health, migration and displacement, food security and land and marine ecosystems. [...]"
Source: World Meteorological Organization (WMO)
Uncovering diversity and metabolic spectrum of animals in dead zone sediments
"Ocean deoxygenation driven by global warming and eutrophication is a primary concern for marine life. Resistant animals may be present in dead zone sediments, however there is lack of information on their diversity and metabolism. Here we combined geochemistry, microscopy, and RNA-seq for estimating taxonomy and functionality of micrometazoans along an oxygen gradient in the largest dead zone in the world. [...]"
Source: Communications Biology
Authors: Elias Broman et al.
Even fish at the bottom of the ocean can’t escape climate change
"The fish that live at the bottom of the sea are a hardy bunch. They’re adapted to handle crushing pressure, little to no sunlight, and a meager supply of food. But these otherwise gritty fish are also very sensitive to changes in the climate of the water around them, a new study suggests.
Scientists surveyed different patches of seafloor in the Gulf of California and saw that variations in temperature and oxygen levels had a huge impact on whether the fish community was thriving or sparse. In particular, the researchers found that one specific combination—warmer waters mixed with low oxygen levels—didn’t bode well for deep sea fish. This means that these creatures are likely to be vulnerable to the impacts of climate change, the researchers reported March 5 in Marine Ecology Progress Series. [...]"
Source: Popular Science
Special issue | Ocean deoxygenation: drivers and consequences – past, present and future (BG/CP/OS inter-journal SI)
Special issue jointly organized between Biogeosciences, Climate of the Past, and Ocean Science.
"The distribution of oxygen in the ocean is controlled by physical, biogeochemical and biological processes. Both the supply and consumption of oxygen are sensitive to climate change in ways that are not fully understood. Recent observations suggest that the oxygen content of the ocean is declining (ocean deoxygenation) and the oxygen minimum zones and costal hypoxia sites are expanding with tremendous effects on the ocean’s ecosystems and living organisms. Following the EUR-OCEANS conference on “Ocean Deoxygenation” in Toulouse, France, in 2011, the 46th International Liège Colloquium on “Low Oxygen Environments in Marine, Fresh and Estuarine Waters” in 2014 and the discussion meeting of the Royal Society London on “Ocean Ventilation and Deoxygenation in a Warming World” in 2016, the purpose of the international conference on “Ocean Deoxygenation: Drivers & Consequences – Past|Present|Future” that took place in Kiel, 3–7 Sept 2018 organised by the Collaborative Research Centre 754 “Climate-Biogeochemical Interactions in the Tropical Ocean” was to − focus on the past, present and future state of oxygen in the ocean on global, regional and local scales − analyse mechanisms and feedbacks critical to identify natural and anthropogenic causes of oxygen variability − determine impacts on biogeochemical cycles and ecosystems. [...]"
The issue is closed as of 29th February 2020. The submissions are listed here.