The soundscape of the Anthropocene ocean
"Oceans have become substantially noisier since the Industrial Revolution. Shipping, resource exploration, and infrastructure development have increased the anthrophony (sounds generated by human activities), whereas the biophony (sounds of biological origin) has been reduced by hunting, fishing, and habitat degradation. Climate change is affecting geophony (abiotic, natural sounds). Existing evidence shows that anthrophony affects marine animals[...]".
Authors: Carlos M. Duarte et al.
Variable coastal hypoxia exposure and drivers across the southern California Current
"Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in dissolved oxygen dynamics and hypoxia exposures can drive differences in vulnerabilities of coastal ecosystems and resources, but documentation of variability at regional scales is rare in open-coast systems. Using a regional collaborative network of dissolved oxygen and temperature sensors maintained by scientists and fishing cooperatives from California, USA, and Baja California, Mexico, we characterize spatial and temporal variability in dissolved oxygen[...]"
Source: Nature Scientific Reports
Authors: Natalie H. N. Low et al.
Ocean Optimism: Moving Beyond the Obituaries in Marine Conservation
"While the ocean has suffered many losses, there is increasing evidence that important progress is being made in marine conservation. Examples include striking recoveries of once-threatened species, increasing rates of protection of marine habitats, more sustainably managed fisheries and aquaculture, reductions in some forms of pollution, accelerating restoration of degraded habitats, and use of the ocean and its habitats to sequester carbon and provide clean energy. Many of these achievements have multiple benefits[...]"
Source: Annual Reviews
Authors: Nancy Knowlton
A Lagrangian study of the contribution of the Canary coastal upwelling to the nitrogen budget of the open North Atlantic
"The Canary Current System (CanCS) is a major eastern boundary upwelling system (EBUS), known for its high nearshore productivity and for sustaining a large fishery. It is also an important but not well quantified source of nitrogen to the adjacent oligotrophic subtropical gyre of the North Atlantic. Here, we use a Lagrangian modeling approach to quantify this offshore transport and investigate its timescales, reach and contribution to the fueling of productivity in the offshore regions. In our Lagrangian model, we release nearly 10 million particles off the northwestern African coast and then track all those that enter the nearshore region and upwell along the coast between 14 and 35∘ N. We then follow them as they are transported offshore, also tracking the biogeochemical[...]"
Authors: Derara Hailegeorgis et al.
Oceanographic processes control dissolved oxygen variability at a commercial Atlantic salmon farm: Application of a real-time sensor network
"Open ocean fish farming involves containment of cultured animals under environmental conditions influenced by seasonal variation and water quality. Recently, an important area of research focus has been on water quality monitoring to improve aquaculture management. The development of novel sensors that report in real-time is critical to improve the monitoring capacity of farms, while increasing the understanding of the dynamics of environmental variables. In this study, commercially available, real-time dissolved oxygen and temperature sensors were distributed in the center of 19 cages at a commercial[...]"
Source: Science Direct
Authors: Meredith Burke et al.
'Dead zone' volume more important than area to fish, fisheries
Dubravko Justic, the Texaco Distinguished Professor in the LSU Department of Oceanography & Coastal Sciences, and Research Associate Lixia Wang recently co-authored a study suggesting that measuring the volume rather than the area of the Gulf of Mexico's dead zone, is more appropriate for monitoring its effects on marine organisms.
"The dead zone, a hypoxic zone, is a region of low oxygen that results from runoff of high nutrients, such as nitrogen and phosphorus, often found in fertilizer, flowing from the Mississippi River into the coastal ocean. It is the largest recurring hypoxic zone in the U.S., occurring most summers, and is located off the coast of Louisiana. This nutrient pollution, coupled with other factors, is believed to have a negative impact on fisheries because it depletes the oxygen required to support most marine life in bottom and near-bottom waters. [...]"
Source: Science Daily
Consequences of climate-induced low oxygen conditions for commercially important fish
"Oxygen availability is key in determining habitat suitability for marine fish. As a result of climate change, low oxygen conditions are predicted to occur more frequently and over a greater geographic extent. Studies assessing the long-term chronic effects and impacts for commercially important fish are rare. To assess the potential effects of climate-induced low oxygen on fisheries, physiological data, such as critical thresholds, derived from laboratory experiments on 5 commercial fish species were integrated with hindcast and future oxygen projections from the hydrodynamic-biogeochemical model GETM-ERSEM. [...]"
Source: Marine Ecology Progress Series (2017)
Authors: Bryony L. Townhill et al.
Hypoxic volume is more responsive than hypoxic area to nutrient load reductions in the northern Gulf of Mexico – and it matters to fish and fisheries
"While impacts of low oxygen on marine organisms have been reviewed from physiological and ecological perspectives, relating broad population- and ecosystem-level effects to the areal extent of hypoxia (dissolved oxygen concentration below 64 µM, or 2 mg/l) has proven difficult. We suggest that hypoxic volume is a more appropriate metric compared to hypoxic area because volume better integrates the effects of hypoxia on ecological processes relevant to many marine taxa. [...]"
Source: IOP Science
Authors: Donald Scavia et al.
Large-scale ocean deoxygenation during the Paleocene-Eocene Thermal Maximum
"The consequences of global warming for fisheries are not well understood, but the geological record demonstrates that carbon cycle perturbations are frequently associated with ocean deoxygenation. Of particular interest is the Paleocene-Eocene Thermal Maximum (PETM), where the carbon dioxide input into the atmosphere was similar to the IPCC RCP8.5 emission scenario. Here we present sulfur-isotope data that record a positive 1 per mil excursion during the PETM. Modeling suggests that large parts of the ocean must have become sulfidic. [...]"
Authors: Weiqi Yao, Adina Paytan, Ulrich G. Wortmann
Changing storminess and global capture fisheries
"Climate change-driven alterations in storminess pose a significant threat to global capture fisheries. Understanding how storms interact with fishery social-ecological systems can inform adaptive action and help to reduce the vulnerability of those dependent on fisheries for life and livelihood."
Source: Nature Climate Change
Authors: Nigel C. Sainsbury et al.