Tropical Atlantic climate and ecosystem regime shifts during the Paleocene–Eocene Thermal Maximum
"The Paleocene–Eocene Thermal Maximum (PETM, 56 Ma) was a phase of rapid global warming associated with massive carbon input into the ocean–atmosphere system from a C-depleted reservoir. Many midlatitude and high-latitude sections have been studied and document changes in salinity, hydrology and sedimentation, deoxygenation, biotic overturning, and migrations, but detailed records from tropical regions are lacking. [...]"
Source: Climate of the Past
Authors: Joost Frieling et al.
Oceans suffocating as huge dead zones quadruple since 1950, scientists warn
Areas starved of oxygen in open ocean and by coasts have soared in recent decades, risking dire consequences for marine life and humanity
"Ocean dead zones with zero oxygen have quadrupled in size since 1950, scientists have warned, while the number of very low oxygen sites near coasts have multiplied tenfold. Most sea creatures cannot survive in these zones and current trends would lead to mass extinction in the long run, risking dire consequences for the hundreds of millions of people who depend on the sea. [...]"
Source: The Guardian
Declining oxygen in the global ocean and coastal waters
"Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. [...]"
Authors: Denise Breitburg et al.
Multifarious anchovy and sardine regimes in the Humboldt Current System during the last 150 years
"The Humboldt Current System (HCS) has the highest production of forage fish in the world, although it is highly variable and the future of the primary component, anchovy, is uncertain in the context of global warming. Paradigms based on late 20th century observations suggest that large-scale forcing controls decadal-scale fluctuations of anchovy and sardine across different boundary currents of the Pacific. We develop records of anchovy and sardine fluctuations since 1860 AD using fish scales from multiple sites containing laminated sediments and compare them with Pacific basin-scale and regional indices of ocean climate variability. [...]"
Source: Global Change Biology
Authors: Renato Salvatteci et al.
Evaluating the promise and pitfalls of a potential climate change–tolerant sea urchin fishery in southern California
"Marine fishery stakeholders are beginning to consider and implement adaptation strategies in the face of growing consumer demand and potential deleterious climate change impacts such as ocean warming, ocean acidification, and deoxygenation. This study investigates the potential for development of a novel climate change-tolerant sea urchin fishery in southern California based on Strongylocentrotus fragilis (pink sea urchin), a deep-sea species whose peak density was found to coincide with a current trap-based spot prawn fishery (Pandalus platyceros) in the 200–300-m depth range. [...]"
Source: ICES Journal of Marine Science
Authors: Kirk N Sato et al.
Deep oceans may acidify faster than anticipated due to global warming
"Oceans worldwide are undergoing acidification due to the penetration of anthropogenic CO2 from the atmosphere. The rate of acidification generally diminishes with increasing depth. Yet, slowing down of the thermohaline circulation due to global warming could reduce the pH in the deep oceans, as more organic material would decompose with a longer residence time. [...]"
Source: Nature Climate Change
Authors: Chen-Tung Arthur Chen
Read the full article here.
Ocean deoxygenation – a climate-related problem
"Many take for granted low oxygen as “just another water-quality issue”. Excessive loads of nutrients from non-point and point sources, including sewage, enter aquatic ecosystems where they increase biological oxygen demand and promote eutrophic conditions that can lead to periods of hypoxia or anoxia (in coastal areas somewhat misnamed as “dead zones”). [...]"
Source: Frontiers in Ecology and the Environment
Authors: Karin E Limburg, Denise Breitburg, Lisa A Levin
Ocean acidification could doom key Arctic fish species: study
Ocean acidification combined with warming of the world oceans and loss of oxygen is having a severe impact on key Arctic marine species such as polar cod in the Barents Sea, according to a new study conducted by German scientists.
"The eight-year interdisciplinary study, which began in 2009 and involved more than 250 scientist in the German research network on ocean acidification BIOACID (Biological Impacts of Ocean Acidification), investigated how different marine species respond to ocean acidification – a change in the ocean chemistry that occurs when carbon dioxide (CO2) from the atmosphere dissolves in seawater.
In addition to ocean acidification, the study, Exploring Ocean Change: Biological Impacts of Ocean Acidification, also examined the cascading effect of other stressors such as ocean warming, deoxygenation, overfishing and eutrophication – the increased concentration of nutrients in estuaries and coastal waters that causes harmful algal blooms, ocean dead zones and fish kills. [...]"
Source: The Independent Barents Observer
Sound physiological knowledge and principles in modeling shrinking of fishes under climate change
"One of the main expected responses of marine fishes to ocean warming is decrease in body size, as supported by evidence from empirical data and theoretical modeling. The theoretical underpinning for fish shrinking is that the oxygen supply to large fish size cannot be met by their gills, whose surface area cannot keep up with the oxygen demand by their three-dimensional bodies. [...]"
Source: Global Change Biology
Authors: Daniel Pauly, William W. L. Cheung
Using fuzzy logic to determine the vulnerability of marine species to climate change
"Marine species are being impacted by climate change and ocean acidification, although their level of vulnerability varies due to differences in species' sensitivity, adaptive capacity and exposure to climate hazards. Due to limited data on the biological and ecological attributes of many marine species, as well as inherent uncertainties in the assessment process, climate change vulnerability assessments in the marine environment frequently focus on a limited number of taxa or geographic ranges. [...]"
Source: Global Change Biology
Authors: Miranda C. Jones, William W. L. Cheung