Tags: Climate Change, Changes in Alaska Marine Ecosystems, Ocean Acidification
In its recent ocean news update, SeaWeb summarized several articles from the June 18, 2010, issue of Science related to the effects of ocean warming.
Absorption of carbon dioxide and heat - the scale and pace of change in chemical and physical conditions have set in motion a wide range of biological responses, including:
**Changes in the distribution, abundance, and productivity of phytoplankton communities
**Acidification and stratification of the ocean
**Decrease in annual productivity by at least six percent since the early 1980s with nearly 70 percent of this decline occurring in the polar and subpolar regions
**Rising temperatures in polar regions are reducing ice thickness and extent, removing habitat for species from polar bears to penguins and fundamentally altering marine ecosystems.
**Warming waters are prompting a poleward shift in the distribution of a number of species, resulting in an increase in the number of invasive or exotic species, including pathogens. (Hoegh-Guldberg and Bruno)
**Ocean pH is lower now than it has been in 20 million years. (Kerr)
**The rate of ocean pH is unprecedented, a factor of 30 to 100 times faster than changes in the recent geological past, and perturbations will last many centuries to millennia. (Doney)
**Some marine species may benefit from higher CO2 levels such as phytoplankton, seagrass, and seaweed species that increase their rate of photosynthesis. (Doney) MORE >>
The evidence of climate change presented for Alaska's seas at the 2010 AMSS included effects of both warmer years than on average and colder years than on average as well as evidence that different areas and species will respond differently to climate change. MORE >>
A research team at the NOAA NMFS Auke Bay Lab explored the physiological effects of acidification on marine fishes with an experiment to determine the effects of lowered pH on survival and growth of Pacific herring embryos. MORE >>
Tags: Ocean Acidification, Climate Change, Noise in the Ocean
Researchers realized that human-made carbon dioxide not only warms and acidifies the ocean -- it also affects acoustical properties of seawater, making it more transparent to low-frequency sound. MORE >>
A new study has yielded surprising findings about how the shells of marine organisms might stand up to an increasingly acidic ocean in the future. Under very high experimental CO2 conditions, the shells of clams, oysters, and some snails and urchins partially dissolved. But other species seemed as if they would not be harmed, and crustaceans, such as lobsters, crabs, and prawns, appeared to increase their shell-building. MORE >>
Two scientific journal articles published in November, 2009, related the extent of sea ice melt to undersaturation of aragonite which is required for shell-building by many plankton and invertebrate species in Arctic waters. A combination of processes are now working to increase acidification and lower the concentrations of forms of calcite used for shell-building:
**increased carbon dioxide in the ocean from anthropogenic sources,
**freshening and dilution as ice melts,
**increased biological activity after the ice melts which takes up calcite from surface waters and depletes it in subsurface waters as organic matters decays and produced CO2, and
**upwellings of low pH waters. MORE >>
The Arctic Ocean is becoming acidic so quickly that it will reach corrosive levels within 10 years, a leading scientist has warned. Waters around the North Pole are absorbing carbon dioxide at such a rate that they will soon start dissolving the shells of living sea creatures. MORE >>
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