Synergistic effects of ocean acidification and warming on overwintering
pteropods in the Arctic
«
Pteropods in Peril» is not the stuff of headlines, nor have Fabry's findings grabbed our attention like the plight of the polar bears.
Not exact matches
But Fabry found that
in water as corrosive as their aquatic habitat may be
in 2100, the shell of at least one
pteropod species turns opaque and begins to dissolve.
To gauge how acidification might be affecting the Pacific, biological oceanographer Nina Bednaršek of the National Oceanic and Atmospheric Administration (NOAA)
in Seattle and colleagues collected
pteropods at 13 sites during a 2011 research cruise between Washington and southern California.
The same year, researchers reported that
pteropods collected at one site
in the Southern Ocean around Antarctica showed signs of shell damage.
The shells of marine snails known as
pteropods, an important link
in the marine food web, are already dissolving.
The acidification of oceans may well be the most insidious and pervasive threat to life
in the oceans everywhere, simply because so many different plants and animals that play key roles
in ecosystems will likely be affected — coccolithophores,
pteropods, corals, mollusks (clams, mussels, oysters, snails), echinoderms (urchins, seastars), arthropods (lobsters, crabs, shrimp), etc., etc..
«The primary sources of calcium carbonate for deep sea sediments are pelagic calcitic coccolithophores and foraminifera that grow dominantly
in the phototic zone (typically upper 100 m) and to a lesser extent aragonitic
pteropods.
Decreasing the amount of carbonate ions
in the water makes conditions more difficult for both calcite users (phytoplankton, foraminifera and coccolithophore algae), and aragonite users (corals, shellfish,
pteropods and heteropods).
Fifty - three percent of all
pteropods sampled
in the coastal region using a fine mesh net had severely dissolved shells.
During a survey
in August 2011 along a stretch of the continental shelf from northern Washington to southern California, researchers found a high percentage of
pteropods with dissolving shells.
The photos show what happens to a
pteropod's shell
in seawater that is too acidic.
Orr 2005 lamented rising atmospheric CO2 would reduce
pteropod habitat and survival, leading to ecosystem collapse
in polar regions.
And although tropical waters are the most supersaturated and the most unlikely to promote shell dissolution,
pteropods are least abundant
in those tropical waters.
As
pteropod skeletons are aragonite based, it is unlikely that
pteropods will be able to adapt quickly enough to survive
in the Southern Ocean.
Of far greater concern than corals
in particular is the ocean food chain
in general, because while acidification will probably result
in more oceanic dead zones as the amount of CO2 goes up and the amount of oxygen falls, if you kill off the plankton and
pteropods that use carbonate to make their shells, then you kill off the food supply for the vast majority of higher organisms (like mollusks, fish, and even marine mammals).
It shows an empty
pteropod shell dissolving over 45 days
in water purportedly as it would be
in the year 2100; presumably pH 7.9 bicarbonate (they don't say).
Yeah, not so good:
In addition to
pteropods, report co-author Fiona McLaughlin told Reuters that mussels and clams on the sea floor could also be affected.
Here's a not so comforting discovery: A new paper
in Science magazine says that Arctic sea ice melting is starting to dilute surface waters and threatening the tiny shellfish called
pteropods that are the base of the Arctic food chain.