Posted on CBC News: 17 Jul 2012 — Vancouver Island researchers use artificial tide pools to study threat
UBC marine biologist Chris Harley says it is ‘highly likely’ we are in a period of mass extinction. (CBC)
The Pacific Ocean is growing more acidic at a much faster rate than anticipated, scientists say, putting everything from corals to mussels in jeopardy.
Researchers say carbon dioxide from the atmosphere forms carbonic acid in the ocean, changing the seawater enough that it can dissolve the shells of coral and shellfish.
The water off the west coast of Vancouver Island is changing at an unprecedented rate, meaning vulnerable life forms in the ocean’s food chain must adapt or die.
UBC PhD student Kathryn Anderson says sea urchins are one of the many species extremely sensitive to the changes now underway.
“It’ll hit the larval stage, it’ll hit the fertilization stage, it’ll hit the adult stage,” she said.
“Urchins are going to be hit from many different angles … this is stuff that we do know. Urchins will be highly negatively impacted.”
Tidal pools along the coast are home to a complex web of life, with dozens of species dependent on each other.
“All the species we look at interact pretty tightly with each other,” Anderson said.
“A single species may be affected less directly by ocean acidification, but because another species that it consumes or consumes it is highly affected by ocean acidification, that can cascade down the food web, through connections of competition and affect the entire community structure.
“People are only just starting to even consider these concepts.”
‘A spectacular environment’
As ocean acidification continues, some species will die off and others will grow faster, creating an imbalance in the food chain.
Pisaster, or starfish, grow faster and eat more in response to ocean acidification, while its main food source, mussels, grow slower. (CBC)
“Our top predator, the pisaster [a starfish], is pretty interesting,” she said.
“It has calcium carbonate in it but mostly in the form of spicules, and the research from our lab actually found that pisaster grow faster in response to ocean acidification and consume more.
“And this is an interesting problem because their main food source are mussels, which grow slower in response to ocean acidification. So they’re becoming more voracious carnivores, while their food source is having a harder time calcifying and growing.”
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