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Thursday, December 07, 2006

Global Warming kills plankton

Extracts from
Ocean Warming Withers Food Chain
by Larry O'Hanlon for Discovery News

Dec. 7, 2006 — Almost ten years of unprecedented color satellite imagery of Earth’s oceans has now made one thing crystal clear: When the water gets warmer, ocean life declines.

The orbiting Sea-viewing Wide Field-of-view Sensor (SeaWiFS) has been collecting data on the colors of the oceans since 1997. That global data, combined with detailed ocean temperature data, shows an undeniable connection between the vibrancy of phytoplankton — the microscopic plants that anchor the ocean food web — and the temperature of the water, scientists announced on Wednesday.

"On a global scale there’s a very strong correlation between climate and ocean plants," said Michael Behrenfeld, an ocean plant ecologist at Oregon State University in Corvallis. "(Phytoplankton) are very sensitive to changes in climate."

The climate connection in the oceans is hugely important, Behrenfeld explained, because phytoplankton is the food of the animals that, in turn, are the mainstay of the fish we eat.

What’s more, the tiny green plants are also a gigantic player in fighting the rise in the greenhouse gas carbon dioxide in our atmosphere. It’s estimated that ocean plants account for about half the Earth’s capacity to absorb carbon dioxide, he said.

The problem is that when the surface waters are dramatically warmer than the waters deeper down, there's a lot less mixing of waters up and down. This hurts the phytoplankton because it’s the deeper cold waters that contain the nutrients they need to thrive.

"This is incredibly important to life on Earth as we know it," commented Oscar Schofield, an aquatic biologist at Rutgers University.

Not only do ocean plants feed fish and eat carbon dioxide, he pointed out, they also create much of the oxygen that we breathe. That’s why everyone should be very interested in how climate change affects the oceans.

The consequent shifts in food for local ocean wildlife are expected to be dramatic and could have a disastrous effect on fisheries.

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At 1:08 PM, Anonymous Anonymous said...

12/14/06 I have thought a lot about this article since you posted it. My two passions (after family of course), sailing and diving put me in direct contact with the ocean on a weekly basis. SCUBA diving especially has allowed me to see a life, world really, that seems to exist completely independent from our lives above water. Of course that's not true as we are one gigantic ecosystem dependent on many factors that we all share.

Since you posted this article I have heard 1) a talk on NPR how global warming is negatively impacting the ability of crocodiles (an indicator species) in the Okavanga Delta to maintain their male population, 2) that the polar bear population in the Arctic is in crisis due to thinning ice, and 3) that the Arctic Sea may be melted away by 2040.

When I hear how we humans may be negatively impacting our beloved oceans and earth it fills me with great despair and sadness.


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