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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