`Declining algae threatens ocean food chain`

The algae in the oceans has declined over the last century which threatens ocean food chain.

Updated: Jul 29, 2010, 10:03 AM IST

Paris: A century-long decline in tiny algae
called phytoplankton could disrupt the global ocean food
chain, including the human consumption of fish, according to a
study released on Thursday.

The microscopic organisms -- which prop up the pyramid of
marine animal life from shrimps to killer whales -- have been
disappearing globally at a rate of one per cent per year,
researchers reported.

Since 1950, phytoplankon mass has dropped by about 40
per cent, most likely due to the accelerating impact of global
warming, they reported.

"Phytoplankton is the fuel on which marine ecosystems
run," said lead author Daniel Boyce, a professor at Dalhousie
University in the Canadian province of Nova Scotia.
"A decline affects everything up the food chain,
including humans."

The pace of the decline -- heaviest in polar and tropical
regions -- matched the rate at which surface ocean
temperatures have increased as a result of climate change, the
study said.

Like all plants, phytoplankton need sunlight and
nutrients to grow.

But warmer oceans become more stratified, creating a
"dead zone" at the surface in which fewer nutrients are
delivered from deeper layers.