Friday, October 13, 2006

Who or what stirs the ocean?

Is it possible that paddling feet, fins, and flukes do more to mix ocean waters than big winds and currents? Maybe.

This surprising answer may force us to rethink how oceans work.

Tiny paddling krill do more to mix ocean waters than all other forces combined in a recent Canadian study. The krill feed near the ocean surface at night, then swim down deep during the day (presumably to hide). The swimming swarm moves enough water to win the ocean mixing contest.

Now oceanographers are ready with a whole new set of questions, like what about the passage of big whales or schools of fish--do they leave a changed ocean in their wake? And does overfishing reduce ocean productivity by slowing down nutrient transport?

This reminds me of the revolution in thinking that followed the discovery that salmon swimming upstream to spawn and die are a major source of nutrients for the growth of their offspring. Now we all accept that salmon fertilize tiny headwater streams and are a major source of nutrient transport from ocean depths to mountain ecosystems. Ocean-derived nutrients have been found in plants and bears on hilltops, and in wine made from grapes grown along salmon streams.

Science is now renewing ancient wisdom...krill can move an ocean.

Photo: Edgar, 1997 from

1 comment:

Anonymous said...

I like the question about overfishing. Our actions can have so many unforseeable side-effects. I'm excited to see what studies come up on that. The ocean is such a beautiful place, we really have to be careful.