Posted by Wayne on January 13, 2003 at 20:23:35:
In Reply to: Boring Subject "Sea Urchin" posted by Steve on January 13, 2003 at 13:22:18:
A couple of years ago I assisted one of my daughters in a kelp 'science fair' project. A few things I remember (cause I found them interesting) that were easily found in the literature:
As long as there was leafy debris on the bottom, the urchin never attacked the holdfasts. In other words, as long as the kelp was healthy, the urchins did not harm it.
Only in times of starvation did the urchins march through the forest and decimate it.
The temperature issue was really a function of upwelling. In other words the reason the kelp likes it cold was more about the cold water upwellings which bring in nutrient rich water rather than a direct temperature vs growthrate.
We correlated 50 years of kelp biomass versus sea surface temperature and the correlation is amazing. And the reduction in the el nino years was quite amazine. But as devestating as the warm el nino years are to the total biomass, the recovery was equally amazing in the regular and la nina years. Most of the data we found is easily located with the exception of the biomass data which we managed to get from a friendly biologist who somehow got it from Kelco (Off hand I forget what their name changed to a few years ago).
Did you know, that we stood to lose WW I except for kelp? During the war we lost access to important chemicals needed for explosives. To satisfy the need, the chemicals acetone and potash were extracted from kelp here in California for the war effort. Betcha didn't know that!
Wayne