Posted by Wayne on January 11, 2002 at 14:28:06:
In Reply to: Hmmm. BBS comments requested here. posted by seahunt on January 11, 2002 at 13:06:50:
Science fair for the kids. But my kids are required by me to do real science and this included some detailed literature review.
Siltiness seemed to be a factor relating to localized kelp growth and this was related to urban runoff and construction activities. Urchins were a factor, but only when the kelp was already in trouble. The advancing line of urchin mowing down entire fields only seems to happen when there is insufficient kelp leaf debris on the sea floor. They appear to prefer this to eating the stalks and holdfasts.
We saw nothing about boat anchors or other man made devices making any difference in the kelp biomass. And we read many scholarly works.
The number one thing that correlated was always Sea Surface Temperature. It is interesting to note that the temperature itself does not kill off the kelp or retard the growth. It is that temperature is a function of upwellings of deep, nutrient-rich water. It is the nutrients from the upwellings that are associated with the growth rates.
For those interested in what we did, we got 50 years worth of weekly data from over 100 locations along the California coast. The kids then got the NOAA SST data for the last 25 years and loaded all of it into a humongous spreadsheet and plotted the relationship at three sites that were near NOAA bouys.
You could clearly see El Nino and La Nina events in both SST and Biomass. Even in the uneventful years the variance in SST and biomass was striking.
So if you love kelp, you gotta love long periods of cold water and lack of rain, storms, and erosive construction near shore.
Wayne