They share many of the same qualities as old growth forests, but the only way to really appreciate these magnificent places is through the lens of a diving mask. Sometimes encompassing several miles of area with towering vegetation, thick canopies, and abundant wildlife, these underwater forests are unfamiliar destinations for the average weekend hiker. In the May issue of Ecological Monographs, researchers from the Scripps Institution of Oceanography at the University of California San Diego (UCSD) investigate the demography of one of earth's largest underwater kelp forests.
Within the Point Loma kelp forest community off the coast of San Diego, researchers have been conducting long term ecological kelp studies over three decades. The goal of their research is to evaluate the roles of large-scale, low frequency oceanographic processes on the demography patterns of the area's most conspicuous species of kelp. These processes range from seasonal climate variability to episodic nutrient-rich La Ninas and warm water, nutrient-poor El Ninos.
"As expected, we found considerable differences in the habitat adaptations of the specific kelps over large temporal and spatial scales," says marine ecologist Paul Dayton from UCSD. "Standard experiments of the type that ecologists often do at small scales give different results under different oceanographic climate conditions."
By repeating experiments over an extended period of time and in different areas,
researchers were able to observe certain changes within the community that occur
from episodic shifts in nutrients and temperature. For instance, during the
nine-year study, Macrocystis species were not affected by competitive effects
from other species of kelp. On the other hand, Pterygophora californica, an
important understory species, exhibited reduced growth and reproduction by the
light-limited conditions and competition with Macrocystis during La Nina periods
when Macrocystis thrived. When El Nin
Contact: Alison Gillespie
Ecological Society of America