Ed Ricketts Memorial Lecture
Michael S. Foster
Moss Landing Marine Laboratories
The Biology of Giant Kelp: Implications for Kelp Forests and Beyond
The distribution and abundance of organisms is the dynamic outcome of interactions between their life histories and biological requirements, and the environment. This is especially obvious in plants that cannot pull up their holdfasts and swim away to avoid unfavorable conditions. Thus plant population dynamics, combined with knowledge of their biology, can be used to understand environmental change from the inside out. Giant kelp (Macrocystis pyrifera) is an especially good indicator of conditions in the nearshore ecosystem as it samples from the bottom to the surface at scales from microns to kilometers, responds relatively rapidly to variation in substrate, sedimentation, light, nutrients and wave forces, and the responses can be assessed remotely.
The efficacy of using giant kelp as an indicator is shown by a re-analysis of the extent and causes of kelp forest declines in southern California beginning in the 1940s. Declines were primarily in two large, mainland kelp forests and the patterns of decline reflected increases in sedimentation, reduction in benthic light, and increases in toxic chemicals from sewage discharge and coastal development. Low nutrients and high temperatures during the 1957-9 El Niño caused additional losses. The forests began to recover in the 1960s - 1970s with improvements in sewage management but complete recovery has not occurred due to habitat loss and likely continued sedimentation and impaired water quality. This and other examples illustrate how giant kelp populations can inform about past and present environmental change. They also show that from giant kelp's point of view marine reserves with more and bigger fish are fine, but successful management largely depends on maintaining benthic and water quality.
About Michael S. Foster
Mike Foster's interest in marine science began in 1964 while an undergraduate in the Spring Course at Hopkins Marine Station. This led to a Ph.D. from UC Santa Barbara in 1972, and 30 years as a professor at Moss Landing Marine Laboratories. His primary research interest is the population and community ecology of macroalgae. His research has ranged across many habitats and themes, including the causes of intertidal zonation, the structure and organization of kelp and rhodolith communities, and the impacts of oil spills and thermal discharges from power plants on temperate reefs.
Mike has been a Fulbright Scholar in Mexico, and is a Fellow of the California Academy of Sciences. His interests in understanding nature continue to be inspired by his early mentors and friends Michael Neushul and Isabella A. Abbott, the enthusiasm and abilities of his students and colleagues, and the magnificence of seaweeds.