As a marine ecologist, I am interested in the trophic interactions
between primary producers and their consumers. Interactions between
the giant kelp, Macrocystis pyrifera, and its grazers
is a subject well studied in southern California, but greatly
overlooked in central California. However, an understanding of
the strength of trophic interactions is essential to determine
the overall dynamics of the kelp forest community.
Studies of grazing on the giant kelp Macrocystis pyrifera
have mainly focused on conspicuous herbivores such as abalone
and urchins that can devour entire kelp forests. The purpose of
my study is to evaluate how the most abundant kelp forest herbivore
in central California, the turban snail Tegula, affects
the productivity, reproductive output, and survivorship of Macrocystis
pyrifera within central Californian giant kelp forests. Three
Tegula species, T. montereyi, T. pulligo, and T.
brunnea, preferentially graze Macrocystis in this
region. The effects of these grazers will be investigated using
experimental field manipulations of Macrocystis sporophytes
at two central California locations, Stillwater Cove, Carmel and
Monterey Bay Aquarium (MBA), Monterey. By comparing ten treatment
levels of Macrocystis (sporophytes stocked with a gradient
of lesser to greater densities of T. pulligo), differences in
growth rate, sporophyll production, and mortality can be analyzed.
This project will represent the first study of grazing on whole-sporophyte
physiology in central California. The research will also increase
the understanding of the interactions between the three Tegula
subtidal species and their preferred food source, Macrocystis
pyrifera. With this information, conclusions may be drawn
regarding the importance these intermediate-sized predators have
in regulating kelp density and what role they may have in the
overall health of Macrocystis pyrifera over time.
