The distribution of Macrocystis integrifolia in British Columbia as related to environmental parameters

Abstract

The general distribution of the brown alga Macrocystis integrifolia Bory in British Columbia is related to seasonal seawater temperatures and salinities. This species is restricted to regions having little seasonal variation of seawater temperature and salinity or regions where the lower salinities occur during the winter. Locally, Macrocystis distribution is restricted to moderately wave-exposed areas or areas subjected to appreciable tidal currents, provided solid substrate is available. The vertical distribution is usually determined by substrate availability and sea urchins. Macrocystis blade morphology varies regularly with wave exposure. However, transplant studies indicate that this may, in part, be genetically determined and thus may not be a plastic phenotypic response.