Distribution of Bluegreen Algae in a Mississippi Gulf Coast Salt Marsh1

Edaphic bluegreen algal communities were sampled from five menotypic angiosperm zones in Grvelline Bay Marsh near Ocean Spring. Mississippi. Samples and environmental data were taken on a quarterly basis from October 1976 to June 1977 beneath the following marsh angiosperms: Distichlis spicata (L.) Green, Scirpus olneyi gray, SPartina patens (Aiton) Muhl., Sp. alterniflora Loisel., andJuncus roemerianusScheele. Communities in all five zones were dominated by Schizothrix calcicola (Ag.) Gom. (sensu Drauet) throughout the study, while the subdominant bluegreens varied according to season. The number of individuals in all zones was greatest in the summer and lowest in the winter. An examination of the structure of the five edaphic communities indicated a single, nearly homogeneous community exists over the entire surface of the marsh shaded by a angiosperm canopy. Light intensity appears to be the major factor affecting the distribution of bluegreen algae in this salt marsh.