Productivity and utilization of the seagrass Halodule wrightii and its attached epiphytes1

Abstract

Epiphytic algae growing attached to shoalgrass ( Halodule wrightii ) blades accounted for nearly half of the aboveground live biomass and primary productivity of two seagrass meadows in southern Texas from June–December 1980. They also accounted for the major fraction of recognizable diet material of common seagrass meadow macroinvertebrates, such as grass shrimp ( Palaemonetes ), crabs ( Callinectes ), snails ( Anachis and Bittium ), and amphipods ( Cymadusa ). Significant shading of seagrass by epiphytes did not appear evident at the light intensities normally encountered by these populations. The passage of Hurricane Allen near the area in early August 1980 did not seem to have a major impact on the seagrass meadow, despite wind gusts of 150 kph and storm tides of +3 m.