Biological Communities of the South Texas Continental Shelf

A multi-disciplinary study of the south Texas continental shelfin 1975–1977 investigated physical, chemical, geological,and biological characteristics over spatial and temporal scales,and the results are briefly summarized here. Chlorophyll a concentrationsand zooplankton density and biomass showed reductions relatedto distance from shore. These factors also displayed north-southgradients and correlations with surface salinities. Bottom sedimentsgraded seaward from fine sands nearshore to silts and clayson the outer shelf. Coarser sediments were associated with geologicand physical features such as ancestral deltas and wave action.Benthic populations were distributed in relation to sedimenttype, but other features such as depth, bottom water variability/stability,and primary production in the overlying waters were also importantin determining benthic community structure. The study providesa baseline for future process-oriented investigations and environmentalassessments.