BENTHIC FORAMINIFERS AS INDICATORS OF ENVIRONMENTAL STRESS IN NORTHERN LAGUNA MADRE, TEXAS

Northern Laguna Madre is a large hypersaline lagoon extending from Corpus Christi Bay to Baffin Bay along the South Texas coast. The body of water is shallow with a depth of approximately two meters, and it is heavily stressed by both natural and anthropogenic factors. The natural conditions are extreme ranges in temperature, salinity and dissolved oxygen. Anthropogenic activities include boating and shipping along the Intracoastal Waterway, and an electrical power plant on the western shore. The purpose of this research is to study the foraminiferal response in this stressed environment. Replicate cores were taken from four stations on an east-west transect closer to and farther away from the power plant. The foraminiferal populations were sampled from the top two centimeters of the cores. Aside from numerous poorly preserved allogromiids, only three species of foraminifers were observed: Ammonia parkinsoniana, Elphidium gunteri and Quinqueloculina seminula jugosa. These species are generally present in low numbers as compared to other estuaries in the area, though densities increase towards the western shore closer to the plant intake. High percentages of Ammonia, ranging from an average of 3.45% to 22.93%, are observed to have dissolved shells or some form of morphological deformities. Statistical analyses show that populations are significantly different among stations, and the numbers of Ammonia are the reason for this difference. This study documents low abundance and abnormal tests of foraminifers from Northern Laguna Madre. Future sampling of populations will provide continued habitat monitoring.