BENTHIC SUPERHEROES: ESTUARINE FORAMINIFERA FACE ENVIRONMENTAL ELEMENTS

Studies of living foraminiferal assemblages provide a wealth of information about their roles in present environments and additional perspective for interpretation of the past. In modern coastal settings, foraminifera act as ecological barometers in their responses to different conditions such as food availability, oxygen, salinity, and trace metals. A detailed survey of foraminiferal populations was undertaken in the Mission-Aransas National Estuarine Research Reserve (MANERR), Texas, close to the time of its establishment in 2006. The purpose of the study was to gauge the overall status of populations and provide baseline data for future comparison. Located in an arid climate, the south Texas Gulf Coast is a prime example of a varying and often harsh environment. Biota face extremes in temperature and precipitation along with multiple anthropogenic stressors. Despite these rigors, living foraminifera are flourishing in the MANERR. This paper discusses the results from Mission, Mesquite, and Copano Bays, secondary and tertiary bays in the reserve. Populations are robust in each bay, with highest numbers corresponding to areas of greater circulation. Ubiquitous framboidal pyrite in the sediment and in shells does suggest that foraminifera are frequently subject to low oxygen conditions. Elemental analysis of shell composition was prompted by presence of sulfur in sediments and by yellow tests, and showed presence of barium, strontium, and iron. Healthy living numbers, tolerance of low oxygen conditions, and the ability to cycle elements emphasize the resilience of foraminifera in taxing environments and their integral position as lower trophic level community members.