NUTRIENT AND METAL TRANSPORT THROUGH OCEAN WATER, PORE WATER, AND THE SEDIMENTARY PROFILE OF THE LAGUNA MADRE, TEXAS

The Laguna Madre is one of three large hypersaline lagoons in the world. The Laguna Madre has an average depth of ~2.5 feet, making it unique amongst the large hypersaline lagoons. While the movement of nutrients and metals has become understood in other ecosystems, little is understood about this movement in the Laguna Madre ecosystem. Cores were taken starting from the shoreline and taken 2 meters apart moving landward along a transect and analyzed for nitrate, nitrite, phosphorus, ammonia, silica, and manganese. Ocean water and pore water samples were also gathered and analyzed. These preliminary studies have shown a general increase in concentrations of nitrate, nitrite, ammonia, phosphorus, and silica from the shoreline moving landward and a decrease in manganese concentrations along the same path (Cavazos and Dirrigl 2012). Another study has shown that there is a pathway for arsenic that moves from sea grasses to shore flies and finally to tiger beetles (Hernandez and Dirrigl 2010). This study will focus on the lateral movement of selected nutrients and metals though the stratigraphic profile, and how this movement affects the accumulation of nutrients and metals in selected biota of the Laguna Madre.

• Hernandez, A. and F. Dirrigl. 2010. Arsenic Uptake in the Ephydridae (Insecta: Diptera) and Cicindelidae(Insecta: Coletoptera) of the Laguna Madre, Texas. HESTEC 2010.
• Cavazos, A. and F. Dirrigl. 2012. Nutrient and metal transport and fate in water, pore water, sediments, and selected biota of the Laguna Madre, Texas. TAS 2012