Reassessment of Seagrass Distribution and Biomass in the Lower Laguna Madre, Texas

Summary

The project will document seagrass distribution and biomass patterns in the Lower Laguna Madre (LLM) and assess recovery of seagrass following the 2010 historic freshet due to Hurricane Alex.  The project will employ the transect method for recording vegetative cover and biomass patterns utilized by Quammen and Onuf (1993) and Onuf (1996, 2007) and will use their sampling sites located by GPS. Biomass sampling and sediment grain size analysis will follow methods of Kowalski et al. (2009) and Folk (1964). Transects will run perpendicular to shore spaced at approximately 5 km intervals. At each sampling site, the presence or absence of seagrass and associated macroalgae will be noted and, where seagrass and/or algae are present, percent cover assessed (N = 4) with 50 cm by 50 cm quadrats and scored using a Braun-Blanquet index for seagrasses (Fourqurean et al. 2002). Four seagrass cores (9 cm diameter by 15 cm deep) will be collected at each site, as well as sediment samples for sediment grain size analysis. Water depth, temperature, salinity, and Secchi depth will be recorded at each site.