Spatial configuration of seagrass community attributes in a stressed coastal lagoon, southeastern Gulf of Mexico

Terminos Lagoon is the largest coastal lagoon in the southern Gulf of Mexico and is a highly biodiverse and productive system that supports important seagrasses. These key habitats are under significant stress due to anthropic activities around and inside the lagoon. Considering the lack of updated information about their distribution, cover, and ecological condition, the objectives of this study were to assess the current morphological and seascape conditions of seagrass meadows in Terminos Lagoon and to evaluate their morphological changes in almost one decade (2010-2018). We combined remote sensing and fieldwork to assess environmental parameters (sea surface temperature and a light attenuation index), quantify seascape metrics, evaluate morphometric variables of seagrasses, and quantify organic carbon budgets. Three species of seagrasses (Thalassia testudinum, Syringodium filiforme and Halodule wrightii)were distributed in the lagoon and showed the highest densities and cover in sheltered zones, where shallow and more transparent water conditions occurred. In general, the seascape-cover diversity was regularly distributed in the study area, with the highest meadow connectivity mainly along the inner littoral region of the island. While the values we recorded for T. testudinum leaf length (X? = 18.6 cm), shoot densities (X? = 249.5 m?2)and total biomass (X? = 195.2 g DW m?2)were consistent with other recent studies, they were lower compared with other coastal systems in southeastern Gulf of Mexico and different between 2010 and 2018 in the lagoon, presumably associated with strong anthropic influences in the region. Finally, we provide a spatially explicit baseline information on morphology, seascape configuration and the first sensitivity map for one of the most important coastal lagoons in Mexico.