Incremento de nitrógeno en Thalassia testudinum por el aporte de nitrógeno disuelto inorgánico de aguas residuales durante precipitaciones extraordinarias

The Mexican Caribbean reef lagoons are oligotrophic ecosystems, where residual water discharges (RWD) associated with tourist activity to groundwater aquifer systems supply additional dissolved inorganic nitrogen (DIN) to these lagoons. The contribution of DIN can be exacerbated in years with extraordinary precipitation (> 2500 mm in 2013) in the Mexican Caribbean. Thalassia testudinum seagrass is characterized by a nitrogen content < 2 % dry weight. If the DIN flow increases in exceptional rainfall, it is expected that the content of nitrogen in T. testudinum will increase with respect to the historical average precipitation (1200 mm) of the last 30 years. In the present work the nitrogen content in T. testudinum is quantified in order to determine changes associated with the RWD during the dry and rainy season from 2010 to 2016 in Akumal Bay. The nitrogen content in the leaves of T. testudinum was quantified in an elemental analyzer. In the years of 2010, 2012, 2015 and 2016 the nitrogen content in T. testudinum was similar between dry and rainy season. In the years of 2013 and 2014, the nitrogen content was higher in the rainy season with respect to the dry season. This evidence suggests that in periods of extraordinary rainfall, the flow of DIN to the coastal lagoons of the Caribbean increases, making this nitrogen available to the seagrass T. testudinum.