Nutrient dynamics in coastal lagoons and marine waters of Vieques, Puerto Rico.

Determining the efficacy of efforts to conserve natural systems requires that environmental baseline data exist; without such baseline data, it is impossible to determine if management actions are working. This study presents water quality baseline data (nutrients) for the coastal waters of the island of Vieques, Puerto Rico. As the island's economy shifts more towards tourism, these data can be used to verify that conservation efforts to preserve the ecology of the coastal waters are succeeding. Surface waters were sampled at 40 sites, selected using a stratified random sampling design, on 7 occasions between July 2007 and March 2008. Nutrient concentrations were similar to what has been observed in other systems in Puerto Rico, except for in the near coastal lagoons which had significantly higher observed concentrations. Variations in nutrients between lagoons are driven by connectivity to the ocean and lagoon depth. Because of these relationships, and because there are no obvious major sources of point or non-point sources of pollution on the island that would affect only the lagoons, it is hypothesized that these high nutrient levels are the natural status of the system, rather than evidence of eutrophication.