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CONTAMINANTS PLAY A KEY ROLE IN UNDERSTANDING ECOSYSTEM FUNCTION IN TROPICAL URBAN ESTUARIES.
Citation:
Oczkowski, A., I. Cappielo Cosme, M. Molina, Alana Hanson, M. Schwartz, E. Huertas, AND D. Katz. CONTAMINANTS PLAY A KEY ROLE IN UNDERSTANDING ECOSYSTEM FUNCTION IN TROPICAL URBAN ESTUARIES. Association for Tropical Biology and Conservation, 58th Annual Meeting, NA, Cartagena, COLOMBIA, July 10 - 14, 2022.
Impact/Purpose:
Here we will present basic information on the water quality of the San Juan Bay Estuary in Puerto Rico. We are trying to understand how urban runoff is impacting the downstream estuary and have measured a range of ecological (nutrients, turbidity), microbial (fecal indicator bacteria), and geochemical (caffeine and sucralose) parameters to begin to identify spatial variability in influence. This presentation will introduce the preliminary results of this study.
Description:
Tropical urban estuaries are understudied and researchers often apply conceptual frameworks of ecosystem function developed for temperate systems to tropical ones. But it is becoming increasingly clear that the ecosystem dynamics driving tropical estuaries are different from temperate systems. Given concerns about human impacts on urban coastal waters and the dearth of tropical biogeochemical research, this study looked for indicators of human influence on the biogeochemistry and productivity of the San Juan Bay Estuary (SJBE) in San Juan, Puerto Rico. We observed a mismatch between high counts of fecal indicator bacteria (fecal coliform and Enterococci) but low dissolved inorganic nitrogen (N) concentrations and stable isotope values in SJBE waters. Sucralose and caffeine concentrations also indicated high human sewage loads. Very low N stable isotope values in the most urbanized stretches suggest that, despite bacterial and chemical indicators of extensive sewage contamination, the microbial community may be adding new N. Sewage N contributions may support only a small portion of the net ecosystem production and urban carbon contributions may be indirectly fueling ecosystem production in the most impacted regions of the estuary.
