Mangrove forests occupy around 105 km2 worldwide, and cover 75 percent of the tropical and subtropical coastlines of the Americas (Field 1995). These highly productive ecosystems are involved in the global carbon cycle and are traditionally viewed as large exporters of carbon, although limited work has been done to quantify carbon export from tropical mangrove ecosystems. Sedimentary organic matter is inputted into the mangrove forest from terrestrial, mangrove and marine sources that can be traced using the stable isotopic signatures of carbon, nitrogen and sulfur. This study investigates nutrient cycling in mangrove forest sediments by comparing sedimentary stable isotopic values with those from terrestrial, mangrove and marine plants in a variety of mangrove ecosystems on the Yucatan Peninsula, Mexico (Dittmar, Lara et al. 2001; Kendall, Silva et al. 2001). By investigating the role of these organic matter sources and their direct contribution to sedimentary organic matter, it is possible to evaluate anthropogenic impacts on nutrient cycling within the mangrove ecosystem. Anthropogenic impacts on coastal areas are a growing concern in the face of global warming, so it is important to determine how these systems will respond.

Dittmar, T., R. J. Lara, et al. (2001). “River or mangrove? Tracing major organicmatter sources in tropical Brazilian coastal waters.” Marine Chemistry 73: 253-271.

Field, C. (1995). “Impact of expected climate change on mangroves.” Hydrobiologia 295: 75-81.

Kendall, C., S. R. Silva, et al. (2001). “Carbon and Nitrogen isotopic compositions of particulate organic matter in four river systems across the United States.” Hydrological proceses 15: 1301-1346.