HR: 16:15h
AN: H44A-04    [Abstracts]
TI: Using Stable Isotopes to Link Nutrient Sources in the Everglades and Biological Sinks in Florida Bay: A Biogeochemical Approach to Evaluate Ecosystem Response to Changing Nutrient Regimes
AU: * Hoare, A M
EM: ahoare@seas.marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave S., St. Petersburg, FL 33701 United States
AU: Hollander, D J
EM: davidh@seas.marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave S., St. Petersburg, FL 33701 United States
AU: Heil, C
EM: Cindy.Heil@MyFWC.com
AF: Florida Fish and Wildlife Research Institute, Florida Fish and Wildlife Commission, 100 8th Ave SE, St. Petersburg, FL 33705 United States
AU: Glibert, P
EM: glibert@hpl.umces.edu
AF: University of Maryland Center for Environmental Research, Horn Point Laboratory, P.O. Box 775, Cambridge, MD 21613 United States
AU: Murasko, S
EM: smurasko@seas.marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Ave S., St. Petersburg, FL 33701 United States
AU: Revilla, M
EM: marta.revilla@euskalnet.net
AF: University of Maryland Center for Environmental Research, Horn Point Laboratory, P.O. Box 775, Cambridge, MD 21613 United States
AU: Alexander, J
EM: jalexand@hpl.umces.edu
AF: University of Maryland Center for Environmental Research, Horn Point Laboratory, P.O. Box 775, Cambridge, MD 21613 United States
AB: Anthropogenic influences in South Florida have led to deterioration of its two major ecosystems, the Everglades wetlands and the Florida Bay estuary. Consequently, the Comprehensive Everglades Restoration Plan has been proposed to restore the Everglades ecosystem; however, restoration efforts will likely exert new ecological changes in the Everglades and ultimately Florida Bay. The success of the Florida Everglades restoration depends on our understanding and ability to predict how regional changes in the distribution and composition of dissolved organic and inorganic nutrients will direct the downstream biogeochemical dynamics of Florida Bay. While the transport of freshwater and nutrients to Florida Bay have been studied, much work remains to directly link nutrient dynamics in Florida Bay to nutrient sources in the Everglades. Our study uses stable C and N isotopic measurements of chemical and biological materials from the Everglades and Florida Bay as part of a multi-proxy approach to link nutrient sources in the Everglades to biological sinks in Florida Bay. Isotopic analyses of dissolved and particulate species of water, aquatic vegetation and sedimentary organic matter show that the watersheds within the Everglades are chemically distinct and that these signatures are also reflected in the bay. A large east-west gradient in both carbon and nitrogen (as much as 10‰ for δ¹⁵N POM) reflect differing nutrient sources for each region of Florida Bay and is strongly correlated with upstream sources in the Everglades. Isotopic signatures also reflect seasonal relationships associated with wet and dry periods. High C and N measurements of DOM and POM measurements suggest significant influence from waste water in Canal C-111 in eastern Florida Bay, particularly during the dry season. These observations show that nutrients from the Everglades watersheds enter Florida Bay and are important in controlling biogeochemical processes in the bay. This study proves that stable isotopic measurements are important tools in determining nutrient source and biogeochemical processing in these ecosystems and can be used to evaluate future ecological responses to hydrologic restoration.
DE: 0400 Biogeosciences
DE: 1803 Anthropogenic effects
DE: 1890 Wetlands
SC: Hydrology [H]
MN: 2005 Joint Assembly