title: El Niño Southern Oscillation (ENSO) enhances CO2 exchange rates in freshwater Marsh ecosystems in the Florida everglades.
abstract: This research examines the relationships between El Niño Southern Oscillation (ENSO), water level, precipitation patterns and carbon dioxide (CO2) exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009-2013) from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS) and the long-hydroperiod site (Shark River Slough; SRS) fluctuations in precipitation patterns occurred with changes in ENSO phase, suggesting that extreme ENSO phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics. Variations in both ENSO phase and annual net CO2 exchange rates co-occurred with changes in wet and dry season length and intensity. Combined with site-specific seasonality in CO2 exchanges rates, El Niño and La Niña phases magnified season intensity and CO2 exchange rates at both sites. At TS, net CO2 uptake rates were higher in the dry season, whereas SRS had greater rates of carbon sequestration during the wet season. As La Niña phases were concurrent with drought years and extended dry seasons, TS became a greater sink for CO2 on an annual basis (-11 to -110 g CO2 m-2 yr-1) compared to El Niño and neutral years (-5 to -43.5 g CO2 m-2 yr-1). SRS was a small source for CO2 annually (1.81 to 80 g CO2 m-2 yr-1) except in one exceptionally wet year that was associated with an El Niño phase (-16 g CO2 m-2 yr-1). Considering that future climate predictions suggest a higher frequency and intensity in El Niño and La Niña phases, these results indicate that changes in extreme ENSO phases will significantly alter CO2 dynamics in the Florida Everglades.
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States of America; Rocky Mountain Research Station, US Forest Service, Ft. Collins, CO, United States of America.
authors.forename: Sparkle L
authors.initials: SL
authors.lastname: Malone
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States of America.
authors.forename: Christina L
authors.initials: CL
authors.lastname: Staudhammer
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL, United States of America.
authors.forename: Steven F
authors.initials: SF
authors.lastname: Oberbauer
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL, United States of America.
authors.forename: Paulo
authors.initials: P
authors.lastname: Olivas
authors.affiliation: Rocky Mountain Research Station, US Forest Service, Ft. Collins, CO, United States of America; Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, United States of America.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ryan
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL, United States of America; Department of Biology, West Chester University, West Chester, PA, United States of America.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Schedlbauer
authors.affiliation: National Ecological Observatory Network Inc., Boulder, CO, 80301, United States of America; Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, United States of America.
authors.forename: Henry W
authors.initials: HW
authors.lastname: Loescher
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States of America.
authors.forename: Gregory
authors.initials: G
authors.lastname: Starr
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D055907:Climatic Processes; D005431:Florida; D005618:Fresh Water / Q000737:chemistry; D062070:Hydrology; D053833:Wetlands
chemical_list: D002245:Carbon Dioxide