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SHIFTING LONG-TERM BIOGEOCHEMICAL BASELINES: ENHANCED MARINE CONNECTIVITY INCREASES NUTRIENT AVAILABILITY IN COASTAL WETLAND ECOSYSTEMS

Enhanced marine connectivity in coastal ecosystems is driven by storm pulses, sea-level rise (SLR), and saltwater intrusion. Biogeochemical changes of increasing saltwater intrusion into brackish and freshwater wetland ecosystems are uncertain. We analyzed 15 years (2000 – 2014) of continuous data from the Florida Coastal Everglades Long Term Ecological Research Program (FCE LTER) to assess spatiotemporal shifts in carbon (C) and phosphorus (P) along two freshwater-marine gradients (Shark River Slough, SRS; Taylor Slough/Panhandle, TS/Ph). We specifically tested 1) how ecosystem P allocation (water, plant, soil) varied among wetland ecosystems with differential marine connectivity and P demand, and 2) how differences in ecosystem P allocation are explained by differences in water source (freshwater, marine), P loading, and ecosystem productivity. Surface and porewater total P in freshwater, brackish and marine wetlands along the SRS increased up to 3× from 2005 through 2014 in both wet and dry seasons, following Hurricane Wilma impact; whereas surface and porewater total P increased up to 3× throughout TS/Ph primarily occurred during the dry season. Soil total P was highest in SRS marine and brackish wetlands and steadily increased in both gradients from freshwater to marine wetlands. Above and belowground total P in a dominant freshwater plant species Cladium jamaicenses was 2× higher in SRS than TS/Ph and increased from 2010 through 2014 in wetlands nearest to the freshwater-marine ecotone. Long-term effects of nutrient uptake on C storage in oligotrophic ecosystems likely balance ecosystem nutrient allocation and net ecosystem productivity at the landscape level.

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Authors

Kominoski, J. S., Florida International University, USA, jkominos@fiu.edu

Casteñada-Moya, E., Florida International University, USA, ecastane@fiu.edu

Davis, S. E., Everglades Foundation, USA, sdavis@evergladesfoundation.org

Gaiser, E. E., Florida International University, USA, gaisere@fiu.edu

Marazzi, L., Florida International University, USA, lmarazzi@fiu.edu

Rivera-Monroy, V. H., Louisiana State University, USA, vhrivera@lsu.edu

Sola, A., Florida International University, USA, asola035@fiu.edu

Surratt, D., Everglades National Park, USA, donatto_surratt@nps.gov

Details

Oral presentation

Session #:003
Date: 02/28/2017
Time: 12:15
Location: 306 A

Presentation is given by student: No