A synthesis of long-term research by the Florida Coastal Everglades LTER Program

Abstract

This paper synthesizes research conducted during the first 5-6 years of the Florida Coastal Everglades Long-Term Ecological Research Program (FCE LTER). My objectives are to review our research to date, and to present a new central theme and conceptual approach for future research. Our research has focused on understanding how dissolved organic matter (DOM) from upstream oligotrophic marshes interacted with a marine source of the limiting nutrient, phosphorus (P), to control productivity in the oligohaline estuarine ecotone. We have been working along freshwater to marine transects in two drainage basins located in Everglades National Park (ENP). The Shark River Slough transect (SRS) has a direct connection to the Gulf of Mexico, providing this estuarine ecotone with a source of marine P. The oligohaline ecotone along our southern Everglades transect (TS/Ph), however, is separated from this marine P source by the Florida Bay estuary. We originally hypothesized an ecosystem productivity peak in the SRS ecotone, driven by the interaction of marine P and Everglades DOM, but no such productivity peak in the TS/Ph ecotone because of this lack of marine P. Our research to date has tended to show the opposite pattern, however, with many ecosystem components showing enhanced productivity in the TS/Ph ecotone, but not in the SRS ecotone. Water column P concentrations followed a similar pattern, with unexpectedly high P in the TS/Ph ecotone during the dry season. Our organic geochemical research has shown that Everglades DOM is more refractory than originally hypothesized. We have also begun to understand the importance of detrital organic matter production and transport to ecotone dynamics and as the base of aquatic food webs. Our future research will build on this substantial body of knowledge about these oligotrophic estuaries. We will direct our efforts more strongly on biophysical dynamics in the oligohaline ecotone regions. Specifically, we will be focusing on inputs to these regions from four primary water sources: freshwater Everglades runoff, net precipitation, marine inputs, and groundwater. We are hypothesizing that dry season groundwater inputs of P will be particularly important to TS/Ph ecotone dynamics because of longer water residence times in this area. Our organic geochemical, biogeochemical, and ecosystem energetics work will focus more strongly on the importance of detrital organics and will take advantage of a key Everglades Restoration project, scheduled for 2008 or 2009, that will increase freshwater inputs to our SRS transect only. Finally, we will also begin to investigate the human dimensions of restoration, and of a growing population in south Florida that will become increasingly dependent on the Everglades for critical ecosystem services (including fresh water) even as its growth presents challenges to Everglades sustainability.

New perspectives on an iconic landscape from comparative international long‐term ecological research

“…The Everglades represents an ''upside-down'' estuary based upon the supply of nutrients that originate from marine sources, rather than from upland freshwater drainages, as is the case for many other coastal estuaries (Childers 2006). Long-term biogeochemical data have shown that v www.esajournals.org tidal exchange with the coastal ocean (Fourqurean et al 1992) and submarine groundwater discharge (Herbert and Fourqurean 2009) provide the primary supply of the limiting nutrient, phosphorus (P), to the seagrass meadows of Florida Bay.…”

Spatiotemporal Variation in Abundance and Social Structure of Bottlenose Dolphins in the Florida Coastal Everglades

“…The Florida Coastal Everglades is a spatially and temporally heterogeneous system which extends from small creeks where freshwater marshes transition to mangrove forests through mangrove-lined channels and inland bays to the coastal oceans of the Gulf of Mexico and Florida Bay (Childers 2006). The system is relatively oligotraophic and phosphorous-limited.…”

“…The Florida Everglades is a system of subtropical wetlands comprising a number of distinct habitats that terminates in oligotrophic mangrove estuaries adjacent to Florida Bay and the Gulf of Mexico (Childers 2006). Within the coastal Everglades, there is an assemblage of multiple, distinct aquatic habitats including sloughs, creeks, rivers, shallow bays with mangrove islands, and coastal oceans.…”

An Economic Analysis of Carbon Sequestration and Storage Service by Mangrove Forests in Everglades National Park, Florida

“…The combined presence of the strong environmental gradients and a high recurrence of tropical storms and hurricanes results in a distinct gradient of mangrove productivity and biomass in the Everglades (Chen & Twilley, 1999b;Childers et al, 2006;Rivera-Monroy et al, 2011). The different presses (e.g., sea level rise, water management, coastal development) and pulses (e.g., hurricanes) that operate at varying spatial and temporal scales on the mangroves of ENP influence the carbon storage capacity of these productive forested wetlands.…”