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Our FCE I research focused on understanding how dissolved organic matter from upstream oligotrophic marshes interacts with a marine source of phosphorus (P), the limiting nutrient, to control estuarine productivity where these two influences meet-in the oligohaline ecotone. This dynamic is affected by the interaction of local ecological processes and landscape-scale drivers (hydrologic, climatological, and human). During FCE I, our ideas about how these "upside-down" estuaries (Childers et al. 2006) function has evolved, and we have modified our central theme to reflect this new understanding. Our focus in FCE II will be even more strongly on the oligohaline ecotone region of our experimental transects. For FCE II, our overarching theme is: In the coastal Everglades landscape, population and ecosystem-level dynamics are controlled by the relative importance of water source, water residence time, and local biotic processes. This phenomenon is best exemplified in the oligohaline ecotone, where these 3 factors interact most strongly and vary over many [temporal and spatial] scales.Hypothesis 1: Increasing inputs of fresh water will enhance oligotrophy in nutrient-poor coastal systems, as long as the inflowing water has low nutrient content; this dynamic will be most pronounced in the oligohaline ecotone. Hypothesis 2: An increase in freshwater inflow will increase the physical transport of detrital organic matter to the oligohaline ecotone, which will enhance estuarine productivity. The quality of these allochthonous detrital inputs will be controlled by upstream ecological processes. Hypothesis 3: Water residence time, groundwater inputs, and tidal energy interact with climatic and disturbance regimes to modify ecological pattern and process in oligotrophic estuaries; this dynamic will be most pronounced in the oligohaline ecotone. Childers, D.L., J.N. Boyer, S.E. Davis, C.J. Madden, D.T. Rudnick, and F.H. Sklar, 2006. Relating precipitation and water management to nutrient concentration patterns in the oligotrophic "upside down" estuaries of the Florida Everglades. Limnology and Oceanography, 51(1): 602-616.

Coastal ecosystems are being modified at unprecedented rates through interacting

pressures of global climate change and rapid human population growth, impacting natural coastal

resources and the services they provide. Located at the base of the shallow-sloping Florida peninsula, the Everglades wilderness and 6 million human residents are exceptionally exposed to both pressures. Further, freshwater drainage has accelerated saltwater intrusion over land and into the porous limestone aquifer, resulting in coastal ecosystem transgression and seasonal residential freshwater shortages. The unprecedented landscape-scale Everglades restoration process is expected to reverse some of these trends. However, it is not clear how uncertainties about climate change prognoses and their impacts (e.g., sea level rise (SLR), changes in storm activity or severity, and climate drivers of freshwater availability) may influence human activities (e.g., population growth, resource use, land-use change), and how their interaction will affect the restoration process that is already steeped in conflict. The Florida Coastal Everglades Long-Term Ecological Research (FCE LTER) program is dedicated to long-term coupled biophysical and cultural studies that expose and unravel complex feedbacks that generate distinctive patterns and processes in vulnerable coastal ecosystems. The overarching theme of FCE research is: In the coastal Everglades, climate change and resource management decisions interact to influence

freshwater availability, ecosystem dynamics, and the value and utilization of ecosystem services by people. Because they are highly sensitive to the balance of freshwater and marine influences,

coastal wetlands of the Florida Everglades provide an ideal system to examine how socio-ecological systems respond to and mitigate the effects of climate change and freshwater allocation decisions. The trans-disciplinary science conducted by the large FCE research team is revealing how estuary hydrodynamics and biogeochemistry may tilt on a fulcrum defined by the magnitude by which coastal pressures (SRL, storms) are mitigated by freshwater flows. We employ a socio-ecological framework to address how climate change interacts with political decisions to determine the sustainability of interconnected human-natural systems. In FCE I, we discovered how coastal nutrient supplies create an unusual “upside-down” productivity gradient in karstic estuaries. FCE II research used growing long-term datasets to reveal the sensitivity of this gradient to changes in hydrodynamics, nutrient availability, and salinity. In FCE III, we will use South Florida as an exemplary system for understanding how and why socio-ecological systems resist, adapt to, or mitigate the effects of climate change on ecosystem sustainability. We will examine how decisions about freshwater delivery to the Everglades influence -and are influenced by - the impact of SLR in this especially vulnerable landscape. Biophysical studies will focus on how this balance of fresh and marine sources influences biogeochemical cycling, primary production, organic matter dynamics, and trophic dynamics, to drive carbon gains and losses. We expand our spatio-temporal domain by employing powerful long-term datasets and experiments to determine legacies of past interactions, and to constrain models that will help guide a sustainable future for the FCE.

Coastal ecosystems like the Florida Everglades provide many benefits to society. They protect coastlines from storms and store carbon. They provide habitat and food for important fisheries. They also support tourism and local economies, and store freshwater for millions of people. The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) program addresses how and why coastal ecosystems are changing in response to sea level rise and the actions of people. Like many coastal ecosystems, the Florida Everglades are threatened by the diversion of freshwater to support urban and agricultural expansion. At the same time, sea level rise has caused coastal ecosystems to become saltier, threatening the freshwater supply, stressing freshwater plants, and causing the soils to collapse. When the soils beneath coastal wetlands disappear, seawater invades even more quickly. Researchers in the FCE LTER are continuing long-term studies and experiments to understand how these changes influence ecosystem functions and services. They are also developing tools for resource managers to create an effective freshwater restoration program. The science team includes an active community of graduate students. As a group, they reach the public through education and outreach activities, and regularly advise policy-makers on resource management decisions. The FCE LTER research program addresses how changing fresh and marine supplies of water influence coastal ecosystem dynamics through: (i) continued long-term assessment of changes in biogeochemistry, primary production, organic matter, and trophic dynamics in ecosystems along freshwater-to-marine gradients, (ii) maintenance of existing in situ and ex situ long-term experiments, (iii) use of high-resolution remote sensing, coupled with models to forecast landscape-scale changes, (iv) addition of synoptic satellite sites to capture discrete spatio-temporal responses to episodic disturbance, and (v) initiation of new experimental manipulations to determine drivers and mechanisms of resilience to saltwater intrusion. Data syntheses integrate month-to-annual and inter-annual data into models of water, nutrients, carbon, and species dynamics throughout the Everglades landscape to compare how ecosystems with different productivities and carbon stores respond (maintain, increase, or decline) to short- (pulses) and long-term changes (presses) in hydrologic connectivity. Understanding and predicting the drivers of abrupt changes in ecosystems is a key challenge in ecosystem ecology.

Coastal ecosystems like the Florida Everglades provide many benefits and services to society including protection from storms, habitat and food for important fisheries, support of tourism and local economies, filtration of fresh water, and burial and storage of carbon that offsets greenhouse gas emissions. The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) program addresses how and why coastal ecosystems and their services are changing. Like many coastal ecosystems, the Florida Everglades has been threatened by diversion of fresh water to support urban and agricultural expansion. At the same time, sea-level rise has caused saltwater intrusion of coastal ecosystems which stresses freshwater species, causes elevation loss, and contaminates municipal water resources. However, restoration of seasonal pulses of fresh water may counteract these threats. Researchers in the FCE LTER are continuing long-term studies and experiments to understand how changes in freshwater supply, sea-level rise, and disturbances like tropical storms interact to influence ecosystems and their services. The science team is guided by a diversity and inclusion plan to attract diverse scientists at all career stages. The team includes resource managers – who use discoveries and knowledge from the FCE LTER to guide effective freshwater restoration – and an active community of academic and agency scientists, teachers and other educators, graduate, undergraduate, and high school students. The project has a robust education and outreach program that engages the research team with the general public to advance science discoveries and protection of coastal ecosystems.

The Everglades land margin ecosystem in southwest Florida represents a combination of different mangrove ecological types in mainland carbonate environments with gradients in amount of nutrients, hydroperiod and salinity. Resource competition and stress theory will be utilized to understand mangrove community development due to these shifts in nutrient pools and hydroperiod across the coastal gradients of the South Florida mangrove ecotone. These ecological properties are important because potential changes in nutrient and hydrology in the inland watershed may be important impacts on the structure and function of mangroves in the coastal margin of southwest Florida. Initial studies and preliminary modelling efforts of these specific properties of mangroves in the Shark River estuary and those in the Taylor Slough Region will be used to test specific hypotheses in the LTER study. The biogeochemical properties of mangroves are the least understood of ecological processes along the transition from upland to coastal margin ecosystems. Thus the specific nature as to how the distribution of nutrients influences mangrove structure and productivity, and the role of mangroves on the fate of nutrients in sub-tropical estuaries are poorly understood. Continued efforts monitoring these biogeochemical processes along with synoptic studies of productivity, together with further development of ecological models, will provide insights on the response of mangroves to changes in water mangement of subtropical coastal watersheds.

National Science Foundation under Grant # 9910514