Surface Water Sulfate Dynamics in the Northern Florida Everglades

Abstract

Sulfate contamination has been identified as a serious environmental issue in the Everglades ecosystem. However, it has received less attention compared to P enrichment. Sulfate enters the Arthur R. Marshall Loxahatchee National Wildlife Refuge (Refuge), a remnant of the historic Everglades, in pumped stormwater discharges with a mean concentration of approximately 50 mg L(-1), and marsh interior concentrations at times fall below a detection limit of 0.1 mg L(-1). In this research, we developed a sulfate mass balance model to examine the response of surface water sulfate in the Refuge to changes in sulfate loading and hydrological processes. Meanwhile, sulfate removal resulting from microbial sulfate reduction in the underlying sediments of the marsh was estimated from the apparent settling coefficients incorporated in the model. The model has been calibrated and validated using long-term monitoring data (1995-2006). Statistical analysis indicated that our model is capable of capturing the spatial and temporal variations in surface water sulfate concentrations across the Refuge. This modeling work emphasizes the fact that sulfate from canal discharge is impacting even the interior portions of the Refuge, supporting work by other researchers. In addition, model simulations suggest a condition of sulfate in excess of requirement for microbial sulfate reduction in the Refuge.

Soil and periphyton indicators of anthropogenic water-quality changes in a rainfall-driven wetland

“…This conclusion is consistent with the results of recent water-quality modeling efforts (Wang et al 2009), which indicate a greater potential for canal-water movement across the Refuge than previously realized. While sites could be classified based on the level of canal influence on soil and periphyton parameters, even the least affected category may represent a transitional zone rather than a zone of pristine chemistry.…”

Sulfur in the South Florida Ecosystem: Distribution, Sources, Biogeochemistry, Impacts, and Management for Restoration

“…At interior marshes within the WCAs, there is an overall gradient in sulfate concentration from north to south, with the exception of WCA-1 (the Arthur R. Marshall Loxahatchee National Wildlife Refuge), which is somewhat protected from canal inputs by a rim canal. Recent data show that during the wet season sulfate from canal water penetrates into WCA-1's interior marsh (Wang et al, 2009). Elevated sulfate concentrations occur near major canals throughout the ecosystem, even in areas to the south such as along the L-67 canal in southern WCA-3A and where the L-67 terminates in ENP.…”

Soil Nutrient Assessment and Characterization in a Degraded Central Florida Swamp

“…These concentrations, combined with the low redox potential associated with wetland soils, suggest the possibility of sulfide toxicity as one plausible mechanism in the observed dieback of N. sylvatica var. biflora (Delaune et al, 1987;Koch et al, 1990;Wang et al, 2009).…”