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  ABSTRACTS
top     TEXT (2009) Bohlen, P.J., Lynch, S., Shabman, L., Clark, M., Shukla, S. and Swain, H. Paying for environmental services from agricultural lands: an example from the northern Everglades. Frontiers in Ecology and the Environment 7(1), 46-55.
  Abstract
There is growing interest in implementing market-like programs that would pay farmers and ranchers for producing environmental services (beyond those that generate food and fiber) from working agricultural lands. However, few examples exist of programs that pay directly for quantified services. Since 2005, a coalition of non-governmental environmental organizations, state and federal agencies, ranchers, and researchers has been developing a Pay-for-Environmental Services (PES) program that would compensate cattle ranchers in Florida's northern Everglades region for providing water storage and nutrient retention on private lands. We use our experience with this program to identify key challenges to PES program design, including identifying a buyer and defining the environmental services; agreeing upon credible, yet practical, approaches to quantifying the services provided; reducing programmatic costs in light of existing policies and complex regulatory issues; and maintaining an adaptive approach to program design and implementation, while satisfying the concerns of multiple stakeholders.
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(2009) Chang, C.C.Y., McCormick, P.V., Newman, S. and Elliott, E.M. Isotopic indicators of environmental change in a subtropical wetland. Ecological Indicators 9(5), 825-836.

Abstract
The delta N-15 and delta C-13 signatures of major organic matter (OM) pools were measured across chemical and hydrologic gradients in a large (58,800 ha) subtropical wetland to evaluate whether stable isotopes were useful indicators of environmental change. Once a rainfall-driven wetland, the Loxahatchee National Wildlife Refuge in the Florida Everglades now receives agricultural and urban drainage that has increased phosphorus (P) and mineral loads around the wetland perimeter. Additionally, water impoundment at the southern end has produced a latitudinal hydrologic gradient, with extended hydroperiods in the south and overdrained conditions in the north. Detritus (-4.8 parts per thousand to 8.6 parts per thousand), floc (-1.4 parts per thousand to 3.6 parts per thousand), and metaphyton (-6.6 parts per thousand to +7.4 parts per thousand) delta N-15 declined southward with changes in hydrology as indicated by water depth. This pattern was attributed to higher mineralization rates under shorter hydroperiods. These signatures were also strongly correlated with increased nutrient and mineral loading. Rooted macrophyte delta N-15, by contrast, appeared more responsive to soil nutrient pools. Cattail (-8.9 parts per thousand to +7.7 parts per thousand) was restricted to the wetland perimeter and had the widest delta N-15 range, which was positively correlated with soil P. Sawgrass (-5.3 parts per thousand to +7.7 parts per thousand) occurred across most of the wetland, but its ON was not strongly correlated to any gradient. Patterns for delta C-13 were more strongly related to chemical gradients caused by canal intrusion than to latitude or hydrology. Again, metaphyton and detrital signatures were more sensitive to water chemistry changes than macrophytes. This pattern is consistent with their locations at the soil-water (detritus-floc), and air-water (metaphyton) interface. Metaphyton delta C-13 (-36.1 parts per thousand to -21.5 parts per thousand) which had the broadest range, was affected by DIC source and pool size. In contrast, cattail delta C-13 (-28.7 parts per thousand to -26.4 parts per thousand) was more closely related to soil P and sawgrass delta C-13 (-30.1 parts per thousand to -24.5 parts per thousand) was not related to any environmental gradient except latitude. There was no correlation between the two isotopes for any OM pool except cattail. These results indicate that isotopic signatures of microbial (metaphyton and detrital) pools are more responsive to changes in wetland hydrology and water chemistry while those of rooted macrophytes respond only to the extent that soil chemistry is altered. Rooted macrophytes also differ in the sensitivity of their isotopic signatures to environmental change. The selection of OM pools for isotopic analysis will, therefore, affect the sensitivity of the analysis and the resulting patterns. Furthermore, delta N-15 may be more robust and interpretable than delta C-13 as an indicator of ecosystem change in wetlands exposed to multiple or complex anthropogenic gradients.
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(2009) Harvey, J.W. and McCormick, P.V. Groundwater's significance to changing hydrology, water chemistry, and biological communities of a floodplain ecosystem, Everglades, South Florida, USA. Hydrogeology Journal 17(1), 185-201.

  Abstract
The Everglades ( Florida, USA) is one of the world's larger subtropical peatlands with biological communities adapted to waters low in total dissolved solids and nutrients. Detecting how the pre-drainage hydrological system has been altered is crucial to preserving its functional attributes. However, reliable tools for hindcasting historic conditions in the Everglades are limited. A recent synthesis demonstrates that the proportion of surface-water inflows has increased relative to precipitation, accounting for 33% of total inputs compared with 18% historically. The largest new source of water is canal drainage from areas of former wetlands converted to agriculture. Interactions between groundwater and surface water have also increased, due to increasing vertical hydraulic gradients resulting from topographic and water-level alterations on the otherwise extremely flat landscape. Environmental solute tracer data were used to determine groundwater's changing role, from a freshwater storage reservoir that sustained the Everglades ecosystem during dry periods to a reservoir of increasingly degraded water quality. Although some of this degradation is attributable to increased discharge of deep saline groundwater, other mineral sources such as fertilizer additives and peat oxidation have made a greater contribution to water-quality changes that are altering mineral-sensitive biological communities.
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(2009) Hoang, T.C., Schuler, L.J., Rogevich, E.C., Bachman, P.M., Rand, G.M. and Frakes, R.A. Copper Release, Speciation, and Toxicity Following Multiple Floodings of Copper Enriched Agriculture Soils: Implications in Everglades Restoration. Water Air and Soil Pollution 199(1-4), 79-93.

  Abstract
 This study characterizes the effects of water-soil flooding volume ratio and flooding time on copper (Cu) desorption and toxicity following multiple floodings of field-collected soils from agricultural sites acquired under the Comprehensive Everglades Restoration Plan (CERP) in south Florida. Soils from four field sites were flooded with three water-soil ratios (2, 4, and 6 [water] to 1 [soil]) and held for 14 days to characterize the effects of volume ratio and flooding duration on Cu desorption (volume ratio and flooding duration study). Desorption of Cu was also characterized by flooding soils four times from seven field sites with a volume ratio of 2 (water) to 1 (soil) (multiple flooding study). Acute toxicity tests were also conducted using overlying waters from the first flooding event to characterize the effects of Cu on the survival of fathead minnows (Pimephales promelas), cladocerans (Daphnia magna), amphipods (Hyalella azteca), midges (Chironomus tentans), duckweed (Lemna minor), and Florida apple snails (Pomacea paludosa). Acute tests were also conducted with D. magna exposed to overlying water from the second and third flooding events. Results indicate that dissolved Cu concentrations in overlying water increased with flooding duration and decreased with volume ratio. In the multiple flooding study, initial Cu concentrations in soils ranged from 5 to 223 mg/kg (dw) and were similar to Cu concentration after four flooding events, indicating retention of Cu in soils. Copper desorption was dependent on soil Cu content and soil characteristics. Total Cu concentration in overlying water (Cu-w) was a function of dissolved organic carbon (DOC), alkalinity, and soil Cu concentration (Cu-s): log(Cu-w) = 1.2909 + 0.0279 (DOC) + 0.0026 (Cu-s) -aEuro parts per thousand 0.0038 (alkalinity). The model was validated and highly predictive. Most of the desorbed Cu in the water column complexed with organic matter in the soils and accounted for 99% of the total dissolved Cu. Although total dissolved Cu concentrations in overlying water did not significantly decrease with number of flooding events, concentrations of free Cu2+ increased with the number of flooding events, due to a decrease in DOC concentrations. The fraction of bioavailable Cu species (Cu2+, CuOH+, CuCO3) was also less than 1% of the total Cu. Overlying water from the first flooding event was only acutely toxic to the Florida apple snail from one site. However, overlying water from the third flooding of six out of seven soils was acutely toxic to D. magna. The decrease in DOC concentrations and increase in bioavailable Cu2+ species may explain the changes in acute toxicity to D. magna. Results of this study reveal potential for high Cu bioavailability (Cu2+) and toxicity to aquatic biota overtime in inundated agricultural lands acquired under the CERP.
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(2009) Jin, G., Eilts, K., Kelley, T.R. and Webb, J.W. Preliminary water quality assessment of Spunky Bottoms restored wetland. Journal of Environmental Science and Health Part a-Toxic/Hazardous Substances & Environmental Engineering 44(3), 235-243.

  Abstract
  The approximately 1200-acre "Spunky Bottoms" wetland in Southern Illinois has been undergoing restoration to conditions prior to levying of the Illinois River and draining of adjacent floodplain for intensive agriculture (circa 1900). As part of a long-term water quality impact assessment of this restoration project, baseline water quality monitoring was conducted soon after restoration began. During this baseline/preliminary assessment, water samples were taken every 2-4 weeks from 10 sampling wells and seven surface water sites throughout the wetlands area for a period of 18 months. Measured parameters include nutrients (nitrate (NO3-) and phosphate (PO43-), cations and anions (SO42-, Cl-, Na+, K+, Mg2+, Ca2+) commonly found in surface and well water, trace metals (Al, Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn), total dissolved solids (TDS), pH, and trace organics (triazine herbicides and their metabolites). In general, highest concentrations of ions were found in the southwest and northeast perimeter of the wetland area for both surface and ground water samples. Primarily low concentrations of heavy metals and organic compounds were found throughout the wetland sampling area. Distribution of NO3--N suggests that this restored wetland, even at its infant age, may still contribute to biogeochemical (particularly N) element cycling. Continued monitoring and further research is necessary to determine long-term specific contribution of restored wetland to biogeochemical cycles.
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(2009) Miao, S.L. and Zou, C.B. Seasonal variation in seed bank composition and its interaction with nutrient enrichment in the Everglades wetlands. Aquatic Botany 90(2), 157-164.

  Abstract
In the Florida Everglades, nutrient enrichment from agricultural outflow and the change in hydrology have collectively contributed to the expansion of cattails (Typha spp.). To assess the effectiveness of prescribed fire in controlling cattails and to predict vegetation dynamics after the fire, it is important to understand the seasonal variation of the soil seed bank and how the seed bank is affected by nutrient enrichment and fire. This paper investigates the effects of season, nutrient enrichment, and fire on soil seed bank species composition, richness, and density along a nutrient gradient in Water Conservation Area 2A (WCA 2A) of the Florida Everglades. Species richness was significantly affected by nutrient enrichment and season but not their interaction. Total seed density, however, was significantly affected by the interaction between nutrient enrichment and season. Yet, at species level, the relationship between seed density, nutrient enrichment and season varied. The highest seed density of cattail occurred in summer at highly enriched sites, but that of sawgrass occurred in fall regardless of enrichment; the seed density of water lily was very low regardless of season and nutrient enrichment, and the highest Amarathus seed density occurred at highly enriched sites year round. Moreover, germination timing differed greatly among species. While cattail seeds had a short incubation period and started to germinate 2-3 days after initiation of the germination assay, sawgrass seeds generally started to germinate 4 weeks later. Further, both the prescribed summer fire at the highly enriched site and the natural winter fire at the moderately enriched site reduced the seed density of cattail but not of sawgrass. Our results suggest that fire application for vegetation recovery in WCA 2A would benefit from explicitly considering seasonal dynamics of the seed bank.
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(2009) Ozturk, Z., Katsenovich, Y., Tansel, B., Laha, S., Moos, L. and Allen, M. Enhancement of TCE Attenuation in Soils by Natural Amendments. Soil & Sediment Contamination 18(1), 1-13.

  Abstract
The objective of this study was to identify low-cost natural amendments that could be used as carbon sources and sustain a bioactive zone to promote biodegradation of TCE in contaminated shallow groundwater. The natural amendments were compared based on their geophysical characteristics as well as TCE adsorption capacities. The amendments studied included low-cost natural and agricultural materials such as eucalyptus tree mulch, pine bark mulch, muck from the Florida Everglades, SRS wetland peat, commercial compost, and peat humus. These natural substrates have relatively high organic fractions that can retard the movement of TCE while serving as carbon sources. Batch sorption studies were conducted to determine the sorption and retardation characteristics of the amendments for TCE. The experimental results were analyzed in relation to the geophysical characteristics of the amendments and compared with those of natural soils.
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(2009) Wright, A.L. Soil phosphorus stocks and distribution in chemical fractions for long-term sugarcane, pasture, turfgrass, and forest systems in Florida. Nutrient Cycling in Agroecosystems 83(3), 223-231.

  Abstract
Phosphorus distribution and stability in soils of the Everglades Agricultural Area (EAA) of south Florida is important because of changing land uses. We investigated the effects of land use on P distribution in the soil profile and between chemical fractions for a histosol of the Florida Everglades. Labile, Fe-Al bound, Ca-bound, humic-fulvic acid, and residual P pools in 0-15, 15-30, and 30-45 cm depths were determined for drained soils planted to sugarcane (Saccharum sp.) for 50 yr, pasture for 100 yr, turfgrass for 60 yr, and forest for 20 yr. The P concentrations of all chemical fractions decreased with depth in the profile, indicating accumulation in surface soil resulting from oxidation and fertilization. Trends in P distribution between chemical fractions were similar between land uses. Labile P comprised less than 1% of total P. Fe-Al bound P averaged 2.9% of the total P for turfgrass and forest, but 11.4 and 9.6% for sugarcane and pasture. Increasing soil disturbance and long-term fertilization increased P allocation to inorganic fractions, as Ca-bound P contained 49% of total P for sugarcane but 28% for other land uses. Total P stocks in the soil profile (0-45 cm) averaged 1,323, 2,005, 2,294, and 2,317 kg P ha(-1) for pasture, sugarcane, turfgrass, and forest, respectively. Under current land uses P in organic fractions represents an unstable pool since the soil is prone to oxidation under drained conditions. In contrast, P sequestered in inorganic fractions is more stable under current land uses, thus sugarcane cultivation and incorporation of bedrock CaCO3 into surface soil by tillage will enhance long-term P sequestration.
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(2009) Wright, A.L. and Inglett, P.W. Soil Organic Carbon and Nitrogen and Distribution of Carbon-13 and Nitrogen-15 in Aggregates of Everglades Histosols. Soil Science Society of America Journal 73(2), 427-433.

  Abstract
Oxidation of Histosols in the Everglades Agricultural Area (EAA) of South Florida leads to decreases in soil depth, changes in biogeochemical properties, and may limit land use Options in the future. The objectives of this study were to determine how long-term cultivation influences organic matter dynamics and C and N distribution throughout the profile Of a drained Histosol. We measured organic C and N stocks, aggregation, and the natural abundance of delta C-13 and delta N-15 in aggregates from Histosols 100 yr after drainage for two land uses: sugarcane (Saccharum officinarum L.) and prairie. Macroaggregates comprised the bulk of total soil for both land uses, averaging 81% of the total soil in fractions > 0.25 mm. Macroaggregation increased with depth and the proportion to whole soil was 65% higher at 30 to 45 cm than 0 to 15 cm. Cultivated soil averaged 13% higher organic C, but 11 lower organic N than prairie throughout the profile (0-45 cm). The majority of the organic C (76%) and N stocks (77%) was in macroaggregare fractions > 0.25 mm. The distribution of organic matter among aggregate-size fractions generally did not differ between land uses, except that organic C and N were 39 and 44%, respectively, greater For macroaggregares in prairie than cultivated soil at 0 to 15 cm. The delta N-15 decreased with depth for both land uses, indicating that organic matter was more decomposed and humified in surface soil (0-15 cm). The decrease with depth likely resulted from inundation of subsurface soils and low O-2 levels, which subsequently lowered rates of decomposition. The delta C-13 decreased with depth for Cultivated soil but increased for prairie, and was significantly higher for soil cropped to sugarcane (-25.37 parts per thousand) than prairie (-26.20 parts per thousand). Soil organic matter under Cultivation was less humified than prairie soil due to recent C inputs from Sugarcane. The 2-mm fraction had 12% lower delta N-15 than other fractions, indicating that recent organic matter inputs accumulated in macroaggregate fractions. Smaller aggregates contained higher delta N-15 and older organic matter. In contrast to most studies of mineral soils, Cultivation of Histosols increased C storage relative to prairie, with the major difference between land use being higher soil organic matter levels in the Subsurface (15-45 cm). Thus, cropping may reduce the rate of oxidation of Histosols ill Southern Florida relative to the prairie ecosystem.

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(2008) Carriger, J.F. and Rand, G.M. Aquatic risk assessment of pesticides in surface waters in and adjacent to the Everglades and Biscayne National Parks: I. Hazard assessment and problem formulation. Ecotoxicology 17(7), 660-679.

   
   
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