Freshwater wetland ecosystems do not effectively conserve phosphorus in the way that terrestrial ecosystems do. The phosphorus retention capacity varies greatly among bogs, fens, and swamps and is concomitant with the amorphous acid oxalate-extractable aluminum and iron content in the soil. However, the phosphorus adsorption potential in wetland ecosystems may be predicted solely from the extractable aluminum content of the soil. Wetlands tested as wastewater filtration systems became phosphorus-saturated in a few years, with the export of excessive quantities of phosphate.

U.S. land management can contribute 1.2 Pg CO2e year−1 of greenhouse gas mitigation, 76% of which costs USD 50 Mg CO2e−1 or less.

Transformations and long-term fate of engineered nanomaterials must be measured in realistic complex natural systems to accurately assess the risks that they may pose. Here, we determine the long-term behavior of poly(vinylpyrrolidone)-coated silver nanoparticles (AgNPs) in freshwater mesocosms simulating an emergent wetland environment. AgNPs were either applied to the water column or to the terrestrial soils. The distribution of silver among water, solids, and biota, and Ag speciation in soils and sediment was determined 18 months after dosing. Most (70 wt %) of the added Ag resided in the soils and sediments, and largely remained in the compartment in which they were dosed. However, some movement between soil and sediment was observed. Movement of AgNPs from terrestrial soils to sediments was more facile than from sediments to soils, suggesting that erosion and runoff is a potential pathway for AgNPs to enter waterways. The AgNPs in terrestrial soils were transformed to Ag 2 S (∼52%), whereas AgNPs in the subaquatic sediment were present as Ag 2 S (55%) and Ag-sulfhydryl compounds (27%). Despite significant sulfidation of the AgNPs, a fraction of the added Ag resided in the terrestrial plant biomass (∼3 wt % for the terrestrially dosed mesocosm), and relatively high body burdens of Ag (0.5−3.3 μg Ag/g wet weight) were found in mosquito fish and chironomids in both mesocosms. Thus, Ag from the NPs remained bioavailable even after partial sulfidation and when water column total Ag concentrations are low (<0.002 mg/L).

Soil bacteria regulate wetland biogeochemical processes, yet little is known about controls over their distribution and abundance. Bacteria in North Carolina swamps and bogs differ greatly from Florida Everglades fens, where communities studied were unexpectedly similar along a nutrient enrichment gradient. Bacterial composition and diversity corresponded strongly with soil pH, land use, and restoration status, but less to nutrient concentrations, and not with wetland type or soil carbon. Surprisingly, wetland restoration decreased bacterial diversity, a response opposite to that in terrestrial ecosystems. Community level patterns were underlain by responses of a few taxa, especially the Acidobacteria and Proteobacteria, suggesting promise for bacterial indicators of restoration and trophic status.16S rDNA ͉ land use ͉ phylogenetic analysis ͉ restoration ͉ soil pH S oil bacterial communities play a critical role in regulating the cycling, retention, and release of major nutrients and soil carbon in freshwater wetlands, with demonstrably large effects on water quality (1) and global carbon cycling (2). However, little is known about the taxonomic composition of uncultured soil bacteria in freshwater wetlands relative to other ecosystems, despite the disproportionate influence of wetlands in controlling biogeochemical cycling at landscape scales (3). With a single exception in a Sphagnum bog (4), existing knowledge of bacterial communities in freshwater wetlands has been obtained using DNA fingerprinting (5, 6), group specific probes (7-9), or culture-based methods (8), which either have not identified bacterial taxonomic groups or do not adequately represent the vast diversity of uncultured soil bacteria (10). Furthermore, the environmental and anthropogenic factors controlling the distribution and abundance of bacterial groups in freshwater wetland soils are unknown.To predict the effects of ecosystem change on wetland functions, improved understanding of the ecological responses of uncultured bacterial communities to ecosystem alteration is needed to compliment existing knowledge of bacterial functional groups controlling specific biogeochemical processes. The importance of understanding controls over wetland bacterial communities is underscored by the unique nature of wetlands as transitional ecosystems, the role wetland bacteria play in regulating biogeochemical fluxes across different ecosystem types, and increasing efforts to restore the functionality of degraded wetlands subjected to land-use change (11). In our unique study, we demonstrate the spectrum of uncultured bacterial communities across a range of freshwater wetland types and quantify the influence of soil chemistry, land use, restoration, and soil nutrient concentrations on bacterial assemblages.Freshwater wetlands are transitional gradients between terrestrial and aquatic ecosystems, and thus may have environmental and anthropogenic controls over bacterial community structure similar to those of their neighboring ecosystems. Land use (12, 13) an...

Fens represent a large array of ecosystem services, including the highest biodiversity found among wetlands, hydrological services, water purification and carbon sequestration. Land-use change and drainage has severely damaged or annihilated these services in many parts of North America and Europe; restoration plans are urgently needed at the landscape level. We review the major constraints on the restoration of rich fens and fen water bodies in agricultural areas in Europe and disturbed landscapes in North America: (i) habitat quality problems: drought, eutrophication, acidification, and toxicity, and (ii) recolonization problems: species pools, ecosystem fragmentation and connectivity, genetic variability, and invasive species; and here provide possible solutions. We discuss both positive and negative consequences of restoration measures, and their causes. The restoration of wetland ecosystem functioning and services has, for a long time, been based on a trial-and-error approach. By presenting research and practice on the restoration of rich fen ecosystems within agricultural areas, we demonstrate the importance of biogeochemical and ecological knowledge at different spatial scales for the management and restoration of biodiversity, water quality, carbon sequestration and other ecosystem services, especially in a changing climate. We define target processes that enable scientists, nature managers, water managers and policy makers to choose between different measures and to predict restoration prospects for different types of deteriorated fens and their starting conditions.