Macrophytes increase habitat complexity, have a structuring role, and support an array of biogeochemical services in aquatic ecosystems as O 2 production, nutrient uptake, and particulate matter retention (Sand-Jensen 1998). The increase of pelagic primary production and sedimentation rates has resulted in large inputs of labile organic matter (OM) to surface sediments with a positive feedback for nutrient regeneration and a negative feedback for macrophytes recovery (Hilt et al. simplified (microbial-dominated) benthic communities.Įutrophication in inland waters has resulted in widespread loss of biodiversity, including dramatic reduction of rooted macrophytes and associated macrofauna (Egertson et al. Such experiments demonstrate a large decrease in methane emission and nutrient loss/retention in biodiverse (macrophytes and macrofauna colonized) vs. With manipulative laboratory experiments reproducing a gradient from bare sediments to sediments colonized by macrophytes and macrofauna, we provide evidence of important biogeochemical services offered by vegetation and associated invertebrates in organic sediments. However, current canals management minimizes hydraulic resistance via mechanical removal of vegetation, which affects their potential to reduce greenhouse gas emissions and improve biological habitat and water quality. The same canal networks represent an opportunity for restoration of lowland ecosystems due to the large area that canals cover nowadays. Results suggest that the maintenance of vegetation and associated macrofauna in organic sediments promotes their combined ecosystem services, resulting in significant reduction of greenhouse gas emission and nutrient release to the water column.Īrtificial drainage and irrigation canals have converted floodplains into productive agricultural areas, resulting in extensive loss of biodiversity and ecosystem services. Oligochaetes increased N 2 production by ~ 200 mmol N m −2 and nitrate consumption by a factor of 4, whereas macrophytes reduced nitrogen losses by ~ 65 mmol N m −2. Along a 12-d experiment, CH 4 ebullition in bare sediment (470 ± 13 mmol m −2) decreased by 67%, 88%, and 97% in the presence of plants, oligochaetes, and both organisms, respectively. We tested this hypothesis via incubations of microcosms reproducing four treatments: bare sediment, sediment with oligochaetes, sediment with macrophytes, and sediment with both organisms. They may display lower methane (CH 4) emissions and increase nutrient retention when macrophytes and macrofauna are present, due to oxygen leakage from roots and bioirrigation. Box 413, Milwaukee, Wisconsin 53201, USA.Organic sediments are greenhouse gas and nutrient hotspots. Department of Biological Sciences, University of Wisconsin-Milwaukee, Lapham Hall, P.O.Fundamental interspecific differences in submerged leaf shape, associated with differences in their geographic distributions and habitats, are explained as adaptations for different nutrient uptake regimes. Interspecific comparisons of leaf shape were made using analysis of covariance. A leaf shape analysis was performed by regressing surface area with volume for each species.

The geographic location and habitat of the species explained the greatest percentage of total variance for these variables when compared by analysis of variance. The species were separated into two categories based on their distribution and habitat differences and their surface area, volume, dry mass, specific leaf area and surface to volume ratios were compared. 1992 from a total of 34 different lakes and 1 bay in Wisconsin and the Upper Peninsula of Michigan. verticillatum) collected during Aug./Sep. An image analysis system was used to calculate the surface area and volume of the submerged leaves of seven species of Myriophyllum (namely M.

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