80 research outputs found
Testate amoeba response to acid deposition in a Scottish peatland
Peatlands around the world are exposed to anthropogenic or volcanogenic sulphur pollution. Impacts on peatland microbial communities have been inferred from changes in gas flux but have rarely been directly studied. In this study, the impacts of sulphuric acid deposition on peatland testate amoebae were investigated by analysis of experimental plots on a Scottish peatland almost 7 years after acid treatment. Results showed reduced concentration of live amoebae and changes in community structure which remained significant even when differences in pH were accounted for. Several possible explanations for the impacts can be proposed including taphonomic processes and changes in plant communities. Previous studies have inferred a shift from methanogenic archaea to sulphate-reducing bacteria in sulphate-treated peats; it is possible that the impacts detected here might relate to this change, perhaps through testate amoeba predation on methanotrophs
Soil Inorganic N Leaching in Edges of Different Forest Types Subject to High N Deposition Loads
Intermediate-scale community-level flux of CO2 and CH4 in a Minnesota peatland: putting the SPRUCE project in a global context
Sources, Composition, and Export of Particulate Organic Matter Across British Estuaries
Estuaries receive and process a large amount of particulate organic carbon (POC) prior to its export into coastal waters. Studying the origin of this POC is key to understanding the fate of POC and the role of estuaries
in the global carbon cycle. Here, we evaluated the concentrations of POC, as well as particulate organic nitrogen (PON), and used stable carbon and nitrogen isotopes to assess their sources across 13 contrasting British estuaries during five different sampling campaigns over 1 year. We found a high variability in POC and PON
concentrations across the salinity gradient, reflecting inputs, and losses of organic material within the estuaries. Catchment land cover appeared to influence the contribution of POC to the total organic carbon flux from the estuary to coastal waters, with POC contributions >36% in estuaries draining catchments with a high percentage of urban/suburban
land, and <11% in estuaries draining catchments with a high peatland cover. There was no seasonal pattern in the
isotopic composition of POC and PON, suggesting similar sources for each estuary over time. Carbon isotopic
ratios were depleted (â26.7 ± 0.42â°, average ± sd) at the lowest salinity waters, indicating mainly terrigenous
POC (TPOC). Applying a two-source mixing model, we observed high variability in the contribution of TPOC at the highest salinity waters between estuaries, with a median value of 57%. Our results indicate a large transport of terrigenous organic carbon into coastal waters, where it may be buried, remineralized, or transported offshore
Headwater Mires Constitute a Major Source of Nitrogen (N) to Surface Waters in the Boreal Landscape
Nitrogen input together with ecosystem nitrogen enrichment predict nitrate leaching from European forests
- âŠ