Contrasting responses of phytoplankton and benthic algae to recent nutrient enrichment in Arctic tundra ponds

摘要: Summary Tundra ponds are a dominant feature on the Arctic Coastal Plain, but their response to warming, especially in long-term, is largely unknown. Our study assessed changes algal nutrient limitation over 40-year period historically studied that may have been affected by either human development region or increased temperatures leading permafrost thaw and release. We also compared of algae pelagic benthic zones at landscape level. Nutrient diffusing substrata (NDS) bottled incubations, which expose natural communities known quantities nitrogen (N) phosphorus (P), were utilised determine phytoplankton limitation, respectively, series north slope Alaska, USA. This included where was examined 1971–1973 as part International Biological Program (IBP), well remote protected area others near village Barrow. Nutrient status has changed since original IBP 40 years ago from P NP co-limitation. One-third regional enrichment experiments indicated no growth, none exhibited single-nutrient limitation. shift coincident with water column nutrients due degrading permafrost, expansion into macrophytes, compete for available nitrogen. A comparison across revealed differences among these predominance absence zone, reflecting contrasting within same ponds. Permafrost probably reintroducing previously frozen stores N sediment surface, quickly taken up periphyton become limited column. Grazing invertebrates, not excluded assays, influenced results. While Barrow had higher levels, there obvious effect urban status, nor did appear historic pond sites.