title: Forest die-back modified plankton recovery from acidic stress.
abstract: We examined long-term data on water chemistry of Lake Rachelsee (Germany) following the changes in acidic depositions in central Europe since 1980s. Despite gradual chemical recovery of Rachelsee, its biological recovery was delayed. In 1999, lake recovery was abruptly reversed by a coincident forest die-back, which resulted in elevated terrestrial export of nitrate and ionic aluminum lasting ~5 years. This re-acidification episode provided unique opportunity to study plankton recovery in the rapidly recovering lake water after the abrupt decline in nitrate leaching from the catchment. There were sudden changes both in lake water chemistry and in plankton biomass structure, such as decreased bacterial filaments, increased phytoplankton biomass, and rotifer abundance. The shift from dominance of heterotrophic to autotrophic organisms suggested their substantial release from severe phosphorus stress. Such a rapid change in plankton structure in a lake recovering from acidity has, to the best of our knowledge, not been previously documented.
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 31, 37005, Ceske Budejovice, Czech Republic, jaroslav.vrba@prf.jcu.cz.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Vrba
authors.forename: Jiří
authors.initials: J
authors.lastname: Kopáček
authors.forename: Jan
authors.initials: J
authors.lastname: Fott
authors.forename: Linda
authors.initials: L
authors.lastname: Nedbalová
mesh_terms: D015258:Acid Rain; D017753:Ecosystem; D005858:Germany; D006863:Hydrogen-Ion Concentration; D060106:Lakes / Q000737:chemistry* / Q000469:parasitology; D010933:Plankton; D013312:Stress, Physiological
chemical_list: D015258:Acid Rain