caa a22 4500 467886075 CHVBK 20180406152734.0 cr unu---uuuuu 170328e20060301xx s 000 0 eng 10.1007/s10021-004-0016-z doi (NATIONALLICENCE)springer-10.1007/s10021-004-0016-z Cascading Trophic Interactions in an Oligotrophic Species-poor Alpine Lake [Elektronische Daten] [Brian Parker, David Schindler] Non-native brook trout (Salvelinus fontinalis) were eradicated from alpine Bighorn Lake, Alberta, Canada, to test whether strong cascading trophic interactions (CTI) can occur in oligotrophic, high seston C:P, species-poor lakes. Fishless alpine Pipit Lake was used as a reference ecosystem. Bighorn Lake zooplankton biomass increased from 0.14:1 relative to Pipit Lake before fish removal began in 1997 to 0.6:1 afterwards due to an increase in the abundance of adult cyclopoid copepods beginning in 1997 and the reappearance of Daphnia middendorffiana in 1998. Following the reappearance of Daphnia, Bighorn Lake total phytoplankton biomass fell from 64:1 relative to Pipit Lake to 0.9:1. Over the same periods Bighorn Lake:Pipit Lake chlorophyll-a ratios declined from 2.4:1 to 1.6:1, although the decrease was not statistically significant. Mid-summer Secchi disc depth in Bighorn Lake increased from 3.1 m before manipulation to 9.2 m, the maximum depth of the lake, in 2001 and 2002. Increased transparency was most likely due to increased filtration of suspended inorganic particles from the water column by higher abundances of large zooplankton. Post-manipulation increases in dissolved inorganic nitrogen (DIN), DIN:total dissolved phosphorus (TDP) ratio and declines in TDP in Bighorn Lake were not attributable to ecosystem manipulation, similar changes were observed in reference Pipit Lake. We conclude that strong pelagic CTI, expressed as change in total phytoplankton biomass and largely mediated by Daphnia, can occur in oligotrophic, high seston C:P, species-poor ecosystems. However, strong CTI responses in phytoplankton biomass may lag trophic manipulation by several years. Springer Science+Business Media, Inc., 2006 trophic cascade nationallicence alpine lakes nationallicence zooplankton nationallicence phytoplankton, water transparency nationallicence nutrients nationallicence Parker Brian Department of Biological Sciences, University of Alberta, T6G 2E9, Edmonton, Alberta, Canada aut Schindler David Department of Biological Sciences, University of Alberta, T6G 2E9, Edmonton, Alberta, Canada aut Ecosystems Springer-Verlag; www.springer-ny.com 9/2(2006-03-01), 157-166 1432-9840 9:2<157 2006 9 10021 https://doi.org/10.1007/s10021-004-0016-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-004-0016-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Parker Brian Department of Biological Sciences, University of Alberta, T6G 2E9, Edmonton, Alberta, Canada aut NATIONALLICENCE 700 1- Schindler David Department of Biological Sciences, University of Alberta, T6G 2E9, Edmonton, Alberta, Canada aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/2(2006-03-01), 157-166 1432-9840 9:2<157 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer