title: The jellification of north temperate lakes.
abstract: Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic herbivores (Ca-rich Daphnia species) by Holopedium glacialis, a jelly-clad, Ca-poor competitor. In some lakes, this transformation is being facilitated by increases in macro-invertebrate predation, both from native (Chaoborus spp.) and introduced (Bythotrephes longimanus) zooplanktivores, to which Holopedium, with its jelly coat, is relatively invulnerable. Greater representation by Holopedium within cladoceran zooplankton communities will reduce nutrient transfer through food webs, given their lower phosphorus content relative to daphniids, and greater absolute abundances may pose long-term problems to water users. The dominance of jelly-clad zooplankton will likely persist while lakewater Ca levels remain low.
authors.affiliation: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
authors.forename: Adam
authors.initials: A
authors.lastname: Jeziorski
authors.affiliation: Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Downing St., Cambridge CB2 3EA, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tanentzap
authors.affiliation: Department of Biology, York University, 4700 Keele St., Toronto, Ontario, Canada M3J 1P3.
authors.forename: Norman D
authors.initials: ND
authors.lastname: Yan
authors.affiliation: Ontario Ministry of the Environment and Climate Change, Dorset Environmental Science Centre, 1026 Bellwood Acres Road, PO Box 39, Dorset, Ontario, Canada P0A 1E0.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Paterson
authors.affiliation: Ontario Ministry of the Environment and Climate Change, Environmental Monitoring and Reporting Branch, 125 Resources Road, Toronto, Ontario, Canada M9P 3V6.
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Palmer
authors.affiliation: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 Department of Biology, University of Ottawa, 75 Laurier Avenue East, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Korosi
authors.affiliation: Ontario Ministry of the Environment and Climate Change, Dorset Environmental Science Centre, 1026 Bellwood Acres Road, PO Box 39, Dorset, Ontario, Canada P0A 1E0.
authors.forename: James A
authors.initials: JA
authors.lastname: Rusak
authors.affiliation: Department of Chemistry and Biology, Ryerson University, 350 Victoria St., Toronto, Ontario, Canada M5B 2K3.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Arts
authors.affiliation: Cooperative Freshwater Ecology Unit, Laurentian University, 935 Ramsey Lake Road, Greater Sudbury, Ontario, Canada P3E 2C6.
authors.forename: Wendel Bill
authors.initials: WB
authors.lastname: Keller
authors.affiliation: Ontario Ministry of the Environment and Climate Change, Dorset Environmental Science Centre, 1026 Bellwood Acres Road, PO Box 39, Dorset, Ontario, Canada P0A 1E0.
authors.forename: Ron
authors.initials: R
authors.lastname: Ingram
authors.affiliation: Department of Biology, York University, 4700 Keele St., Toronto, Ontario, Canada M3J 1P3.
authors.forename: Allegra
authors.initials: A
authors.lastname: Cairns
authors.affiliation: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 smolj@queensu.ca.
authors.forename: John P
authors.initials: JP
authors.lastname: Smol
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis*; D033361:Cladocera / Q000502:physiology*; D004175:Diptera / Q000502:physiology; D020387:Food Chain; D060106:Lakes / Q000737:chemistry*; D008954:Models, Biological; D009864:Ontario; D011157:Population Dynamics; D013045:Species Specificity; D015048:Zooplankton / Q000502:physiology*
chemical_list: D002118:Calcium
keywords: Daphnia; Holopedium; calcium decline; jellification; lakes; nutrients