title: Cliff-nesting seabirds influence production and sediment chemistry of lakes situated above their colony.
abstract: Seabirds that congregate in large numbers during the breeding season concentrate marine-derived nutrients to their terrestrial nesting sites, and these nutrients disperse and enhance production in nearby terrestrial, freshwater and marine ecosystems. In the Canadian Arctic, large seabird colonies (>100,000 breeding pairs) nest on cliff faces that drain directly in the ocean, ultimately returning the nutrients back to the marine environment from which they were derived. However, strong winds blowing up cliff faces could transport nutrients up in elevation and onto surrounding terrestrial and aquatic environments. Here, we assess the degree to which seabird nutrients and metals have been delivered to coastal lakes near Hudson Strait (Nunavut, Canada) over the past century. Three lakes located at a higher elevation and increasing distance from a thick-billed murre (Uria lomvia) colony (~400,000 breeding pairs) were sampled for surface water chemistry. In addition, algal assemblages, nitrogen isotopes, and metal/metalloids were analyzed in four dated sediment cores. Elevated nutrients and major ions, as well as an enriched δ15N signature in the sediment cores, were measured in the lake <100m from the cliff, whilst no comparable changes were recorded in lakes >1km from the seabird colony. In contrast, similar oligotrophic and benthic diatom assemblages were identified in all three lakes, suggesting that diatoms were not influenced by enhanced nutrient inputs in this Arctic environment. Chemical tracers (e.g., total mercury) and algal assemblages in the lake near the colony suggest climate warming since ~1950 was the most likely driver of limnological changes, but this effect was muted in the more distant lakes. These pronounced changes in the seabird-impacted lake suggest that, with warming air temperatures and diminished lake ice cover, longer growing seasons may allow for aquatic organisms to more fully exploit the seabird nutrient subsidies.
authors: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada; Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada. Electronic address: kathrynhargan@gmail.com.
authors: K E
authors: KE
authors: Hargan
authors: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
authors: N
authors: N
authors: Michelutti
authors: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
authors: K
authors: K
authors: Coleman
authors: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
authors: C
authors: C
authors: Grooms
authors: Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors: J M
authors: JM
authors: Blais
authors: Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors: L E
authors: LE
authors: Kimpe
authors: Wildlife Research Division, Science and Technology Branch, Environment Canada, Ottawa K1A 0H3, Canada.
authors: G
authors: G
authors: Gilchrist
authors: Department of Biology, Acadia University, 33 Westwood Ave., Wolfville, NS, B4P 2R6, Canada.
authors: M
authors: M
authors: Mallory
authors: Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
authors: J P
authors: JP
authors: Smol
mesh_terms: D000818:Animals; D001110:Arctic Regions; D046091:Charadriiformes; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry*; D009425:Nesting Behavior; D020957:Nunavut
keywords: Diatoms; Eastern Arctic; Metals; Nutrients; Paleolimnology; Seabirds