Zoe Kane, PhD Candidate, Smol Lab Using changes in Cladocera assemblages to determine how ornithogenic inputs structure freshwater ecosystems Seabirds can be considered biovectors, transporting large concentrations of nutrients (e.g., nitrogen (N), phosphorous (P)) and metals (e.g., Cd, Zn, Hg) from their marine feeding grounds to their terrestrial breeding grounds. Seabird fertilizes their nesting sites by depositing feces, feathers, carcasses, and eggshells, which can be tracked directly (e.g., sterol/stanol to characterize guano deposits) or from their influence on nearby waterbodies (e.g., nutrient enrichment and/or pH changes traced using subfossil algal assemblages over time). Recent paleolimnological studies from PEARL reconstructed and hindcasted the population dynamics of Baccalieu Islands vulnerable Leach's Storm petrel population (Hydrobates leucorhous, hereafter LESP) to assess the effects of natural and anthropogenic stressors.
Adding to the several paleolimnological proxies used to track and reconstruct historical LESP inputs on ponds on Baccalieu island (Lunin, Brister, Gull and Mainland Reference ponds), I have implemented Cladocerans, or water fleas, which are well-known paleolimnological indicators (but as yet unexplored in these novel ornithological-limnological studies) as their species-specific exoskeletal remains are well preserved in sediment. They have a pivotal role in aquatic food webs, occupying an intermediate trophic position between top-down regulators and bottom-up factors, providing a critical link between the eutrophication process and the implications of elevated nutrient conditions on higher trophic levels. My results build on previous work that examined how seabird-derived nutrients influence primary production and algal assemblages in highly impacted ponds. I demonstrate that shifts from littoral/benthic to pelagic cladoceran taxa coincide with peaks in the inferred LESP population, highlighting the importance of seabird inputs to limnological conditions and eutrophication in several ponds on Baccalieu Island. Comments are closed.
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