A long-term temporal analysis of heavy metal concentrations in seabird feathers with implications for overgeneralized trophic dynamics
Date
2019-04-26
Author
Advisors
Van Houtan, Kyle
Pimm, Stuart
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Abstract
Anthropogenic deposition and natural cycling of heavy metal can impact ecosystem function:
They can accumulate in marine sediment layers and remain there for long periods of
time. As these metals accumulate and move through the ecosystem to higher trophic
level organisms, these metals have known toxic effects including decreased reproductive
success and compromised immune systems. Seabird feather levels may be representative
of broader ecosystem signals and heavy metal cycling. This study combines heavy metal
concentration data from seabird feathers and builds on the results of previous studies
looking at trophic declines across time. The aim is to emphasize the importance of
tracking trophic levels of top predators, looking at heavy metal concentrations from
the 1880s to 2016, as well as carbon and nitrogen stable isotopes to determine if
changing trophic levels will alter estimated trends and environmental heavy metal
concentrations. We present temporal trends in seabird tissue concentration, and examine
the complex field of trophic transfer, proposing a protocol for interpreting environmental
concentrations. Our results show that trophic declines do not drastically impact directional
trends, but that extrapolating to other trophic levels creates a large margin of uncertainty.
We observe declines in heavy metals that correspond with relevant legislation, and
suggest further studies into lesser known metals to strengthen environmental monitoring
methods.
Type
Master's projectPermalink
https://hdl.handle.net/10161/18438Citation
Johnson, Elizabeth (2019). A long-term temporal analysis of heavy metal concentrations in seabird feathers with
implications for overgeneralized trophic dynamics. Master's project, Duke University. Retrieved from https://hdl.handle.net/10161/18438.Collections
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