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CC BY V4.0, Open Access
Dissertation
EFFECTS OF SPATIALLY AND TEMPORALLY HETEROGENEOUS DISTURBANCE ON BENTHIC, NEARSHORE BIOTA IN LARGE, DEEP, OLIGOTROPHIC LAKES
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000003143
Handle:
https://hdl.handle.net/2376/124753
Abstract
Ecosystem integrity is threatened by disturbance from human activities. Although disturbances can take many different forms, human disturbances are inherently heterogeneous, as these disturbances tend to occur where and when people are present. This inherent spatio-temporal heterogeneity means that we can investigate how independent and intersecting spatial and temporal components of ecological disturbances can influence biotic communities.
Wastewater released into aquatic systems is an example of a high-impact human disturbance that can reshape aquatic communities. Algal communities, especially in oligotrophic lakes, can rapidly assimilate nutrients, causing increased biomass and altered resources for grazers, which may likewise relocate or adjust behavior and physiology to compensate. Despite seeming straightforward, associating times and locations of nutrient loading with explicit biological responses is challenging, as heterogeneities in nutrient loading and biological succession can obfuscate patterns.
Using Lake Baikal (Siberia) and Flathead Lake (Montana, U.S.) as study systems, this dissertation investigates how human disturbance can alter nearshore communities in large oligotrophic ecosystems. Despite Baikal being remote and globally the largest lake by volume, low-level sewage pollution is suspected near certain small lakeside settlements. To investigate potential sewage pollution along a 40-km transect, we sampled water column sewage-associated micropollutants (i.e., microplastics and pharmaceuticals and personal care products – PPCPs), algal and macroinvertebrate abundance, as well as fatty acid profiles that provide insights on trophic interactions. Within the U.S. Pacific Northwest, Flathead Lake also is relatively well protected from human influence yet has demonstrated localized signs of sewage pollution. Building on our spatial study at Lake Baikal, we sampled 15 locations in Flathead Lake over four months for PPCPs as well as periphyton composition, stoichiometry, and fatty acids. Together, these studies evaluate how spatio-temporally heterogenous sewage loading can not only influence community composition, but also nutritional content available to the lake’s larger food web. For Lake Baikal and Flathead Lake, these results are timely, as both lakes are experiencing increasing tourism and an aging wastewater management infrastructure. For lakes worldwide, this work details how ecosystems can respond to eutrophication, while also providing data and infrastructure for continued study intensively within systems and extensively across scales.
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Details
- Title
- EFFECTS OF SPATIALLY AND TEMPORALLY HETEROGENEOUS DISTURBANCE ON BENTHIC, NEARSHORE BIOTA IN LARGE, DEEP, OLIGOTROPHIC LAKES
- Creators
- Michael F Meyer
- Contributors
- Stephanie E Hampton (Advisor)Erica J Crespi (Committee Member)Alexander K Fremier (Committee Member)Ted Ozersky (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 319
- Identifiers
- 99900651901101842
- Language
- English
- Resource Type
- Dissertation