Advisor

Angela Strecker

Date of Award

Spring 5-21-2015

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Environmental Science and Management

Department

Environmental Science and Management

Physical Description

1 online resource (vii, 60 pages)

Subjects

Freshwater zooplankton -- Washington (State) -- Mount Rainier National Park, Ecological disturbances -- Washington (State) -- Mount Rainier National Park, Freshwater zooplankton -- Effect of acid deposition on -- Washington (State) -- Mount Rainier National Park, Freshwater zooplankton -- Effect of atmospheric deposition on -- Washington (State) -- Mount Rainier National Park, Atmospheric nitrogen compounds -- Washington (State) -- Mount Rainier National Park, Plankton populations -- Washington (State) -- Mount Rainier National Park, Fish stocking -- Environmental aspects -- Washington (State) -- Mount Rainier National Park

DOI

10.15760/etd.2391

Abstract

Freshwater ecosystems are subject to a wide variety of stressors, which can have complex interactions and result in ecological surprises. Non-native fish introductions have drastically reduced the number of naturally fishless lakes and have resulted in cascading food web repercussions in aquatic and terrestrial habitats. Additional anthropogenic influences that result from increases in global airborne emissions also threaten wildlife habitat. Atmospheric nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of wilderness ecosystems. Planktonic communities have shown declines in response to predation and shifts in composition as a result of nutrient inputs and acidification, both of which are potential fates of nitrogen deposition. This study identified the response of zooplankton communities from two lakes (fish present vs. absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance event in mesocosms. The experiment used a 2 x 2 factorial design with acid and nitrogen treatments. Treatments resulted in significantly elevated nitrogen and decreased pH conditions from control mesocosms over 42 days, indicating that the treatment effects were achieved. Results indicate that zooplankton communities from lakes with different food web structure respond differently to the singular effects of acid and nitrogen addition. Surprisingly, the interaction of the two stressors was related to increases in community metrics (e.g., abundance, biomass, body size, richness, and Shannon-Weiner diversity) for both lake types. This work can aid management decisions as agencies look to restore more aquatic montane habitats to their historic fishless states, and assess their abilities to recover and afford resistance to atmospheric pollution.

Persistent Identifier

http://archives.pdx.edu/ds/psu/15699

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