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Date Permissions Signed

9-7-2021

Date of Award

2009

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Environmental Sciences

First Advisor

Matthews, Robin A., 1952-

Second Advisor

Bodensteiner, Leo R., 1957-

Third Advisor

Homann, Peter S., 1953-

Abstract

An artificial stream system was constructed to study responses of autotrophic and heterotrophic stream communities to salmon-derived nutrients. The artificial stream system contained 12 raceways (1.2 m long x 20 cm wide x 13 cm tall) that were provided with a constant flow of well water. The experimental treatment group consisted of clay pots filled with pureed salmon carcasses and agar to simulate decomposing salmon carcasses; a control group was included consisting of pots containing agar without salmon tissue. Unglazed clay tiles were placed downstream from the clay pots for periphyton to colonize. Periphyton samples were collected from these tiles. Measurements were taken twelve times over the course of 84 experiment days. Water samples were analyzes for nitrogen (total nitrogen, ammonium, and nitrate+nitrite) and phosphorus (total phosphorus, soluble reactive phosphorus). Periphyton samples collected were analyzed for chlorophyll, ash-free dry weight, and respiration. The artificial stream successfully introduced salmon-derived nutrients, especially salmon-derived nitrogen, in a manner that enhanced periphyton. Total nitrogen and ammonium were usually significantly higher in the fish+agar treatments than in the agar treatment group. Phosphorus leached rapidly from the experimental treatment group, while the agar treatment group followed the source water fairly consistently. Periphyton was rarely different among treatments. This may have been due to high background nutrient concentrations in the source water. In addition, there was extensive growth of periphyton along the raceway sides in the fish+agar treatment group that was not reflected in the growth on the tiles and may have shaded periphyton growth on the fish+agar tiles. I determined that the artificial stream system was an appropriate tool for studying the effects of salmon-derived nutrients on autotrophic and heterotrophic communities. Subsequently, other researchers modified the water source and periphyton sampling procedure to successfully study the movement of salmon-derived nutrients into stream communities.

Type

Text

Publisher

Western Washington University

OCLC Number

463483618

Digital Format

application/pdf

Genre/Form

Academic theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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