Title
Phytoplankton Variation in Four Shallow High-Elevation Lakes in the Upper North Fork Nooksack River Watershed of the North Cascades, Washington (USA)
Document Type
Article
Publication Date
5-1-2016
Keywords
limnology, mountain lakes, North Cascades, phytoplankton, principal components analysis
Abstract
High-elevation lakes are recognized as being sensitive to changes in climate, atmospheric deposition, and other global effects. Most studies of high-elevation lakes in the North Cascades have used a landscape-scale approach to describe aquatic systems, but smaller scale research is needed to examine natural variation in these types of lakes. We conducted a watershed-scale study encompassing four close-proximity lakes near Mt. Baker (Whatcom Co., WA) in order to examine the variation in phytoplankton and water quality in these lakes. The lakes were sampled weekly during the ice-free season of 2012 to measure seasonal changes. Chlorophyll-a levels were < 2.0 µg L-1, confirming the oligotrophic nature of these lakes. Nitrogen limitation was indicated by median DIN:TP < 3 at all sites, along with significant correlations between chlorophyll-a and nitrogen. The phytoplankton were represented by 49 genera (79 unique taxa), which was comparable to landscape-scale studies of North Cascades lakes. Ordination of phytoplankton samples separated the lakes into two groups: one group dominated by diatoms and the other dominated by Chlorophyta, Cyanobacteria, and Ochrophyta. The diatom group was associated with lower water temperatures and total nitrogen concentrations, and higher pH, dissolved oxygen, nitrate, and phosphate concentrations. Results aligned with differences in the lakes' external physical environments, including lakeshore vegetation and ice-melt timing. Our results demonstrated that close-proximity, high-elevation lakes can differ in phytoplankton and water quality, which should be taken into account when evaluating larger scale patterns across multiple watersheds and mountain ranges.
Publication Title
Northwest Science
Volume
90
Issue
2
First Page
119
Last Page
135
DOI
https://doi.org/10.3955/046.090.0205
Recommended Citation
Siana W. Wong, Robin A. Matthews, and Karl Bruun "Phytoplankton Variation in Four Shallow High-Elevation Lakes in the Upper North Fork Nooksack River Watershed of the North Cascades, Washington (USA)," Northwest Science 90(2), 119-135, (1 May 2016). https://doi.org/10.3955/046.090.0205
Type
Text
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Language
English
Format
application/pdf