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2008 Alaska Park Science Symposium
October 14, 2008
Physical, Chemical, and Biological Characteristics of Streams in the Central Noatak National Preserve: An Assessment of Current Status for Future Trends
William B. Bowden1, Michael B. Flinn2, Bruce J. Peterson3, Andrew W. Balser4, Julia R. Larouche5, Angela R. Allen6
1Rubenstein School of Environment and Natural Resources, University of Vermont, 304 Aiken Center, Burlington, VT, 05405, USA, Phone 802-656-2513, Fax 802-656-8683, breck.bowden@uvm.edu
2Rubenstein School of Environment and Natural Resources, University of Vermont, 304 Aiken Center, Burlington, VT, 05405, USA, Phone 802-859-3086, Fax 802-656-8683, michael.flinn@uvm.edu
3The Ecosystems Center, Marine Biological Laboratory, Water St., Woods Hole, MA, 02543, USA, Phone 508-548-3705, peterson@mbl.edu
4Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr., Fairbanks, AK, 99775-7000, USA, Phone 907-257-2733, fnawb@uaf.edu
5Rubenstein School of Environment and Natural Resources, University of Vermont, 304 Aiken Center, Burlington, VT, 05405, USA, Phone 802-859-3086, Fax 802-656-8683, julia.larouche@uvm.edu
6Department of Ecology and Evolutionary Biology, Brown University, P.O. Box 1951, Providence, RI, 02912, USA, Phone 678-637-5779, aallen@mbl.edu
The Noatak River and its surrounding watershed of over 3 million hectares constitute the Noatak National Preserve, an internationally recognized UNESCO Biosphere Reserve that was established for its unique contribution to the conservation of biological diversity and biological resources in the Arctic. The Noatak River is a Wild and Scenic River, and the Noatak Preserve harbors a diverse array of freshwater ecosystems that are relatively undisturbed by human activity. Though undisturbed these freshwater resources have important subsistence values to indigenous cultures and important recreational values to visitors from around the world. The Noatak Preserve is vast and difficult to access, and so relatively little research has been done on the freshwater resources in the area. The most comprehensive previous assessment was done in 1973 and focused primarily on lakes. Beginning in 2005 a group of NPS and university scientists began a collaboration, sponsored by the NPS Arctic Network (ARCN) Inventory and Monitoring program, to assess rivers and lakes in the Noatak Preserve. One objective of this work was to provide a point of comparison to the 1973 work, but the larger objectives were to provide a baseline for future comparisons and to devise a framework for monitoring the freshwater resources of the ARCN parks in the future.
In 2006 we explored the feasibility of using a sampling framework that was based on the underlying lithology of the landscapes in this area. Lithology differs significantly across the preserve and recent work – also supported by the ARCN initiative – showed that lithology strongly influences terrestrial vegetation diversity and productivity. We reasoned the combined effects of contrasting lithologies and related differences in terrestrial soils and vegetation were likely to significantly influence the characteristics of streams draining this area. In July 2006 we sampled a suite of streams in the Feniak Lake area of the Noatak National Preserve. We selected headwater (1st to 3rd order) streams that arose entirely on contrasting lithologies, including ultramafic, non-carbonate, and complex sedimentary formations. Important physical, chemical, and biological characteristics differed significantly among these lithologies, consistent with our a priori hypotheses. Nitrogen chemistry of stream water draining these contrasting lithologies differed significantly and ranged over concentrations at least as great as those observed in streams as diverse as mountain, spring, and tundra streams on the North Slope. Chlorophyll a concentrations were highly variable within and between lithologies but patterns suggest highest production in non-carbonate watersheds. Significantly higher (P<0.05) amounts of metals (Fe, Ni, Si (3x)), base cations (Mg++, Ca++), dissolved organic carbon (4x), and benthic organic matter (5/3x) were found in streams in non-carbonate watersheds compared to ultramafic watersheds. Analysis of macroinvertebrate communities revealed similar trends with significantly (P<0.01) higher abundance (2x), biomass (5x), taxa richness (4/3x), Shannon’s diversity (2x) and ratios of collector-filterer (3/2) and scraper (4x) functional feeding groups in streams of non-carbonate versus ultramafic origin. Streams with complex sedimentary watersheds were variable, but were mostly intermediate with respect to the other two lithologies. These data (and similar data from 2005) suggest that lithology is an important variable that can be used to direct future surveys of freshwater resources in the Noatak River basin and may provide guidance for other high latitude ecosystem studies.
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