thumbnail

Nitrogen deposition effects on diatom communities in lakes from three National Parks in Washington State

Water, Air, and Soil Pollution

By:
, , , ,
DOI: 10.1007/s11270-013-1857-x

Links

Abstract

The goal of this study was to document if lakes in National Parks in Washington have exceeded critical levels of nitrogen (N) deposition, as observed in other Western States. We measured atmospheric N deposition, lake water quality, and sediment diatoms at our study lakes. Water chemistry showed that our study lakes were ultra-oligotrophic with ammonia and nitrate concentrations often at or below detection limits with low specific conductance (<100 μS/cm), and acid neutralizing capacities (<400 μeq/L). Rates of summer bulk inorganic N deposition at all our sites ranged from 0.6 to 2.4 kg N ha−1 year−1 and were variable both within and across the parks. Diatom assemblages in a single sediment core from Hoh Lake (Olympic National Park) displayed a shift to increased relative abundances of Asterionella formosa and Fragilaria tenera beginning in the 1969–1975 timeframe, whereas these species were not found at the remaining (nine) sites. These diatom species are known to be indicative of N enrichment and were used to determine an empirical critical load of N deposition, or threshold level, where changes in diatom communities were observed at Hoh Lake. However, N deposition at the remaining nine lakes does not seem to exceed a critical load at this time. At Milk Lake, also in Olympic National Park, there was some evidence that climate change might be altering diatom communities, but more research is needed to confirm this. We used modeled precipitation for Hoh Lake and annual inorganic N concentrations from a nearby National Atmospheric Deposition Program station, to calculate elevation-corrected N deposition for 1980–2009 at Hoh Lake. An exponential fit to this data was hindcasted to the 1969–1975 time period, and we estimate a critical load of 1.0 to 1.2 kg N ha−1 year−1 for wet deposition for this lake.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nitrogen deposition effects on diatom communities in lakes from three National Parks in Washington State
Series title:
Water, Air, and Soil Pollution
DOI:
10.1007/s11270-013-1857-x
Volume
225
Issue:
1857
Year Published:
2014
Language:
English
Publisher:
Springer
Contributing office(s):
Washington Water Science Center
Description:
23 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Water, Air, and Soil Pollution
Country:
United States
State:
Washington