Relationships among catchment land use and concentrations of nutrients, algae, and dissolved oxygen in a southern California river

Klose, K; Cooper, SD; Leydecker, AD; Kreitler, J

HERO ID

3608056

Reference Type

Journal Article

Year

2012

Language

English

HERO ID 3608056
In Press No
Year 2012
Title Relationships among catchment land use and concentrations of nutrients, algae, and dissolved oxygen in a southern California river
Authors Klose, K; Cooper, SD; Leydecker, AD; Kreitler, J
Journal Freshwater Science
Volume 31
Issue 3
Page Numbers 908-927
Abstract Rapid human population growth engenders landuse changes and alters nutrients, algal biomass (as chlorophyll a [chl a]), and dissolved O2 concentrations (DO) in streams, but quantitative information on these relationships is limited in regions with a Mediterranean climate. We surveyed macroalgal % cover and chl a and physicochemical factors in spring and summer at 15 stream and estuarine sites in a catchment in southern California with a mosaic of undeveloped, agricultural, and urban areas to examine relationships among land use, nutrients, algae, and DO. We used nutrient diffusing substrata (NDS) at 12 sites to assess the nutrient(s) limiting algal growth. Algal chl a and pH often exceeded suggested or mandated water-quality impairment thresholds at sites affected by human activity, particularly those downstream from a wastewater treatment plant. Total N (TN) affected total and benthic algal chl a in spring and summer, total P (TP) affected benthic algal chl a in summer, and light influenced algae in summer. N was the sole or primary limiting nutrient at ½ of the sites and was colimiting with P at another ? of the sites. Nutrient ratios (molar TN?TP) were poor predictors of algal responses to nutrient enrichment. Diel changes in dissolved O2 were related positively to discharge and negatively to algal chl a, particularly when floating macroalgae were present. In June, N, chl a, and macroalgal % cover were positively related to human landuse patterns at the subcatchment scale, whereas in September, P and chl a were related to landuse patterns at more local scales (500 m, 1000 m). Mediterranean streams present a variety of challenges for water-quality managers because of high seasonal and interannual variation in discharge and nutrient flux, high accumulations of algae during the dry season, low nutrient thresholds that generate nuisance algal blooms, and human population growth and associated changes in landuse patterns.
Doi 10.1899/11-155.1
Wosid WOS:000309905100018
Url http://www.jstor.org/stable/10.1899/11-155.1
Is Certified Translation No
Dupe Override No
Is Public Yes
Language Text English
Keyword nutrients; streams; land use; Mediterranean; algae; dissolved oxygen; nutrient diffusing substrata
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