Identifying nutrient reference sites in nutrient-enriched regions-Using algal, invertebrate, and fish-community measures to identify stressor-breakpoint thresholds in Indiana rivers and streams, 2005-9
Year: 2013
Type: report
Abstract: Excess nutrients in aquatic ecosystems can lead to shifts in species composition, reduced dissolved oxygen concentrations, fish kills, and toxic algal blooms.In this study, nutrients, periphyton chlorophyll a (CHLa), and invertebrate-and fishcommunity data collected during 2005-9 were analyzed from 318 sites on Indiana rivers and streams.The objective of this study was to determine which invertebrate and fish-taxa attributes best reflect the conditions of streams in Indiana along a gradient of nutrient concentrations by (1) determining statistically and ecologically significant relations among the stressor (total nitrogen, total phosphorus, and periphyton CHLa) and response (invertebrate and fish community) variables; and(2) determining the levels at which invertebrate-and fish-community measures change in response to nutrients or periphyton CHLa.For water samples at the headwater sites, total nitrogen (TN) concentrations ranged from 0.343 to 21.6 milligrams per liter (mg/L) (median 2.12 mg/L), total phosphorus (TP) concentrations ranged from 0.050 to 1.44 mg/L (median 0.093 mg/L), and periphyton CHLa ranged from 0.947 to 629 mg/L (median 69.7 mg/L).At the wadable sites, TN concentrations ranged from 0.340 to 10.0 mg/L (median 2.31 mg/L), TP concentrations ranged from 0.050 to 1.24 mg/L (median 0.110 mg/L), and periphyton CHLa ranged from 0.383 to 719 mg/L (median 44.7 mg/L).Recursive partitioning identified statistically significant low and high breakpoint thresholds on invertebrate and fish measures, which demonstrated the ecological response in enriched conditions.The combined community (invertebrate Identifying Nutrient Reference Sites in Nutrient-Enriched Regions: Indiana Rivers and Streams, 2005-9 group indicates that low nutrient concentrations are a result of nutrient uptake and increased algal growth.This study highlights the importance of assessing multiple lines of evidence when attempting to identify the trophic condition of a site.
Source: Scientific investigations report
DOI: 10.3133/sir20125243
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: bronze
Funder: U.S. Geological Survey
OpenAlex ID: W3366977