Community change and ecosystem functional complexity: A microcosm study of copper toxicity

James R. Pratt, James L. Rosenberger

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Toxic chemicals can alter ecosystem structure and ecological processes. The functional redundancy of systems - an assumption that biotic communities have several members that perform similar functions - is used to explain how communities maintain processes such as nutrient cycles and production-respiration patterns under stress. We tested community functional redundancy by analyzing the uncoupling of multispecies processes. We used continuously collected pH values in replicate laboratory microcosms to compare changes in the pH spectrum (an analog of diurnal net primary production and respiration) to changes in community structure (species richness, composition, standing crop). Spectral analyses identified the repeating frequencies in continuous pH records and showed that severe uncoupling of diurnal production and respiration patterns in microcosms treated with copper 9.9-205 ug Cu/L) occurred at concentrations near or below numerical water quality criteria (ca. 20 ug Cu/L). Changes in the pH spectrum were coincident with the loss of species from the microcosms. Changes in spectral density and community structure were indicative of adverse ecological effects, and these changes occurred at lower concentrations than detectable changes in nutrient cycles and standing crop biomass (protein, chlorophyll). Results of these experiments suggest that functional redundancy in communities does not extend to continuous measures of community metabolism. As such, the concept of functional redundancy is questioned: the failure to detect changes in processes belies alterations in process dynamics. The concept of functional redundancy is probably a result of insufficient statistical power rather an inherent ecosystem property.

Original languageEnglish (US)
Title of host publicationASTM Special Technical Publication
EditorsJoseph W. Gorsuch, James F. Dwyer, Christopher G. Ingersoll, Thomas W. La Point
PublisherPubl by ASTM
Pages88-102
Number of pages15
Edition1216
ISBN (Print)0803114850
Publication statusPublished - Dec 1 1993
EventProceedings of the Symposium on Environmental Toxicology and Risk Assessment: Aquatic, Plant, and Terrestrial - Pittsburgh, PA, USA
Duration: Apr 26 1992Apr 30 1992

Publication series

NameASTM Special Technical Publication
Number1216
ISSN (Print)0066-0558

Other

OtherProceedings of the Symposium on Environmental Toxicology and Risk Assessment: Aquatic, Plant, and Terrestrial
CityPittsburgh, PA, USA
Period4/26/924/30/92

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Pratt, J. R., & Rosenberger, J. L. (1993). Community change and ecosystem functional complexity: A microcosm study of copper toxicity. In J. W. Gorsuch, J. F. Dwyer, C. G. Ingersoll, & T. W. La Point (Eds.), ASTM Special Technical Publication (1216 ed., pp. 88-102). (ASTM Special Technical Publication; No. 1216). Publ by ASTM.