The Role of Benthic Macroinvertebrates in Detritus Dynamics of Streams: A Computer Simulation

Abstract

Detritus dynamics in Big Hurricane Branch, a second-order stream at Coweeta Hydrologic Laboratory in the southern Appalachian Mountains, were simulated with a computer model, using data from a variety of Coweeta stream studies. The model was used to evaluate the role of macroinvertebrates in the stream. Macroinvertebrates accounted for only a small portion of the respiration of detritus; their major role was conversion of benthic detritus into transported detritus. Macroinvertebrates were responsible for 27% of annual particulate organic matter (POM) transport, though when they were removed there was only a 10% reduction in POM transport because of a compensatory increase in storm transport. The contribution of macroinvertebrates to POM transport during nonstorm periods was much more significant, as high as 83% in late summer.Based on an annual budget, macroinvertebrates decrease the efficiency of detritus processing in low-order streams, because they increase transport loss. On a longer time scale, however, macroinvertebrates prevent accumulation of large amounts of detritus in the stream and major losses during infrequent large storms. By stabilizing long-term detritus export dynamics, they provide an important link between low-order and higher-order streams.

Experimental evidence quantifying the role of benthic invertebrates in organic matter dynamics of headwater streams

“…1982a;Cuffney, Wallace & Webster, 1984). Calculations of detritus consumption based on shredder ingestion and production data also reveal that, whereas shredders may assimilate only a small portion of energy (Fisher & Likens, 1973), they may ingest 32-80% of annual litter inputs (Cummins, 1971;Webster & Patlen, 1979;Webster. 1983) and.…”

Modélisation d'un système lotique pollué par une charge organique : prise en compte de l'activité des microorganismes benthiques

“…L'interprétation des campagnes de mesures (FONTVIEILLE et CAZELLES, 1985 ;FONTVIEILLE et CAZELLES, 1988) complétée par une première étude bibliographique (BOLING et al, 1975 ;CLESCERI et al, 1977 ;Mac INTIRE et COLBY, 1978 ;O'NEIL et al-, 1979a ;WEBSTER et al, 1979 ;THERIEN et al, 1981 ;NEWBOLD et al, 1983 ;WEBSTER, 1983) ont conduit à l'écriture d'un modèle global du système "Albenche" (CAZELLES, 1987) centré sur les transferts de carbone organique (éqs (1)) dont la structure est schématisée a la figure 2. Basée sur le principe de conservation de masse, la formulation mathématique du modèle est constituée par un système d'équations aux dérivées partielles qui décrivent l'évolution de chaque compartiment en fonction du temps et de la distance longitudinale.…”

Organic Carbon Concentrations in Hyporheic Zone Sediments: A Tool for Measuring Stream Integrity

“…Lower order streams often receive the majority of allochthonous organic matter from terrestrial leaf litter, large woody debris and soil particles that are washed into the stream from the watershed (Allan 1995). Particulate organic matter (POM) is a vital component of stream energy budgets (Cummins 1974) and influences consumer populations (Webster 1983). POM concentrations in hyporheic zones (Runkel et al 2003) reflect a balance among inputs, transport, and retention (Wallace et al 1982).…”