New Zealand Journal of Marine and Freshwater Research abstracts
Artificial substrate exposure times for periphyton biomass estimates in rivers
BARRY J. F. BIGGS
Hydrology Centre
Division of Water Sciences
Department of Scientific and Industrial Research
P. O. Box 22 037, Christchurch, New Zealand
Abstract
The time for periphyton biomass to accrue lo approximately natural levels on a new artificial, substrate sampler, designed for use in harsh river environments, was investigated. Six 8-week experiments were attempted in 9 New Zealand rivers of differ ing nutrient status. Accrual rales were highly variable and results between experiments were inconsistent within rivers. The colonisation stage, and the low biomass communities, were dominated by heterotrophic organisms and/or detritus. In unenrichcd and enriched rivers, biomass on the artificial substrates approximated natural substrate communities after 4 weeks. In moderately enriched rivers results were highly variable and artificial substrate biomass gave only a fair representation of natural substrate levels after 8 weeks of accrual. Because of variability in accural rates, adopting standard accrual times for artificial substrate sampling of New Zealand's shallow, swift rivers is not recommended. Samplers should be checked regularly and removed just before sloughing starts at the most productive site, to avoid comparing sloughed and non-sloughed communities.
Keywords periphyton; artificial substrates; standing crop; chlorophyll; biomass; monitoring; water quality; rivers
New Zealand Journal of Marine and Freshwater Research, 1988, Vol. 22: 507-515 ; Crown copyright 1988Received 4 September 1987; accepted4 December 1987
PDF file of entire paper: medium quality (668K); (scanned from paper original: notes about this process)
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