We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Laboratory sources of error for algal community attributes during sample preparation and counting.
- Authors
Andrew J. Alverson; Kalina M. Manoylov; R. Jan Stevenson
- Abstract
Applied algal studies typically require enumeration of preserved cells. As applications of algal assessments proliferate, understanding sources of variability inherent in the methods by which abundance and species composition data are obtained becomes even more important for precision of measurements. We performed replicate counts of diatoms on permanently fixed coverglasses and all algae in PalmerMaloney chambers to assess precision and accuracy of measurements derived from common counting methods. We counted diatoms and all algae with transects and random fields. Variability estimates (precision) of diatom density, species diversity, and species composition on permanent coverglasses were low between replicate subsamples and between replicate transects. However, average density estimates of diatoms settled on coverglasses determined with transect methods were 4252% greater than density estimates made with random fields. This bias was due to a predictable, nonrandom distribution of diatoms on the coverglass with few diatoms near edges. Despite bias in density when counting diatoms along coverglass transects, no bias was observed in estimates of species composition. Estimates of density and taxa richness of all-algae in PalmerMaloney chambers also had low variability among multiple transects and high similarity in species composition between transects. In addition, counting method in PalmerMaloney chambers did not affect estimates of algal cell density, taxa richness, and species composition, which suggested that counting units were distributed randomly in the chambers. Thus, most sources of variability in sample preparation and analysis are small; however, transect counts should not be used to estimate cell density, and sufficient numbers of random fields must be counted to account for edge effects on cell distribution with material settled on permanently fixed coverglasses.
- Publication
Journal of Applied Phycology, 2003, Vol 15, Issue 5, p357
- ISSN
0921-8971
- Publication type
Article