Diatom Assemblages as Indicators of Water Quality in Freshwater Habitats of Guam

摘要

Periphytic diatoms were collected on immersed glass slides in five bodies of polluted/unpolluted freshwater for 10-14 days, concomitant to the collection of water samples on three separate days. The water samples were analyzed for 22 water quality parameters. Data from counting at least 750 diatom frustules on randomly-selected slide areas were used to calculate species diversity indices, a sample similarity index, and to determine whether diatom assemblages occur according to water quality or habitat type. Bodies of water from urban runoff had diatoms dominated by Nitzschia palea and low species diversity, particularly where nutrient (nitrate and phosphate) enrichment occurred. Gomphonema parvulum diatoms dominated ponded habitats where mineral nutrients were excessively low (below 0.020 mg/liter). High sample similarity between river stations over time indicated that district diatom assemblages exist according to water quality and habitat type.