Lotic Diatoms as Environmental Indicators for Modern and Paleo Studies

The ecological impacts of anthropogenic activities on aquatic environments have led to the development of new methods of environmental monitoring (Cohen et al 1993, Kelly and Whitton 1995). Benthic algae represent a ubiquitous group of photosynthetic organisms that play a pivotal role in stream food webs but may also be used for observing long-term trends in community changes that can occur because of non-point source pollution (Lowe and Pan 1996). Diatoms in particular are useful ecological indicators because they are abundant in most lotic systems and have been used in a number of trophic indices for water quality monitoring (USEPA report, Kelly and Whitton 1995 and authors therein). The persistence of diatom frustules in the environment enables prehistoric conditions to be reconstructed based on the narrow ecological preferences of most species (Lowe and Pan 1996).