The use of scaled chrysophytes in long term monitoring programs for the detection of changes in lakewater acidity

The addition of a biomonitoring component to a routine chemical monitoring program would enhance the potential of the monitoring effort to measure shifts in lakewater acidity. We provide evidence that changes in the species composition of scaled chrysophytes can provide an effective means for identifying and quantifying changes in lakewater acidity. As a result, it is consluded that a scaled chrysophyte component would provide an excellent addition to a long term monitoring effort. Specific and subspecific taxa of scaled chrysophytes are differentially distributed along a pH gradient. The distributions along a pH gradient of many of the well defined and cosmopolitan taxa are summarized and the taxa arranged into different pH groups. The importance of pH, relative to other variables, in controlling the distribution of scaled chrysophytes is discussed utilizing evidence from both neolimnological and paleolimnological studies. A plan for the incorporation of a biomonitoring component utilizing scaled chrysophytes into a long term monitoring program for acidity is outlined. The plan includes analyses using discrete water samples, sediment traps and sediment cores. Several programs are outlined and discussed based on the frequancy of sampling events.