Lake Pocotopaug Lake and Watershed Restoration Evaluation ...

12.4 Additional Investigative SamplingIn addition to the water quality sampling program above, up to 20 samples should be allocatedfor suspected contaminants as warranted by the above investigations. This investigativesampling allowance will enable investigation of any suspicious inputs or events relating to thelake.12.5 Algal AssaysThe occurrence of blooms in Lake Pocotopaug at relatively low phosphorus levels is unusual,and the ability of ambient phytoplankton (especially the assemblage dominated by Anabaenaaphanizomenoides) to grow at successively lowered nutrient levels should be investigated. Labassays using lake water, diluted lake water, and distilled water can be run to determine thegrowth potential of Lake Pocotopaug algae. These algae may still be getting some nutritionfrom the sediments as stored reserves in the resting stages before they germinate each year, ormay just be very effective at using low ambient levels of phosphorus. This effort should be ableto determine the proper target for phosphorus in Lake Pocotopaug to prevent these blooms, andwhether additional nutrient inactivation (in other parts of the lake) is necessary.12.6 Fish AssaysThe apparent stress on fish each winter can be investigated by lab assays using lake water andtest fish under controlled laboratory conditions. Assays should be run using water from the lakeor tributaries to determine if observed effects in the lake can be duplicated in the lab. Assaysshould occur in December and possibly January, at the time of known past stress. Assaysshould include water from near the bottom of the lake and any suspicious input source.Lake Pocotopaug Restoration Evaluation 125May 2002