NUTRIENT LIMITATION IN A SOUTHWESTERN DESERT RESERVOIR - EUTROPHICATION OF LAS-VEGAS-BAY, LAKE MEAD, NEVADA

Algal bioassay tests were conducted with Selenastrum capricornutum and natural algae on inner Las Vegas Bay, Lake Mead, Nevada, from Decembe r 1992 through September 1993, to identify any nutrient limitation in an area of the reservoir that has experienced problems associated with severe nutrient enrichment. Three areas were sampled based on a gradi ent of water quality conditions that existed in Las Vegas Bay (LVB). D isodium ethylenedinitrilotetraacetate (EDTA) significantly stimulated algal growth compared to non-EDTA treatment. Algal bioassays indicated that phosphorus (P) was the primary limiting nutrient at ail stations for most of the test dates. Chi a response with EDTA + phosphorus (ED TA+P) was significantly greater (p<0.05) than the control response. Th ese tests suggest that continued P enrichment of fewer LVB may well re sult in increased algal productivity.