Phosphorus incubations in an oligotrophic alpine lake and copper sulfate treatment of a eutrophic montane lake

Two types of lakes were studied during the summer of 2012 in the Rocky Mountains. The first is Green Lake 4 in the Boulder Creek Watershed. It is an oligotrophic alpine lake that sees very little human influence. The second is Mirror Lake at Big Elk Meadows. It is the antithesis to Green Lake 4. Mirror Lake is a eutrophic montane lake that is currently under heavy phosphorus load from local septic tanks. At Green Lake 4 we conducted phosphorus enrichment experiments in mesocosms. The goal was to see if adding phosphorus affected the DOM and phytoplankton in drought conditions vs a non-drought year. Similar previous experiments during a wetter summer looked at limiting nutrients, but pH fluxuations affected the incubations making analysis of DOM and phytoplankton very difficult. Mirror Lake on the other hand is a residential community lake that is home to recreational fish populations. They are currently having problems with algae blooms which when they die create anoxic lake conditions. These conditions create large scale fish kills that are unfavorable for the residents of Big Elk Meadows. A Copper Sulfate treatment was applied to samples of Mirror Lake to determine effectiveness of algae mitigation. We will present results from the 2012 field season.