While blue-green algae has been noted as becoming problematic for one of Chautauqua County's most valuable assets, it may be what lurks beneath that is becoming a major concern.
One of the lake's biggest threats is invasive species, such as zebra mussels and water chestnuts.
While water chestnuts have yet to be seen as a major issue, David Spann, district field manager for the county Soil and Water Conservation District said an influx of zebra mussels in the last decade poses a threat.
Zebra mussels originated in southern Russia, and made their way to Chautauqua Lake through the Great Lakes system. They primarily digest the same matter small minnows and fish eat during the first stages of life, and an adult zebra mussel can filter up to one gallon of water per day.
"That doesn't sound like a lot, but when you compound tens of thousands of them in the lake, it's pretty impressive what they can process," Spann said.
The influx of invasive species is due to humans, he said, just like many of the lake's other issues.
The concept of rising phosphorus levels in Chautauqua Lake has garnered the attention of county and state representatives, but it's not just a crumbling septic infrastructure contributing to problems underwater.
According to Spann, increased development along the lake and other environmental factors have had a hand in the lake's growing amount of weeds and invasive species.
"There's more than one issue influencing the lake," Spann said. "It's sewers, septic systems, sedimentation from highways, road ditches and urban runoff flowing into the lake from lawns."
One hundred years ago, 80 percent of communities around the lake were not yet developed, or were pervious, only 30 percent of the land remains untouched.
This, along with severe weather, has contributed to the lake's increasing phosphorus levels over the course of the last 3-4 years. Excessive rain in May contributed to carrying nutrients from stream beds into the water.
County legislator Pierre Chagnon, R-Bemus Point, agreed with Spann.
"Man is responsible for much of the loading of the lake," he said. "Also, whether we believe in global warming or not, we have seen an increase in average air temperature and lake temperature."
This results in a conducive environment for weed and algae growth.
Chagnon introduced a resolution to the County Legislature in January requesting an annual report on the progress of implementation of phosphorus management strategies to achieve the Total Maximum Daily Load limit, or TMDL.
"The lake is a very complex ecosystem, and it's not a simple lightning strike of one action," Chagnon said.
In 2004, the north and south basins of the lake were both added to the New York State Department of Environmental Conservation's list of impaired water bodies that do not meet water quality standards due to phosphorus impairment.
The report is in progress and will be completed by the Environmental Management Council, to be presented to the legislature in July.
Meanwhile, county departments want to implement preventive measures when it comes to future urban development around the lake.
"We're learning from this, and we're trying to make it better," Spann said. "We can't really fix what's happened already but we can prevent more from happening in the future."