Harmful Algal Blooms – the three C’s

Harmful Algal Blooms – the three C’s

William Dean, PhD, Robert Werner PhD, Fan Rotunno Fish

The emergence of HAB’s in Skaneateles Lake, a lake that has long been described as one of the most pristine bodies of water in the state, has an impact that is Critical, Complex and Costly to local residents as well as those depending on the lake for their water supply.

While the emergence of HABs on Skaneateles Lake has raised Critical safety concerns over water quality it will also have significant impacts on the watershed community as a whole. Its impact on many components of the lifeblood of the area is not only Complex, but also Costly to the watershed/lake community, the city of Syracuse, and Onondaga County.

The Skaneateles Lake Association, in collaboration and coordination with its many partners, has been intensively studying the lake and its tributaries for the past two years. The SLA’s Nutrient Management Committee, a team of SLA Board members, watershed community residents and governmental representatives with a broad range of science and technology backgrounds has been working on the HAB challenge.

An extensive study of the lake and watershed has been mounted to understand the chemical, physical and biological processes involved. The information obtained on tributary studies will be critical in identifying where to place remediation efforts. The data from the extensive study of the lake will be instrumental in understanding the complexities of the lake, its nutrient composition, complex ecology, and fluid dynamics. This data will be used to develop a watershed and lake model. These models will help identify areas that contribute to HAB development by supplying nutrients that HAB’s require.

To mount studies of this complexity and importance, the efforts must be coordinated and collaborative. Through the SLA’s Nutrient Management Committee, the SLA is working with the NYS Dept of Environmental Conservation (DEC), Town of Skaneateles, Onondaga County, City of Syracuse Water Dept, Finger Lakes Land Trust (FLLT), The Nature Conservancy (TNC), Onondaga County Soil and Water Conservation District, Syracuse University, SUNY-ESF and many more. This integrated approach has been very focused, action oriented and beneficial.

Some examples of our coordinated activities studying the lake and its tributaries are outlined below. The data obtained from these studies will be analyzed to identify the factors contributing to HABs. The data will also be utilized to build Lake/Watershed Models which will further aid in identifying key targets for remediation and generating predictive “what if” models.

  1. Citizens State Lake Assessment Program (CSLAP): This is a DEC funded effort to monitor temperature profiles, nutrient levels, dissolved oxygen, chlorophyll and a variety of other parameters at two lake sites, one north and one south. SLA Board members in private boats using DEC provided equipment take samples of lake water throughout the water column. Temperature, pH, conductivity and other physical parameters are measured and samples are processed and sent to the Upstate Freshwater Institute for chemical and biological analysis. This year sampling was coordinated with overhead satellite measurements in an effort to correlate conditions in the lake with satellite views of the lake.
  2. US Geological Survey Sonde: The US Geological Survey operates a sonde at the north CSLAP site which automatically makes physical measurements of water quality.
  3. DEC Transit Study: DEC is studying the biological content of waters off shore from multiple tributaries This project is designed to collect detailed temporal, vertical, and spatial data at multiple locations ranging from the open-water to nearshore. The information will be used to help understand the formation of HABS and cyanobacteria biomass in low/moderate nutrient lakes. In addition to determine the representativeness of the open water, long-term monitoring location compared to intensively monitoring, additional sites from this study.
  4. Sediment Study: The nutrient content of lake sediments is very high. These nutrients are potentially available to algae and HABs. This one-year Syracuse University study, funded by the SLA Legacy Fund, has taken 130 samples on 17 transects (from near shore to deeper waters) and will be analyzing the chemical composition and physical properties of the sediment. This information will help us understand the role sediments are playing in supporting algal growth.
  5. Zebra Mussel Program: DEC will initiate this state funded program in 2020. The purpose is to understand what role zebra mussels are playing in the occurrence of HAB’s. Studies on lakes in Michigan have suggested that in oligotrophic lakes such as Skaneateles Lake, mussels can facilitate algal blooms.
  6. Nutrient Loading studies:
    1. The town of Skaneateles has contracted with Upstate Freshwater Institute (UFI) over the past several years to monitor the 4 major tributaries flowing into the lake: Shotwell Brook, Grout Brook, Bear Swamp Creek, and Harold Brook. This monitoring has been extensively supported by the Legacy Fund as well. The resulting data collected will, when combined with other tributary and lake studies, aid in identifying key remediation sites.
    2. Nine minor tributaries are being monitored by Syracuse University. They are: 10 mile creek, 5 mile creek, Hardscrabble Brook, Withey Brook, 1 mile creek, Dowling Brook (2 sites), Fisher Brook, Bentley Brook and Glen Cove. They will be sampled on a regular basis under base flow conditions and during storm events. Sample collection is being done by a team of volunteers assembled by the SLA with collection of the samples coordinated by the SLA Executive Director.


  1. Atmospheric Loading: A significant fraction of the total nutrient loading to the lake occurs as a result of rain, snow and dust settling on the lake surface. The atmospheric contributions are being collected and analyzed by scientists and Syracuse University.
  2. Submergent Vegetation: The annual decomposition of submerged aquatic vegetation makes a contribution to the pool of available nutrients each year. Little is known, however, what the magnitude of this source is. Studies have been initiated in 2019 when samples of aquatic vegetation from around the lake were collected and analyzed for nutrient content.

All of these efforts are costly but they are producing critical data which will be utilized to build watershed and lake models. This data and resulting modeling efforts will be used to identify key areas of focus for remediation efforts. The remediation efforts, like the studies necessary to determine the causes of HABs are also Critical, Complex and Costly. The SLA with funding from the Legacy Fund for Skaneateles Lake has identified numerous smaller, but still costly remediation projects for early intervention as we anticipate NYS funds for the larger remediation projects that will be necessary.

The prevention of future HABs will depend on information from the studies being done and development of effective remediation, but prevention will also depend upon a watershed community of individuals committed to these efforts and each doing all that he/she can do to protect the lake. This includes every resident of the watershed community using effective landscaping practices (shoreline barrier planting to slow and control runoff into the lake, limitation of fertilizing to only what is indicated by soil testing, not clear cutting in the watershed and planting trees especially evergreens which are major filters of water). It also includes maintenance of septic systems and keeping roadside ditches clear of debris and yard waste and ensuring that they are not stripped to bare soil.   The Skaneateles Lake Association is available to provide access to resources to assist watershed residents in all of these areas. Use the “contact us” tab at SkaneatelesLake.org to request assistance or advice. Everyone in the watershed has a role in preventing HABs and we hope that each watershed resident will join the Skaneateles Lake Association to help support our efforts. You can join the SLA and donate to the Legacy Fund online at SkaneatelLake.org or call 315-685-9106 to request a Member Registration Form and return envelope.

Source  Press Observer 12/4/18