Harmful Algal Bloom Monitoring in the Finger Lakes Region, New York

Background: 
 
Harmful algal blooms (HABs) are increasingly a global concern because they pose a threat to human and aquatic ecosystem health and cause economic damages. Cyanobacterial HABs (CyanoHABs) represent a substantial threat to drinking-water supplies, aquatic ecosystem health, and safe recreational uses of freshwater resources in New York. Toxins produced by some types of cyanobacteria (called cyanotoxins) can cause acute and chronic illnesses in humans. Aquatic ecosystem health is also affected by cyanotoxins and changes in aquatic food webs caused by an over-abundance of cyanobacteria. The U.S. Geological Survey (USGS) worked with the New York State Department of Environmental Conservation (NYSDEC) to establish an advanced water-quality monitoring program in three of the Finger Lakes recently affected by CyanoHABs: Owasco Lake, Seneca Lake, and Skaneateles Lake. Knowledge gained from this effort has enhanced our scientific understanding of the environmental factors associated with CyanoHAB occurrence and serves to inform the development of an advanced monitoring strategy for the State and Nation.
 
Objectives: 
 
The objectives of the project were to: 1) better understand CyanoHAB development in New York lakes using a multi-tiered approach to monitor the occurrence of and contributing factors to CyanoHABs in Owasco Lake, Seneca Lake, and Skaneateles Lake over several years; and 2) evaluate water-quality sensors and data to help inform the development of an advanced CyanoHAB monitoring strategy for New York State and the Nation. 
 
Approach: 
 
1. Deployment of advanced water-quality instrumentation in all three lakes, to collect water-quality and meteorological data relevant to the dynamic processes of CyanoHABs. A multiparameter sonde was deployed at three depths to characterize the water column and include sensors for temperature, specific conductance, dissolved oxygen, pH, dissolved organic matter, turbidity, and chlorophyll and phycocyanin fluorescence. In addition, water-temperature and light data were collected approximately every meter throughout the water column. Nitrate and orthophosphate analyzers were deployed to collect near-surface nutrient data. Data were telemetered directly to the USGS and displayed in near real-time through the USGS National Water Information System (NWIS; https://waterdata.usgs.gov/ny/nwis/rt/).

2. Discrete water-quality samples were collected from the instrumented locations at three depths. Analyses included nutrients, organic carbon, phytoplankton community composition (by multiple methods), cyanotoxins, genetic potential for cyanotoxin production, and chlorophyll a and phycocyanin pigments. Solid phase adsorption toxin trackers (SPATTs) were deployed between discrete sample collection dates.

3. Synoptic surveys of tributaries and near-shore water-quality conditions were conducted. Discrete water-quality samples collected as part of the synoptic surveys included nutrients and organic carbon. Near-shore mapping was conducted using multiparameter sondes and nitrate analyzers with the same configurations as those deployed in the lakes to provide baseline data for lake-wide conditions, identify potential sources of nutrients not captured by tributary sampling, and identify areas with localized CyanoHABs.