The Jefferson Project's Response

Deploying a vertical profiler on Tuesday, November 10th    Research Specialist Candace Schermerhorn driving back to DFWI


The immediate response of the Jefferson Project research team 

 During seven years of monitoring the lake, the Jefferson Project has built a comprehensive dataset that tracks the weather, runoff, and circulation of water in the Lake George basin, and the species of plants, animals, and algae that live in it. With the discovery of the HABs in Lake George on Monday, November 9, the Jefferson Project immediately assembled its team of more than 20 researchers to develop and execute a research plan aimed at understanding the cause of the HAB. This JP Research Plan has included five major research activities:


  1. Deployment of an advanced sensor platform to Middle Bay (just north of Harris Bay, Sandy Bay, and Warner Bay) to monitor changes in the water column.
  2. Deployment of a second sensor platform to Calves Pen, to monitor changes in the water column at a deeper site.
  3. Completed lake surveys at 37 sites around the south basin to monitor physical parameters, algal abundance, algal composition, and nutrient abundance (i.e. phosphorus, nitrogen), and algae. Survey initiated on Nov. 10 and conducted over three weeks.
  4. Running computer models to understand the roles that weather and lake circulation may have played in causing the HABs.
  5. Conducting analyses comparing current versus past lake conditions.

Bottles prepped to collect surface phytoplankton samples Phytoplankton sample from the DFWI dock on Monday, November 9th                                          

What do we know so far?

Saturday, Nov. 7: 

Suspicious Bloom first noticed in Harris Bay. It dissipated later that day. The Lake George Association first reported the bloom to DEC based on the assessment of a staff member who had been trained in HAB identification as part of the DEC’s Citizens Statewide Lake Assessment Program.


Monday, Nov. 9:

Suspicious Blooms observed in Harris Bay, Sandy Bay, Warner Bay, and at the southern end of the lake near Lake George Village. LGA and JP staff collected water samples. All blooms dissipated later that day.


Thursday, Nov. 12: 

NYS DEC confirms the dominant algae is in the genus Dolichospermum.

JP sample (Greenwater Labs) confirms the dominant algae is the species Dolichospermum fuscum.


Friday, Nov. 13: 

NYS DEC announces a Confirmed Bloom in Harris Bay with no detectable toxins. DEC tests found toxin levels safely below the Environmental Protection Agency’s 10-day drinking water health advisory level of 0.30 micrograms per liter.

No confirmation of a HAB in Sandy Bay, Warner Bay, and Lake George Village.


Wednesday, Nov. 18:

JP water sample was tested for four known toxins produced by the dominant algae and found them to be “non-detectable.”



The Key Questions

To understand the underlying causes of the confirmed and suspicious HABs, the Jefferson Project team is addressing two overarching questions:

  1. Were the confirmed and suspicious HABs that were observed in various locations produced in those locations or transported by surface currents to those locations?
  2. Was this an unusual natural event and/or was it somehow connected to human activities?
  3. What conditions were different in Fall 2020 compared to past years?


Jefferson Project research activities since the HAB event

To answer these questions, the Jefferson Project research team has rapidly moved forward on a large number of research efforts.


Completed research efforts

  1. Completed nutrient testing of more than 70 water samples from three surveys around the south basin conducted immediately after the confirmed HAB event
  2. Completed assessment of abundance of total algae and total cynaobacteria during the three surveys of the south basin immediately after the HAB event was confirmed
  3. Completed assessment of total algae and total cyanobacteria during Fall 2020 compared to previous years based on JP monitoring data
  4. Improved and validated the JP circulation model in the areas where the HABs occurred to determine how surface currents may have moved the algae
  5. Assessed historic weather conditions to characterize weather conditions at or around the time of the HAB events (e.g. to quantify the rarity of the calm, warm weather that occurred during the HAB event)

Ongoing research efforts

  1. Identifying algal composition of more than 70 water samples from three surveys around the south basin conducted immediately after the confirmed HAB event
  2. Identifying eight years of historic algal samples (2013-2020) to determine the typical populations of Dolichospermum in the lake during the fall
  3. Assessing historic Dolichospermum fuscum (the species of cyanobacteria of the confirmed HAB) abundance in the lake by reviewing past studies of Lake George, going back several decades
  4. Continuing analysis of vertical profiler data on physical measurements (i.e. water-column profilers of temperature, dissolved oxygen, pH, turbidity, etc.)
  5. Examining satellite images of the region before, during, and after the HABs using remote sensing
  6. Assaying sediment nutrients and akinetes (cyanobacteria resting stages).


The multi-faceted approach of the Jefferson Project research team is intended to understand the underlying causes of the confirmed and suspicious HABs on Lake George. This holistic approach requires a large number of researchers and several months to acquire and analyze all of the data, but this approach will allow us to provide the most complete understanding of the event.


The Jefferson Project is committed to sharing its discoveries with the public in Spring 2021.


Learn More:

What was observed?

What is a HAB?