Lake Foam

“JUST WHAT IS THAT FOAM?” 

 

The foaming of surface waters on lakes is not a new phenomenon. It is a natural process that has been going on for a long time in many different parts of the world. Foam is created when the surface tension of water (attraction of surface molecules to each other) is reduced and the air is mixed in, forming bubbles.  When organisms, such as algae, plants, fish and/or zebra mussels die and decompose they release cellular products (surfactant) into the water, which reduces the surface tension.  When the wind blows, the waves on the lake agitate this surface agent, thus transforming it into sudsy white foam.  Currents and boats also mix air with the organic compounds present in the lake to produce foam.  The foam will frequently form parallel streaks in the open water, caused by wind-induced surface currents.  It will also collect in large quantities on windward shores, coves, or in eddies.

In 2003, Researchers from SUNY ESF, Finger Lakes Community College and the Canandaigua Lake Wateshed Council performed chemical testing on the foam.  Report can be found here:  2003 Foam Report.

In recent years, CLWA launched a research initiative with Global Aquatic Research to further examine the composition of the foam during the harmful algae bloom season. A summary of this research can be found below.

FOAM STUDY SUMMARY: CANANDAIGUA LAKE

Global Aquatic Research (GAR) and the Canandaigua Lake Watershed Association (CLWA) surveyed and sampled lake foam with the help of citizen scientists throughout the late summer and fall of 2019.

NEW RESEARCH CONDUCTED 

  • Many chemical analyses were performed on the foam and the results were compared with the chemical signatures of tributary streams, lake water, invasive mussels, plankton, and seaweed, in order to identify the source of the foam.
  • Carbon isotope and fatty acid signatures indicate the source of the foam comes from within the lake.
  • Very high concentrations of carbon and low concentrations of nitrogen in the foam suggest it is enriched in one type of biological component that is low in nitrogen. This means that invasive mussel proteins are not the source.
  • FTIR (fourier-transform infrared spectroscopy), an advanced technique used to identify organic substances, indicated the foam is primarily made of carbohydrates, in particular polysaccharides, which are long chains of sugars. A range of aquatic organisms commonly produces these, but the FTIR signature of the foam was most similar to the
    phytoplankton sample from the lake.
  • All measurements were consistent with Microcystis algae, the cyanobacteria that are responsible for the harmful algal blooms (HABs) and produce the microcystin toxins responsible for beach closures, as the source of these foam-causing polysaccharides.

WHAT’S GOING ON IN THE LAKE? 

  • Plankton, which include all microscopic plants and animals suspended in the lake water, are filtered by the invasive zebra and quagga mussels. Microcystis cyanobacteria are a poor food source for the mussels. The mussels eat other plankton and spit the cyanobacteria out. Over time this selectively concentrates the cyanobacteria in the water.
  • Phosphorous and nitrogen concentrations in the lake support phytoplankton growth, and during the summer when sunlight is abundant, cyanobacteria grow at fast rates.
  • Microcystis cyanobacteria release polysaccharides outside of their cells in order to create large colonies and to regulate their environment. These “exopolysaccharides” or “EPSs” are produced in large quantities during phytoplankton blooms and change the chemistry of the surface of the lake.
  • Invasive mussels get “sick” when feeding on the cyanobacteria and start producing polysaccharide rich mucus of their own while recycling and ejecting the cyanobacteria EPSs, exacerbating the problem.
  • Over time, these EPSs, which are not very soluble in the water and are stable in the environment, accumulate in the SML (see Foam Facts) and provide the right conditions for foam production. In fact, these types of polysaccharides are used in industries to stabilize foam and create emulsions.

IS THE FOAM SAFE?

Some foam can concentrate pollutants at much higher levels than in the surrounding environment. This part of the study is ongoing. However, we have found microcystin toxins in the foam at higher concentrations than in nearby lake water, and in a few cases, higher than the NYS Department of Health’s recreational limit.

PFAs TESTING IN LAKE FOAM

In 2023 Canandaigua Lake Watershed Association was awarded a grant from Freshwater Future to expand upon previous lake foam research. They partnered with Global Aquatic Research LLC (GAR), who investigated the potential of lake foam to accumulate the emerging contaminant, PFAS (per- and polyfluoroalkyl substances).

On October 19th, 2023 GAR collected 3 surface foam samples and 1 lake water sample at the north end of Canandaigua Lake to test for per- and polyfluoroalkyl substances (PFAS). They were analyzed for 30 PFAS compounds using EPA method 537m. The foam was analyzed as non-potable water after allowing air bubbles to dissipate (90% of foam is air). The full PFAs data report can be found here.

KEY FINDINGS:

  • Total PFAS concentrations in Canandaigua Lake water were detected at low levels of 5.4 ng/L, while foam samples showed much higher levels, averaging 385 ng/L. This means the water that makes up the foam contains over 70 times more PFAS compared to the surrounding lake water.
  • Seven PFAS compounds were detected in lake water, all within enforceable safety thresholds, while up to 13 compounds were found in the foam samples, with six exceeding method reporting limits. Enforceable safety limits for foam are not yet established.
  • Foam samples contained high levels of PFOS (Perfluorooctane sulfonic acid) and some Perfluoroalkyl carboxylic acids (PFCAs), which were not detected in the lake water.

For more information about PFAS and drinking water, visit the EPA website.

Health Implications: Scientific research indicates that exposure to certain PFAS chemicals may cause adverse health effects. Ongoing studies are working to better understand how varying levels of exposure to different PFAS compounds may impact health. While this research is non-regulatory, the findings suggest the need for continued monitoring of PFAS levels in Canandaigua Lake and other Finger Lakes.

Due to the potential for aquatic foam to accumulate chemicals and toxins at greater concentrations than the surrounding water, it is best to avoid foam when possible and wash thoroughly after you come into contact with it.

Global Aquatic Research PFAS Data Report 

PFAs in Lake Foam: Summary from Canandaigua Lake

NEXT STEPS

Future research should continue to assess the foam’s potential to accumulate heavy metals and industrial toxins (including PFAS) in addition to further investigation of microcystin toxins in the foam.

CLWA needs your support to fund this expanded foam research and to support our efforts to improve water quality throughout our watershed.

As part of this ongoing research initiative, we are documenting observations of lake foam from citizens using the survey form below. Your reports help us document the extent and timing of these foaming events, and may help us make research decisions on sampling efforts.

If you would like to submit a foam report, please use our Lake Foam Observation Survey.

LAKE FOAM SURVEY