Truesdale Lake  

South Salem, New York

Road Salt and Lake Health

Cross-posting from the Nextdoor Truesdale site:

I have been noticing large amounts of road salt in certain areas around the lake, and it made me wonder what sort of effects the salt can have on lake ecology. I started Googling, and discovered that road salt run-off can actually cause blue-green algae problems like the one we experienced last summer! Here are links to a couple of articles I found, but there are many more if you Google “road salt, algae“. -Ami N.

Here are some links to online articles that clearly state the problem with adding sodium chloride (NaCl, or ‘road salt’) to our water column. In short, when the water chemistry is changed, it can kill off green algae and phytoplanktons — which do not tolerate higher salt concentrations well — and leaves an opportunity for blue-green algae to flourish. This type of algae is less desirable, has a foul odor, and some species can be irritating to the skin or mildly toxic. Not something we want in our lake.

There are alternatives (check the New York Water article, linked below), or we can simply do without the rock salt treatment around the lake watershed.

Article excerpt: “The major threat to the lake from salt is a change in how the lower levels of the food web work. The rising sodium levels are shifting the lake’s chemical composition from being dominated by calcium carbonate to sodium chloride. That results in a shift in the phytoplankton population from one dominated by diatom algae to one dominated by blue-green algae.

Blue-green algae is much less nutritious than diatom for the rest of the food web, and some blue-green algae species are notorious for toxic blooms” (pdf file brochure)

“Autotrophs, or primary producers that create their own food through chemo- or photosynthesis, such as algae and terrestrial plants are in particular danger of road salt. The presence of increased sodium chloride in an aquatic environment brings about an opportunity for invasive cyanobacteria to enter and dominate the inhabiting species. The cyanobacteria in question here are capable of withstanding the brackish conditions and they flourish accordingly, out-competing the other algae and smothering other organisms within the aquatic ecosystem.”

“Zooplankton…those are the tiny invertebrates that propel themselves around the water column, feeding on algae. If salt kills zooplankton, that’s not just going to mean more green scum on the water, it could also mean that larger predators, like the many species of fish that feed on zooplankton, go hungry.”

“Chronic salt concentrations can damage algae that are food sources for insects that local fish eat; in high concentrations, it can kill amphibians and plants and leach into drinking wells.”


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