By Heidi Cho
Nation & World Editor
College Spokesperson Dave Muha warned against fishing, drinking, swimming and coming into contact with water from Lake Sylva on Tuesday, Aug. 29., in a campus-wide email.
On Aug. 25, the New Jersey Department of Environmental Protection was alerted of a potentially hazardous algae bloom in Colonial Lake in Lawrenceville, according to NJDEP Bureau of Freshwater and Biological Monitoring Section Chief Victor Poretti.
During the summer, there was a toxic cyanobacterial algae bloom that originated in Lake Sylva that traveled downstream to Shabakunk Creek and Colonial Lake, according to Poretti.
“Because the last occurrence affected all three waterbodies, we resampled Sylva as a precaution,” Poretti said.
The sample results showed that the algae bloom in Lake Sylva is indeed toxic. Poretti said that the cyanobacterial bloom exceeded both toxin and cell count risk thresholds.
Cyanobacteria is usually a normal part of a lake’s algal community. Cyanobacteria is only harmful if there is an excessive amount, or when the toxin level exceeds risk thresholds, as it currently does in Lake Sylva.
Shabakunk Creek, however, harbors no such harmful algae bloom as of Aug. 31, according to Poretti.
The Ewing Health Department alerted the College of the return of the toxic algae bloom that Tuesday, and no earlier, according to the College’s Head Media Relations Officer Luke Sacks.
By the morning of Wednesday, Aug. 30, advisories about the toxic bloom were posted, and samples of the water were collected and analyzed, according to Poretti.
Poretti listed possible reasons for the presence of a harmful algae bloom, also known as a HAB. Environmental factors like heat, still water and high nutrient concentrations can promote the growth of a HAB. High nutrient concentrations can be caused by geese byproducts, lake sediment or fertilizer runoff.
The specific reason for the return of the toxic algae bloom as of Aug. 31 has not been identified, according to Poretti.
Heat and still water caused the previous toxic harmful algae bloom to last a few weeks in the summer, according to the Ewing Mayor Bert Steinmann.
The current harmful algae bloom is primarily composed of Anabaena sp., according to Poretti.
“Also noted to be present, but not in countable amounts were the taxa Aphanizomenon sp., Microcystis sp., and Coelosphaerium sp.,” Poretti said.
Algae blooms can last up to a few weeks, Poretti added.
“Disturbing or killing the algae can result in release of toxins,” Poretti said.
The current toxic bloom should subside naturally over time, as did the previous bloom, according to Poretti.