To Pat Sned, whose home backs up to the Salt Pond, a large apparent algae bloom that caught her eye about a month ago seemed a little out of place. She said that, in her 15 years of owning her home, she had never noticed anything like it.
“It’s quite extensive” she said, of the yellowish muck that sits on the edges of the southeast corner of the Salt Pond. What Sned can see out her back door in the Villas of Bethany West is the area where the Bethany Loop Canal meets the Salt Pond, coming from the Bethany Beach side (behind the Army National Guard building on Route 1).
“The people from DNREC came, and they said it isn’t so unusual that it’s growing here, but none of us had ever seen a growth like that. I have not seen any growth, and never algae. My concern was “what has changed?”
She said Bethany Beach town officials and DNREC came out, but she was told the water was too shallow for them to use their machines to cut the algae.
According to the state Web site, development and runoff in local waterways have increased nutrients deposited in waterways, which results in macro-algae growth. (Macro-algae is algae that can be seen with the naked eye — as opposed to micro-algae, which cannot). And macro-algae can beneficial — to a point.
“Attached macro-algae are beneficial in that they provide habitat for juvenile crabs and fish,” according to the DNREC Web site. “When the algae become detached and begin to accumulate along shorelines and in near-shore areas, these buildups then become both environmental and nuisance concerns. For this reason, the DNREC Macro-Algae Harvesting Team, under the direction of the Division of Soil & Water Conservation, initiates harvesting activities to remove these problem buildups.”
(Calls to DNREC about the program were not answered before Coastal Point press time.)
Ed Whereat of the University of Delaware Citizen Monitoring Program, which has volunteers monitoring water quality throughout the coastal watershed, said he is ”not alarmed,” about the algae.
He said that, whether it grew there or just concentrated there because of an outside force, such as prevailing winds, is anybody’s guess.
“Whether it grew there or grew somewhere else and was concentrated by wind, I can’t say. It starts off attached to the bottom but can float around.”
Asked whether there is remediation available, he said there isn’t a simple solution, “Except maybe remove the biomass, but I doubt homeowners are going to go out there with rakes and harvest it themselves. And it doesn’t look like the State can with their machines, because it is too shallow... You just hope it decays and doesn’t return next year in the same place at the same time.”
Sned said she had been told by DNREC that if they couldn’t get the machines in there to harvest, they would have to let nature “take its course — but I don’t know what that means,” she said.
Whereat explained that, with the heat of summer, the algae should start to decay and, once that happens, there could be oxygen depletion issues in the water. He added that he hopes it doesn’t cause odor or fish-kills, but said it is possible.
Whereat said the latest dissolved oxygen readings in the pond were 1.5 ppm, which were taken by volunteer Nancy Steckel from the west side of the pond, were “low enough to cause some stress to aquatic organisms or make them leave the area.” He also explained that “low” is less than 4.0 ppm, which is the State standard for a single-sample reading. He couldn’t say definitely if the two were related but did say that he would suspect that conditions are even poorer on the northeast side, where the bloom is.
Steckel said that, each year, they get the floating mats of yellowish green algae which, she said — depending on the wind — may accumulate on the shoreline or get blown over to the east side by the National Guard base.
She explained that she was out of town and hadn’t visited the Salt Pond from early May to late June, during the weeks that Sned started to notice the bloom, so she wasn’t able to collect data from that time, but said that the 1.5 ppm from June 28 was ”one of the lowest I’ve recorded.”
Whereat said that, while the bloom’s presence can’t really be explained with certainty, in general it is not something for people to worry about.
“I can’t be certain in any way why that area is having a problem this year,” said Whereat. “It pops up in different areas. But it is not alarming.”
For more information on DNREC’s algae harvesting program, visit http://www.dnrec.state.de.us/macroalgae/default.shtml. For information on University of Delaware’s Citizen Monitoring Program, visit http://citizen-monitoring.udel.edu.