Harwich High School students learn aquaculture while getting paid through a Summer of Work and Learning Program. The students (from left to right) are Mark Stines, Katie Nydam, Heidi Erdmann and Allison Toner. Photo by William F. Galvin
By SUSAN MILTON
ORLEANS - Saltwater ponds on Little Pleasant Bay are getting sick, warned a group of trained volunteers who have monitored the ponds' health since 1988. The ponds are Meeting House Pond, Kescayoganset or Lonnie's Pond, Arey's Pond, Paw Way Pond and Quanset Pond, all small ponds with limited tidal flows from Little Pleasant Bay. "Some of them appear to be in critical condition," said Robert Wineman, leader of the sampling program which has shown that, at times, the ponds are suffering from eutrophic conditions that cause fish kills and algae and plant growth.
The natural process of eutrophication is accelerated when nutrients from manmade sources, such as lawn fertilizers and septic systems, and natural sources, such as marshes, flow into water bodies and spur the growth of plants and algae. They consume more oxygen, leaving little for fish and shellfish, which die. The group's findings contrast with studies by the Cape Cod Commission a couple of years ago, Wineman said. The engineering calculations of tidal action in each pond indicated that the water would be exchanged in less than 24 hours, flushing out nitrogen and other nutrients.
"I don't think that's possible with what we see in the ponds today," Wineman said, comparing the findings from actual samples of pond water with the more theoretical calculations of the study. The group is preparing a report, with recommendations, to distribute to town boards and the general public, Wineman said. The ponds' condition should be monitored carefully, he said, and the group should switch to use plant material as indicators of health, not just chemicals in the water.