This spring a handful of students in the Advanced Placement Environmental Sciences class at Scarborough High School are helping the Friends of Scarborough Marsh trace pollution in Mill Brook in the hope that steps can be taken to improve the overall health of the marsh.

The students, along with their teacher, Mike Carroll, took water samples last week from Mill Brook near the middle school. The goal, according to Carroll, is to see if the students can find any points along the stream that contain elevated levels of fecal coliform bacteria.

According to the Friends of Scarborough Marsh, the students are continuing with water quality testing they first began several years ago. If the source of the bacterial pollution can be found, then it would lead to improvement in the health of the marsh, as well as the eventual reopening of clam flats that have been closed for years.

Rick Vogel, president of the Friends of Scarborough Marsh, said the objectives of his group include both education and stewardship and that one of the main priorities, is to engage local residents and schools in marsh preservation.

Vogel said the joint water quality project with students at Scarborough High accomplishes all of these goals, and the hope is that it will also “deepen the community’s understanding about the marsh” and raise awareness “of the value and beauty of this natural resource.”

The 3,100-acre Scarborough Marsh is the largest salt marsh in the state. It includes five tidal rivers, including the Libby, Nonesuch and Dunstan rivers, several smaller streams, some coastal freshwater marsh, tidal flats and about 200 acres of upland habitat.

The long-range objective for the marsh, according to both the Friends of Scarborough Marsh and the Maine Department of Inland Fisheries and Wildlife, is to provide habitat for a variety of wildlife species, as well as provide access for outdoor recreation.

The marsh has been recognized for its biological productivity and diversity and it provides habitat for a number of fish, bird and plant species, as well as several state and federally threatened or endangered species.

Vogel said ongoing water quality testing has been done in Mill Brook, which originates behind Oak Hill and feeds into the marsh below the Willowdale Golf Club course, but the source of the fecal coliform bacteria has not yet been found.

That’s why the Education Committee of Friends of Scarborough Marsh reached out to the high school and suggested that students take on the task of pinpointing the source or sources of the pollution.

The committee has asked the students to complete several tasks, including identifying sites where water samples should be collected, setting up a sampling schedule, collecting and testing water samples and analyzing the data collected.

The committee expects that either the pollution sources will be pinpointed or more detailed testing will be needed.

Carroll told the Current that the research his students are conducting would be “an initial survey and should provide a baseline for further study. When we’ve finished the research, we’ll submit our report to the Friends of Scarborough Marsh.”

He said four students in his Environmental Sciences class are collecting water samples from five to six sites along Mill Brook in the next couple weeks and that finding the source of the bacterial pollution is “a puzzle these students would love to explore.”

Carroll said he initially met with Linda Woodard, director of the Scarborough Marsh Audubon Center, who asked if his students might be interested in testing Mill Brook for fecal coliform bacteria.

“She indicated that (there was) evidence of elevated levels of (bacteria) at a point in the watershed and she showed me a map of the area with the data point,” Carroll said.

He added, “I jumped at the chance because (this) would be a great end-of-the-year project for (my students) to work on after they’ve taken their AP exam.”

In testing the water in Mill Brook, Carroll’s students will use the membrane filter technique, which allows water to flow through a round piece of filter paper while trapping the bacteria. The students will then place the filter paper in a sterile Petri dish and saturate it with a growing medium full of nutrients and incubate it at about 44.5 degrees Celsius.

He said that temperature is high enough to kill most other bacteria, but not fecal coliform bacteria. After 24 hours of incubation, the students will count the number of fecal coliform colonies in the Petri dish to determine the level of this type of bacteria in the water sample.

“This specific project is important because if we can more accurately pinpoint where the bacteria levels seem elevated, we might be able to assist in identifying the source of the problem,” Carroll said.

“It’s a great chance for my students to test their intellectual and scientific mettle,” he said. “I taught them how to do some basic types of research but the question is, can we put together some field research and write up a report based on the data that real scientists will find valuable?”

The 3,100-acre Scarborough Marsh Wildlife Management Area includes approximately 2,700 acres of salt marsh, five tidal rivers, several smaller streams, some coastal freshwater marsh, tidal flats and some upland areas.Courtesy image