The Friends of Casco Bay are looking for green slime. They are so concerned about its increased presence in the bay they’ve created a poster: “Wanted: Green Slime Sightings,” calling for volunteers to report this manifestation of nitrogen pollution.

When green slime covers a mudflat, it can suffocate anything living beneath, including clams, snails and mussels. Slime is an indicator of a potential environmental problem that Joe Payne, baykeeper of Casco Bay, says “isn’t here yet, but is knocking on our door.”

Green slime is an algae that thrives on nitrogen. Its presence indicates nitrogen overload in the water, which can cause multiple environmental problems. Payne has developed a PowerPoint presentation that shows the consequences of nitrogen pollution in waters all over the world. Among the disasters are dying manatees in Florida, West coast birds afflicted by neurotoxins, loss of food supply for Native Americans on the West Coast where clams are infected, dead zones in rivers and coastal waters, proliferations of jellyfish, masses of green algae on formerly pristine Hawaiian beaches, and algae covering an underwater statue, Christ of the Abyss, off the Florida Keys.

The principal causes of nitrogen pollution are water runoff carrying fertilizers from lawns and agriculture; the air, which drops particles from car exhaust and smokestack emissions; and sewage treatment plants and septic systems.

Another result of nitrogen pollution highlighted by Payne is an overabundance of the algae that causes red tides. A photo of waters off the western coast of Florida reveals a bloom of Karenia brevis , which causes red tide in the Gulf waters. (Alexandrium fundyense creates Maine red tides, which are not visible.) The more nitrogen in the waters, the earlier red tides are apt to appear and the longer they last. Payne notes that this year, Maine’s first red tide appeared earlier than ever before. The Florida red tide in the photo can be seen as a huge blot that lines the western coast of the state. That particular occurrence, he says, lasted an unprecedented 13 months. Another photo shows new patches of the same type of red tide forming on the east coast of Florida, which had hitherto been spared.

Excess nitrogen, Payne adds, can also create oxygen-starved coastal waters, resulting in fish kills like the infamous fragrant pogie die-off in Midcoast Maine in 1989. Payne says that near the mouth of the Mississippi River, an oxygen “dead zone” formerly the size of Rhode Island has grown to the size of Massachusetts. “All bets are off as to what will happen with it this year,” he adds.

These “dead zones” happen, he explains, because nitrogen run-off from land causes micro-organisms to double, even quadruple, and then bacteria consume oxygen while breaking down the micro-organisms, thus creating the oxygen depletion. Mike Doan, who coordinates seasonal research initiatives for Friends of Casco Bay (FOCB), says for 12 years, they have been monitoring the New Meadows Lake, which hovers on the brink of oxygen starvation. In July, tests showed 4 to 5 milligrams of oxygen per liter of water at the surface instead of a healthy 7 or 8 parts, and no oxygen along the bottom of the lower lake. This happens in the lake because there is a limited water exchange and fertilizer, which drains from property along the shore, cannot be flushed out.

Nitrogen pollution allows one particularly noxious algal bloom that contains the neurotoxin Domoic acid to grow and thrive. Payne says that in 2003, twenty-one whales that ingested Domoic acid died in the Gulf of Maine, and that nine other whales and dozens of dead seals were suspected to have been poisoned by the lethal nerve toxin. That year, he adds, over 800 dead seals were recorded, and although they were not tested for Domoic acid, it was thought to be the cause. Mammals, seabirds and humans who eat shellfish contaminated with domoic acid can be harmed.

FOCB has been working on many levels to address nitrogen pollution and other threats to the Bay’s health. Payne is particularly proud that FOCB successfully convinced the State Legislature to pass LD 1297 in June, 2007, which requires the Department of Environmental Protection (DEP) to set a time line enacting nitrogen criteria for Maine waters. “We already have limits set for fecal coliform bacteria and industrial copper,” he says, “but there’s no limit for nitrogen.” Recently, he says, Angela Dubois filled the position of lead biologist for the marine unit of the DEP, which had been vacant for several years, leaving a void as far as enforcing LD 1297. “Our job is to help her see that nitrogen pollution is one of the highest priorities for the coast of Maine,” says Payne. “We’re not being Chicken Little about this. It’s knocking at our door. The DEP has to move forward and develop nitrogen criteria, as the bill requires.”

FOCB’s Water Quality Monitoring program, conducted by staff, interns and volunteers, and coordinated by Peter Milholland, collects data, including nitrogen and oxygen levels, from about 50 stations throughout the Bay. Samples are taken according to a strict protocol which is EPA approved and are sent to a lab for nitrogen levels. FOCB measures oxygen levels directly in the field.

FOCB worked with other organizations to gain passage in February, 2008, of a $61 million dollar bond to pay for upgrades in the sewage plants overflow system in Portland. Presently, when heavy rains send greater than usual amounts of freshwater into the sewage system, the sewage plants release combined sewage overflows of storm water mixed with raw sewage. To address the problem, work needs to be completed to divert storm water before it reaches the treatment plants. Mary Cerullo, FOCB Associate Director, says South Portland has almost completed its updates.

The FOCB pump out program, which began in 1995 and now has 22 stations and a pump-out boat, has prevented over 100,000 gallons of raw sewage from entering the bay. As a result of a campaign led by Payne and Cerullo, Casco Bay has been designated a “No Discharge Area,” which means it is illegal to dump boat sewage within three miles of the coast between Small Point and Two Lights.

Another FOCB program, BayScaping, which partners with the Maine Board of Pesticide Control, teaches homeowners in the Casco Bay Watershed to maintain their lawns without using large amounts of pesticides and nitrogen rich fertilizers. Cerullo takes the results of storm water sample analysis directly to homeowners in neighborhoods where samples were collected, so that people can understand the direct impact of their lawn maintenance on the Bay. Cerullo teaches homeowners environmentally responsible ways to maintain their lawns. Homeowners who follow a simple six-step program may display BayScaper signs: “Another green yard keeping Casco Bay blue.” (for details, see the FOCB website.)

“I always tell people, ‘Don’t do what Scott’s tells you,'” says Payne. “People don’t understand what is in a product like Weed and Feed.” (Because of the damage it causes to wildlife and rivers, Weed and Feed has been banned in the Canadian province of Alberta.)

To Payne, the story of Mussel Cove is an encouraging example of how a homeowner’s management of coastal property can make a huge difference in nitrogen levels. He explains that the owner of property along the cove put in a pipe to capture water that was draining from his and his neighbor’s lawns because it was washing out his driveway. As a result, Mussel Cove turned green with slime. “Rather than filtering through the ground, the water was flowing straight into the cove, carrying all the excess nutrients from each person’s lawn,” Payne says. The owner took out the pipe and within a year, the cove was clean again.

Casco Bay watershed collects water from 53 towns all the way to Bethel, Maine. For those who doubt the influence of what goes into inland property, Payne likes to tell the story of the storm that brought the pumpkins floating down the Presumpscot River. “You can think about things smaller than pumpkins and picture them as big orange things if you want,” he says. “Everything comes down the river.”

Payne, who became Baykeeper in 1991, says he will continue to “push and nag” citizens, organizations, legislators, business owners, city officials-whoever needs to be prodded – to help FOCB fulfill its mission of protecting the waters of Casco Bay.