—By Barbara A. Branca, NYSG's Communications Manager
This article was featured in NYSAC News Spring/Summer 2015 (pdf)
New York State, with its bounty of freshwater lakes and ponds and miles of coastal ocean is now experiencing a rainbow of algal blooms—some of them toxic to aquatic life and pets. Harmful algal blooms or HABs have become a worldwide phenomenon, posing a significant threat to public health, economies, water quality, and fisheries. New York waters have more than their fair share.
During the 1950s there were green tide blooms in Long Island’s (LI) south shore bays that negatively impacted the oyster fishery. This year of 2015 marks the 30th anniversary of brown tides occurring in LI’s south shore and east end bays, destroying eelgrass beds, decimating scallop fisheries and greatly reducing New York’s historically profitable scallop and hard clam fisheries. Since 2006, toxin-producing red tide blooms have caused shellfishery closures within LI estuaries. For decades, the toxins in cyanobacteria (formerly known as blue-green algae) have negatively impacted drinking water in New York’s Great Lakes region and even fresh water ponds on Long Island. A highly publicized recent example was in 2014 when the city of Toledo, Ohio, had to shut down its public water supply because of cyanobacteria in the Lake Erie waters surrounding its intake.
For the last two decades, New York Sea Grant researchers have been observing and studying the causes of such blooms and educating the public and officials about possible ways to mitigate their effects.
Generally, growth of these algal blooms can be linked to the addition of everyday chemicals like nitrogen and phosphorus that enter waterways from our waste water as well as from natural processes. Nitrogen and phosphorus act like nutrients, encouraging cell growth. Unchecked, the algae become the dominant species, crowding out other species in the living community.
High concentrations of brown tide harm shellfish, but do not pose health risks to humans. Some red tide (Alexandrium) can cause illness in people who consume shellfish contaminated with its toxin. But in fresh water, some species of blue-green cyanobacteria produce potent toxins that may result in nerve and liver damage – even death—in animals that have been exposed. Unfortunately, those animals are sometimes our dogs.
New York Sea Grant Extension’s Dave MacNeill, based in SUNY Oswego and organizer of a recent HAB workshop, had observed that every year in New York’s Great Lakes region there was an increasing number of dogs who were being exposed to harmful algal blooms. Those exposed to blooms with high levels of toxins had a poor outcome—either death or permanent disability. And those exposed over long periods of time to lower levels of toxins still suffered cumulative effects. “People get sick, but dogs die,” said MacNeill.
According to Cornell Veterinary College’s Dr. Karyn Bischoff, the number of reported cases of HABs poisoning in dogs is probably underestimated because pet owners are not aware of the problem. The Center for Disease Control reported there were about 400 documentable cases of canine poisoning by blue-green algae during the past century but acknowledge this is a small fraction of cases that have occurred. The time is now to let dog owners know of the risks of letting their dogs play in water contaminated by cyanobacteria.
According to Dr. Greg Boyer, Professor of Biochemistry at the SUNY College of Environmental Science and Forestry, cyanobacteria are one of the most common life forms on earth, making up an important part of the food chain. Of the 8,000 species, only about 40 or so produce toxins. Cyanobacteria cells are microscopic, but grow into large colonies or surface “scums” that can accumulate on shorelines. Warm temperatures, runoff of nutrients that ‘feed’ the cyanobacteria, and other factors dictate the severity of a bloom. Dogs rarely ingest enough toxins simply by drinking contaminated water, but can easily accumulate a toxic dose by swallowing dense, windblown scums of blue-green cyanobacteria that line the shore.
As seen in this September 2011 picture, it's pretty easy to spot the Harmful Algal Blooms that plague Lake Erie's waters in the summer months. Most HABs are caused by planktonic bacteria, which are suspended in the water and rely on currents to move them. Near Ohio's South Bass Island, you'll find Microcystis blooms, which have been at high levels in recent years during the summer months. Photo: Paul C. Focazio, NYSG.
If a dog begins to show signs of HAB poisoning—lethargy, vomiting, abdominal swelling—and requires intense veterinary care, dog owners may be spending more to care for their pets. Many waterfowl hunters take their trusty retrievers with them—dogs that may cost anywhere from $500 to $2000. According to US Fish and Wildlife Service, waterfowl hunters spend about a $1000 per year maintaining and outfitting their hunting dogs. This adds up to $900 million annually, with $20 million spent in New York State alone. The very real threat of HABs, which can affect the health of waterfowl as well, may affect the $2.4 billion impact waterfowl hunting has on the US economy.
Cyanobacteria have not only harmed pets and tainted some water supplies, they can be devastating to the local tourism-based economy. Case in point is Sodus Bay, NY, a popular boating destination on the east end of Lake Ontario. The 2010 bloom that occurred in Sodus Bay jeopardized the drinking water of its residents and unexpectedly and prematurely ended the tourism season, and generally harmed the local businesses.
In New York Sea Grant funded research, Dr. Boyer examined what was driving the algal blooms that occurred in late summer during the height of the 2010 tourism season. His team compared the amount of nutrients and toxins in the waters around marinas and other shoreline sites around Sodus Bay during the following summers of 2011 and 2012. Phosphorus was the limiting nutrient for these blooms. There was little difference between marinas and the other sites, strongly suggesting that non-point sources such as the surrounding watershed or bay sediments was the source of this phosphorus.
We generally think of New York’s freshwater resources as being the State’s two Great Lakes, the Finger Lakes, and New York’s great river systems and their tributaries. However, in the summer of 2014, cyanobacteria were detected in Suffolk County on eastern Long Island, according to Dr. Chris Gobler, Stony Brook University’s School of Marine and Atmospheric Sciences, a recognized expert on brown tide, red tide, “rust tide,” as well as cyanobacteria. In fact, Dr. Gobler points out, more positive tests come up for cyanobacteria in Suffolk County than any other county in the state. In 2012, the New York Department of Health linked a canine death in Suffolk County to a cyanobacteria bloom.
What can people do to prevent harmful algal blooms? According to the NYS Department of Environmental Conservation, New Yorkers can do their part by reducing the amount of nutrients (phosphorus and nitrogen) that goes into the State’s water bodies. Try limiting lawn fertilization, maintaining septic tanks and shoreline buffers, and reducing erosion and stormwater runoff. Because HABs develop best in stagnant water that does not circulate, boaters can try maintaining water movement by using the same ‘bubblers” in summer that are used to keep ice from forming in winter. Boaters and property owners, pet lovers and tourists alike--let’s do our part and keep New York’s waters safe for ourselves and our pets.
For more on dogs and HABs, read NYSG’s publication written by Dave MacNeill with help from Drs. Bischoff, Boyer, and Gobler (who contributed to this article) along with experts from the USEPA, NYSDEC and NOAA. Go to: www.nyseagrant.org/btide/pdfs/HABsBrochure-0814.pdf.
To find out if cyanobacteria are in water bodies in your county, check out the NYSDEC Web site.