Severe erosion at Cliff Pond--one cause of the algae blooms

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At 90 feet, Cliff Pond is the deepest pond on Cape Cod. It's located in Nickerson State Park, and is a popular for swimming and boating.

But starting a 1998, toxic algae blooms there became a problem, resulting in the death of at least two dogs* that had been swimming in the pond.

Closures of the pond to swimming have increased in recent years.  Last year, park officials closed the pond for a total of 99 days.  This summer, the pond was closed from June 25 to July 9.

The reason was high levels of blue-green algae.

The microscopic plant is present all the time,** but the timing of "blooms," when it multiplies out of control, is unpredictable.  Not all blooms result in dangerous toxins.  How the weather leads to a toxic bloom isn't well understood.  Experts expect more and more blooms as the climate warms.

Cape Cod from space

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Seen from space, the Cape is incredibly small, fragile, and delicate.  It's unique on the planet--and in the universe.

The Cape is a lacework of blue ponds, etched on sand...

Ponds around the world--Indiana

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Coastal plain ponds are a rare and endangered ecosystem.  Although most are found along the Atlantic coast north of New York City, Indiana claims a few.  They are located SE of Chicago--one could say on the coastal plain of Lake Michigan.

They are found in Jasper-Pulaski State Park, famous as a place to view Sandhill Cranes during migration (below).

"Although a popular destination for hunters, anglers, and Sandhill Crane enthusiasts, few are aware of the global significance of Inland Coastal Plain ponds and marshes at Jasper-Pulaski. These ephemerally wet, shallow basins are host to an impressive array of unusual flora.

Ponds around the world--New York State

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Coastal plain ponds...

...are a unique and rare ecosystem found from New Jersey north along the Atlantic coast.  They include the amazing ponds of Cape Cod.  Some people consider seepage ponds in Midwestern states--formed along the glacial margin like those on the Cape-to be close relatives.

A pond in New York State (Long Pond, Sag Harbor), by Steven Young

Ponds around the world--Switzerland

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"Global warming, a concern for its effects on the world's oceans, is also causing harm to the globe's freshwater lakes, researchers in Switzerland say.

Researchers... said a study of Lake Zurich showed that because of global warming, there is insufficient water turnover in the lake following the winter and harmful algae known as Burgundy blood algae are increasingly thriving.

Lake Zurich, by Chris Brown

Many large lakes in Central Europe became heavily overfertilized in the 20th century through sewage, and as a result algal blooms form, reducing oxygen content in the water and threatening fish stocks, they said.

Dead fish in Shangri-La

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All around the world, lakes are in trouble--with fish kills or toxic algae blooms.  Usually, the culprit is excess nutrients washing into the lake.  It's happening even at pristine lakes, long thought to be immune to these problems.

From time to time, I'll feature problems of lakes in a different parts of the world.  The root cause is growing populations and affluence, plus the difficulty of managing thousands of small sources of nutrients.

Indian Kashmir used to be a place people compared to mythical Shangri-La--verdant and unspoiled.  And Nigeen Lake (above), in a green valley surrounded by the Himalayas, is considered by waterways officials to the least polluted waterway in the city of Srinagar (population 1.3 million).

But a few days ago, there was a big fish kill on the lake.  "The fisheries department has attributed the deaths to depletion of oxygen, fluctuation of temperature and flow of untreated sewage into the lake."  Residents say they've never seen anything like this before. Source

Toxic algae bloom reported in Eastham

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"Town officials are warning swimmers and pet owners to avoid Molls Pond off Alston Avenue because of the growth of blue-green algae." The problem was noticed when a dog became sick, after drinking from the pond.

"Possible health effects range from rashes, hives or skin blisters to runny eyes and nose, sore throat, diarrhea and vomiting.  In rare cases, exposure can lead to neurological symptoms, including drooling, weakness, staggering, convulsions, and death in dogs.  Humans may experience dizziness, numb lips or tingling fingers. Source