Thanks to Sarah Nelson & Amanda Gavin for contributing this article!
Tumbledown Pond sits at 818 meters (~2700 feet) elevation, just below the peaks of Tumbledown and Little Jackson Mountains. A popular, but challenging, hike on public lands leads to the pond, but it serves as more than an incredible viewpoint—Tumbledown Pond has been part of long-term research that began in the 1980s and provided early evidence of acidification in Maine’s lakes and ponds. A set of High-Elevation Lakes in Maine (HELM) lakes have been sampled most years since 1986, some years by helicopter, and some years on foot, or even skis. Because of the long-term monitoring at these lakes and others in the US EPA’s Long-Term Monitoring network, we have been able to see that the sulfur pollution that largely causes acid rain in the northeast has declined dramatically. The Clean Air Act Amendments reduced sulfur coming from coal-burning power plants and other sources by about 90% since 1990. As a direct result of policy changes, sulfur in HELM lakes has also drastically reduced. This is a big success story – when we regulate pollutants, we can see changes in the environment and improvements in water quality.
Even with the success of the Clean Air Act Amendments, Tumbledown Pond, and other HELM lakes, are not out of the woods. Climate change in New England has led to warmer and wetter conditions, milder winters with less persistent ice cover, and an increase in extreme weather events. The HELM lakes that we continue to sample were the sentinels for acid rain, and we think they quickly respond to the influence of climate change as well. Not unlike the canary in the coal mine, the chemistry and biology of these ponds respond to increases in air temperature and precipitation and can help scientists make predictions about the severity of climate change and how it will impact other ecosystems. For example, dissolved organic carbon (DOC), which imparts a tea-colored stain to freshwaters, increased in most of the HELM lakes since the 1980s and is linked to warmer and wetter conditions and recovery from acidification.
Combining Maine’s HELM lakes with those in the White and Green Mountains, the Adirondacks, and the Berkshires, recent research showed that the DOC increase is happening across the Northeast, and has potential to influence the base of the foodwebs in these unique ponds. In addition to monitoring the chemistry of these ponds, researchers have been studying how water temperature, thermal stratification, and ice cover is changing in HELM lakes by deploying sensors to record temperature throughout the water column for the past ten years. This will provide more insight into the sentinel response of mountain ponds to climate change.
Mountain ponds, like Tumbledown, are charismatic staples of the Maine landscape that are beloved by Maine’s most seasoned adventurers and a great jumping off point for those new to exploring the freshwater wonders of Maine. For all visitors, practicing leave no trace principles while exploring lakes will help protect the lakes, along with the plants and animals that live within the watershed, for generations to come.
With an area of over 75 thousand acres, Moosehead is Maine’s largest lake (but not its deepest - that record is held by Sebago). Its size and its convoluted shape is why this lake has so many water quality monitoring stations. Daphne Merrill’s book “The Lakes of Maine” includes many tidbits of information (facts, legends) about Moosehead (link is HERE - scroll down to page 34).
The heyday of tourism at Moosehead was in the late 1800s and early 1900s. Many tens of steamboats catered to tourists during these years. Following the decline of the steamboat industry, many vessels were scuttled in the lake. BBC Travel has recently published an article about the steamboats of Moosehead and includes links to several videos showing the sunken vessels. These pieces make for interesting reading & watching!
People often ask: What is the difference between a lake and a pond? Back in 2010, Linda Bacon (ME DEP) wrote an informative article in VLMP’s Water Column newsletter *. Quoting Linda, “One classic distinction is that sunlight penetrates to the bottom of all areas of a pond in contrast to lakes, which have deep waters that receive no sunlight at all. Another is that ponds generally have small surface areas and lakes have large surfaces…..Some of Maine’s large and deep bodies of water are indisputably lakes. Others are ponds – small and shallow. But there is a transition between the two where the definition becomes fuzzy…..The one distinction that has any legal application is the designation of a body of water as a Great Pond. Maine state statutes define lakes and ponds greater than ten acres in size as Great Ponds…..” Read more about the differences between lakes and ponds HERE.
A waterbody’s name, however, is certainly not a clear guide as to its biological / limnological status - as illustrated by these two waterbodies, both on Mount Desert Island. Some so-called Ponds are clearly lakes. Some so-called Lakes function more like ponds.
To delve further into how waterbody names (“lake” / “pond”) relate (or don’t) to size, take a look at this interactive graphic
Aug. 12 - Breana Bennett (Maine CDC) presents Heavy Metals, PFAS, Cyanotoxins in Maine Lakes - How Maine CDC determines much is too much chemical contamination in fish tissue and how that is considered in deriving fish consumption advisories? Also: What are challenges developing advisories for harmful algae blooms?
Click here to view current water quality conditions on a representative sample of Maine lakes during summer, or view which lakes have experienced ice-cover in the fall and ice-out in the spring.
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