Opportunities / Science

High Pond: The story and celebration of our first sentinel lake Lay Monitor

Would you be willing to hike to a remote lake once a week during the summer months? What about following up that hike with a paddle in an inflatable boat to collect lake water samples? Sound challenging? Well this is exactly how a Vermont Lay Monitor spent last summer.

Let us begin with High Pond. High Pond is a clear lake with a small, forested watershed at 1,033 feet in elevation in Sudbury, Vermont. According to a report by Middlebury College’s 2014 Paleolimnology class, the pond was most likely created about 14,000 years ago as the Laurentide ice sheet retreated from the northern end of the Taconic Mountain Range. Fast forward to the mid 1900s, and wealthy adventurer W. Douglas Burden purchased the lands surrounding High Pond to create a private ski area and preserve. Following Burden’s passing in the 1980s, The Nature Conservancy (TNC) stepped in, buying the land and protecting it from an impending timber sale. TNC’s High Pond Preserve includes pasture in various stages of regrowth, forested land with a virgin hemlock stand, old mixed hardwoods, numerous wetlands, and of course, the 22.9-acre pond.


Looking southwest across High Pond, Sudbury.

Though High Pond lacks a large number of rare species, the preserve is valued for several reasons. It has a very long baseline of biological study, including more than two dozen scientific papers on acid rain, snowshoe hares, and other topics. Few places in Vermont, and especially in the Champlain Valley, have been studied for so long or so thoroughly, offering an excellent background against which to plot future change. High Pond’s value is further enhanced by its location. At the far northern tip of the Taconic Mountains, its unfragmented forest serves as a stepping stone for large mammals and other species moving between the Adirondacks and Green Mountains. Such natural stepping stones offer connectivity between large forested areas that are key to migrating species.

So, what is a sentinel lake? And why was High Pond selected as one? In 2011, 13 Vermont lakes were chosen as reference lakes for the 2012 National Lakes Assessment as well as for long-term study sites to examine the impacts of climate change, acid rain, and lakeshore development. High Pond and the 12 other “sentinel lakes” are minimally disturbed, with significant portions of their watershed conserved. Each lake is representative of a certain temperature class (warm to very cold), alkalinity (acidic to alkaline), and nutrient status (eutrophic to meso-oligotrophic). Lakes with existing aquatic invasive species, acidification stress, heavy development, or artificial water level manipulation were avoided to the greatest extent possible. In other words, sentinel lakes are shining examples of a Vermont lake in its most natural state.

Vermont’s 13 sentinel lakes serve as reference points for long-term monitoring.


Lake Town
BALD HILL Westmore
LONG (GRNSBO) Greensboro
LONG (SHEFLD) Sheffield
ROUND (SHEFLD) Sheffield
VAIL Sutton

The Lakes and Ponds Program now samples these lakes every year as part of the spring turnover sampling effort called “Spring P”. Phosphorus readings taken in the spring indicate the amount of phosphorus a lake will have available for the growth of phytoplankton, algae, and aquatic plants. Samples collected by Lay Monitors later in the year provide additional insight. The Vermont Lay Monitoring Program trains and equips volunteers (Lay Monitors) to collect lake water samples during the summer months. Most Lay Monitors are stationed near lakes that are easily accessible; however, Skip Abelson opted for a more challenging location.

Skip graciously gave us an inside look at the work and reward of being a Lay Monitor on a sentinel lake.


Meet Skip Abelson, High Pond Lay Monitor.

Do you need an excuse to get out into the woods every 7-10 days and spend quality time hiking to a remote lake? Well then volunteering to monitor a remote lake is the thing to do! High Pond is a bit up the trail, 22 minutes jogging, 45 minutes walking and if you are carrying a canoe, which is what [the Lakes and Ponds monitoring staff] must do, who knows how long it takes. We decided to pack in an inflatable raft. We hide it in the woods and store it in a plastic bin to keep the little rodents away. It takes about 30 minutes to set up, 15 to deflate. Then you paddle out into the deepest part of the lake. A word of caution, this thing is a beast to paddle, the rowing position is awkward and if the wind is blowing, forget about it. You need to put in near your desired location.

First there is the Secchi disk used to measure water clarity. Drop it over board until you can’t see it anymore. Next you take a weighted garden hose and drop it to just 3 feet off the bottom, carefully bring it back to the surface in a way that captures water from the bottom to the top. Then you pour it off into a bucket. From the bucket, spill it into a sample bottle. Prepare to get wet. Paddle back to shore and go home.

Once home, you need to prepare the samples carefully so that there is no contamination. Using tweezers to handle the filter, you place it on the filtering device, pump the water through, and then save the filter paper. This is stored in the freezer, in a container that blocks all light. Then you take a precise amount of the sample water, put it in a vial, and store in in the refrigerator, again blocking all light.

That’s it – 4 hours, plus or minus.

Why do I volunteer to do all this? It’s a pretty selfish reason! I feel good about helping contribute to the ecological preservation of our environment, I want to do what I can to give back to the earth, and I like to be outside.

Skip’s efforts have provided some fascinating insights into what our remote sentinel lakes are doing. For most freshwater lakes and ponds, phosphorus is the limiting nutrient for photosynthesis – more phosphorus often results in more algae and cloudier water. Interestingly, despite its high phosphorus and algae (as measured by a green pigment called chlorophyll a), High Pond has the 7th clearest water of all the lakes in the Lay Monitoring Program.


Water quality data collected on High Pond during the summer of 2017.

Digging deeper into WHY this lake with moderate phosphorus levels remains so clear required a good old-fashioned science experiment. In response to Skip’s findings, Lakes and Ponds Program scientists conducted a contained nutrient enrichment experiment on High Pond, in conjunction with other lakes across the Northeast, as part of a larger Global Lake Ecological Observatory Network study. The experiment suggested that High Pond isn’t solely phosphorus limited; it’s actually dependent on both phosphorus and nitrogen for production. It’s discoveries like this that will help us better understand how our lakes function and how they might respond to an ever-changing environment.

Next year Vermont will celebrate the 40th year of its Lay Monitoring Program, but this year we celebrate our first volunteer willing to sample an especially hard-to-reach lake. Thank you, Skip!

Are you up for a challenge? The Lakes and Ponds Program is currently seeking additional Lay Monitors. Check out the map above and consider spending your summer on a Vermont sentinel lake.

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