What’s in a name?

  • George Loiselle of Hooksett takes advantage of the beautiful day by fishing on Hot Hole Pond in Concord in June 2016. Monitor file

  • Two men fish at sunset under the Interstate 89 bridge over Turkey Pond near St. Paul€™’s School in Concord on June 22. Despite being quite large, the waterbody is called a “pond.” Monitor file

  • Logs still rest near the boat ramp at Turkey Pond in Concord, one of the few remaining signs of the sawmill. Monitor file

For the Monitor
Published: 7/14/2020 8:52:23 AM

Getting into the clear, refreshing water of a lake or pond is one of the things I enjoy most about summer. When it comes to choosing a place to swim, fish or go boating though, not all bodies of water are equal. Some are lakes and some are ponds, but what is the difference?

Most people would say that a lake is larger and a pond is smaller. In fact Webster’s dictionary states that a lake is “an inland body of fresh water larger than a pond” and defines a pond as “a body of standing water smaller than a lake.” But size can be measured in various ways and there is actually no standard scientific definition according to size that distinguishes these lentic (standing water) habitats. But we will explore some features that do make a difference in terms of biological activity within lakes and ponds.

A size designation can be done by surface or depth. Generally lakes are considered to be deeper than ponds. Ponds are shallow enough throughout to allow sunlight to reach the bottom. Officially the entire body has a “photic zone.” This enables plants to grow at the bottom and on the surface. By contrast lakes will have zones that are “aphotic” where light cannot penetrate and provide for photosynthesis of plant life.

This difference is easily noticed by casual observers. If there are broad leaves of water lilies floating on the surface in the middle of a pond, it’s clear that light is filtering through the entire water column and enabling the plants to take root. The middle of a deeper lake is plant free.

The presence of plant life of course impacts the types of animals that live there. Stems and leaves of submerged or floating vegetation provide greater cover for fish, amphibians and insects. The edges of deeper bodies will have these features as well. These edge zones, like the junction of a forest and field are called ecotones and have a richness of biota that is far greater than the deeper regions.

The influence of the sun not only determines where plants can grow but also impacts the temperature of the water. Ponds generally have little temperature variation throughout, whereas lakes have layers of differing temperatures or thermoclines. It makes sense that shallower places warm up more quickly and larger bodies of water will hold a temperature longer. Therefore a deeper lake will take longer to warm up in the spring than a shallow pond.

Water temperature in turn determines what types of fish will live there. This is partly because temperature impacts the amount of oxygen that can dissolve in the water and be available to the creatures. Cold water holds more oxygen than warm water. Some fish like largemouth bass, pickerel and catfish (horned pout) survive well in warmer water while trout require colder water and more oxygen. For example, lake trout prefer water that is about 50 degrees and will drop down into lower zones if the upper area gets too warm. People who fish know these distinctions. In fact, fishing guides are usually divided into warm water fishing and cold water fishing.

Some invertebrates are also more adapted for surviving in areas of lower oxygen (i.e. shallow, warmer water). Leeches come to mind. They are most often found in quiet, shallow areas of ponds and lake edges where plant debris is plentiful. More appealing (at least to humans) are the nymphs of dragonflies and damselflies which can often be found in these shallower zones. If dissolved oxygen in these areas gets too low for them, they climb out of the water and take in oxygen from the air which diffuses into the film of water on their bodies and then into a network of tiny air tubes within their body.

Many other adaptations enable a wide variety of flora and fauna to live in these water bodies. So whether you call a 40 foot deep lake a name like Hot Hole Pond or are surprised that a 332-acre expansive water body is called Turkey Pond, know that what is on and under the water is something more important than its name.

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