Just about everyone loves a nice walk by the waterside, whether it’s a seaside beach or an inland body of water. But, have you ever wondered about the difference between a lake and a pond? Most people understand that lakes are generally larger, and ponds are typically smaller. But, where do we draw the line?
The short answer is that there’s actually no scientific definition between a pond and a lake. However, there are a few unofficial distinctions between them, so let’s dive into those to see what we can learn.
Depth & the Photic Zone
The first unofficial way people compare lakes to ponds is by looking at sunlight penetration. There’s a limit to how deep sunlight can reach underwater—that’s called the “photic zone.” Some people believe the difference between lakes and ponds is that ponds are shallow enough to allow sunlight to reach the bottom. Lakes, on the other hand, will have parts that are too deep for any light to reach. These dark areas are called “aphotic zones.”
Because, in theory, ponds have photic zones spanning their entire length and width, they can support rooted plants growing across their entire surface, whereas lakes cannot.
One issue that comes up with using light penetration to differentiate ponds and lakes is the size of the body of water. Some large bodies of water that are shallow enough not to have an aphotic zone are technically ponds. While a smaller body of water—one you could easily throw a stone across—could have an aphotic zone which technically would make it a lake.
Acreage is another factor in determining whether a body of water is a pond or a lake. This definition, however, has a lot of disagreement. Some ecologists say a lake is anything above 5 acres, yet others say it must be 12 acres or even 20 acres. One of the founders of modern ecology also stated lakes must be at least 99 acres. So, it’s clear that size isn’t the best way to think about the difference between ponds and lakes.
Temperature & Wave Action
Going along with the idea that ponds are completely photic zones whereas lakes have aphotic zones, temperatures are believed to vary between the two. Some people think ponds will have roughly the same water temperature everywhere. Whereas lakes will have stratified areas of warmer water and cooler water, depending on how much sunlight reaches certain areas.
Also, some people consider ponds to completely dry up in the summer and completely freeze solid during the winter, while lakes will never dry up and never freeze completely.
One final way to try and differentiate between a pond and a lake is to look at how big the waves are. For ponds, there will be hardly any waves, and if there are, they will be minimal. On the other hand, lakes will generally have wave action constantly.
No matter how you choose to tell the difference between lakes and ponds, one thing is for sure—both ponds and lakes are a great place to spend a summer day!