11 Interesting & Fun Facts About Pond Habitats

Ponds are some of the most diverse and productive bodies of freshwater in wetland regions and urban settings. Though they are relatively small compared to most freshwater systems, every square inch of their space can be rife with life. Shallow enough for sunlight to reach the bottom layers of water and the pond floor, natural ponds are a haven for both plants and animals that require light to survive.

Home to critters from virtually all orders of life, ponds have nutrient-rich microhabitats supporting the metabolic needs of microscopic to large members of the food chain. All aspects of their physical and biological components are intricately intertwined to establish a well-balanced and complex ecology. Their benefits trickle far beyond their margins. You’d be surprised to find that even the smallest of garden ponds can heavily impact the world around them.

As clean freshwater is a limited resource and therefore considered precious in nature, even terrestrial animals rely on their access to ponds to survive. Pond habitats are vital for connectivity, especially in an increasingly fragmented environment. Without them, thousands of ecologically important species would cease to exist. Though small, ponds are as important to many plants and animals as the oceans are to us humans. Read on below for some more interesting facts about them.

1) The largest pond is as big as a lake

Ponds are not necessarily smaller than lakes as they are largely defined by their maximum depth instead of their surface area. If all parts of a large and fairly calm body of freshwater are within the “photic zone”, meaning sunlight can penetrate through to the bottom, it can be considered a pond. There’s a fine line between deep ponds and fairly shallow lakes, and even their connectivity with other bodies of water can influence how they are classified.

With a surface area of more than 3,000 hectares, the Great Pond of Maine is larger than some of the smallest lakes! As it is so large for an enclosed body of water, with several islands to boot, why isn’t it considered a lake? The answer lies in its maximum depth. The deepest point of this pond is a mere 69 feet (21 meters). With clear water and a high visibility profile, sunlight can easily reach this depth and support a thriving diversity of submerged flora and fauna.

2) There are more than 100 million ponds in the world

Experts have estimated that there are around 500 million ponds and lakes across the globe. Considering ponds tend to be more numerous due to their smaller size, with many being man-made, it’s safe to say there could easily be more than 100 million ponds in the world. In North America alone, there are more than a million natural ponds due to the considerably large wetland regions and diversity of biomes.

Despite their widespread occurrence, the existence of pond habitats is under threat due to global warming and anthropogenic activities. Wetland regions are disappearing at an alarmingly fast rate as they are converted into farmlands, urban zones, designated mining areas, etc. Conservation of ponds is largely lacking in most areas that need them the most. Moreover, pond waters are simply not as clean as they used to be due to the persistent use of harmful, manmade chemicals everywhere.  

3) Some pond habitats have brackish water conditions

Compared to freshwater ponds, brackish ponds are those which have low salinity levels. These levels may fluctuate due to rainfall levels or exposure to rising tides. Manmade or natural, these are usually situated along coastal areas. These may contain thriving communities of animals and plants (such as mangroves) that favor low salinity conditions. Fully saltwater or anchialine ponds may also exist as a part of the coast becomes landlocked. These may have a subterranean connection to the sea or ocean.

Brackish water ponds are frequently used in aquaculture, as many coastal animals, particularly their young, thrive best in low salinity conditions. In tropical countries, many of these are man-made and used to grow fish and crustaceans at various density levels. Those that are stocked at conservative levels (extensive densities) usually support a high diversity of plant life, birds, and various species of fish. These tend to generate less waste compared to intensive pond systems.

4) Every drop of pond water contains a microcosm of life

A single drop of pond water can contain more than a million microscopic organisms. Invisible to the naked eye, these life forms include various bacteria, algae, parasites, fungi, protozoa, and tiny arthropods. Though they are tiny, they are extremely vital in ponds as they form the backbone upon which larger animals thrive. A well-balanced population of microbes, which develops over time, helps ensure the resilience of a pond.

The presence of these microbes may not necessarily be indicative of the cleanliness of water as there are some extremists which thrive best in polluted systems. Stable populations of beneficial microbes should ideally aid in rehabilitating water conditions.

Beneficial microbes aid in converting potentially toxic nutrients into harmless byproducts, creating biofilms that young animals and small fish may need to feed on to survive. Most importantly, they hasten the breakdown of waste products and decaying organisms, freeing up nutrients to support the needs of other plants and microbes. Though they may be free-floating, they are usually most concentrated as colonies in microhabitats containing a high surface area.

5) Many animals need pond habitats to reproduce and mature

Apart from fish, thousands of species rely on ponds to serve as an adequate environment for laying their eggs and to provide their young with their requirements for survival. These animals include aquatic and semi-aquatic insects, semi-aquatic reptiles, and amphibians. Sexually mature individuals are frequently found in or around pond environments as they search for their mates and lay their eggs there. Most of the time, their eggs need to be fully bathed with clean water to develop correctly and hatch.

Those with all life cycle stages in water will go on to mature and reproduce in the same pond, while those with terrestrial adult stages eventually leave the pond. They may return to the same pond to mate and reproduce or look for other bodies of water, expanding the distribution of their populations and possibly increasing genetic variation. Without freshwater bodies, these animals would cease to exist.  

Though waterfowl do not necessarily need ponds to reproduce, they may remain close to one as these provide their young with a safe space to learn to swim and catch food. Highly productive and diverse ponds provide young waterfowl with various food choices that may not require expertise or stealth to catch. Semi-aquatic mammals, such as otters and beavers, also need ponds despite their capacity to survive outside of water. The submerged portions of their homes keep them protected and allow for easy access to prey.

6) Ponds are repositories for carbon

Ponds are naturally able to sequester considerable amounts of carbon, making them instrumental in decelerating climate change. One study has shown that their bottom sediments act as an organic carbon sink with a burial rate of about 140 grams of carbon per square meter each year. This is significantly higher than the carbon burial rates of other vital ecosystems like forests or grasslands.

Unfortunately, rising temperatures have increased the rates at which the stored carbon in ponds is released. Depending on ambient temperatures, ponds can act as a carbon sink or a carbon source. Their role in carbon cycling is increasingly becoming more acknowledged, making them not only vital refuges for wildlife but also extremely important resources to combat global warming. Even an ornamental pond in your very own garden could be used as a tool to help save the planet!

7) Pond habitats can be permanent or temporary

As ponds tend to be quite shallow compared to other bodies of freshwater, seasonal fluctuations, weather abnormalities, and climate change can readily change their physical parameters. In some areas, pond habitats are as fleeting as the occurrence of wildflowers as they last for just a few months and become drained or dry out in a matter of days. These types of ponds are called seasonal ponds, vernal pools, or ephemeral pools.

Vernal pools are extremely important for wildlife as they provide necessary refuge and water when it is needed most by the local flora and fauna. In fact, many ecosystems rely on the timely occurrence of vernal ponds, which allow many animals to reproduce and feed once the final frosts have thawed in spring. These ponds rarely become occupied by fully aquatic animals as they last for such a short while before they dry out. They are thus unable to support complex aquatic ecosystems.

Permanent ponds are, of course, those that do not disappear due to the occurrence of warming temperatures or brief droughts. These are rarely situated in sloping areas and usually have a more complex depth structure. These will usually have a maximum depth of at least 12 feet or more. Depth levels may slightly fluctuate throughout the year, but eventual rains and the entry of stormwater should make up for considerable water losses.

8) Ponds are home to many rare specialists

For millennia, many unique animals have evolved to thrive in the microhabitats of certain types of ponds. Fairy and tadpole shrimps are just some of these rare specialists, which are perfectly suited to the conditions of ponds. Fairy shrimp populations can even survive in vernal ponds that intermittently dry out as they can enter a mode of dormancy called diapause. Tadpole shrimp produce dormant eggs that can persist in dried-up ponds. The dormant forms of both types of shrimp can withstand extreme conditions, such as hypersalinity, drought, and frost.

Other fascinating specialists in ponds are creatures with multiple means of respiration. Relying on just gills or skin for respiration can be detrimental to the survival of many pond animals as dissolved oxygen levels can easily be depleted in water. Some types of fish (e.g. lungfish, mudskippers) are thus able to breathe through their skin or have lungs that are able to function in cases of poor aeration or whenever their habitat dries out.

9) Natural ponds support submerged vegetation

Aquatic plants are equipped with many adaptations that allow them to thrive while rooted to the pond floor. Although these tend to grow toward the surface, they do so as a means of exposing their foliage to more sunlight and not necessarily for access to more air. Clean, natural ponds are the perfect environments for these plants as they provide all the necessary nutrients, ample aeration, and grazing communities to both encourage and control submerged plant growth.

Submerged vegetation is extremely important in ponds because they provide protection and food for small fish. Fry are rarely able to survive without the coverage that foliage provides. Moreover, the surfaces of their leaves serve as anchor points for fish and amphibian eggs. They are also ideal surfaces for the growth of biofilm, which are nutrient-rich accumulations of microbial colonies.

10) Healthy ponds require aeration

Oxygen is extremely vital for the health of ponds as it facilitates the conversion of nitrates and carbon-based substances into harmless and free-floating compounds. When oxygen is absent, anaerobic processes take place and result in the production of potentially harmful and sulfur-rich compounds. When these are present in large quantities, such as in dense accumulations of fish waste, hardly any animals are able to survive. Only specialized microbes can persist in very low oxygen conditions.

In ponds, aeration may come in the form of oxygen (as a byproduct of photosynthesis) produced by microscopic algae and submerged, marginal, and floating plants. It is also introduced into the water via a current or the mechanical disturbance of the water’s surface. As ponds are relatively small and may have still water, they rely on the presence of plants to remain oxygenated. A mechanical aerator is usually necessary for ornamental ponds as the plants are unable to provide enough oxygen to meet the needs of a thriving fish community.

11) Many ponds are historically significant

Ponds are both historically and culturally significant as they provide a fundamental need – water. Many historical communities settled close to bodies of water as this proximity ensured that they would not have to travel far just to collect water. Now that pipes, aqueducts, dams, and complex water lines are commonplace, people need not live close to ponds, lakes, or rivers to survive.

Ponds are also sites of recreation and sources of desirable and protein-rich types of food. The largest ones have been heavily exploited by man for their personal needs and for entertainment. Maine’s Great Pond, for example, is surrounded by many villages that obtain food from its waters. Many riparian animals also live close to its waters, which are a source of favorable prey items.

Many man-made ponds have historical significance as they were seen as a desirable addition to have in private dwellings. They were beneficial receptacles of rainwater and could serve as a water source for garden plants. Until today, they are used as a focal feature to add interest to gardens and to naturalize open spaces.

Ponds can also be historically significant in the sense that their physical features are able to depict the natural history of a place. Deep layers of pond sediments provide a localized glimpse of erosion events, carbon concentrations, and even water conditions through time. In some rare cases, they may even contain fossils.