Did You Know?
Approximately 41 percent of all known species of fish on our planet are found in freshwater sources like rivers, lakes, creeks, etc.
The aquatic biome is home to millions of species of fish, reptiles, amphibians, etc. Add to it the number of species which are indirectly dependent on this biome and the number just swells. This biome is divided into two parts: marine biome (comprising saline water sources like oceans and estuaries) and freshwater biome (comprising freshwater sources like rivers, lakes, ponds, and wetlands).
The freshwater biome may just be a small facet of the planet's ecosystem, but the plants and animals in it play a crucial role in smooth functioning of the ecosystem as a whole.
Freshwater Biome: An Overview
Also known as freshwater ecosystem, freshwater biome contains 0.009 percent of the total water on the planet. While 70 percent of the Earth's surface is covered with water, freshwater sources only account for 0.8 percent of the same. These include rivers, lakes, ponds, streams, wetlands, brooks, creeks, canals, etc. Roughly about half of the total drinking water available on the planet is stored in freshwater sources, while the other half is stored in the form of glaciers and ground water.
Freshwater Biome Animals
Other than all those species of fish, amphibians, reptiles, and some mammals, freshwater biome also has some species of birds and terrestrial animals indirectly depending on it. While rivers and streams, which are typically characterized by moving water, house different types of freshwater fish, wetlands―with stagnant water―provide ideal conditions for a variety of amphibians and reptiles as well as some insect species. With so many freshwater sources on the planet, the biodiversity that this biome boasts of shouldn't really come as a surprise for anyone.
The freshwater biome is home to as many as 41 percent of the fish species found on the planet. If we are to put that in numbers, roughly about 10,000 of the world's 25,000 species of fish are found in this biome. Then there are diadromous species, i.e., species that migrate between the sea and freshwater sources. Some of the most common freshwater species are perch, catfish, bluegill, bullheads, barbs, tetras, eels, salmon, bass, trouts, piranhas, etc.
Amphibians found in freshwater include aquatic frogs (like the African dwarf frog and Western clawed frog), salamanders (like the Mexican salamander and Chinese giant salamander), and newts (like the Spotted paddle-tail newt and Alpine newt). This biome also boasts of housing the largest amphibian in the world, the Chinese giant salamander which measures an impressive 5 ft 11 inches in length. It's also worth noting that most of the amphibians require fresh water when it comes to reproduction.
Insects are quite common in freshwater sources, especially in stagnant water sources which are ideal breeding grounds for them. These include mayflies, water beetles, water bugs, etc. Similarly, there also exist water fleas, i.e., tiny creatures which feed on cyanobacteria in the water, in this biome. Aquatic insects also act as a food source for various other animals in this biome, and thus, form a crucial part of the freshwater food chain.
As for reptiles, water snakes such as water moccasins, northern water snakes, banded water snakes, etc., are quite common. While the Brazilian smooth snake is a venomous species, those belonging to genus Enhydris are considered mildly venomous. Other reptiles include crocodiles (freshwater crocodiles), alligators (American alligators), and hundreds of species of turtles (Asian softshell turtles, yellow-spotted river turtles, river cooters, etc.) Australia alone has 23 species of turtles.
Birds and Mammals
While several species of birds and mammals are dependent on the freshwater ecosystem for food, there are a few which themselves form an important part of this ecosystem. In fact, they spend most of the time in these water sources. As for birds found in this biome, the list is dominated by ducks and geese. On the other hand, the list of mammals includes river otters, beavers, river dolphins, manatees, etc. These birds and mammals form an important part of the freshwater biome food web.
The fact that freshwater biome contains mere 0.009 percent of the total water on the planet gives the impression that it is least important from the ecological point of view. That, however, is far from true considering that it is the most important biome not just for the plants and animals which thrive in it, but also for us humans. If we don't put in efforts to save rivers, lakes, and ponds on the planet today, tomorrow it might be too late for us to even try.