Fresh Water Habitats, Meaning, Types and Characteristics

By /

Welcome to this hall on fresh water habitats, types and characteristics

Table of Contents

At the end of this article, students should be able to know the:

  1. Meaning of Fresh water habitats
  2. Types of fresh water habitats
  3. Characteristics of fresh water habitats
  4. Plant and Animal species and their adaptive features.
  5. Food chain in Fresh water habitat
  6. Factors affecting fresh water habitats.

Read Also

Meaning Of Fresh water Habitat

Freshwater habitat is a body of water formed mainly from inland waters and contain very low level of salinity. Examples of freshwater habitats are rivers, ponds, streams, spring and the lakes.

Types Of Fresh Water

Fresh Waters are classified on the basis of their mobility. Based on this, two types are identified. These are:

  1. Lotic fresh waters: These include all running Waters which can flow continuously in a specific direction. In other words, these are flowing or running Waters, e.g, rivers, springs and streams.
  2. Lentic fresh waters: These include standing or stagnant Waters. These waters do not flow nor move. Examples of lentic fresh Waters are lakes, ponds, swamps and dams.

Characteristics Of Fres hwater Habitats

The following characteristics are associated with fresh water habitats:

  1. Low salinity: Fresh water habitats normally contain very low level of salt. It has about 0.5% of salt compared to about 3.5% of sea water.
  2. Small in size: Fresh water habitat is usually very small compared to the ocean water which is about 75% of the earth’s surface.
  3. Variation in temperature: The temperature of fresh water habitat usually varies with season and depth. Temperature at the surface of the water varies slightly with that at the bottom of the water.
  4. High concentration of oxygen: Oxygen is usually available in all parts of the fresh water especially in the surface of the water.
  5. Shallowness of water: Most fresh water habitats are very shallow, hence sunlight can easily penetrate through the water to the bottom.
  6. Seasonal variation: Some freshwater habitats like streams and Rivers normally dry up during the dry season while others have the volume reduce. The volume of water in rivers also increases during the rainy season. Turbidity and fast flow of rivers are also high during the rainy season than in dry season.
  7. Currents: Another characteristics of fresh water habitats is current. Current can affect the distribution of gases, salt and small organisms in freshwater habitat such as rivers and streams.

Major Ecological Zones of fresh water habitats

The zones of a lentic fresh water habitat, e.g lake are similar to those of the Marine habitat but they are no supratidal and inter-tidal zones.

There are two major zones in a lentic fresh water habitat. These are littoria and benthic zones.

1. Littoral zone: Littoral zone is the swallow part of fresh water habitat. It contains several plant and animals. The littoral zone has rooted vegetation at its base. It has the highest level of primary Production because sunlight can easily penetrate the zone, hence photosynthetic activities are Common.

Plants associated with this zone include

  • spirogyra
  • chlamydomonas
  • water lettuce
  • water fern
  • Duckweed
  • Diatoms
  • Sedges

Animals associated with this zone includes

  • Water fleas
  • Water snails
  • Flatworms
  • Frogs
  • Toads
  • Waters skaters
  • Ducks
  • Snakes.
  • Crocodiles
  • Tadpoles
  • Hydrae
  • Hippopotamus

1. Benthic zone: Benthic zone is the deepest part of the lentic freshwater habitat. The benthic zone does not have rooted vegetation like the littoral zone although flowering plants may occur at it surface system in the mud. These plants include:

  • Water lily
  • Water arum
  • Ferns
  • Crinum Lily
  • Comelina and grasses.

Animals associated with the bentic zone includes:

  • hydrae
  • Tilapia fish
  • Mudfish
  • Catfish
  • Leeches
  • Caddish fly lavae
  • Lavae and pupae of mosquito
  • Water snail
  • Water spider
  • Crayfish
  • Water Scorpion
  • Water boatman and
  • Water bugs.

Lotic Freshwater Habitat

In a lotic freshwater habitat, e.g, rivers, there exist two zones:

  1. Pool zone: In this zone, water is relatively slow and calm.
  2. Rapid zone: In this zone, water is very fast. The lotic freshwater habitat is not as stratified as the lentic freshwater habitat.

Adaptive Features Of Some Organisms in Freshwater Habitat

Some plants and their adaptive features

  1. Water lily (Nympaea): The plant has air bladers, expanded shape and lightweight which keep its a float. It has long petioles attached at the center of the leaf blade which prevent them from being drawn underwater by the current.
  2. Water hyacinth (ipomea grassipis): They have cavities and intercellular air spaces which give them the ability to float or maintain buoyancy on the water.
  3. Spirogyra: The plant has mucilagenous cover which protect them in water.
  4. Water lettuce (pistia): Water lettuce has hairs on their leaves which help them to trap air and enable them to float.
  5. Hornwort (ceratophyllum): The plant have submerge or thin dissected leaves which increases their surface area to sunlight and gaseous exchange.
  6. Water weed (Elodea): The plant has a long and flexible submerged petiole which enables it to swing with water currents.

Some Animals And Their Adaptive Features

  1. Protozoa: These animals possesses contractile vacuoles which enable them to carry out osmoregulation in water.
  2. Tilapia fish: They have swim bladers which enable them to float (buoyancy) in water. They also have gills for respiration.
  3. Duck: It has webbed digit on it feet for easy locomotion and serrated beak for sieving food in water into its mouth.
  4. Long fish (protopterus): The animals obtain oxygen through the gills but when the water dries out during the dry season, they dig into the mud and breathe with lungs until the rain comes again.
  5. Hydra: It has slippery surface, hooks and suckers for attachment to water particles.
  6. Pond skaters (Gerris): This animals has long legs with which it skates on water surface.
  7. Water boatman: This animal can carry bubbles of air with it as it goes below the water surface to the bottom and use this as their Air supply (respiration) underwater.

Food Chain In Freshwater Habitat

Diatoms, spirogyra, detritus, water lily and most of the flowering plants are the major producers in freshwater habitat. Some examples of food chains are:

  1. Diatom – fish fly- tilapia
  2. Detritus – worm – Shrimps – birds.
  3. Spirogyra – tadpoles – carps – kingfishers.

Energy Flow In Freshwater Habitat

  • Energy flow from sun/radiant energy/solar energy is received.
  • It is then absorbed/trapped by green plants/algae/phytoplankton (of freshwater/pond/stream/rivers etc.)
  • This is used in photosynthesis, to synthesize/manufacture organic substances.
  • Zooplankton/fish/animals of the pond would now depend or feed on the green plants for food
  • The feeding is direct if they are herbivores as the plants are eaten by herbivores.
  • The feeding is indirect if they are carnivores as herbivores are eaten by carnivores.
  • When plants or animals organisms die or when animals discharge their droppings/wastes, they are decomposed via the action of saprophytes/fungi/bacteria -decomposers micro-organisms.
  • By sodaing, energy is lost.

Factors Affecting Freshwater Habitats

Factors which affect freshwater habitats are both biotic and abiotic factors

1. Biotic Factor

  • Plants/producers
  • Animals/consumers
  • Parasites
  • Decomposers/saprophytes/micro-organisms
  • Predators.

2. Abiotic Factors

  • Temperature
  • Sunlight/light
  • Wind
  • Inorganic compounds
  • Turbidity/suspended particles/transparency
  • Topography
  • Dissolved energy
  • pH/dissolved Co
  • Water current/currents
  • Rainfall/precipitation.

READ ALSO – Types and Characteristics of Estuarine Habitat

Quick Revision Questions for Students

  1. Define fresh water habitat.
  2. (a) Explain the types of fres hwater habitats and give two examples of each type (b) state five characteristics of freshwater habitats
  3. (a) name three plants and three animals associated with each of the zones (b) describe the adaptive features of the plants and animals named in these zones (d) give an example of food chain in a freshwater habitat.
  4. List four factors affecting fresh water habitats (b) describe the energy flow in a freshwater habitat (c) list three abiotic factors and five biotic factors which affect plants in Freshwater habitat. (WASSCE exam question)
Scroll to Top