AQUATIC HABITAT
HABITAT (AQUATIC HABITAT)
A habitat is a place where organisms (plants,microorganisms and animals) are naturally found e.g. the
habitat of the tadpole is the bottom of freshwater ponds or streams.
There are three main types of habitats, namely:
Aquatict (in or around water),
Terrestrial habitat (in or on land)
and Arboreal (in or on trees)
There are three kinds of aquatic habitat;
1. marine/saltwater habitat e.g. ocean, seas
2. brackish water habitat (where salt and freshwater mix) e.g. delta, lagoon, bay
3. Freshwater habitat (contain little or no salt) e.g. lakes, rivers, streams.
MARINE HABITATs
Characteristics of marine habitats are as follow:
1. The marine habitats constitute the largest habitat in the biosphere (70% of the earth's
area)
The biosphere is made up of the parts of Earth where life exists.
2. They do not undergo sudden or rapid changes in physical factors such as temperature, PH and specific
gravity. Hence they show the greatest stability of all habitats.
3. Chemical composition:- marine water consists of many kinds of dissolved ions including Nat, Kt, Mg2*,
Ca2*, Pb4*,T, NO* .
4. Hydrogen (H*) concentration (PH):= saltwater is alkaline in nature with a PH of about 8.0- 9.0 near the
surface.
5. Salinity (salt concentration of water). The seawater has high salinity. The average salinity of seawater
is 35 parts per thousand.
6. The density of marine water is high. It is about 1.028 while that of freshwater is 1.0. This allows many
organisms to float in it.
ESTUARINE HABITATS (BRACKISH WATER HABITATS)
An estuary is a body of water formed at the coast where freshwater flowing towards the sea mixes with
the sea (salt water) flowing inland. Estuarine habitats include deltas, lagoons and bays.
CHARACTERISTICS OF ESTUARINES
1. The salinity fluctuates.
2. The specific gravity is less than that of the sea
3. They have high turbidity due to frequent disturbances. Hence the rate of
photosynthesis and respiration by organisms reduces.
4. The water is shallow.
5. They have a low diversity of species compared to marine habitat.
6. They have a high level of nutrients
7. They have low oxygen content, hence anaerobic activities are common.
PLANTS DISTRIBUTION AND ADAPTATION IN ESTUARINES
Plants found in estuaries include planktons, algae, red and white mangrove
FRESHWATER HABITATS
This is a body of water formed mainly from inland waters and it contains very low or no salt.
Freshwater is of two types based on its mobility;
1. Lotic freshwaters: - These are running waters flowing continuously in a specific direction
e.g. rivers, springs, streams
2. Lentic freshwaters:- These are stagnant waters which do not flow e.g. lakes, ponds,
puddles, swamps and dams
CHARACTERISTICS OF FRESHWATER HABITATS
1. It contains little or no salt. Salinity is 5 parts per thousand i.e. 0.5%.
2. It is small in size.
3. Oxygen concentration is high, being available in all parts of the water body, especially at the
surface.
4. The water is shallow, hence sunlight penetrates to the bottom.
5. The temperature varies with seasons and depth.
6. It has seasonal variation; decreasing or drying up in the dry season and increasing in the
rainy season
7. Water currents affect the distribution of organisms, salts and gases, especially in lotic
freshwaters
WERK 2
TERRESTRIAL HABITATS
Organisms of the land are called terrestrial organisms. They include plants and animals that are
found living on the ground and under the ground.
Basically, terrestrial habitat is subdivided into four main parts, namely,
1. marsh
2. forest
3. grassland/ savanna
4. arid land/ desert
MARSH
A Marsh is low land, flooded in rainy season and usually waterlogged because of poor drainage. The
vegetation is predominantly of grasses and shrubs.
When trees grow in a marsh, it is called a swamp.
Marsh is a transition between the aquatic habitat and terrestrial habitat.
Marshes
Swamps
FORMATION OF A MARSH
Marshes develop as a result of water overflowing it's banks to accumulate on the adjoining coastal or
low land area such as flood plains of rivers. This can be enhanced with rainfall.
When ponds and lakes are filled up with soil and organic debris of plants, marshes can also be
formed. Marshes formation is, therefore, a gradual process. Marshes can either be freshwater or
saltwater marshes.
CHARACTERISTICS OF A MARSH
1. A marsh is a lowland.
2. It is always flooded, wet and waterlogged.
3. It sometimes has a pool of standing water.
4. It has a high relative humidity
5. Its water sometimes contain many decaying
organisms
6. The water has a foul smell
Animals found in the marsh include mangrove crabs, lagoon crabs, hermit crabs, mud-skippers, fishes,
frogs, snakes, crocodiles, mammal e.t.c.
Adaptive features of organisms of the marsh include
1. They must be able to tolerate the salinity of the soil or water
2. They have to tolerate low oxygen concentration in the soil or water of freshwater marsh have other
adaptive
eaures similar to those of freshwater habitatIo
Plants of freshwater marsh have other adaptive ,features similar to those of freshwater habitat. Likewise
the plants of saltwater marsh.
Saprophytic organisms (e.g. bacteria) which live on dead organic matter in marshes have to adapt to the
anaerobic condition.
FORESTS
A forest is a community of plants in which trees species are dominant. There are different kinds of
forests whose distribution is determined mainly by climatic factors such as temperature, rainfall and at
times by soil elevation and man's activities such as farming, Ilumbering, bush burning, construction of
roads and building. The major type of forest in Nigeria is the rain forest
CHARACTERISTICS OF A FOREST
1. The forest is rich in epiphytes and climbers
2. The interior of the forest has high humidity,
low light intensity and damp floor.
3. Presence of tall trees with canopies and
existing in layers (stratified).
4. Trees are mesophytes with broad leaves.
5. The trees have buttress roots to support their
heavyweight and height.
6. The trees have thin barks for gaseous
exchange and transpiration.
