In nature, ecosystem can be divided into two major categories Terrestrial and aquatic
Forests, Grasslands and desserts are example of the Terrestrial ecosystem. The aquatic ecosystem can be either freshwater (Ponds, takes, streams) or salt-water (marine, estuaries) type. Ecosystem can generally be physically delineated. But sometime ecosystem integrates with each other. At large, All Ecosystems are interconnected by flow of energy and transfers of materials. For example, leaves of river bank Trees dropping in river water represent transfer of energy and material from Terrestrial to aquatic ecosystem.
Natural Ecosystem in Environment
Aquatic Ecosystem: Aquatic ecosystem includes freshwater and marine ecosystem.
Fresh Water Ecosystem: Freshwater habitats (ponds, lakes, rivers, streams, marshes etc) are highly diversified and market by a wide range of physiochemical conditions. The environment of organism consists of number of factors such as a temperature, amount of Sunlight, penetrating water, density and chemical composition of water etc., that play important role in controlling the abundance, survival and distribution of organisms. Fresh water ecosystem has following characteristics:
a) Fresh waters are scattered and are of lesser volume and death in comparison to marine water.
b) It is physical and chemical link between Terrestrial and Marine Habitat.
c) Environmental factors such as a temperature, dissolved gases, light, food etc. are always in changing condition in fresh water.
d) Fresh water is characterized by Low salinity. Sufficient quantity of biogenic salt remains present in fresh water.
e) The animal and plant life is greatly affected by the concentration of Oxygen and Carbon dioxide in the aquatic environment. They act as a limited factor.
f) The PH of rivers and stream remain fairly constant while in ponds and lakes it fluctuates greatly. This affects the distribution of plants and animals.
g) There is a danger of drying up of fresh water bodies at higher temperature.
Marine Ecosystem: The marine ecosystem is largest and most suitable aquatic ecosystems. It covers approximately 73% of Earth’s surface. The major characteristics of marine ecosystems are as follows:
a) The average depth of oceans is above3, 750 meters.
b) The temperature varies from 32 degree Celsius in the tropics to -4.2 degree Celsius in the Arctic regions.
c) Animal in the deep sea are exposed to a very large pressure.
d) Marine water is rich in oxygen, nitrogen, carbon dioxide and other gases. Their concentration varies in temperature and depth.
e) Marine water contains high salt contents which range from 3 to 3.7%.
f) Marine ecosystem exhibits many kinds of water and tides.
g) The marine ecosystem is continuous as all the oceans of the world are connected with each other.
h) The sea water always remains in circulation due to currents of water. These currents helps in movement of organisms and also in the distribution of food materials.
Terrestrial environment unlike aquatic environment changes very soon. The changes are generally in temperature, rainfall, sunlight, moisture, soil etc. These changes are responsible for the formation of well defined zone called biomass. Each biome supports a characteristic community of living organisms.
The Terrestrial ecosystem has following characteristics:
a) Moisture is a major limiting factor for plant and animal life on it.
b) Terrestrial animals and plants are exposed to higher temperature variations.
c) Oxygen and Carbon dioxide are only two required substance that are nearly constant in amounts.
d) The soil in various regions very tremendously in the texture, structure and relative amount of mineral substances and organic material. Different kind of soil in various regions supports very much varied flora and fauna.
e) The animal life on earth depends mainly on the trapping of Sunlight and other electromagnetic radiation by plants.
f) Geographical barriers along with climate barriers from the major limiting factor for distribution of plants and animals on the terrestrial ecosystem.
Major Ecosystems of the World: Natural and Terrestrial Ecosystem