SS2 Biology Third Term: Aquatic Habitat

Topic: Aquatic Habitat

Introduction

Aquatic habitat is a body of water in which certain organisms live naturally. In other words, aquatic habitats are habitats or places that relates to lives in water. Organisms that live in water are called aquatic organisms. Examples of aquatic organisms are fish, crabs, toads, plants etc.

Types of Aquatic Habitats

There are three types of aquatic habitats. These are marine or salt water habitats, estuarine or brackish water habitats and fresh water habitats

MARINE HABITATS

Marine habitats refer to aquatic habitats which contain salt water. Marine habitats include the oceans, lakes, shores and the open seas.

Characteristics of Marine Habitat

The marine or salt water habitat has the following characteristics:

1. Salinity: Salinity is defined as the degree of saltiness or concentration of salt solution in oceans. The marine habitats have a high salinity and its average salinity is put at 35.2 per 1000. In other words, the average salinity of the ocean is 35.2 parts of salts by weight per 1000 parts of water.
2. Density: the density of marine water is high, hence many organisms can float in it. While the density of ocean water is about 1.028, that of fresh water is 1.00. So, the density of ocean water is higher than that of fresh water.
3. Pressure: Water pressure increases in depth at the rate of one atmosphere for every ten metres. In other words, pressure varies from one atmosphere at the surface level to about 1000 atmosphere at the greatest depth. This is why animals in marine habitats have features which enable them to adapt especially at the deep level of the sea.
4. Size: Marine habitats represent the largest of all the habitats. The ocean alone occupies over 70% or 360 million square kilometers of the earth’s total area of 510 million square kilometers. Examples of oceans are Atlantic ocean, Indian ocean, Pacific ocean (the largest)
5. Currents: Currents are always produced by wind at the surface of the ocean. Currents are also produced down the ocean as a result of certain variations such as salinity and changes in temperature.
6. Tides: Tides are the alternate rise and fall of the surface of the ocean approximately twice a day. This alternate rise and fall in water level is due to the gravitational effects of the moon and sun.
7. Oxygen concentration: The concentration of oxygen in the ocean is highest at the surface while it decreases with depth, and in the very deep parts of the oceans there is practically no oxygen.
8. Hydrogen ion concentration: Salt water is known to be alkaline in nature with pH of about 8.0-0.9 near the surface.
9. Waves: Waves are movement of surface waters of the oceans and it can take any direction and are caused by winds. Waves bring about the mixing of sea water especially on the surface of the ocean.
10. Light penetration: Light penetrate the ocean water only to a maximum depth of 200 metres. Therefore, plant life is limited to the upper layers of the ocean where light can penetrate. Penetration of light depends on the water turbidity.

Read more below:

SS2 Biology Third Term: Aquatic Habitat