Answer
The coastal regions are rich in nutrients because of their close proximity to the rivers and human settlement areas. The open seas/oceans are nutrient poor because of their depth and no minimum disturbance from human activities.
Work Step by Step
The loss of nutrients from the land is takes place through leaching by water and wind. They are ultimately deposited in the seas and oceans, which are therefore rich in nutrients. However, the open oceans are nutrient poor in comparison to the coastal areas and intertidal habitats.
The mouth of the river opens in the seas and oceans and carries a major amount of nutrients. These nutrients are deposited into the oceans in this zone, which become quite fertile and rich in nutrients. This region has continuous turbulence because of upwelling from the oceans and continuous water supply from the rivers.
These nutrients reach the open oceans and get settled into the ocean floor. The open oceans are generally calm due to their depth and low tide zone. Therefore, the nutrients fail to appear on the surface from the bottom and it makes this area nutrient poor.
