Waters in the coastal ocean tend to be more productive than waters of similar depth in the open ocean. What is the main reason for the productivity difference?

The coastal ocean seems to be more productive than the waters of the similar height in the open ocean due to ample availability of water, sunlight, and nutrients. The coastal ocean has more nutrients due to the process of upwelling, that is, movement of water offshore by the currents.

Also, water situated on the continental shelves is comparatively shallower and thus it is turbulent. This mixing or turbulence keeps settling the nutrients stirred up and accessible, and eventually, ample of nutrients erode off the continents themselves and so water nearby to the shore seems to be greater in nutrients.  

On the other hand, in the surface water away from the coastlines, usually, there is a lot of sunlight but no availability of adequate nutrients. Therefore, the majority of the ocean surface is not much productive.

Explanation:

increase soil erosion                                             reduce soil erosion

cattle grazing                                                         hydroseeding

deforestation                                                         contour plowing

                                                                                planting vegetation

plant roots basically hold the top soil

together and stop soil erosion because

in such situation top soil is not removed

during flood but cattle grazing causes

soil erosion because cattle consume the

grasses and herbs and top soil is exposed.

same situation occurs because of

deforestation, the trees and plants are cut

down to expose top soil which causes soil

erosion

what are the options