What ecological factor limits the spread of plants to great depths in the world’s oceans?

Lack of light is an ecological factor that limits the spread of plants to great depths in the world’s oceans. Because a plant, like any living organism, needs sunlight to come to it. Due to the hit of sunlight on the plant, vital processes arise for it. In the absence of an acceptable norm of light, the plant simply cannot exist for a long time and will die. Therefore, due to its lack, plants practically do not spread to great depths.