The plankton of the ocean is important.

The contamination in the sea has been an often big problem in ,the outflow of the crude oil of a cargo, an outflow and an Illegal abandonment of , and the stranding of a tanker etc. The sea covers 70 percent on the earth. What thing does it mean if the sea is ruined? Now, compared with tropical forest, we is not conscious of the plankton of the ocean. The phytoplankton of the ocean is photosynthesizing like a plant on land. Moreover, the CO2 is absorbed and fixed. It is said that the total amount is almost equal to the total amount of CO2 fixed with the whole plant on land. Volume of the sea is huge. Therefore, concentration detection of a chemistry substance is very difficult. However, it being unable to measure does not mean no existing. Moreover, a chemistry substance is condensed by the food cycle. It will enter into the man who finally makes it a mouth by quite high concentration. It is difficult to solve what course the chemistry substance of the ocean has followed. A lot of [ the outflow from a river or direct abandonment owing to ] chemistry substances in the coast of the ocean are accumulated to the seabed etc. There are many factories which treat such a chemistry substance by one side. There are some which are carried by the ocean current. However, it thinks [ that it may be carried via the atmosphere, and ]. Moreover, use is forbidden to some of high agricultural chemicals of accumulation nature, and chemistry substances in our country. However, the whole world, especially use in developing countries have been increasing rather. Therefore, in the whole world, it cannot be said that it is decreasing.