Riches of the Bering Sea

Acre for acre, the huge continental shelf area of the Bering Sea may be the most valuable real estate on the Earth's surface. This view, expressed by a past director of the University of Alaska's Institute of Marine Science, Dr. Donald Hood, takes into account the Bering Sea's potential for petroleum and mineral development. But most important probably is the renewable food resource.

As our knowledge of the oceans has increased these last few years, we are being forced to abandon the myth that the oceans are an endless and uniform storehouse of food. We are beginning to realize that only certain parts of the ocean are rich and that most of the oceanic volume is a comparative desert.

Primary food production in the ocean is by plant forms that perform photosynthesis, a process that can only take place only in the top 200 meters. Required also for maximal photosynthetic production are elemental materials such as phosphorus and nitrogen. These are most abundant in water where photosynthesis is impossible. Thus, where upwelling of deep waters brings nutrients to the surface, photosynthesis proceeds most rapidly.

Rapid mixing of surface water with deep water is the key to high production of food in the oceans. On this score, the Bering Sea has three things going for it. The long reach of shallow bottom extending from Alaska well out toward Kamchatka drags against water currents created by the tides and causes mixing of the deeper and shallower water. Winds blowing across the Bering Sea in winter when it is partially ice covered causes upwelling at the boundary between the ice pack and the open water. Also, near this boundary and near open leads scattered throughout the ice pack, freezing of surface water causes a circulation to be set up in surrounding water, and this circulation creates vertical mixing.

The region near the ice front seems to be particularly productive because of the mixing. Here marine mammals tend to congregate because of the enhanced food supply.