The deep affects the surface and the surface affects the deep

Explain

The role of the oceans and of climate science in the lives of Native Alaskans is an integral part of their cultures because for thousands of years, their livelihood and food sources have depended on their relationship and understanding of the ocean and climate. Respect and honor for the land and sea are are values taught and lived. In some cultures the bowhead whale, in other cultures, salmon and other fish are not just meat but a connection of their lives to the sea. The bottom currents warming and rising bring nutrients up to the surface to support these creatures' diets, which in turn provide food for Native Alaskans. People who have depended on the resources the land provides make observations because survival depends on it. Jack Lorrigan, a biologist for the local tribal government in Sitka, Alaska said of Native Alaskans that, "they are probably the consummate scientists that researchers could only hope to be today." Scientists make observations as a matter of research and data collection, but indigenous people have a large knowledge base in some of the same subject areas because of matters of life or death.

Salt and Temperature

Two of the things that affect ocean cycles are salt and temperature. The thermohaline circulation of water in the ocean is what causes the colder, denser water to go in a circular pattern. Water sinks near the north pole where surface temperature is low and ice formation at the surface increases salinity of the water. The colder and higher-salinity water is more dense and sinks to the bottom to travel along slow-moving, deep, ocean currents. It rises to the surface when it begins to warm. The heat transport helps to moderate the climate. The entire process takes as long as 1,000 years to complete. Currents rising from the deep ocean bottom carry nutrients and dissolved gasses from the depths to become available to life closer to the surface. Another climate variable besides changes in temperature and salinity at different ocean depths is the amount of fresh water being added to this system at points in the process. Large amounts of fresh water, such as sudden sea ice and glacier melt could slow down the circulation. Time scales of these deep ocean currents are centuries long, compared with the quick-moving surface currents. Atmospheric warming plus the rotation of the earth cause prevailing winds which drive surface currents in the ocean. Interestingly, it was Benjamin Franklin who was the first to map the powerful river under the sea and name it "The Gulf Stream." This strong surface current is 150 times as powerful as all the earth's rivers combined.

Extend

The European Space Agency currently has a highly sophisticated satellite called GOCE which is collecting data on the earth's magnetic fields and also deep ocean currents. Reiner Rummel, a professor at the Institute of Astrophysics and Physical Geology at the Unversity of Munich spoke about this new satellite and its ability to help us learn more about how this system of deep ocean currents is working. He says, "First you need to have data, you need to have evidence of how these things really move." The following video shows more on this topic.

Evaluate

The Inupiaq whale hunt represents a connection of the ways that the deep affects the surface and the surface affects the deep. The deep ocean currents bring nutrients to the surface that feed the whales' food source. In these same arctic waters where the whales are providing food for Native Alaskans, the very waters the whales are pulled from are losing heat, increasing in salinity and sinking down in the deep currents to return again years later with nutrients to feed the whale and feed the people. The climate, culture and ocean are all connected in this way.