On her part, MacKinnon is finding oceanography even more exciting than she thought it would be. MacKinnon's first research cruise was in 1996, when she participated in the Coastal Mixing and Optics project, a large, interdisciplinary research program on the continental shelf off Martha's Vineyard in New England. The fall of 1997 found her on the other side of the continent, on a cruise to study mixing in Monterey Canyon, on the continental shelf south of San Francisco. In the fall of 1998, she traveled south of the equator to the shallow Banda Sea, an area of the Indonesian through-flow thought to be a region where water from the Pacific might be mixing with water from the Indian Ocean. MacKinnon's research, which is funded under a National Defense Science and Engineering Graduate fellowship, focuses on the small-scale processes that control mixing on continental shelves.
Energy is pumped into the ocean by the winds and tides.
In order to balance the energy budget, the energy that is added to the ocean must be offset by energy that is subtracted from the ocean. Much of this energy is dissipated through turbulent mixing. Turbulent mixing in the open ocean has been studied for many years. Understanding mixing on the continental shelves is important not only because of its role in balancing the energy budget but also because of its effect on properties such as sediment transport, sound propagation, and biological productivity. Nutrients on the shelves are limited and must be replenished from deeper water.