The Manganese Nodule Program (MANOP) began in 1977 with funding from the International Decade of Ocean Exploration (IDOE). It replaced an earlier IDOE program that was started in 1972 in part by Maurice Ewing. MANOP's view is that the composition and occurrence of nodules can be best understood in the context of the large variations in the rain rate of organic matter to the deep-sea floor and the variable sedimentary geochemistry of their environment. Therefore, from the beginning much of MANOP's effort has been directed toward understanding the cycling of the biologically active elements—02, C, nutrients, and trace metals—in the deep sea; in fact, this aspect has itself become a primary goal of our work.