A cruise, aboard the R/V Moana Wave was held during April-May 1974 and investigated an area 1,400 km S.S.E. of Honolulu, Hawaii, designated as DOMES site 'A' by a panel consisting of industry, government and academic representatives managing the Deep Ocean Mining Environmental Study (DOMES) under the coordination of NOAA Environmental Research Laboratory (ERL). This investigation was conducted in order to understand the effects of commercial ferromanganese mining on the oceanic environment. Baseline studies were made on the water column and ocean floor in typical areas prior to a possible full-scale mining operations in the area of the Pacific Occean stiruated between the Clarion and Clipperton fracture zones.

he proposed mining of ferromanganese deposits from the deep sea will affect benthic and pelagic environments depending to a great extent on the method of nodule retrieval and separation. Three basic deep-ocean mining systems have been proposed, each of which will effect the removal under varying conditions of water, sediment and nodules from the ocean floor. This report summarizes existing oceanographhic information on potential manganese nodule mining areas at the date of publication and presents the results of field observations in a manganese nodule area of the North Atlantic Ocean surveyed during Cruise 15 of the R/V Robert Conrad.