Observations of the surfaces of manganese nodules from various areas of the Pacific have revealed an entire community of attached encrusting protozoans, including over twenty species of agglutinating foraminifera and at least as many unidentified forms. Preliminary studies indicate that a great abundance and diversity of these organisms are found in the Northeast Equatorial Pacific. The highest density of organisms are associated with the portions of nodules in contact with the sediment-water interface which shows structural evidence for relatively rapid and variable growth rates and concentrations of trace elements. Remains of these organisms have also been detected within internal portions of nodules. Chemical analyses of the tests of such organisms indicate that many forms are responsible for concentrating trace elements found in nodules. However, there is no direct evidence that benthic foraminifera are responsible for copper and nickel enrichment in manganese nodules.