Slow recolonisation of deep-sea sediment

Abstract

USING the submarine ALVIN, experiments on deep-sea benthic communities have been designed to follow the recolonisation of defaunated deep-sea sediments and to provide estimates of growth rates and time to maturity in individual species. Small brood size and the high proportion of adults in a number of deep-sea benthic taxa suggest relatively low rates of recruitment, growth and mortality in the deep sea¹. Large individuals (8.4 mm) of the deep-sea bivalve, Tindaria callistiformis, have been estimated to be at least 100 yr old². Measurements of microbial activity and community respiration indicate rates one to three orders of magnitude lower than in shallow water^3,4. In contrast with the view that there is a general slowing of life processes, the first in situ deep-sea measurements on molluscan borers in wood panels have indicated rapid rates of recruitment, growth and maturation. Wood is, however, an ephemeral resource and its occurrence in the deep sea is unpredictable, while the majority of deep-sea habitats are thought to be highly predictable, therefore favouring less opportunistic life histories.