Aspects of the biology of komokiagea and xenophyophoria

Abstract

Most larger groups of Protozoa have been shown to be represented at great depths, and protozoans are generally attributed a significant role in the composition and function of deep-sea communities. Mudballs and ‘natural concretions’ present a number of problems, viz. during the sieving procedure, and in determining their origin, their function on the bottom, and their classification relative to organisms. A large part of what has been classified as these formations are, in fact, komokiaceans and xenophyophores. The body size of komokiaceans and xenophyophores is large, but the plasma constitutes only a very small part of the volume, while accumulations of faecal pellets are strikingly extensive. Vacuole-based intracellular digestion may here have been elaborated into a system based on extracellular transport and digestion of food particles. This might be combined with a long-term utilization of the nutrients, as the enclosed masses of faecal pellets could protect a commensal microflora providing a relatively rapid (compared to conditions in the sediment) turnover because of enriched nutritive conditions.