It is estimated that sea cucumbers constitute more than 90 percent of the mass of all creatures living at a depth of 26,000 feet [8,000 m], making them the dominant organism in some ocean trenches.
Arvestuste järgi moodustavad meripurad 8000 meetri sügavusel elavate organismide kogumassist rohkem kui 90 protsenti, mistõttu nad on mõne ookeanisüviku domineerivad organismid.