Seafloor
animals can tell a story
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The animals found living on the seafloor are very helpful for distinguishing new from old lava flows. Sessile (non-moving) and slow-colonizing animals like sponges, seafans, and crinoids are only found on old lava away from hydrothermal vents. Hydrothermal vents can be colonized quickly. Newly colonized hydrothermal vents (on new lava) typically have few species and individuals, and tubeworms are white and small (<50 cm), if present. Older established vents (on old lava) have more species and animals, and the tubeworms are brown and larger (>50 cm). Octopuses, crabs, and fish are mobile and can be found on either old or new lava. | ||