Copepoda Harpacticoida: Biology (Ecology)

Harpacticoid copepods are essentially free-living organisms, although a few are planktonic (Microsetella, Euterpina, Clymnestra, Macrpsetella) or found in association with other organisms . In marine sedimente, they are usually the second most abundant meiofaunal taxon afternematodes but tend to become the dominant taxon in coarsed-grained sediments and on marine algae. Generally, there is a reduction in abundance with increasing depth of water. Harpacticoids can be found living in sediment particle interstices, burrowing in the sediments, or living on the sediment surface. Small, vermiform, interstit10al speciesnd broad, slightly flattened, epibenthic species dominate the sand sediments but the former disappear from community when silt/clay content of the sediment exceeds about 10%. In addition to species assemblages being associated with particular substrata, there is both horizontal and vertical zonation of species within the sediment. Harpacticoid is general are known to be intolerant of anaerobic conditions and are therefore confined to the oxygenated layers of the sediment, usually the top 1 cm in muddy sediments but as much as the top 50-100 cm on high energy sand beaches.