Meiofaunal colonization of artificial substrates in an estuarine embayment

Artificial substrates were used to investigate the cryptic meiofauna of a L ouisiana estuary. Three types of collectors were used as artificial habitat s in colonization studies. Mesh collectors (composed of a plastic thread, a pproximately 74 m long, woven into a pad) and bottle brushes (with approxim ately 4400 plastic bristles per brush, each 2.5 mm long) were colonized equ ally well by meiofauna; Hester-Dendy plates with less structural complexity were colonized at a slower rate, especially by copepods. Nematodes and har pacticoid copepods were always the two most abundant meiofaunal taxa collec ted. Mesh collectors were retrieved in July and December after a 2-week col onization period to examine seasonal trends. Starting in December, a longte rm colonization study was also performed to determine if an equilibrium abu ndance could be achieved; artificial substrates were collected after 2, 4 a nd 8 weeks. Meiofauna achieved high abundances (means ranged from 1000-20,0 00 individuals per collector) on artificial substrates regardless of season , and abundance was related to supply, water flow and capture efficiency of the substrates as well as behavior of the meiofauna. Copepod species diver sity was low (6 species were observed in July and Ii in December). Diversit y and evenness were significantly different between July and December, and among the three collections in the long-term study. The copepod species ass emblage qualitatively differed between July and December. Our data suggest that an abundant and dynamic but understudied meiofaunal assemblage is pres ent in this estuarine embayment. This assemblage is not associated with mac roalgae but rather related to presence of hard substrates and seasonally ab undant filamentous microalgae.