Meiobenthic interactions with macrobenthic larvae and juveniles: an experimental assessment of the meiofaunal bottleneck

Abstract

The meiofaunal bottleneck hypothesis states that permanent meiofauna (eg nematodes, copepods, foraminifera) negatively affect macrofaunal larval settlement and juvenile survivorship. Field studies suggest enhanced meiofaunal densities decrease recruitment of some macrofauna but do not identify whether this is a settlement or post-settlement process. Experiments examined the settlement response of the spionid polychaete Streblospio benedicti and the venerid bivalve Mercenaria mercenaria to functionally different meiofaunal taxa (burrower, epibenthic, sediment sweeper). ANOVA revealed no significant effect of any meiofaunal taxon on macrofaunal settlement. Further experiments on emigration of recently-settled (<24h old) juvenile S. benedicti and M. mercenaria showed no difference in burial times (time from initial juvenile contact with the sediment surface until complete burial below the sediment surface) between meiofaunal treatments and control sediments. If the meiofaunal bottleneck exists, it is not a settlement phenomenon nor does it cause emigration of these recently-settled macrofauna. -Authors