MEPS 163:145-153 (1998) - doi:10.3354/meps163145
Role of Halicryptus spinulosus (Priapulida) in structuring meiofauna and settling macrofauna
Katri Aarnio1,*, Erik Bonsdorff2, Alf Norkko1
Priapulids are potentially important in structuring soft-bottom communities in temperate and arctic regions, and this study is a first attempt to evaluate their importance in zoobenthic communities. Halicryptus spinulosus is an important component of the zoobenthos of the northern Baltic Sea. It is competitive in harsh environmental conditions as it can withstand hypoxia and hydrogen sulphide. The natural food selection of H. spinulosus consists mainly of detritus (62 to 68% of the stomach contents) and 10 infaunal categories (the amphipod Monoporeia affinis and other crustaceans being most frequent). The effects of H. spinulosus on both meio- and macrofauna were studied experimentally. Significant negative effects were found for both meiofauna (nematodes and total abundance) and macrofauna (Manayunkia aestuarina, oligochaetes and total abundance). The effects on recruitment (mainly larval Macoma balthica) were also significant. In the field, total abundance and the number of nematodes were also significantly reduced by the presence of H. spinulosus. The effects of H. spinulosus on other fauna is suggested to be a consequence of predation in combination with disturbance.
Halicryptus spinulosus · Priapulida · Meiofauna · Macrofauna · Macoma balthica · Recruitment · Predation · Disturbance
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