Sedimentation of loricas of tintinnids (ciliata, protozoa) and shells of bivalve larvae in the landlocked fjord, Lindåspollene, Norway

Abstract

Summary The patterns of sedimentation of loricas of the tintinnids Leprotintinnus pellucidus ( Cleve ), Parafavella denticulata ( Ehr. ), and Salpingella sp. and the shells of bivalve veliger larvae in Lindaspollene (max. depth 89 m) were studied by means of sediment traps added chloroform. The tintinnids showed distinct peaks of sedimentation at the time of maximum abundances in the water column. The decline of the population of L. pellucidus was attributed partly to predation and partly to cyst formation. Both the sedimentation fluxes of the tintinnids and bivalve larvae as well as the percentages of loricas containing protoplasm decreased with depth of water. It is suggested that this partly reflects capture by the traps of vertically migrating tintinnids and bivalve larvae in the surface layer, and consequently that the sedimentation fluxes of the tintinnids and the bivalve veliger larvae in the surface traps have been overestimated. The daily fluxes of loricas to the deepest traps were equivalent to 1–7% of the average integrated numbers in the water column. During the investigated period a total of 8.9×106 loricas·m-2 of P. denticulata sedimented to the deepest part of the fjord. This is equivalent to 0.038 g C · m-2, or approximately 0.04 % of the annual primary production.