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Titolo:
GRAZING IN THE MICRON AND THE SUBMICRON PARTICLE-SIZE RANGE - THE CASE OF OIKOPLEURA-DIOICA (APPENDICULARIA)
Autore:
BEDO AW; ACUNA JL; ROBINS D; HARRIS RP;
Indirizzi:
PLYMOUTH MARINE LAB WEST HOE PL1 3DH ENGLAND UNIV OVIEDO,DEPT BIOL ORGAN & SISTEMAS,ECOL LAB ASTURIAS SPAIN
Titolo Testata:
Bulletin of marine science
fascicolo: 1, volume: 53, anno: 1993,
pagine: 2 - 14
SICI:
0007-4977(1993)53:1<2:GITMAT>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
FLUORESCENT LATEX BEADS; FRESH-WATER; FILTER; BACTERIA; FOOD; VANHOEFFENI; HOUSE; ULTRASTRUCTURE; ZOOPLANKTON; RATES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
46
Recensione:
Indirizzi per estratti:
Citazione:
A.W. Bedo et al., "GRAZING IN THE MICRON AND THE SUBMICRON PARTICLE-SIZE RANGE - THE CASE OF OIKOPLEURA-DIOICA (APPENDICULARIA)", Bulletin of marine science, 53(1), 1993, pp. 2-14

Abstract

We used procaryotic and eucaryotic phytoplankton (1.21 and 4.5 mum = Equivalent Spherical Diameter) and fluorescent carboxylated beads (0.2and 0.75 mum ESD) to obtain direct measurements of grazing by Oikopleura dioica in the micron (0.914-6.025 mum ESD) and submicron particle size range (0.2-0.75 mum ESD). Flow cytometry, used quantitatively, detected processes in the sub-micron range that could not be differentiated by other direct methods, such as low aperture techniques for electronic particle counting. We conclude from our observations that (1) Based on the decrease of particle concentration in the food suspension, filtration by the food concentration filter is a non selective processdown to 0.2 mum. (2) Collection by the pharyngeal filter, and consequently ingestion, of the very fine 0.2 mum beads is less efficient thanthat of the larger 0.75 mum microspheres and apparently diminishes with their concentration in the food suspension. (3) The fraction of 0.2mum beads resuspended after sieving by the pharyngeal filter is accumulated in the filter house (possibly by adhering on the internal wallsof the house due to physico-chemical interactions of their surfaces, though the properties of the beads are probably different from naturally occurring colloids), rather than being expelled as fecal pellets through the water sphincter exit. These observations suggest that, as producers of biogenic particles, O. dioica influence the fate of the fine colloidal material (<0.2 mum) in a different way than that of the slightly larger material (e.g., 0.75 mum), the latter being exported preferentially with fecal pellets while the finer particles would essentially contribute to the enrichment of the filter-house community microcosm.

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Documento generato il 06/04/20 alle ore 02:06:33