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Title: Oceanic heterotrophic dinoflagellates: distribution, abundance, and role as microzooplankton

The primary objectives of this thesis were to determine the distribution and abundance of heterotrophic dinoflagellates across the Gulf Stream system off Cape Hatteras and to assess the potential grazing impact of these microheterotrophs in plankton communities. A list of species encountered in this study and their trophic status based on epifluorescence is presented, as well as observations on the presence of external or internal symbionts. The abundance of heterotrophic dinoflagellates across the Gulf Stream region off Cape Hatteras was determined from bimonthly net tow samples over a year and from whole water samples in March. Their average abundance was twice that of net ciliates in the net plankton and ten times that of ciliates in the nanoplankton. An isotope technique was developed to measure grazing rates of individual dinoflaggellates and other microzooplankton which cannot be separated in natural populations on the basis of size. /sup 3/H-thymidine and /sup 14/C-bicarbonate were used to label natural heterotrophic (bacteria and bacterivores) and autotrophic (phytoplankton and herbivores) food, respectively. Estimates of the grazing impact of heterotrophic kinoflagellates relative to other groups of heterotrophs on phytoplankton and bacteria were made by combining abundance data and clearance rates. Such calculations suggested that heterotrophic dinoflagellates maymore » be an important group of grazers in oceanic waters.« less
Authors:
Publication Date:
OSTI Identifier:
7245689
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Univ. of Rhode Island,Kingston, RI
Research Org:
Rhode Island Univ., Kingston (USA)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CARBON 14 COMPOUNDS; TRACER TECHNIQUES; DINOFLAGELLATE; SPATIAL DISTRIBUTION; TRITIUM COMPOUNDS; ZOOPLANKTON; POPULATION DYNAMICS; ACID CARBONATES; GRAZING; GULF STREAM; THYMIDINE; ANIMALS; AQUATIC ORGANISMS; AZINES; CURRENTS; DISTRIBUTION; HETEROCYCLIC COMPOUNDS; INVERTEBRATES; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; MASTIGOPHORA; MICROORGANISMS; NUCLEOSIDES; NUCLEOTIDES; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PLANKTON; PROTOZOA; PYRIMIDINES; RIBOSIDES; WATER CURRENTS 550701* -- Microbiology-- Tracer Techniques