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 may be an important group of grazers in oceanic waters.
- Research Organization:
- Rhode Island Univ., Kingston (USA)
- OSTI ID:
- 7245689
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ACID CARBONATES
ANIMALS
AQUATIC ORGANISMS
AZINES
CARBON 14 COMPOUNDS
CURRENTS
DINOFLAGELLATE
DISTRIBUTION
GRAZING
GULF STREAM
HETEROCYCLIC COMPOUNDS
INVERTEBRATES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MASTIGOPHORA
MICROORGANISMS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANKTON
POPULATION DYNAMICS
PROTOZOA
PYRIMIDINES
RIBOSIDES
SPATIAL DISTRIBUTION
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
WATER CURRENTS
ZOOPLANKTON