Publication Date:
2022-05-26
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution January, 1980
Description:
The acclimated asexual reproduction rates of many clones of
Emiliania huxleyi (82), Gephrocapsa oceanica (19),
Cyclococcolithina leptopora (31), Prorocentrum micans (28),
Dissodinium lunula (22), Thoracosphaera heimi (20), and Gonyaulax
tamarensis (83) were measured in several light and temperature
regimes. The data were used to determine the amount of genetic
variability and the spatial patterns of genetic differentiation in
these species.
None of the species examined exist purely as clones in nature.
Statistically significant genetic variability is found even among
clones isolated from single water bottles. The amount of genetic
variability in asexual reproduction rates in individual phytoplankton populations ranged from 3 t o 13% (coefficients of
variation). There is no obvious relationship between the amounts of
genetic variability in the populations and the variability or
predictability of the environments from which they were collected.
No genetic differentiation was found within the Sargasso Sea in
any of the oceanic species, but strong genetic differentiation was
found between oceanic and neritic populations of the two species (E.
huxleyi and G. oceanica) found on both sides of the Gulf Stream.
The spatial patterns of genetic differentiation appear to be
different in these two species, however. Genetic differentiation
was found between populations from the Sargasso Sea and the slope
water off New England is G. oceanica. In E. huxleyi the Sargasso
Sea and slope water were similar, but different from the
Gulf of Maine populations.
Of the three species for which populations were collected at
different times of the year (E. huxleyi, C. leptopora, and T.
heimi), there is evidence of significant seasonal genetic changes in
only one (C. leptopora).
Description:
This research was supported by the National Science Foundation, Grant Nos. OCE 77-10876, OCE 78-08858, and OCE 79-03621. I was
supported by a National Science Foundation Graduate Fellowship, a
National Science Foundation National Needs Traineeship, and the
Woods Hole Oceanographic Institution Graduate Education Program.
Keywords:
Marine phytoplankton
;
Variation
;
Population genetics
;
Ecological genetics
;
Oceanus (Ship : 1975-) Cruise OC25
;
Oceanus (Ship : 1975-) Cruise OC35
;
Oceanus (Ship : 1975-) Cruise OC40
;
Oceanus (Ship : 1975-) Cruise OC48
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
Format:
application/pdf
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