Table Of ContentFRONTISPIECE. Three Hving d i n o
flagellates: scanning electron m i c r o
graphs .
F igure 1 . Peridinium cinctum (O. F.
Mόl l er ) Ehrenberg , in lateral v i e w .
X 1 6 4 0 .
F igure 2. Ceratium hirundinela
(O. F. Mόl l er ) Schrank , in dorsa l
v i e w . X 1 4 5 0 .
F igure 3 . Gonyaulax digitalis (Pouchet) K o f o i d , in dorsal v i e w . x l 5 G 0 .
[Photos by courtesy o f D r J . D . D o dge . ]
Fossil and Living
Dinoflagel fates
W . A. S. SARJEANT
D e p a r t m e n t o f G e o l o g i c a l S c i e n c e s
U n i v e r s i t y o f S a s k a t c h e w a n
S a s k a t o o n , C a n a d a
1 9 7 4
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P R I N T E D I N G R E A T B R I T A I N B Y
But ler & T a n n e r L t d , F r o m e and L o n d o n
Preface
When the writing of this book was originally commenced, it was intended
to deal only with fossil dinoflagellates. However, to see the fossils in their
true perspective, it was necessary to consider many aspects of living forms,
in particular their morphology and their mode of life; moreover, other
features of living forms, in particular their genetics, are of particular
interest from an evolutionary viewpoint. In consequence, this section
grew so much that it was decided to include a more detailed account of the
cell physiology and to alter the title to its present form. The primary
stress is still on fossil dinoflagellates; those groups of living forms which
are unknown as fossils (colonial, palmelloid, parasitic) receive only inci
dental attention and no attempt is made to review the geographical dis
tribution of dinoflagellates at the present day.
The references are organized in a fashion which, it is hoped, will
prove most convenient to the reader. References to preparation techniques
and to the classification of modern dinoflagellates are grouped after the
appendices on these topics. A selection of reference works considered of
orime interest to readers wishing to extend their knowledge of dinoflagel-
ates is separately listed and annotated in Appendix D. A comprehensive
list of all works on fossil and modern dinoflagellates that are referred to
in the main text follows in Appendix E, cross-references being given to
works already listed in Appendices  and D.
The index is organized in three parts—an index of authors is given,
then a systematic index and a terminological index. In the latter, all
usages are indexed, with pages on which the terms are defined or explained
indicated in italic type.
Research, both on fossil and living dinoflagellates, is currently proceed
ing at such a pace that new discoveries, often of fundamental importance,
seem to be being published every month. Inevitably, many sections in this
book will be out of date when it appears. It is perhaps appropriate,
therefore, to note that the last revisions to the manuscript were made in
January 1973 and that, in general, no mention may be expected of works
published after that date.
To my parents
HAROLD AND MARGARET SARJEANT
In gratitude for their
unfailing
encouragement and generosity
/ Living Ό im flagellates: Ecology
To the old adage "All flesh is grass", marine biologists have long added
the supplement "and all fish is plankton". Plankton, or more specifically
the microscopic plants it contains {phytoplankton), is indeed the foundation
for the food-chain in the seas and, to an almost equal degree, in lakes.
Its distribution controls the whole pattern of life in the seas and it is thus
of immense direct economic importance. Its indirect importance is also
very great, for, although the exact mechanism of chemical transformation
is still a matter for dispute, plankton is now recognized as being the
ultimate basis for the formation of petroleum.
A number of groups of microscopic plants together make up the
phytoplankton, among them silicoflagellates, chrysomonadines, ebridians,
cryptomonads, blue-green algae and Prasinophyceae. Each of these
groups may attain importance locally in the oceans. Three groups,
however, are particularly prominent; the diatoms in their box-like
siliceous frustules, the coccolithophores with their studded armour of
calcareous platelets, and the dinoflagellates. Their relative abundance
certainly varies according to season, geographical location and water
depth, but these three groups are unquestionably the true biological
foundation of the economics of present-day seas.
Plankton is usually conceived as being confined to the surface waters
of oceans, in which it drifts helplessly, entirely under the control of tide
and current. This is not the case. Phytoplankton is to be found dow*n to a
considerable depth in the oceans, occurring in abundance down to the
so-called "compensation depth", at which light penetration becomes
inadequate to permit sufficient production of oxygen by photosynthesis
to supply the demands of respiration. The compensation depth thus
corresponds approximately to the lowest level of the photic zone; how
ever, since the physiological demands of different species are variable,
the effective compensation depth for a particular species may accord
closely with, or may be markedly shallower than, the limit of light pene
tration. Since this is in turn controlled by the incidence of sunlight, the
2 F O S S I L A N D L I V I N G D I N O F L A G E L L A T E S
compensation depth is greatest at midday: as night approaches, it rises
towards the surface and ceases to exist in complete darkness.
Sea-water temperature is similarly controlled by sunlight; intense
radiation is unwelcome and the surface waters of oceans are virtually
devoid of plankton on sunny days.
In general, the organisms of the phytoplankton prefer to maintain
constant light/temperature relations (though some species are much more
tolerant of changing conditions than are others). In their quest for a
stable environment, they migrate downwards as the sun rises and towards
the surface as it sets. As complete darkness approaches, a fraction of the
phytoplankton (up to one-half) migrates downward again. This secondary
migration clearly represents an attempt to exploit more fully the nutritional
potential of the sea-water by absorbing or ingesting nutrients, especially
nitrogen, from lower layers during the period when photosynthesis is
impossible. It has also been suggested, on the basis of studies of plankton
migration in deep tanks, that the migrating fraction in dinoflagellates
observed (about 50%) was controlled by cell division, since there was
about a 50% population increase within 24 h: however, it could not
be decided whether the fraction migrating were those about to divide
or not (Eppley et al, 1968).
Individual species of dinoflagellates may migrate vertically a few
hundred feet daily, a considerable journey for organisms whose size
rarely exceeds 200 μ. The mechanism of migration is not yet fully under
stood. Observations have shown that cloudy weather lessens the intensity
of migration; the degree of diffusion of solar radiation seems more import
ant than its surface intensity. In their deep-tank experiments, however,
Eppley et aL {ibid.) found that this could not be regarded as straight
forward phototaxis since migration did not coincide with the turning on
or off" of a light source; downward migration began in the evening some
hours before the light was extinguished, upward migration began in the
morning some hours before the light was turned on again. It is clear,
therefore, that a definite rhythm of migration has been developed as
response to the diurnal light-dark cycle, which is not now directly
dependent on phototaxis and must instead be geotactic—reflecting an
ability to sense the gravitational field.
The animals of the plankton (the ^ooplankton) naturally migrate along
with the organisms on which they feed, and the fishes and other marine
FIG. 1 . T h e var ie ty o f f o r m exhibited b y the l i v ing dinoflagel late Ceratium. a. C. vultur
Cleve , b. C. Jmus (Ehrenberg) D u j a r d i n . c-d. C. tripos ( O . F . M ü l l e r ) Nitzsch:
variet ies w i t h 3 and 4 h o r n s , e-f. C. hirtmdinella (O. F . Mül l er ) S c h r a n k , a n o n - m a r i n e
species; variet ies w i t h 3 and 4 h o r n s , g. C. minutum J ö r g e n s e n , h. C. ranipes Cleve ,
i. C. platycorne cmeatum Daday . j . C . longirostrum G o u r r e t . k. C. hexacanthum G o u r r e t .
R e d r a w n f r o m B ö h m , J ö r g e n s e n , Ε . J . F . W o o d and others; n o t to constant scale.
F O S S I L A N D L I V I N G D I N O F L A G E L L A T E S
FIG. 2. T h e a r m o u r e d marine dinoflagellate Peridinium depressum Bailey, s h o w i n g the
tabulat ion typical o f the genus: f o u r apical plates (l '-40, three anter ior interca lary
plates ( l a - 3 a ) , seven preequator ia l plates ( Γ ' - 7 ' 0 , five postequator ia l plates ( 1 ' " - 5 " ' )
and t w o antapical plates {^""-2""). Left: in v e n t r a l v i e w . Right: in dorsa l v i e w .
X C.700.
animals, which prey on both, travel with them. (The migrations of the
plankton and attendent animals may be readily traced, since they form a
sonic layer detectable by echo-sounding equipment.) Zooplankton, fishes
and other marine animals all range down to much greater depths, feeding
directly or indirectly on the rain of dead plankton falling from above.
A wide range of marine planktonic organisms, both plant and animal,
are luminescent, but dinoflagellates are probably the most important
producers of luminescence in the oceans and sometimes cause tropical
seas to glow with phosphorescent light. Hardy and Kay (1964) found
that rising temperature increased luminosity, as, more surprisingly, did
the presence of actively swimming planktonic animals; light, predictably,
inhibited luminosity. Luminescence is developed both in holophytic
species, such as Peridinium depressum Bailey, Ceratium horridum Gran and
C. tripos (O. F. Müller) Nitzsch, and in holozoic species such as Noctiluca
miliaris Suriray. In the dinoflagellates examined to date, bioluminescence
results from the reaction with oxygen of an enzyme {lucijerase) and its
substrate {luciferin). Two distinct bioluminescent systems, a soluble
system exhibiting low kinetics of light emission, and a particulate
system of scintillons, exhibiting faster kinetics in single periodic flashes,
have been described (Fuller et aL, 1972); the soluble system may serve as
precursor pool for the particulate system. The functional significance of
luminescence in dinoflagellates is not yet clear.
In addition to oxygen and carbon dioxide, the phytoplankton requires
as major nutrients carbon, nitrogen, phosphorus and silicon. Phyto-
1. L I V I N G D I N O F L A G E L L A T E S : E C O L O G Y 5
plankton productivity is controlled largely by the availability of these
nutrients, which are in turn derived from land or from rising bottom
currents (the latter serving to recycle nutrients from dead plankton and
organisms falling to the bottom). Optimum conditions will occur in
well-lit waters rich in nutrients, either where deep waters are rising to
the surface or where there are currents rich in land-derived nutrients.
Where rivers discharge, the neighbouring marine waters will contain too
much particulate and dissolved mineral matter, light incidence will be
severely reduced and marine temperatures may be adversely affected: in
such conditions, the phytoplankton will be sparse or even absent.
D. B. Williams (1971a, pp. 92-93) excellently summarises the conditions
controlling the locations for optimum phytoplankton concentrations in
the oceans:
Th e mix ing o f deep waters w i t h the surface water , and the consequent nutr i en t
enr ichment o f the latter, is largely contro l l ed by h y d r o d y n a m i c effects o f the circula
t ion o f oceanic waters . O n e o f the areas w h e r e this is w e l l m a r k e d is at the lines o f
discontinuity between surface w a t e r masses, part icular ly in reg ions o f divergence .
T h e w i t h d r a w a l o f surface w a t e r s in oppos i te direct ions as a resul t o f w i n d - d r i v e n
currents requires replacement o f w a t e r f r o m b e l o w t o maintain the hydrostat ic
equi l ibr ium. Regions o f divergence are therefore often reg ions o f enhanced p r o d u c
t iv i ty . T h e turbulence occurr ing w h e r e a shear is p r o d u c e d between t w o subparal le l
o p p o s e d surface currents can also b r i n g nutr ients t o the surface, w i t h a c o r r e s p o n d i n g
increase in p r o d u c t i v i t y .
T h e eastern margins o f the m a j o r oceanic basins frequent ly s h o w enhanced p r o d u c
t iv i ty . This arises as a combinat ion o f internal circulat ion in the eastern b o u n d a r y
c u r r e n t systems—a direct dynamic effect—and a w i n d stress paral le l t o the coast
w h i c h causes an offshore t r a n s p o r t o f w a t e r , w h i c h is replaced b y u p w e l l i n g o f deep
water .
F I G . 3 . T h e b i v a l v e d marine dinoflagellate Prorocentrum micans E h r e n b e r g , s h o w i n g the
pos i t ioning o f b o t h flagella at the anter ior end. a. Profi le v i e w . b. Side v i e w . X c. 4 2 0 .
