Fossil and Living Dinoflagellates PDF
Preview Fossil and Living Dinoflagellates
FRONTISPIECE. 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 A C A D E M I C PRESS. L o n d o n a n d N e w Y o r k A Subsidiary of Harcourt Brace Jovanovich, Publishers A C A D E M I C P R E S S I N C . ( L O N D O N ) L T D 2 4 / 2 8 O v a l R o a d L o n d o n N W l U.S. Edition published by A C A D E M I C P R E S S I N C . I l l Fifth A v e n u e , N e w Y o r k , N e w Y o r k 1 0 0 0 3 C o p y r i g h t @ 1 9 7 4 by A C A D E M I C P R E S S I N C . ( L O N D O N ) L T D All Rights Reserved N o part o f this b o o k may be reproduced in any f o r m by photos ta t , microf i lm, o r any o th e r means, w i t h o u t wr i t t en permiss ion f r o m the publ ishers L i b r a r y o f Congress Catalog Card Number: 7 4 5 6 5 6 I S B N : 0 - 1 2 - 6 1 9 1 5 0 6 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 .
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