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which normal embryonic/larval development occurs, but by 1) adult temperature tolerances, 2) temperatures needed for growth or spawning, or 3) hydrographic features that limit larval settlement and juvenile survival. Data from experiments carried out by Tyler et al. (2000) showed that the embryonic and larval stages of the Antarctic echinoid Sterechinus neumayeri (Müller) are capable of surviving low temperatures in surface waters, but only tolerate higher pressures when water column temperatures are > 0° C. They infer that the larvae of S. neumayeri might be capable of penetrating the deep sea through the action of formation of Antarctic Bottom Water in the Weddell Sea, since this pattern of temperature increase is seen during deep water formation. Only one experiment has been carried out onto pressure tolerances of embryos the bathyal asteroid species Plutonaster bifrons (Wyville Thomson) (Young et al. 1996a). The greatest percentage of embryos developing normally occurred at pressures equivalent to 2000 m depth, the depth at which the species is most common. No normal development occurred at a pressure corresponding to 3000 m depth. Therefore, embryonic tolerances could determine the bathymetric limits of distribution for this species. 5.2- Effect of hydrodynamic mechanisms on larval dispersal Developmental mode is not the only factor that might determine dispersal distance, but larval dispersal patterns depend also on hydrodynamic mechanisms and such mechanisms may be different in distinct regions. Therefore, larval dispersal patterns vary between populations according to the relative importance of water advection and diffusion at a local scale. The flow of water in the deep sea is still not fully understood compared to the surface circulation. Therefore, in most cases, it is 95
not an easy task to predict where larvae released at a particular location will go and how long the journey will take. As an example Campbell & Rowe (1997) described the new species of asteroid Patiriella paradoxa Campbell and Rowe, which being a temperate taxon inhabits southern Arabian waters. This fact could only be explained in terms of this species being a relict who evolved to survive continual conditions in this tropical location, supported by the influence of local seasonal upwelling. Fenaux et al. (1994) showed that in the Eastern Alborean Sea, where surface currents form a complex frontal zone, with associated eddies and gyres, the distributions of larvae and postlarvae of echinoderms vary according to hydro dynamic structures. Larvae are numerous in the Atlantic Geostrophic Jet, which passes along the African coast and they are accumulated in an anti-cyclonic gyre to the west of the jet. In the anti-cyclonic eddy of Mediterranean water, north of the frontal zone, the larvae by contrast were scarce. Wind forcing increases the effect of advection on larval transport and modifies significantly the level of larval retention. Wind-induced currents however, may produce larval transport from one population to another and might be involved in restoration of depleted populations (Ellien et al., 2000). Marsh et al. (2001) demonstrated the prevailing importance of current flow in determining dispersal potential of the tube worm Riftia pachyptila at deep-sea hydrothermal vents on the East Pacific Rise and suggested that populations at different vent sites may have different dispersal limits depending on local current conditions. In this region at least, it is apparent that the dispersal distance of R. pachyptila was not limited by the physiological performance of the larvae, but by temporal oscillations in the currents and larval loss in their flows. 96
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University of Southampton Research
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Graduate School of the National Oce
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UNIVERSITY OF SOUTHAMPTON ABSTRACT
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Marthasterias glacialis (ECHINODERM
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Acknowledgments I know everybody sa
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Prière de l’étoile de mer Seign
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species of asteroid Patiriella para
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embryonic tolerances could determin
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dispersed over great distances and
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lecithotrophic development. The pre
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al., 1997). In a review (Vrijenhoek
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Although larval dispersal and settl
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larvae of shallow water echinoids f
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few hours, whereas other species su
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een defined as a unique sequence of
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therefore a developing form may wel
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adults” that have the definitive
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The dipleurula is the hypothetical
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among tunicate tadpoles, sponge and
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Fig.2.4. Bipinnaria larvae of the a
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In marine invertebrates there is a
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independent of habitat or mode of n
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whether juveniles derived from larv
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and the northern Mediterranean have
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Wares (2001) performed phylogenetic
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Fig. 3.2. A. Marthasterias glaciali
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3.2.2- Temperature/pressure effects
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Pressure was applied using an Enerp
Page 57 and 58: Fig. 3.7. Bippinaria larvae of Mart
Page 59 and 60: X Data were abnormal. At 150 and 20
Page 61 and 62: X Data all the embryos were abnorma
Page 63 and 64: X Data blastulae, at 200atm 90% of
Page 65 and 66: 50atm more than 90% of embryos were
Page 67 and 68: Those data (Young et al., 1997; Ped
Page 69 and 70: Percentage of individuals swimming
Page 71 and 72: that settling invertebrate larvae d
Page 73 and 74: CHAPTER FOUR- REPRODUCTIVE FEATURES
Page 75 and 76: In 1973, Vance proposed a theoretic
Page 77 and 78: Species Volume Energy Dev Class Ref
Page 79 and 80: 4.1.2- Body Size The reproductive o
Page 81: Species Depth of max. Depth range (
Page 84 and 85: arm, and the minor radius (r), from
Page 86 and 87: From Eqs.1 and 3 we obtain the esti
Page 88 and 89: Data on maximum body size, maximum
Page 90 and 91: 250 200 Body size (mm) 150 100 50 0
Page 92 and 93: Fig. 4.7. Hierarchical cluster anal
Page 94 and 95: (Hymenaster membranaceus Thomson).
Page 96 and 97: gamete production at low population
Page 98 and 99: varies depending on the vitellogeni
Page 100 and 101: size, high fecundity, small egg siz
Page 102 and 103: strategy described by Winemiller an
Page 104 and 105: It seems that evolutionary features
Page 106 and 107: strategy stablished by the Winemill
Page 110 and 111: Larval dispersal from eight populat
Page 112 and 113: These results are very important si
Page 114 and 115: possibility. The opportunistic spec
Page 116 and 117: hypothesis that the Mesozoic and ea
Page 118 and 119: Barnes, H. and H.T. Powell. 1951. T
Page 120 and 121: Chester, C.M. 1996. The effect of a
Page 122 and 123: Crisp, D.J. 1978. Genetic consequen
Page 124 and 125: David, B., A. Guille, J-P. Féral a
Page 126 and 127: Grant, A. 1983. On the evolution of
Page 128 and 129: Inaba, D. 1934. On some holothurian
Page 130 and 131: of the 6 th International Echinoder
Page 132 and 133: Lieberkind, I. 1926. Ctenodiscus au
Page 134 and 135: McEdward, L.R. and S.F. Carson. 198
Page 136 and 137: Minchin, D. 1987. Sea-water tempera
Page 138 and 139: Pawson, D.L. 1976. Some aspects of
Page 140 and 141: Pingree. R.D., B. Sinha and C.R. Gr
Page 142 and 143: Savidge, G., H.J. Lennon, and A.D.
Page 144 and 145: Shilling, F.M. and D.T. Manahan. 19
Page 146 and 147: Turner, R.L. and J.M. Lawrence. 197
Page 148 and 149: Vickery, M.S. and J.B. McClintock 2
Page 150 and 151: (Eds.): Reproduction Genetics and D
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