Causes and Consequences of Fluctuating Coelomic Pressure in Sea Urchins

Ellers, Olaf; Telford, Malcolm

doi:10.2307/1542262

Cited by 38 publications

(23 citation statements)

References 17 publications

(21 reference statements)

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“…; Johnson et al. ), allowing the sutures to act as hinges and reorient in response to forces acting on the skeleton (Ellers & Telford ; Ellers ). Thus, sutural flexibility during growth may control overall sea urchin shape.…”

Section: Discussionmentioning

confidence: 99%

Externally visible fluorochrome marks and allometries of growing sea urchins

Johnson

Salyers

Alcorn

et al. 2013

Invertebrate Biology

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Externally visible, growing calcitic structures can be marked using fluorochromes. Such marks are useful for field recapture studies in ecology, evolution, and aquaculture as well as for studies on mechanisms of growth and development. We marked 2-month-old sea urchins (Strongylocentrotus droebachiensis) with the fluorochromes calcein, calcein blue, and tetracycline by batch-marking via immersion. Neither growth nor survival was affected by marking. Marks were externally visible on the skeletal plates, demipyramids, and spines of 100% of the marked sea urchins up to 63 d post-marking. After 342 d, marks were still externally visible on 100% of calcein-marked, 98% of calcein blue-marked, and 22% of tetracycline-marked sea urchins. Marks were brightest on calcein-marked and faintest on tetracycline-marked sea urchins, in correspondence to the fluorochrome dose. Growth marks in the aboral oculogenital ring, followed for 333 d, showed that genital plate growth in the hoop direction was greatest adjacent to the anal suture and that both the oculogenital ring and periproct grew less than isometrically. Internal marks (not externally visible) were subsequently seen on 99% of the demipyramids at 342 d post-marking. Such fluorochrome marks on demipyramids have previously been used to measure aboral and oral-end demipyramid growth to allometrically calibrate diametrical growth rates of field sea urchins. We found that although aboral demipyramid marks were always clear, 13% of marks on the oral end were obscured. However, we show that measuring only aboral end growth is sufficient for allometric calibration. In a separate experiment, multiple marks of the above three fluorochromes plus alizarin complexone, administered by injection to larger (12.9-37.1 mm diameter) sea urchins, persisted internally for at least 2 years. Multi-color, internally and externally visible, persistent marks will enhance experimental designs in laboratory, field, and common garden experiments.

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Section: Discussionmentioning

confidence: 99%

Externally visible fluorochrome marks and allometries of growing sea urchins

Johnson

Salyers

Alcorn

et al. 2013

Invertebrate Biology

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“…Thompson (Thompson, 1917) first described the shape of the sea urchin test using the analogy of a liquid drop on a flat surface and ascribed the forces producing this shape to coelomic pressure, podia (tube feet) and 'self-weight' (Dafni, 1986;Ellers and Telford, 1992;Ellers, 1993;Johnson et al, 2001). As an urchin grows, the sutures between test ossicles loosen (Ellers et al, 1998;Johnson et al, 2001) and "the entire structure is, in a sluggish way, plastic" [Thompson (Thompson, 1917) p. 662].…”

Section: Discussionmentioning

confidence: 99%

“…The flexibility in the test resulting from this kind of growth is capable of producing rapid changes in height:diameter ratios and morphological plasticity (Figs1, 3). Ellers and Telford (Ellers and Telford, 1992) measured the coelomic pressure in Strongylocentrotus purpuratus relative to the surrounding seawater. They found that it fluctuates with the movements of Aristotle's lantern and the associated tension and curvature changes of the peristomal membrane, and is negative overall (mean  -8 Pa).…”

Section: Discussionmentioning

confidence: 99%

Substratum cavities affect growth-plasticity, allometry, movement and feeding rates in the sea urchinStrongylocentrotus purpuratus

Hernández

Russell

2010

Journal of Experimental Biology

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SUMMARYWe assessed the influence of rock cavities, or pits, on the growth dynamics and behavior of the purple sea urchin, Strongylocentrotus purpuratus. In a paired-designed, laboratory experiment, sea urchins were assigned to sandstone blocks that were either 'Flat' or had a 'Pit' drilled into the center. At the start, both groups were approximately the same shape and size. In just 2 months, the shapes of the tests were significantly different between the two treatments, with the Pit urchins having an increased height:diameter profile. This result demonstrates the plastic nature of the sea urchin test and that, despite its apparent rigidity, it is capable of deforming during growth. In addition, the presence of pits modified behavior and food consumption as well as allometric growth of the test and Aristotle's lantern. Sea urchins on Pit sandstone blocks tended to stay in the cavities and not move about the flat areas, whereas individuals on Flat blocks changed position. Sea urchins in the Pit treatment consumed less food and had relatively larger demipyramids (the 'jaw' ossicle in Aristotle's lantern). These morphological and allometric changes occurred over a short time-period (8-20 weeks). We conclude that microhabitat is an important factor in controlling the behavior and growth dynamics of the bioeroding sea urchin S. purpuratus.

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“…Calculations of the surface area of T. gratilla's test were based on the assumption that its shape is a section of a sphere parallel to the equatorial plane. This assumption was derived from the work of Ellers & Telford (1992) and Ellers (1993), who suggested that the shape of a regular echinoid test is similar to a water-filled balloon resting on a table. Using this criterion, the surface area of T. gratilla's test was estimated as:…”

Section: Methodsmentioning

confidence: 99%

Population dynamics, infestation and host selection of Vexilla vexillum, an ectoparasitic muricid of echinoids, in Madagascar

Vaïtilingon¹,

Eeckhaut²,

Fourgon³

et al. 2004

Dis. Aquat. Org.

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The symbiotic interaction, population and infestation dynamics of the muricid Vexilla vexillum (Gmelin, 1791) on 2 echinoid species, Tripneustes gratilla (Linnaeus, 1785) and Echinometra mathaei (Blainville, 1825), was investigated on the barrier reef off Toliara (Madagascar). V. vexillum is an ectoparasitic muricid which was exclusively found in association with sea urchins, on which it moves freely and browses over the integument. Host recovery from damage caused by muricid grazing was dependent on lesion size. Small lesions regenerated while larger ones were subjected to secondary infections, which led to host death. A 27 mo survey (2000 to 2003) of the muricid's population dynamics revealed annual recruitment episodes during the mid-summer season (December to January). Patterns of recruitment peaks were apparently linked to its reproductive cycle. Demographic parameters including growth and mortality rates of the muricid were estimated from analysis of sizefrequency distributions. Growth was described by the von Bertalanffy function. The model predicts that V. vexillum is a fast-growing species in which asymptotic shell length (L ∞ = 1.024 cm) is reached 6 to 7 mo after recruitment. The growth rate constant K, and shell length at settlement L 0 , were estimated from the model. Estimated mortality rate was 55% yr -1 ; V. vexillum has a short lifespan. The observed high growth rate together with the high mortality rate suggest that V. vexillum is a semelparous species. A field survey of the infestation dynamics of V. vexillum was performed during 3 consecutive years, with seasonal variation in parasite prevalence on both echinoid host species. Although both T. gratilla and E. mathaei were infested, a preference towards T. gratilla was noted. This was attributed to T. gratilla's test morphology (which allows better accessibility for grazing), to the muricid's higher recognition capacity of T. gratilla (as determined by olfactory experiments) and to the high recruitment predictability of that particular host. This study provides novel information on the biology of V. vexillum, an echinoid epidermal grazer, and its relationship with 2 ecologically and economically important echinoid species.

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Causes and Consequences of Fluctuating Coelomic Pressure in Sea Urchins

Cited by 38 publications

References 17 publications

Externally visible fluorochrome marks and allometries of growing sea urchins

Externally visible fluorochrome marks and allometries of growing sea urchins

Substratum cavities affect growth-plasticity, allometry, movement and feeding rates in the sea urchinStrongylocentrotus purpuratus

Population dynamics, infestation and host selection of Vexilla vexillum, an ectoparasitic muricid of echinoids, in Madagascar

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