A new theory to explain the origin of growth lines in sea urchin spines

Ebert, TA

doi:10.3354/meps034197

Cited by 19 publications

(8 citation statements)

References 9 publications

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“…(), although the overall effect is to create conical layers, the calcification appears to occur in a patchwork with migrating cells laying down areas of calcite. Ultimately, the aggregate calcification leads to spine growth lines (Deutler ) that are not entirely age‐ or size‐dependent (Ebert , ) and to a structure with magnesium concentrations toward the outer edge of spines that strengthen the load‐bearing columns in the spines (Tsafnat et al. ).…”

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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“…In this hypothesis, growth of the spine would be triggered to maintain the correct allometric relations between spines and the continuously growing test. As stressed by Ebert (1986) himself, this hypothesis is only valid if spines are not continuously growing. However, Heatfield (1971b) showed a significant incorporation of 3 H-thymidine in intact spines, an observation that questions Ebert's hypothesis.…”

Section: Spine Regenerationmentioning

confidence: 99%

“…The periodic nature vs. the traumatic origin of these rings was much debated. It is now considered that spine rings do not have a periodic origin (and thus cannot be used to age sea urchins) (Ebert, 1986). According to Ebert, they would originate from either a trauma and subsequent regeneration, as explained above, or from an endogenous signal triggered by the tension developing between the base of the nongrowing spine and the continuously growing tubercle (or mam-melon) on which it sits.…”

Section: Spine Regenerationmentioning

confidence: 99%

Regeneration of spines and pedicellariae in echinoderms: A review

Dúbois

Ameye

2001

Microscopy Res & Technique

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Morphogenesis of tissues during regeneration of echinoderm spines and pedicellariae is reviewed. Regeneration of the skeleton is rather well documented while that of associated soft tissues is poorly investigated. In particular, little information is available on the early regeneration stages which follow wound healing. From the available information, it is suggested that regeneration of broken spines proceeds through a morphallactic process of which the organizational information, as well as the involved cells, lies in the stump. In contrast, regeneration of removed spines and pedicellariae may depend on an epimorphic process whose organizational information could be located in the mutable connective tissue that joins the appendage to the main body wall.

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“…The calcite spines covering the test of the sea urchin 129 serve as the primary interface with the environment and predators (Strathman, 1981), and aid in 130 movement (Hyman, 1955), and therefore their repair is important. While the process of spine 131 regeneration has been well established (Ebert, 1967(Ebert, , 1968(Ebert, , 1984(Ebert, , 1986(Ebert, , 19881991), there is 132 some debate as to whether this regeneration is independent of test and reproductive growth. 133 Kawakami (1998) found that a poor quality diet can lead to spine shedding, suggesting a link 134 between nutrition and spine maintenance.…”

Section: Introduction 63mentioning

confidence: 99%

Effects of spine damage and microhabitat on resource allocation of the purple sea urchin Strongylocentrotus purpuratus (Stimpson 1857)

Haag

Russell

Hernández

2016

Journal of Experimental Marine Biology and Ecology

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Though phenotypically plastic responses in echinoids are well studied, the majority of the 35 literature examines the effect of altered diet. Some species, however, such as the purple sea 36 urchin, Strongylocentrotus purpuratus, occur over a large geographic range and thus experience 37 a variety of substrate types and wave forces. To determine whether these factors impact resource 38 allocation in adult intertidal S. purpuratus, a laboratory experiment was conducted using two 39 types of microhabitat based on extremes inhabited by sea urchins in the field (flat substratum vs. 40 concave pit), and two levels of spine damage to simulate wave exposure (monthly clipping vs. 41 control). A suite of measurements were taken to determine the effects of these two treatments 42 including: feeding and movement behavior, test morphometrics, demipyramid (jaw) allometry, 43 spine growth cycles, and mass and stereological counts of gonad sections. When given the 44 3 opportunity, sea urchins remained in their pits for the duration of the experiment, which limited 45 their ability to feed. This behavioral response caused a decrease in weight and volumetric 46 growth, and an increase in jaw growth relative to test growth. Sea urchins in pits also grew more 47 spheroid in shape (increased height:diameter ratio), while those on flat substrates decreased in 48 height:diameter ratio. Further, both males and females in pits showed altered gametogenesis. 49 While spine damage did not affect test growth, sea urchins with clipped spines showed decreased 50 gonad index and altered production of mature oocytes. Altogether, these results are congruent 51 with the life history strategy of long living species like S.purpuratus, in that it spreads 52 reproductive efforts over multiple seasons, while diverting resources toward repairing damage, 53 acquiring suitable refuge, and maximizing attachment area. Therefore, microhabitat and spine 54 damage, by impacting movement, feeding, growth, and reproductive output, likely have 55 important indirect impacts on the intertidal community by way of altered sea urchin grazing rates 56 and susceptibility and value to predators. 57

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A new theory to explain the origin of growth lines in sea urchin spines

Cited by 19 publications

References 9 publications

Externally visible fluorochrome marks and allometries of growing sea urchins

Externally visible fluorochrome marks and allometries of growing sea urchins

Regeneration of spines and pedicellariae in echinoderms: A review

Effects of spine damage and microhabitat on resource allocation of the purple sea urchin Strongylocentrotus purpuratus (Stimpson 1857)

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