Externally visible fluorochrome marks and allometries of growing sea urchins

Abstract

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.

Ultrascale and microscale growth dynamics of the cidaroid spine of Phyllacanthus imperialis revealed by 26Mg labeling and NanoSIMS isotopic imaging

“…However, the latter rate applies to the fast unidirectional linear growth of the inner stereom (growth “pattern A” sensu Dubois and Jangoux, ) during regeneration, not peripheral increments during a normal spine growth as reported in this study. Similar growth rates ranging from few to 210 µm/day have been reported in various sea urchins (Märkel, ; Johnson et al, ).…”

“…In addition to these rather straightforward observations, over the last decades there have been major advances in our understanding of growth dynamics in echinoderms, through application of more direct labeling methods with fluorescent markers (e.g., Kobayashi and Taki, ; Märkel, ; Pearse and Pearse, ; Ebert, ; Russell, ; Kenner, ; Russell et al, ; Ellers and Johnson, ; Johnson et al, and literature cited therein). These markers (including alizarin complexone, calcein, calcein blue, and tetracycline) bind to Ca 2+ and are incorporated into the growing carbonate skeletons, and can be subsequently observed under ultraviolet illumination (for review see Ebert, ).…”

Efficiency of calcein tagging on juveniles of the sea urchins Diadema africanum and Paracentrotus lividus

“…) and 75 mg · l −1 (Ellers & Johnson ; Johnson et al . ) were used to tag Strongylocentrotus droebachiensis . Further, an injection study with Evechinus chloroticus used 500 mg · l −1 (Lamare & Mladenov ).…”

“…; Johnson et al . ). In other taxa, optimal calcein treatments for tagging juvenile individuals successfully have already been tested (Purcell et al .…”

Holistic morphometric analysis of growth of the sand dollar Echinarachnius parma (Echinodermata:Echinoidea:Clypeasteroida)

“…The best fitted models are logistic (Feller 1940), i.e., with exponential growth in the early stage and exponential decline of growth at a late stage. This is the pattern seen in the diametrical growth of the sea urchin Strongylocentrotus droebachiensis (Johnson et al 2013), which has been modeled with various functions (Rogers-Bennett et al 2003). The application of the Verhulst-Pearl logistic process (Pianka 2000), typically used in models of population growth, to model plate growth can be justified as a special case of the Bertalanffy model, in which growth is promoted by a nutritive resource which diffuses outwards from a plate center and is thus regulated by plate size.…”