Sublethal effects of cadmium on arm regeneration in the burrowing brittlestar, Microphiopholis gracillima

Abstract

: To assess the sublethal effects of sediment-bound cadmium on arm regeneration of Microphiopholis gracillima, a burrowing brittlestar, experiments were conducted to quantify the tissue and morphology of regenerating arms, the uptake of cadmium in various tissues and the effect M. gracillima had on the cadmium pools in muddy sediments. Regenerated arms of cadmium-exposed M. gracillima are thinner, with proportionally less soft and skeletal tissue and a greater number of developing ossicles than animals held in sediment without cadmium. Microphiopholis gracillima decreased pore water cadmium concentrations in muddy sediments. Uptake of cadmium in tissues dominated by the calcium carbonate endoskeleton was proportional to the measured sediment cadmium concentration, while concentrations in whole regenerating arms were more closely related to the pore water concentration. Both calcium and cadmium are accumulated in the early stages of arm regeneration with an apparent interaction which interferes with ossicle construction. Sediment-bound cadmium has a negative effect on the organism's recovery from sublethal tissue loss and, ultimately, its long-term survival.

Impact of near-future ocean acidification on echinoderms

“…3 Relationship between time of exposure to low pH (days) and size effect (s) dedifferentiation of myocytes). This typical ''stressresponse'' has been well documented for stressors such as pollutants and temperature (D'andrea et al 1996;Candia Carnevali et al 2001a, b, 2003Gunnarsson et al 1999;Selck et al 2004;Barbaglio et al 2004). Potential costs may then only appear and become important for longer term survival and/or on other trans-generational parameters such as fecundity.…”

“…However, adult echinoderms are valuable test species in marine ecotoxicology and offer a wide range of biological processes, including limb regeneration (see Candia Carnevali in this issue). For example, acute and chronic toxicity tests recently developed using echinoderm limb regeneration (Walsh et al 1986;Gunnarsson et al 1999;D'Andrea et al 1996;Novelli et al 2002;Candia Carnevali et al 2001a, b;Candia Carnevali et al 2003;Selck et al 2004;Barbaglio et al 2004;Sugni et al 2007).…”

Evidence for enhanced bioavailability of trace elements in the marine ecosystem of Deception Island, a volcano in Antarctica

“…The brittlestar O. victoriae, which feeds mostly on sediment (Fratt & Dearborn, 1984), had higher concentrations of trace elements (e.g., Al, Fe, Zn) in the digestive tract than other body parts, except for some elements (e.g., Mn, Sr) that were transferred into ossicles most likely for storage in a chemically non-reactive form, as is common for echinoderms (DÕAndrea, Stancyk, & Chandler, 1996;Temara, Aboutboul, Warnau, Jangoux, & Dubois, 1995). The demersal fish T. scotti, which feeds on detritus and benthic organisms, had higher trace element concentrations in the intestine of Deception Island specimens compared to those from King George Island, although element levels in gills from the two groups were similar.…”

Growth or differentiation? Adaptive regeneration in the brittlestarAmphiura filiformis

“…An unexpectedly high variability in the observed regeneration rate, is the rule in brittle star regeneration (Salzwedel, 1974;Andreasson, 1990;D'Andréa et al, 1996;Nilsson and Sköld, 1996;Sköld, 1996;Sköld and Gunnarsson, 1996;Sköld and Rosenberg, 1996;Gunnarsson et al, 1999;Mallefet et al, 2001;Thorndyke et al, 2003;Selck et al, 2004) and can mask many of the differences among the treatments (D'Andréa et al, 1996) or lead to contradictory results (Gunnarsson et al, 1999;Selk et al, 2004;Granberg, 2004). Our results demonstrate that taking into account the length lost on one arm is a simple and tractable way to standardize experiments and thus significantly decrease the variability of studied parameters (e.g.…”

“…regeneration rate). Moreover, differentiation rate (DR1 or DR2) is also a parameter that can be influenced by environmental factors and therefore this too should be integrated in further studies; for example, acute and chronic toxicity tests recently developed using echinoderm regeneration (Walsh et al, 1986;Gunnarsson et al, 1999;D'Andréa et al, 1996;Novelli et al, 2002;Candia Carnevali et al, 2001a;Candia Carnevali et al, 2001b;Candia Carnevali et al, 2003;Selck et al, 2004;Granberg, 2004;Barbaglio et al, 2004).…”