TY - JOUR
T1 - Acquisition of Ca2+ and HCO3-/CO32- for shell formation in embryos of the common pond snail Lymnaea stagnalis
AU - Ebanks, Sue C.
AU - O'Donnell, Michael J.
AU - Grosell, Martin
N1 - Funding Information:
Acknowledgments We thank Drs. Lynne Fieber and Michael Schmale of the University of Miami, RSMAS for use of their cameras & microscopes and Andrea Kocmarek and Erin Leonard, M.Sc. of McMaster University for their technical assistance during S. Ebanks’ visit to the O’Donnell laboratory. This research was funded in part by the NOAA Educational Partnership Program, Environmental Cooperative Science Center and the RSMAS Marine Science Graduate Student Organization Student Travel Fund.
PY - 2010
Y1 - 2010
N2 - Embryos of the freshwater common pond snail Lymnaea stagnalis develop to hatch within 10 days under control conditions (22°C, Miami-Dade tap water) and this development is impaired by removal of ambient calcium. In contrast, embryos did not exhibit dependence upon an ambient HCO3-/CO32- source, developing and hatching in HCO3-/CO32--free water at rates comparable to controls. Post-metamorphic, shell-laying embryos exhibited a significant saturation-type calcium uptake as a function of increasing ambient calcium concentration. However, changes in ambient bicarbonate concentration did not influence calcium or apparent titratable alkalinity uptake. There was a distinct shift from no significant flux in pre-metamorphic embryos to net uptake of calcium in post-metamorphic stages as indicated by an increased uptake from the micro-environment surrounding the egg mass and increased net uptake in 24-h, whole egg mass flux measurements. Furthermore, HCO3-/CO32- acquisition as measured by titratable alkalinity flux is at least partially attributable to an endogenous carbonate source that is associated with acid extrusion. Thus, calcium requirements for embryonic shell formation are met via uptake but HCO3-/CO32-, which is also necessary for shell formation is acquired in part from endogenous sources with no detectable correlation to ambient HCO3-/CO32- availability.
AB - Embryos of the freshwater common pond snail Lymnaea stagnalis develop to hatch within 10 days under control conditions (22°C, Miami-Dade tap water) and this development is impaired by removal of ambient calcium. In contrast, embryos did not exhibit dependence upon an ambient HCO3-/CO32- source, developing and hatching in HCO3-/CO32--free water at rates comparable to controls. Post-metamorphic, shell-laying embryos exhibited a significant saturation-type calcium uptake as a function of increasing ambient calcium concentration. However, changes in ambient bicarbonate concentration did not influence calcium or apparent titratable alkalinity uptake. There was a distinct shift from no significant flux in pre-metamorphic embryos to net uptake of calcium in post-metamorphic stages as indicated by an increased uptake from the micro-environment surrounding the egg mass and increased net uptake in 24-h, whole egg mass flux measurements. Furthermore, HCO3-/CO32- acquisition as measured by titratable alkalinity flux is at least partially attributable to an endogenous carbonate source that is associated with acid extrusion. Thus, calcium requirements for embryonic shell formation are met via uptake but HCO3-/CO32-, which is also necessary for shell formation is acquired in part from endogenous sources with no detectable correlation to ambient HCO3-/CO32- availability.
KW - Calcification
KW - Calcium uptake kinetics
KW - Carbonate
KW - Development
KW - Freshwater
KW - Snail metamorphosis
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U2 - 10.1007/s00360-010-0469-7
DO - 10.1007/s00360-010-0469-7
M3 - Article
C2 - 20361194
AN - SCOPUS:77956767520
VL - 180
SP - 953
EP - 965
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
SN - 0174-1578
IS - 7
ER -