Activity of the lateral cilia of the oysterCrassostrea virginicagmelin: Response to changes in salinity and to changes in potassium and magnesium concentrationt†

Abstract

Lateral ciliary activity (LCA) on ctenidial filaments of the oyster has been measured in animals acclimated to 30, 15 and 5%o seawater from three to five days. Using shucked, intact tissue with the minimum dissection required to expose the ctenidia, the responses of LCA to rapid changes in salinity have been defined. A linear decline in LCA was observed over the 140 minute exposure period; the slope of the regression line and the percent inhibition of the activity were both proportional to the magnitude of salinity change and were useful indices to the effect of the test medium. The effect of exposure of tissues to changes in potassium ion concentration at the acclimation salinities was found to be salinity‐dependent and is probably exerted on the branchial nerve rather than the ciliated epithelium. Exposure of tissues to changes in magnesium ion concentrations at the acclimation salinities was also salinity‐dependent and probably reflects an effect directly on the ciliated epithelium. The experimental design and procedures used in this study will have broad applicability for quantitatively assessing the effects of environmental factors on ciliary activity of marine and estuarine organisms.