Algae. 2011; 26(1): 61-71.
Temporal and spatial variation in the distribution of life history phases of Chondrus crispus (Gigartinales, Rhodophyta)
David J. Garbary1,*, Elizabeth Tompkins1, Katelyn White1, Peter Corey2 and Jang K. Kim2
1Department of Biology, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada 2Department of Plant and Animal Sciences, Nova Scotia Agricultural College, Truro, NS B0W 2E0, Canada
Thirty populations of Chondrus crispus Stackhouse from Nova Scotia were collected during the years 1993 to 2011. Taken from estuaries, wave exposed open coasts, high intertidal rock pools and shallow subtidal habitats, the populations were evaluated for relative abundance of tetrasporophytic and gametophytic life history phases. Over 2,800 thalli were characterized using the resorcinol-acetal test to distinguish the kappa- and lambda-carrageenan containing fronds of gametophytes and tetrasporophytes, respectively. These populations had 77 ± 5% gametophytes (mean ± 95% confidence interval), with most populations having gametophyte : sporophyte ratios ranging from 2 : 1 to 9 : 1. No population had a dominance of tetrasporophytes, although two populations had 1 : 1 ratios. A meta-analysis of our data along with previously published accounts showed no significant changes in ametophyte dominance with respect to hypothesized gradients of wave exposure, salinity, or water depth. Significant changes occurred in ratios at five sites where replicate sampling occurred in different years. We conclude that C. crispus in Maritime Canada has a natural ratio of 3 : 1 or greater in stable conditions, and that lower ratios represent recovery from disturbance in which bare substratum is created that is subsequently colonized by carpospores from remaining gametophytic thalli.
Keywords : Chondrus crispus; Gigartinaceae; life history; Nova Scotia; resorcinol; Rhodophyta