Figure 7.

Long-term variability in growth in three species of the erect bryozoan Cellarinella from the Weddell Sea. Growth determined from number of zooids produced annually, measured only in living colonies so growth can be ascribed to both colony age and calendar year, and relative growth rate and anomaly calculated using a standard exponential growth rate model for bryozoans. (a) Cellarinella watersi (black diamonds) and C. rogickae (open circles); data presented as relative growth rate anomaly, plotted as mean and s.e. In both species, the decline in growth rate since the 1990s is significant (model 1 least-squares regression, p<0.05), but there is no significant correlation between the two species in growth performance (p>0.05). Redrawn from Barnes et al. (under review). (b) Cellarinella nutti, with data presented as absolute growth anomaly. The overall increase in growth rate since the 1980s is significant (model 1 least-squares regression, p<0.05); note the strikingly strong growth performance in 2003. Redrawn from Barnes et al. (2006b).