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Percentage of individuals swimming after 24 h
1 1 0
1 0 0
9 0
8 0
7 0
6 0
5 0
4 0
1 0 0
8 0
6 0
4 0
1 0 0
8 0
6 0
4 0
1 0 0
5 o C
1 0 o C
1 5 o C
8 0
6 0
4 0
2 0 o C
0 5 0 1 0 0 1 5 0 2 0 0 2 5 0
P r e s s u r e i n a t m
Fig. 3.17. Marthasterias glacialis survival of swimming bipinnaria at 5, 10, 15 and
20°C at 1, 50, 100, 150 and 200 atm for 24 h. Data are mean and SD of 3 replicates.
Comparison of A. rubens and M. glacialis data with those of shallow water
and deep-sea Atlantic echinoids suggests that the early embryos of echinoids are more
tolerant of pressure/temperature changes but that the later larval stages of asteroids
tolerate change more readily than the larval stages of echinoids.
There is increasing evidence for accelerated deep-water formation at the end
of glacial periods (Knorr & Lohmann, 2003). During deglaciation, the Atlantic
thermohaline circulation becomes more vigorous changing from a weak glacial mode
into a strong interglacial mode. There is also recent evidence that there may be a
variety of sites of deep-water formation in the N. Atlantic (Pickart et al., 2003). If this
more vigorous formation of deep water occurs at this transition period it may be that
the warming of surface waters stimulates accelerated reproduction, both through
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