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50atm more than 90% of embryos were late gastrula, the rest were uncleaved, at
100atm ~60 % of embryos were abnormal and the rest were blastulae, at 150atm ~70
% were abnormal and the rest were gastrula, at 200atm more than 90 % were
abnormal, less than10 % were early gastrula. At 20°C at 1 atm ~90 % were abnormal
~10 % were early gastrula, at 50atm ~60 % were early gastrula, ~40 % were
abnormal, at 100atm ~50% were early gastrula and ~ 50% abnormal, at 150atm ~20
% were early gastrula and ~80 % were abnormal, at 200atm all the embryos were
abnormal (Fig. 3.15).
A three-way completely crossed
ANOVA (main effects: pressure,
temperature, species) on percentages of abnormally developing embryos after 40 h
revealed not significant interactions among all factors (Table 3.1) indicating that the
two species do not respond differently to the various combinations of pressure and
temperature.
3.3.2- Temperature/pressure effects on swimming bipinnaria at 24 h.
Asterias rubens
Survivorship of swimming (15 - 20 days) bipinnaria remained high (>70%)
after incubation at all the pressure/temperature combinations. The greatest number of
surviving swimming bipinnaria was 100% at 10 o C/50atm and the lowest was 72% at
15 o C/200atm (Fig. 3.16). Survivorship decreased as pressure increased; nevertheless
most bipinnariae tolerated a pressure of 200 atm for 24h.
Marthasterias glacialis
Survivorship of swimming bipinnaria (30 days) of M. glacialis also remained
high (100 %) after incubation at 1atm at all temperatures. At 5 o C and 20°C
survivorship decrease with pressure increase but remained above 50% and 80%
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