Fig. 4. Activity (i.u. g^-1 wet mass) of (A) citrate synthase (CS), (B) lactate dehydrogenase (LDH) and (C) pyruvate kinase (PK) in flexor tibialis muscle of captive juvenile green turtles (N=5) exposed to summer conditions (filled circles) and after 4 weeks exposure to winter conditions (open circles). CS activity was significantly lower in tissue collected from turtles exposed to winter conditions compared with summer conditions (P<0.001). Conversely, LDH and PK activity were significantly higher during exposure to winter conditions compared with summer conditions (P<0.001), a pattern typical of thermal acclimation. CS, LDH and PK had relatively low thermal dependence over the 15-30°C range of assay temperatures (Q₁₀=1.44-1.69).