Figure 8.

Effects of (a) temperature and (b) oxygen availability on the largest amphipod crustacean sizes for nine marine (filled circle) and three reduced salinity sites (open circle). (a) 95%/5% threshold size (TS95/5, TS95/5 is the cut-off point between the 95% smallest species and the 5% largest species in the size distribution) versus mean annual water temperature (inverted scale). This threshold size is used as a proxy for maximum size to allow for occasions where large, but very rare, species may not have been sampled. (b) TS95/5 versus calculated dissolved oxygen content at saturation (O₂ μmol kg⁻¹), based on mean surface water temperature and salinity. Although not every habitat in a site will experience permanently high oxygen saturation, this 100% value represents optimal conditions for species to attain large size (adapted from Chapelle & Peck, 1999).