Temperature affects biological functions by altering reaction rates. Physiological rates usually double to treble for every 10°C rise, and 1–4 fold encompasses normal biological functions. However, in polar marine species inhabiting temperatures around 0°C many processes are slowed beyond the Arrhenius relationships for warmer water species. Growth, embryonic development, Specific dynamic action (SDA) duration, and time to acclimate to altered temperature, are all 5–12 fold slower in species living near 0°C than at 10°C. This cold marine physiological transition to slower states is absent, however, in oxygen consumption and SDA factorial scope; processes where capacity is related to aerobic scope. My opinion is that processes involving significant protein modification are impacted, and protein synthesis or folding problems cause the slowing of rates beyond expected temperature effects.