concept

Q₁₀ temperature coefficient

The factor by which a biological process speeds up for every 10 °C of warming. For marine ectotherms Q₁₀ runs about 2.0–2.5, so taking an animal from 25 °C surface water down to the 2–4 °C of the deep drops its metabolic rate by a factor of four to six. The common misreading is to treat that as a speed penalty. It is not quite: swimming power scales with the cube of speed, so losing a factor of five in power costs only about 1.7 in speed. The real bite is in timing — twitch frequency and neural conduction scale directly with rate, so cold water slows an animal's *deciding* far more than its *moving*.