Fast deep water warming of a subtropical crater lake.

Water temperature of deep lakes is often used to evaluate climate variability over long periods. Santa Maria del Oro Lake is a sub-tropical crater-lake (60 m maximum depth) almost confined by surrounding mountains, which only receives seasonal fresh water input. In order to evaluate lake thermal variations, we measured water temperatures at bottom, 4 m, 10 m, 25 m, and 32 m depth.