Lake turnover occurs when the layers of water with noted temperature differences begin to mix together and the water and debris that has been sitting at the bottom of the lake begins to mix with the layers of water above it.
Definition of cautious. : careful about avoiding danger or risk cautious investors cautious optimism.
Careful, cautious, discreet, wary imply a watchful guarding against something. Careful implies guarding against mistakes, by paying strict and close attention to details, and, often, trying to use good judgment: He was careful to distinguish between them. Cautious implies a fear of some unfavorable situation and investigation before coming to conclusions: cautious about investments.