This document provides an overview of cave diving environments and characteristics divers need to understand, including:
- Water make-up such as tannic water which stains visibility red, and hydrogen sulfide layers which are toxic and turn equipment black.
- Haloclines, which are the interfaces between salt and fresh water layers, can distort visibility when disturbed.
- Other factors like bottom conditions of sand, mud or clay, and water contamination risks are discussed. Understanding the cave environment is important for safe diving.