What is a risk associated with blue holes?

Blue holes are typically characterized by their extreme depths, which can present significant risks for divers. The depth can create challenges such as increased pressure, which affects air consumption rates and narcosis. As divers go deeper into these underwater caves, the potential for decompression sickness increases, particularly if ascent rates are not carefully managed. Additionally, the extreme depths can make it more difficult to execute safety stops and increases the risk of running low on air supply before a safe ascent can be completed.

While the other options may involve certain risks in different diving environments, they do not accurately reflect the primary concern specific to blue holes, which is the extreme depths that fundamentally alter the diving dynamics and safety protocols necessary for such environments.