What is the effect of dissolved oxygen dynamics in estuaries on juvenile fish and crustaceans?

• A. Hypoxic zones can reduce survival of juvenile fish and crustaceans; tidal flushing can ameliorate oxygen levels.
• B. Hypoxic zones do not affect juvenile life stages.
• C. Estuaries are always well-oxygenated and never experience low oxygen.
• D. Tidal flushing never changes oxygenation.

Answer: (D)