Excess nutrients stimulate Decomposition uses up Low oxygen levels, called "hypoxia", cause shellfish to die, and algae blooms. dissolved oxygen in Bay. fish and crabs to leave habitat or die treating "dead zones". The figure above shows what happens when human-created pollution ends up in the Chesapeake Bay. Explain how low oxygen levels (hypoxia) affect the ability of fish to get the energy needed for life processes. Use cellular (aerobic) respiration, oxygen and ATP in your response