C. pollution is primarily a result of supertanker collisions. D. can be toxic to some organisms, interfering with reproduction, development, and growth. A. Nitrogen B. Phosphorous C. Cadmium D. Mercury 17. In artificial eutrophication A. phytoplankton die of poisoning and are eaten, which causes those higher in the food chain to die as well. B. phytoplankton populations grow which uses up oxygen.
Organisms die as a result of the low levels of oxygen.
The additional decomposition uses up oxygen so organisms die. Additional decomposition uses up oxygen but organisms adapt to take oxygen out of the water more efficiently. Secondary treatment of sewage A. produces sludge. B. is where DOM is completely decomposed, producing nitrates, phosphates, and ammonia. C. is where denitrification occurs, changing nitrates to nitrogen gas.