Hmm, human viruses, are they a problem for corals? I thought they tended to be species-specific. Although treated sewage might of course contain plenty of bacteria disturbing the chemical balance, as well as huge amounts of bacteriophages. Hmm, it might also attract bdellovibro bacteria (fast swimming predator bacteria) that attack the wrong species.
Anders Sandberg Towards Ascension! email@example.com http://www.nada.kth.se/~asa/GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y