Researchers conducted a test that proved why there are no backups. It also illustrates why water-quality problems are growing. Within hours, we could detect the organisms in the canal. Within a few more hours they were in near-shore waters. And within 12 hours they were found at the reef.
Scientists disagree on the effect of the waste water on the coral reefs.
Some say the ecosystem is under stress, but it is unclear how much of the problem may be a result of natural phenomena, such as ocean warming. Others say the reefs are clearly in decline, in large part from high nutrient levels from untreated or poorly treated sewage. Only Key West and tiny Key Colony Beach near Marathon have modern sewage-treatment plants. Most other locations in the Keys rely on small-scale treatment facilities. In addition there are 20,000 septic tanks and 4,000 cesspits, which are basically holes in the ground covered with concrete slabs.