Cultural eutrophication has become the primary water
quality issue for most of the freshwater and coastal
marine ecosystems in the world. However, despite
extensive research during the past four to five decades,
many key questions in eutrophication science remain
unanswered. Much is yet to be understood concerning
the interactions that can occur between nutrients and
ecosystem stability: whether they are stable or not,
alternate states pose important complexities for the
management of aquatic resources. Evidence is also
mounting rapidly that nutrients strongly influence the
fate and effects of other non-nutrient contaminants,
including pathogens. In addition, it will be important
to resolve ongoing debates about the optimal design of
nutrient loading controls as a water quality management
strategy for estuarine and coastal marine ecosystems.