ECOHAB Project Provides Scientific Basis for Consensus on Causes of Maui Algal Blooms
A workshop supported by the National Centers for Coastal Ocean Science (NCCOS) ECOHAB program resulted in a consensus that excess nutrient runoff and reduced herbivorous fish populations are the primary causative factors of nuisance blooms of macroalgae off the coast of Maui. Based on results stemming from a 5-year ECOHAB project on Maui macroalgae, workshop participants concluded that macroalgae (particularly the invasive Hypnea species) use and store excess nutrients from treated wastewater disposed via groundwater injection, fertilizers, and other land-based sources.
These algae are frequently transported along the coast and can not only impact reefs near the sources of nutrient inputs, but also reefs in additional locations. Macroalgal blooms represent a significant ecological and economic threat to the island of Maui. In the Kihei region alone, blooms resulted in an estimated cost of $20 million annually to local governments from lost tax revenue and reduced property value to the Kihei region alone, through noxious odors and reduced aesthetic value.
These algal blooms have also contributed to degradation of coral reefs around Maui, where an ecological shift from productive reefs to algal beds is underway. Coral reefs represent one of the island