Harmful Algal Blooms and Their Effect on Coastal Environments

Throughout the world’s coastal oceans, observations of harmful algal blooms, referred to as red tides in older literature, are being reported with increasing frequency. Often, these events are accompanied by severe impacts to coastal resources, local economies, and public health. Harmful algal blooms - accumulation of microscopic species of algae or larger, multi-cellular species - appear to be more disturbing than ever before, and may be increasing over time. Some species persist in the same geographic regions each year, while others are more sporadic, leading to the unexpected deaths of local fish, shellfish, mammals, and birds. Most harmful algal blooms are caused by both the microscopic species of algae, referred to scientifically as phytoplankton and the microphytobenthos, as well as other larger macro-algae. A bloom occurs when an alga rapidly increases in numbers to the extent that it dominates the local planktonic or benthic community. Such high abundance can result from...