Patricia M. Glibert, Horn Point Laboratory, University of Maryland Center for Environmental Science, PO Box 775, Cambridge, Maryland 21613 U.S.A.(Glibert@hpl.umces.edu) and Robert Magnien, Maryland Department of Natural Resources, 580 Taylor Avenue D-2, Annapolis, Maryland 21401 U.S.A. (magnien@dnr.state.md.us)

Abstract

Harmful algal blooms in the Chesapeake Bay, USA, are not a new phemonemon, but may be increasing in frequency and diversity. Indeed, it is the diversity of such events that creates challenges for monitoring and management. The types of events that typically occur in Chesapeake Bay range from outbreaks of Pfiesteria piscicida (Dinophyceae), and associated fish kills, to blooms of other flagellates, such as Prorocentrum minimum and Aureococcus anophagefferens that have had varying impacts, from shellfish toxicity to environmental damage caused through the development of high biomass.

The Chesapeake Bay Monitoring Program measures a series of key variables, including physical/chemical properties, nutrient limitation of algal growth, ecosystem processes, river inputs of nutrients (inorganic and organic) and sediments, phytoplankton, zooplankton, and benthic organisms at numerous sites through the Bay and its tributaries on a regular basis. In addition, continuous monitoring of water quality conditions is ongoing at over 10 stations. Data from these instruments is available in near real-time on the web. New instruments, including nutrient sensors, are also being tested to determine their reliability in these waters.

Collaborations between academic institutions, state and federal laboratories have been established to respond to harmful algal bloom outbreaks or to other events that may require an immediate response. Upon learning of a potential harmful algal bloom event, samples are collected for identification of the presence of the harmful organism, by both traditional and molecular methods, water quality analysis, as well as potential toxicity. Where necessary, the medical community is also immediately informed. The diversity of types of events requires some different plans to be in effect, depending on causative organism, but the network of institutions and agencies results in a comprehensive response in all cases. The baseline monitoring, together with rapid response studies permits an understanding of how the Bay ecosystem functions as it relates to anthropogenic and natural stresses, and leads to appropriate management actions, such as river closures, when necessary, and long-term nutrient reduction strategies.