South Florida is undertaking a massive restoration effort under the Comprehensive Everglades Restoration Plan (CERP), which was approved by Congress as part of the Water Resources Development Act of 2000. The primary goal of the CERP is to restore more natural freshwater flow through the South Florida ecosystem. In the last century, changes in delivery of freshwater to the estuaries of South Florida, including Biscayne Bay and Florida Bay, have altered their natural patterns of salinity. Many detrimental environmental effects, such as seagrass die-offs and loss of biodiversity, have been blamed on changing salinity. The goal of the U.S. Geological Survey (USGS) Ecosystem History Projects has been to identify natural cycles of change prior to human alteration of the environment and to distinguish natural change from anthropogenic change.

The USGS has replicated several South Florida ecosystems in the USGS Leetown Science Center in West Virginia. Through laboratory studies, we hope to do the following:

• Develop new techniques for deriving water-chemistry information from organisms that secrete calcium carbonate
• Apply these techniques to document seasonal salinity changes during a century or more
• Understand the effects of salinity and other ecosystem fluctuations on submerged aquatic vegetation (including seagrass and macroalgae) and associated animal life
• Develop success criteria for CERP