Paleosalinity as a Key for Success Criteria in South Florida Restoration

The objectives of this project are to 1) test and develop the methodology for extracting water chemistry information from selected calcareous shelled animals that grow within the water; 2) develop an understanding of the biology of the selected organisms so that the water chemistry data extracted from the shells can be put in temporal context; and 3) to apply this information to shells found in soft sediment cores that span the last 100-300 years of South Florida history in order to determine the seasonal variation in salinity and water sources prior to significant human alteration of the environment.

The most critical issue in the Central Everglades Restoration Plan (CERP) is to restore more natural patterns of freshwater flow through the terrestrial ecosystem and into the estuaries and coastal areas. Restoring natural flow includes the timing, delivery, quantity and quality of the water; in other words, 'getting the water right'. In order to recreate natural freshwater flow patterns, it is essential to understand the natural patterns of variation prior to significant human alteration of the system and the natural sources of water. Seasonality of water delivery is critical to the reproductive cycles of many of the organisms within the environment. This study is designed to develop and test a methodology for determining the natural patterns of change in freshwater flow and the sources of input (precipitation, groundwater, or surface flow) by conducting biochemical analyses on the tests of calcareous organisms (mollusks and ostracodes). These organisms preserve the effect of annual and seasonal salinity changes and other data about the water in which they live, and analyses of the individual growth bands of mollusks will allow detailed comparisons of seasonal change over time. Shells analyzed from radiometrically-dated sediment cores taken throughout the region allow reconstruction of seasonal salinity variations and sources of freshwater in the past, prior to significant human alteration of the system. These data will provide the resource managers (SFWMD, ACOE and ENP) with restoration targets and performance measures that will allow them to 'get the water right'.