Salinity and its relation to climate and water management in south Florida is central to restoration activities in Florida Bay. Upstream water management over the last century has disrupted the quantity, quality, timing, and distribution of freshwater flows into Florida Bay which has subsequently affected salinity patterns. An assumed long-term trend toward increasing salinity in the bay and short-term effects of salinity (for example, hypersalinity and freshwater flooding) are integral elements of conceptual models of seagrass die-off. Loss of seagrass habitat beginning with seagrass die-off in 1987 is implicated in changes in sediment dynamics, nutrient dynamics, and nursery function that has characterized the bay over the last decade. Detailed paleoecological studies are underway to reconstruct salinity conditions in a "premanagement" Florida Bay as a possible restoration target. Hydrodynamic models (RMA10, FATHOM, SWIFT2D) are being developed for Florida Bay to aid in predicting circulation, inflow, and the movement of nutrients through the system. The water management system in south Florida is being evaluated and redesigned in the Central and South Florida Comprehensive Review Study. All these studies require salinity data and synthesis for calibration, verification, and interpretation. Despite these needs, present and past spatial and temporal patterns of salinity in Florida Bay have not been adequately summarized.

At this time, direct salinity observations from within Florida Bay extend from 1936 to the present. Anecdotal references to salinity conditions within the bay are known to exist from as early as 1908 within the scientific literature. The historic salinity data for the bay and adjacent waters have been compiled from all sources into a single data base, relating each observation to time and place. These data are useful, spatially and temporally, beginning in the mid-1950's, although significant gaps in both time and space are present. Everglades National Park has been monitoring salinity since 1981 at an increasing number of stations in Florida Bay. The Everglades National Park data base is temporally intensive and includes related rainfall and water-level data. Since 1995, bimonthly spatially intensive salinity surveys have been conducted by the U.S. Geological Survey within Florida Bay (Halley, 1996).

This project will combine these data sets, existing on different time and space scales, along with available anecdotal data, into a synthesis of salinity conditions within Florida Bay from 1900. During the first year, these data sets will be completed, quality analysis/quality checks will be performed, and a relational data base-- including other relevant physical data (rainfall, evaporation, flow, etc.)-- searchable by time, location and depth will be established. During the second year, a synthesis of salinity patterns in the bay, including a relation between salinity and freshwater inflow/rainfall, will be completed using this relational data base.

A significant part of the funding for this research was provided from the U.S. Geological Survey INATURES Program, by the U.S. Department of the Interior, South Florida Ecosystem Restoration Program "Critical Ecosystems Studies Initiative" (administered through the National Park Service); and, in part, from the U.S. Geological Survey, Florida Caribbean Science Center for the "Empirical and Modeling Studies in Support of Florida Bay Ecosystem Restoration Program."

REFERENCE

Halley, R.B., Smith, D., and Hansen, M., 1996, Florida Bay salinity maps, surface and bottom salinity, 11/94; 1,4,6,8,10,12/1995; 2,4,6/1996: U.S. Geological Survey Open-File Report 95-634, various monthly map sheets.

(This abstract was taken from the Proceedings of the South Florida Restoration Science Forum Open File Report)