Study Title: Historical Changes in Salinity, Water Quality and Vegetation in Biscayne Bay
Study Start Date: 3/15/02 Study End Date: 9/30/06
Web Sites: http://sofia.usgs.gov/flaecohist/
Location (Subregions, Counties, Park or Refuge): Biscayne National Park, Miami-Dade County, Monroe County
Funding Source: USGS Greater Everglades Priority Ecosystems Science (GE PES)
Other Complementary Funding Source(s):
SFWMD - Contract # C-13400, 3/02 to 3/03, "Biscayne Bay Paleoecological Salinity Study"
SFWMD - Contract # C-15893, 6/03 to 7/04, "Biscayne Bay Paleoecological Salinity Study"
Principal Investigator(s): G. Lynn Wingard
Study Personnel: Thomas Cronin; Debra Willard; Chuck Holmes; William Orem; James Murray; Marci Marot; US Geological Survey. Gary Dwyer, Duke University. Scott Ishman, University of Southern Illinois; Peter Swart, University of Miami. Contract Labor: Jessica Albietz, Carlos Budet, Ruth Ortiz.
Supporting Organizations: South Florida Water Management District; Biscayne National Park
Associated / Linked Studies: Paleosalinity as a Key for Success Criteria in South Florida Restoration; Ecosystem History of the Southwest Coast-Shark River Slough Outflow Area; Integrated Biogeochemical Studies in the Everglades; and Synthesis of South Florida Ecosystem History Research Projects. Also, DOI Landscape Initiative with Biscayne National Park (USGS Lead: Sonya Jones)

Overview & Objective(s): The objectives of this project are to examine in broad context the historical changes in the Biscayne Bay ecosystem at selected sites on a decadal-centennial scale, and to correlate these changes with natural events and anthropogenic alterations in the South Florida region. Specific emphasis will be placed on historical changes to 1) amount, timing, and sources of freshwater influx and the resulting effects on salinity and water quality; 2) shoreline and sub-aquatic vegetation; and 3) the relationship between sea-level change, onshore vegetation, and salinity. In addition, a detailed examination of historical seasonal salinity patterns will be derived from biochemical analyses of ostracodes, foraminifers, molluscs, and corals. Land management agencies (principally SFWMD, ACOE and Biscayne NP) can use the data derived from this project to establish performance criteria for restoring natural flow, and to understand the consequences of altered flow. These data can also be used to forecast potential problems as upstream changes in water delivery are made during restoration.

Specific Relevance to Major Unanswered Questions and Information Needs Identified: (Page numbers below refer to DOI Science Plan.)

One of the primary DOI activities discussed in the DOI Science Plan is to "ensure that hydrologic performance targets accurately reflect the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14). The primary goal of the Ecosystem History of Biscayne Bay study is to determine the predrainage hydrology and ecology of the Bay and surrounding wetlands. Specifically this study supports the Biscayne Bay Coastal Wetlands Project and the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study, and it provides information relevant to the Combined Structural and Operational Plan (CSOP), Landscape Modeling, Invasive Exotic Plant Detection, and Monitoring and Aquatic Exotic Animals Projects. This study supports these projects by 1) conducting research to understand the predrainage hydrology, including the amount, timing and seasonality of freshwater delivered to the bay historically; 2) examining the historical environmental conditions, including the linkage between hydrology (water quality and quantity), ecology, and habitats; 3) providing the modelers with data on historic conditions in order to set targets and performance measures that reflect natural hydrologic patterns; 4) providing long-term historical data on trends and cycles within the biological component of the ecosystem that can be forecasted to predict the effects of implementation of hydrologic restoration on the ecology of coastal communities; and 5) by determining the timing of introduction and spread of exotics in the Biscayne Bay ecosystem and the coincident changes in the native species.

This study supports the Biscayne Bay Coastal Wetlands Project by addressing the questions "How much freshwater, and in what seasonal patterns, was delivered historically to Biscayne Bay?" (DOI Plan, p. 63), "What are the links between hydrology and ecology in the Biscayne Bay coastal wetlands?" (p. 64), and "What are the key indicators of natural ecological response . . ." and "what are the baseline conditions of the indicators?" (p. 66). The data generated by this project are particularly valuable because they provide 100 to 500 years worth of data on changes to the system.

This study supports the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study by addressing the questions "What were the physical and ecological conditions in . . . Biscayne Bay prior to drainage and modification . . ." (DOI Plan p. 63), "What are the hydrologic targets needed to mimic historic flows . . . ? (p. 63).

In addition, the study contributes to the Combined Structural and Operational Plan (CSOP) and Landscape Modeling projects by providing historical ecological data on trends and cycles that can be forecasted to predict the effects of implementation of hydrologic restoration on the ecology of coastal communities. This addresses questions of the impact of increased flow (p. 63), and expected faunal and floral responses (p. 64, p. 79, p. 80). The study also contributes to the Invasive Exotic Plant Detection and Monitoring and Aquatic Exotic Animals Projects by determining the temporal and spatial distribution of exotics and changes in native species coincident with introduction (p. 118).

Status: Analyses of six cores have been completed and compiled with data from cores collected in 1997-98, and a report produced for SFWMD. This was the final obligation for the 2-year contract with SFWMD. Currently, we are conducting additional analyses on samples to refine age models and preliminary interpretations of cores by filling in data gaps. Statistical analyses will be conducted on data from all cores in Biscayne and compared to historical records of outflow, rainfall, etc. Based on results of compilation, we may consider additional core collection to resolve any questions raised.

Recent Products: OFR 03-375 summarized results of first year of analyses for project - published Fall 03. Four reports generated for SFWMD in FY04.

Planned Products: An OFR summarizing results from year two analyses will be published in Fall 04. A fact sheet also will be produced in Fall 04. These will be followed by a series of journal articles summarizing different aspects of the ecosystem history study of Biscayne Bay.

WORK PLAN

Title of Task 1: Geochronology and paleoecology of Biscayne Bay Cores
Task Funding: USGS Greater Everglades Priority Ecosystems Science (GE PES); SFWMD
Task Leaders:

G. Lynn Wingard
Phone: (703) 648-5352
FAX: (703) 648-5420

Charles W. Holmes
Phone: (727) 893-3100 X3056
FAX: 727-803-2032

Task Status (proposed or active): Active
Task priority: High
Time Frame for Task 1: 3/15/02 to 9/30/07
Task Personnel: G. Lynn Wingard, Charles W. Holmes, Thomas Cronin, Deb Willard, James Murray, Marci Marot and technical and database support to be hired or assigned

Task Summary and Objectives:

The initial and primary task is to determine the age of the selected cores, the general salinity history, the presence of sub-aquatic vegetation (SAV), and the probable abundance of SAV using established geochronologic and paleoecologic methods. This task lays the groundwork for additional analyses as well as providing necessary data for the final interpretation of the cores. The purpose of the overall project is to determine the changes in water quality and salinity over time, and the corresponding changes in onshore and sub-aquatic vegetation. The first step is to determine if the core has a good chronology (i.e. the core has not been disrupted) and if it contains faunal remains for analyses. If the core meets these criteria, then additional work can proceed. If the chronology is not good, or if there are no preserved fauna, than another core will be selected and the tasks repeated until we identify a core that meets these criteria. The chronologic data will be used to interpret all additional analyses. Paleoecological methods also will be used to provide data on the general trends within the core in terms of salinity, SAV, and changes in water quality and nutrient supply.

Core sites are identified and collected, sliced in to 2cm-segments, and processed for paleoecologic, and geochronologic analyses. Faunal samples are processed using standard methods and all fractions are retained for analyses. A portion of the less than 63-micron fraction is used for Pb-210 geochronology and selected shells or plant material will be used for radiocarbon dating. The greater than 63-micron fraction is sorted for faunal analyses; ostracodes, molluscs and benthic forams are picked, sorted and identified. A small portion of core material is retained and processed for diatoms (Gaiser, FIU). Percent abundance is calculated for the faunal and diatom data, and these data are compared to data from 28 sites in modern Florida Bay where faunal and floral associations have been studied between 1996-2000 and to sites established in Biscayne Bay (see work listed in Task 2). These modern data serve as proxies for interpreting the down-core data. The down-core faunal and floral assemblages and the presence or absence of key indicator species allow interpretation of trends in salinity, water quality and the presence of SAV at the core sites.

Work to be undertaken during the proposal year and a description of the methods and procedures:

Additional analyses will be conducted in 2004 on the cores collected in 2002 and 2003. We will increase our analytical resolution, filling in gaps in the sampling of the cores already collected, conduct statistical analyses of the data, and correlate the core data with climatic, outflow, and rainfall records. Additional cores (one or two) may be collected for analyses if the ground-water modelers can locate sites of historical freshwater springs within Biscayne Bay.

Task 1 - obtaining the cores, a preliminary age model, and a model of environmental change over time in - is a first step toward answering the "Major Unanswered Questions and Information Needs" as discussed in the project overview above. The data from task 1 begin the process of establishing "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the Biscayne Bay ecosystem. Specifically this task supports the Biscayne Bay Coastal Wetlands Project and the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study, and it provides information relevant to the Combined Structural and Operational Plan (CSOP). (See details in project overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Specific Task Product(s):

An OFR summarizing results from year two analyses will be published in Fall 04. A fact sheet also will be produced in Fall 04. These will be followed by a series of journal articles summarizing different aspects of the ecosystem history study of Biscayne Bay.

Title of Task 2: Patterns, Causes, and Impacts of Salinity Changes in Biscayne Bay
Task Funding: USGS Greater Everglades Priority Ecosystems Science (GE PES); SFWMD
Task Leaders: Thomas Cronin
Phone: 703-648-6363
Fax: 703-648-6953
Task Status (proposed or active): Active
Task priority: High
Time Frame for Task 2: 3/15/02 to 9/30/07
Task Personnel: T. Cronin, J.B. Murray, S. Smith, G.L. Wingard

Task Summary and Objectives:

Determine salinity history of several regions in Biscayne Bay for the period prior to and during large-scale 20th century urbanization and water diversion using salinity proxies from sediment cores from Biscayne Bay and Card and Barnes Sounds. Relate salinity variability to changes in fresh water flow due to land-use changes and natural variability in rainfall, freshwater runoff and water temperature (evaporation) and determine the extent to which water diversion disrupted natural patterns of salinity. Develop method to use oxygen isotope ratios in ostracodes and foraminifers as proxy of past salinity and/or temperature changes. Compare and "splice" together the sediment core records of paleosalinity and paleotemperature with instrumental records of rainfall, bay salinity and temperature obtained from water monitoring. The reconstructed record of physical and biological conditions in Biscayne Bay will be compared to the history of water quality obtained by W. Orem (task 6). Biscayne Bay ecosystem and salinity history also will eventually be compared to records from Florida and Manatee Bays to examine regional trends.

Proxy methods include 1) oxygen isotope analyses of ostracodes and benthic foraminifera, 2) trace elemental (magnesium/calcium ratios) of ostracodes, and 3) relative proportions of species of forams, ostracodes and molluscs indicative of specific salinity ranges (i.e. oligohaline, mesohaline, etc.)(related to task 1 assemblage analyses). The stable isotopic and trace elemental analyses will be carried out with cooperators using mass spectrometry and direct current plasma emission spectrometry at University of Miami and Duke University, respectively. The use of paired analyses of stable isotopes of forams and Mg/Ca ratios in ostracodes should allow the quantification of changes in salinity and temperature and the impact of these changes could then be assessed from the faunal analyses of benthos from the same samples. Selected intervals identified as representing extreme salinity conditions may also be studied for seasonal salinity variability using molluscan shell chemistry, depending on preservation in cores and status of mollusk calibration studies (related to Paleosalinity as a Key for Success Criteria in South Florida Restoration Project; Wingard, Wardlaw and others).

Work to be undertaken during the proposal year and a description of the methods and procedures:

In 2005, we will more fully analyze the paleosalinity trends in Biscayne Bay focusing on long-term (last 500 years including 20^th century) records from Featherbed, No Name, and Card Sounds and nearshore 20^th century records from Chicken, Middle and Black Point regions. Efforts will be made to correlate the cores based on independent dating techniques and to establish whether estimated changes in salinity are synchronous during the past century at various sites. Efforts also will be made to compare salinity patterns with rainfall and river discharge to consider their effects on nearshore salinity.

Task 2 - calibrating modern proxy data to the estuarine waters - is a critical part of answering the "Major Unanswered Questions and Information Needs" as discussed in the project overview above. The data from task 3 provide the details for establishing "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the Biscayne Bay ecosystem. Specifically this task supports the Biscayne Bay Coastal Wetlands Project and the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study, and it provides information relevant to the Combined Structural and Operational Plan (CSOP). (See details in project overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Specific Task Product(s):

An OFR summarizing results from year two analyses will be published in Fall 04. A fact sheet also will be produced in Fall 04. These will be followed by a series of journal articles summarizing different aspects of the ecosystem history study of Biscayne Bay.

Title of Task 3: Palynological analysis and reconstruction of shoreline vegetation
Task Funding: USGS Greater Everglades Priority Ecosystems Science (GE PES); SFWMD
Task Leaders: Debra Willard
Phone: 703-648-5320
FAX: 703-648-6953
Task Status (proposed or active): Active
Task priority: Medium
Time Frame for Task 3: 10/1/03 to 9/30/07
Task Personnel: C. Bernhardt, T. Sheehan, D. Willard

Task Summary and Objectives:

Reconstruct vegetational trends at selected wetlands sites using pollen and seeds preserved in sediment cores. Although temporal resolution depends on sedimentation rates at core sites, vegetational changes on a decadal scale should be identifiable. Also, fire history may be documented for the region through quantitative analysis of charcoal in sediment cores.

Analyze pollen assemblages to determine vegetational trends. Pollen assemblages in cores samples will be reconstructed through statistical comparison with database of ~200 surface samples collected in different vegetation types throughout the Everglades; secondarily, changes in hydroperiod and water depth will be estimated from vegetational proxies. Charcoal analyses will be undertaken using chemical digestion to isolate charcoal and morphometric analysis to quantify charcoal in each sample. Geochronologies established as part of task 1 will allow determination of the timing of changes in vegetation or charcoal abundance and correlation with specific environmental or anthropogenic changes.

Work to be undertaken during the proposal year and a description of the methods and procedures:

If necessary to improve analytical precision additional analyses will be conducted in 2004 on the cores collected in 2002 and 2003. Data will be correlated to terrestrial records from other portions of southern Florida. Analyses of the marsh cores will be completed. If any additional cores are collected in conjunction with the ground-water modelers (DOI Landscape Funds project) analyses of these cores will be completed.

Task 3 - understanding the processes affecting the shoreline vegetation of Biscayne Bay - contributes toward answering the "Major Unanswered Questions and Information Needs" as discussed in the project overview above. The data from task 3, in conjunction with task 1, help establish "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the Biscayne Bay Ecosystem. Specifically this study supports the Biscayne Bay Coastal Wetlands Project and the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study, and it provides information relevant to the Combined Structural and Operational Plan (CSOP), and Landscape Modeling.

Specific Task Product(s):

An OFR summarizing results from year two analyses will be published in Fall 04. A fact sheet also will be produced in Fall 04. These will be followed by a series of journal articles summarizing different aspects of the ecosystem history study of Biscayne Bay.

Title of Task 4: Geochemical History of Biscayne Bay: Nutrients and Organics
Task Funding: USGS Greater Everglades Priority Ecosystems Science (GE PES); SFWMD
Task Leaders: William H. Orem
Phone: 703-648-6273
FAX: 703-648-6419
Task Status (proposed or active): Active
Task priority: Medium
Time Frame for Task 4: 10/1/03 to 9/30/07
Task Personnel: M. Corum, T. Lerch, B. Orem

Task Summary and Objectives:

Our major objectives are to determine the historical record of eutrophication in Biscayne Bay and to evaluate the linkage between eutrophication and changes in the biotic community in the bay. The approach we will take in this task is to examine the historical record of nutrients in Biscayne Bay from dated sediment cores. Results will also be compared to water flow records to determine if known changes in the water control system of south Florida may correspond to distinct nutrient changes within the cores. These results will be compiled with faunal and floral data from tasks 1 and 2. Comparing the timing of changes in nutrient input to that of changes in the biological community will allow a determination of whether eutrophication of the estuary and changes in biota are directly linked.

Task 4 - determining the geochemical history of the Biscayne Bay ecosystem - contributes toward answering the "Major Unanswered Questions and Information Needs" as discussed in the project overview above. The data from task 4 contribute toward establishing "the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14) for the Biscayne Bay area. Specifically this task supports the Biscayne Bay Coastal Wetlands Project and the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study, and it provides information relevant to the Combined Structural and Operational Plan (CSOP). (See details in project overview above. Note: all four tasks work in conjunction to fully addresses these unanswered questions and information needs. No single task can completely address these questions, but rather each task contributes a piece to the whole "puzzle".)

Specific Task Product(s):