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Robert Halley (retired)
Paleoecological data from cores also indicates that changes in the abundance of seagrass and algae in the Bay have been coincident with salinity changes and that significant loss of seagrass on mud banks and basins has occurred over the last several years. Stable isotope data from sediment cores indicate decreased circulation in the Bay coincident with railroad building and early drainage in South Florida.
Water management practices in South Florida are already being altered in an effort to restore the Everglades and Florida Bay. Resulting changes in water chemistry will first affect biogeochemical processes, and may, subsequently, result in changes in species distributions (such as seagrass, algae, etc.) in the Bay. An extensive water quality monitoring program for Florida Bay has been in operation for several years. Primary participants include ENP - fixed water quality monitoring stations, NOAA -salinity, chlorophyll, and transmittance bimonthly surveys, SFWMD - northeast Bay and north coast monitoring, and Florida International University (FIU) - nutrient monitoring. These programs have provided detailed information on concentrations of water quality parameters in the Bay. However, in situ monitoring of key biogeochemical processes resulting directly from biological activity has not been undertaken. Monitoring changes in biogeochemical processes is critical to early identification of ecological response to restoration and predicting changes in species distribution within the Bay. Additionally, these processes may directly impact water quality.
Calcification, photosynthesis, and respiration directly affect dissolved oxygen, pH, dissolved inorganic carbon and a number of other chemical characteristics of the water column. This information will enable managers to evaluate the progress and success of South Florida restoration efforts.
Pichon, M.; Delesalle, B.; Frankignoulle, M.
Halley, R. B.
Fourqurean, J. W.; Jones, R. D.
Ishman, S. E.
Frayer, M. L.; Durako, M. J.; Brock, J. C.
Roulier, L. M.
Robblee, M. B.
Jey, J. A.; Bjork, R. D.
Zhang, J.; Lee, K.; Campbell, D. M.
Barber, T. R.; Carlson, P. R.; Drako, M. J.; Furqurean, J. W.; Muehlstein, L. K.; Porter, D.; Yarboro, L. A.; Zieman, R. T.; Zieman, J. C.
Chen, Z.; Childers, D. L.; Boyer, J. N.; Fontaine, T. D.
Key, G. S.
Healy, G.; Greer, L.; Lutz. M.; Saied, A.; Anderegg, D.; Dodge, R. E.; Rudnick, D. T.
Fourqurean, J. W.; Frankovich, T. A.
Holmes, C. W.; Halley, R. B.; Bothner, M.; Shinn, E. A.; Graney, J.; Keeler, G.; ten Brink, M.; Orlandini, K. A.; Rudnick, D.
Halley, R. B.
Calcification, photosynthesis, and respiration were measured using the SHARQ incubation system developed by Yates and Halley. Geochemical parameters including pH, dissolved oxygen, fluorescence, and temperature were measured continuously through the SHARQ's flow-through analytical system throughout the duration of incubation periods (from 20-28 hours). Water samples were removed from sample ports every 4 hours for alkalinity measurements via the Gran titration method using methods of Millero. Dissolved oxygen, pH and alkalinity data were used to calculate rates of net calcification, photosynthesis, and respiration for each 4-hour interval between alkalinity measurements during incubation periods. Productivity parameters were calculated using the alkalinity anomaly technique and carbonate system equations of Millero whereby delta concentration of each parameter/deltaT x SHARQ volume/SHARQ surface area = g C m -1. Sample interval rates will be used to calculate net daily production rates that were then used to derive average hourly rates of calcification, photosynthesis, and respiration. Photosynthetically active radiation (PAR) was measured in the air at the waterís surface and on the seafloor at monitoring sites during all monitoring exercises.
Productivity rates at all sites, including mud- and hard-bottom communities, and water column were measured in March 2000.
Additional seagrass sites near Barnes Key (an area of recent seagrass die-off in the western bay monitored by FMRI) were surveyed in March 2000.
Productivity on mudbanks will be determined by measuring spatial geochemical changes along transects across mudbanks using techniques modified from Smith (1973) and Frankignoulle and Disteche (1984). Productivity in basins will be determined by measuring temporal geochemical changes in water masses isolated over the bottom using techniques developed by Halley and Yates employing a large environmental incubation chamber (Submersible Habitat for Analyzing Reef Quality, or S.H.A.R.Q.). Comparison of productivity monitoring data to productivity baselines established in FY2000 and geochemical survey data will provide a measure of the response of biogeochemical processes to changing water quality in the Bay.
FY2003 activities will focus on continued monitoring of production rates at monitoring sites established during FY2000 (Russell Bank, Manatee Key Basin, and Buchanon Bank). Productivity rates will be determined by measuring rates of calcification, photosynthesis, and respiration associated with representative substrate types including seagrass beds, hard bottom communities and mud bottom communities. Biological characterization of geochemical monitoring sites by FMRI and USGS will provide critical information used for hind-casting production rates based on historical information from cores. Rates of productivity at each site will be measured for 24-hour periods, during dry and wet seasons (2 time/year), via two weeks field excursions to establish daily, seasonal, and annual rates of production in the Bay. These data will be compared to baseline productivity data established in FY2000 to identify changes in ecosystem health.
Calcification, photosynthesis, and respiration will be measured using the SHARQ incubation system developed by Yates and Halley. Geochemical parameters including pH, dissolved oxygen, fluorescence, and temperature will be measured continuously through the SHARQ's flow-through analytical system throughout the duration of incubation periods (from 20-28 hours). Water samples will be removed from sample ports every 4 hours for alkalinity measurements via the Gran titration method using methods of Millero (1979). Dissolved oxygen, pH and alkalinity data will be used to calculate rates of net calcification, photosynthesis, and respiration for each 4-hour interval between alkalinity measurements during incubation periods. Productivity parameters will be calculated using the alkalinity anomaly technique (Smith and Key, 1975) and carbonate system equations of Millero (1979). Sample interval rates will then used to calculate net daily production rates that were then used to derive average hourly rates of calcification, photosynthesis, and respiration. Photosynthetically active radiation (PAR) will be measured in the air at the waterís surface and on the seafloor at monitoring sites during all monitoring exercises.
Comparison of bimonthly survey data and NOAA surveys to historical water quality information from the ENP database will be used to identify locations of significant water quality change in the bay and potential new monitoring sites. Dissolved oxygen, pH, DIC speciation, and air:sea CO2 gas flux data from USGS surveys will play a critical role in identifying areas where significant changes in biogeochemical processes may be taking place. Survey data will be coupled with productivity monitoring data to establish condition/response criteria for biogeochemical processes. High frequency, bay-wide geochemical surveys will complement SFWMD water quality monitoring along the Bayís northern coastline, ENP water quality monitoring stations throughout the Bay, and NOAA bimonthly surveys to provide very detailed characterizations of water quality.
Survey tracts will target the perimeter of each of the smaller basins in the Bay, transect larger basins, and include sampling sites near canal and slough discharge areas. Salinity and conductivity (Orion instrumentation), temperature (Orion), pH (Orion Ross Electrodes and meter), and dissolved oxygen (YSI) will be measured using a flow-through analytical system towed behind a small research vessel at a speed of less than 15 knots. Data from each of these parameters will be logged approximately once every 4 to 8 seconds of travel resulting in collection of approximately 20,000 data points for each parameter throughout the entire bay over a three to four day time period. Water samples for total carbon analyses will be collected from each of 24 sites distributed throughout the Bay. Analyses will be performed using a carbon coulometer. Total carbon and pH data will be used to calculate carbon speciation using the CO2SYS carbon speciation program. Air:sea CO2 gas fluxes will also be directly measured at each of the 24 sample sites using a floating bell and a LiCor 6252 infrared CO2 gas analyzer. Data collected from each geochemical survey will be contoured producing a GIS map layer for each chemical parameter. These maps will be posted on the SOFIA website. These data will establish the effects of alteration of freshwater flow to Florida Bay on critical geochemical parameters and assist in establishing links between changes in water quality, biogeochemical processes, and ecosystem health.
Average rates of carbonate sediment production derived from FY99 through FY03 monitoring exercises will be used to estimate average sediment accumulation rates for various representative substrate types identified by Prager and Halley (1997). This information will be compared to historical sediment accumulation rates derived from dated sediment cores and sediment thickness data. Carbonate sediment production rates from monitoring exercises will be compared to salinity data collected via geochemical surveys to identify potential salinity impacts on sediment production rates.
A similar comparative exercise for organic productivity (rates of carbon fixation) from seagrass and other substrate types is planned for next fiscal year.
During FY03, average rates of carbonate sediment production derived from FY00 through FY03 monitoring exercises were used to estimate average sediment accumulation rates for various representative substrate types identified by Prager and Halley. In FY04, this information will be compared to historical sediment accumulation rates derived from dated sediment cores and sediment thickness data. Carbonate sediment production rates from monitoring exercises will be compared to salinity data collected via geochemical surveys to identify potential salinity impacts on sediment production rates. A similar comparative exercise for organic productivity (rates of carbon fixation) from seagrass and other substrate types will be performed. Data sets from this study will be coordinated with data sets of Wingard, Zieman, Fourqurean, Frankovich, Durako, and Orem. Productivity data will be made available through a database on the SOFIA web site. GIS map products have been generated for all water quality parameters from bimonthly geochemical surveys. Correlation statistics will be used to identify links between specific water quality parameters, and other physical parameters (such as bottom type, etc.) to aid in the identification of processes controlling water chemistry. Data used to generate map products will be incorporated into a database, and will be made available on the SOFIA website. All map products will also be made available as USGS open-file reports.
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