of water turbidity and sedimentation in florida bay and biscayne bay >
Project Proposal for 1998
Program: Fragile Environments
Project Summary: Water turbidity has a major impact on viability of various marine communities such as seagrasses and hardbottoms. Resuspension events can lead to burial or damage to many of the bottom communities in these bays and may lead to introduction of nutrients to the water column, causing algal blooms. This project uses satellite data to examine the clarity of Florida and Biscayne Bays and provides an assessment of the spatial and temporal variability, which can be used in interpreting data from field measurement programs. The satellite imagery is compared with field measurements of light attenuation, water clarity and particulate loads that are made during various monitoring programs, as well as from this project. Changes over several years, between seasons, and during specific events such as cold fronts are examined.
Project Justification: This project will address questions of the clarity of the two bays and provide an assessment of the spatial and temporal variability, which can be used in interpreting data from field measurement programs. The amount of material resuspended by high winds and the duration of these events will be estimated. Improvements in the sensors and available algorithms for processing data will also allow new data to be obtained, such as water color and the distribution of algal blooms. Tile study will also result in validation of techniques for distinguishing material in the water from the bottom type in shallow water; this may result in information on changes in the bottom type from the imagery in this study.
Project Objectives: The objective is to understand the conditions causing turbidity in Florida Bay through integration of a combination of satellite imagery with field observations. The project involves the development of a time series of past and current conditions on water temperature and turbidity in Florida and Biscayne Bays to identify changes in the Bay using AVHRR, Landsat TM, and ocean color sensors and coordination with field measurements.
Overall Strategy, Study Design, and Planned Major Products: During 1998, the effort will concentrate on evaluation of changes over the past twelve years, both in turbidity and in benthic habitats, on assessment of current conditions as compared to previous conditions in the Bay, and incorporation of new ocean color sensor data on water color and chlorophyll.
The major products will be CD's on the data set from 1985 to the present, and the inclusion of change
assessments and current status on our web page. One or more papers are expected as well
Finish processing the AVHRR time series for 1985 to present.
Begin analysis of OCTS and SeaWIFS data. These data sets will augment the AVHRR. OCTS will require modifications of the atmospheric correction before it can be used to derive estimates of chlorophyll. The SeaWiFS should be suitable for water color analyses immediately.
Complete processing of Landsat TM data set. This is being done jointly with Florida DEP to identify variations in benthic cover, such as seagrass, that may have altered the water turbidity over the past 12 years. Areas, such as the far western Bay, that had not previously been investigated in any study will be given particular emphasis.
Continue collection of light attenuation data in field for comparison with satellite time series.
Planned Deliverables/Products: Prepare this as a CDROM (as compared to the current CDROM which includes the original 1989 to 1996 data).
Planned Outreach Activities: Provide routine assessments of the current turbidity and changes in the Bay. These assessments will be produced seasonally and presented on the Web. The interpretation will be made drawing on discussions with NOAA-NMFS, FIU, and FDEP. We are also working with FDEP on benthic change mapping by using satellite imagery purchased jointly with them.Accomplishments and Outcomes, Including Outreach:
Efforts proposed for this year are on track.
Expanded the AVHRR data record back to 1985, providing information from before the seagrass dieoffs to the present. We have completed processing of this data set and are beginning analysis. This includes 1038 usable afternoon scenes from over 2000 processed.
We are continuing to provide current imagery for south Florida on the Web. Since October 1, 1996, we have had about 900 (as of June 1, 1997) different accesses to the site from outside the USGS.
We have established relationships to seston, attenuation, Secchi disk depth, and are working on NTU.
We have set up programs for processing of SeaWIFS ocean color data.
A M.S. Thesis on the Landsat MSS imagery should be completed by the end of the year.
Stumpf, R.P. and M.L. Frayer, 1996. Remote sensing of water turbidity and sedimentation and their relationship to algal blooms. Florida Bay Science Conference, Key Largo Florida, Dec. 10-12 1996, p.80 (invited plenary session speaker).
Stumpf, R.P. and M.L. Frayer, 1997. Temporal and spatial change in coastal ecosystems using remote sensing: example with Florida Bay, USA, Emphasizing AVHRR imagery. Fourth International Conference on Remote Sensing for Marine and Coastal Environments, ERIM, v. 1, p. 65-73.
Stumpf, R.P. and M.L. Frayer, (in press). Use of AVHRR imagery to examine long-term trends in water clarity in coastal estuaries: example in Florida Bay. in Kahru, M. and C.W. Brown, Monitoring Algal Blooms: New Techniques for Detecting Large-Scale Environmental Change. chapter 1.
Olson, D.M, M-E. Luther, R.P. Stumpf, J-D. Althausen, 1997. A timeline of environmental degradation
in Florida Bay from 1972 - 1992: change detection analysis of Landsat Multispectral Scanner data.
Fourth International Conference on Remote Sensing for Marine and Coastal Environments, ERIM, v. 1,
Analyst (Stumpf, Frayer)
Names of Key Project Staff: all years: Stumpf, Frayer, Stanley