Grantee Research Project Results
1998 Progress Report: Ecohab: Florida; Hydrography/Physical Oceanography Component
EPA Grant Number: R826792Title: Ecohab: Florida; Hydrography/Physical Oceanography Component
Investigators: Vargo, Gabriel A. , Weatherly, Georges , Sturges, Wilton
Current Investigators: Vargo, Gabriel A.
Institution: University of South Florida , Florida State University
Current Institution: University of South Florida
EPA Project Officer: Packard, Benjamin H
Project Period: June 1, 1998 through May 31, 2001
Project Period Covered by this Report: June 1, 1998 through May 31, 1999
Project Amount: $360,000
RFA: Ecology and Oceanography of Harmful Algal Blooms (1998) RFA Text | Recipients Lists
Research Category: Water Quality , Harmful Algal Blooms , Water , Aquatic Ecosystems
Objective:
The objectives of the ECOHAB:Florida program are to: (1) model the initiation, maintenance, and export of G. breve red tides on the West Florida Shelf at different time and space scales to predict landfall; (2) describe the physical habitat that affects the transport and concentration of G. breve; (3) determine the interactions of cellular, behavioral, life cycle, and community regulation processes with environmental forcing factors during stages of bloom development; (4) determine the sources of inorganic and organic nutrients that allow growth and persistence of large G. breve populations in coastal waters; and (5) determine the production, occurrence, fate, and effects of brevetoxins in the environment during and after G. breve blooms. The specific objectives of this subsection of the ECOHAB:Florida program are to provide: (1) basic current meter and meteorological measurements on the northern West Florida Shelf off Cedar Key; (2) monthly near-synoptic surveys of the physical, chemical, and biological fields within the ECOHAB:Florida control volume; and (3) chlorophyll a and biomass indicators at selected locations within the ECOHAB:Florida control volume.Progress Summary:
Activities by the hydrography section of the ECOHAB:Florida study for fiscal year 1998 include: (1) completing and deploying the underway package for continuous monitoring of temperature, salinity, chlorophyll fluorescence, transmissometry, and turbidity during each monthly synoptic cruise; (2) initiating the monthly synoptic cruises in June 1998 (see Figure 1 for a compilation of all stations occupied along the cruise track); (3) hiring and having in place a post-doctoral/visiting scientist for ECOHAB:Florida hydrographic activities; and (4) providing funds for two graduate students, as research assistants for the monthly cruises and sample analyses.The monthly synoptic cruises currently consist of 59 locations that define the ECOHAB:Florida control volume. In addition to the continuous underway measurements mentioned previously, conductivity, temperature, and depth (CTD) profiles that include in vivo chlorophyll fluorescence are conducted at each of the 59 locations. At every other location, water bottle samples are taken at selected depths throughout the water column for a variety of parameters including live counts for Gymnodinium breve abundance. Tables 1 and 2 provide examples of the status of sample processing, and the type, location, and vertical distribution of each parameter sampled. Analyses of each parameter are ongoing. All data are available for other ECOHAB:Florida investigators.
After the June 1999 cruise, we will have completed a full year of monthly synoptic assessments. An additional 18 months of cruises are planned.
Our monthly cruises also are used as a platform for other ECOHAB:Florida related studies. To date, Dr. John Paul (University of South Florida) has obtained water samples for studying the role of viruses in blooms, and Drs. Paula Coble and Carlos DelCastillo (University of South
Florida) have provided underway measurements of colored dissolved organic matter (CDOM) and vertical profiles of fluorescence spectra using a SAFire spectral fluorometer for most of the past year's cruises. Dr. Robert Griffin, a marine mammal ecologist on a post-doctoral fellowship at Mote Marine Laboratory, also has been conducting dolphin observations along the cruise track for the past 9 months. All of these investigators expect to continue their studies for the remainder of this fiscal year and into the next year.
With the advent of the Office of Naval Research-supported HyCode program on the West Florida Shelf, additional complementary programs also are ongoing or scheduled to start with the new fiscal year. These include: a twice-annual zooplankton census that includes spatial distribution along our Sarasota transect line and estimates of grazing impact; measurements of dissolved iron on each monthly synoptic cruise, del N-15 measurements of surface particulate matter and subthermocline nitrate, Trichodesmium spp. population assessments; and starting in July 1999, monthly optical measurements that include surface reflectance, upwelling and downwelling multispectral irradiance, and multispectral absorbance.
Table 1 summarizes the status of ECOHAB chemical and biological measurements from the hydrographic cruises.
Measurement |
Status* |
Inorganic Nutrients (NO3, NO2, SiO4, PO4, NH3) |
Completed through February 1999 Cruise |
Organic Nutrients |
Total Dissolved Phosphorus (TDP): completed through April 1999 |
Dissolved Organic Nitrogen (DON): currently being analyzed | |
Particulate Nutrients |
Carbon, Hydrogen, and Nitrogen (CHN): completed through April 1999 |
Particulate P: completed through March 1999 | |
Chlorophyll a |
Completed through current survey |
G. breve Cell Concentration |
Completed through current survey |
Phytoplankton Community Composition |
Archived for future; analysis underway |
To meet the objectives of this subsection of the ECOHAB:Florida program, an Acoustic Doppler Current Profiler (ADCP) mooring will be installed and maintained between the 20 and 30 m isobaths along the northern West Florida Shelf at the approximate latitude of Cedar Key. Basic information from this region will be essential for model calibration and validation, because preliminary observations suggest transport through this region is critical. Quarterly maintenance cruises will provide an opportunity to collect samples for cell counts and other variables. To meet Objectives 2 and 3, standard hydrographic measurements (CTD) will be taken monthly for 3 years at 5-nautical-mile intervals along three quasi-synoptic cross shelves and at least one along shelf transects. Water samples at selected depths (5-m intervals at mooring locations in < 50 m depth, 10-m intervals at mooring locations in > 50 m depth) are collected at every other location, and at all mooring locations, for the determination of phytoplankton biomass, abundance, and water column chlorophyll a concentration. Biomass is measured as particulate carbon, nitrogen, and phosphorus. Live cell counts for G. breve are done from the surface and from selected depths along each transect, and bulk water samples are preserved to determine phytoplankton community structure. Additional water samples are collected to determine total dissolved nitrogen (N) and phosphorus (P). They will be used in conjunction with other measurements of the inorganic fractions of each nutrient to assess the organic N and P concentrations. These results will establish the boundary conditions for the ecological and physical model and provide data sets for calibration and validation. Phytoplankton community composition and chlorophyll a data also will provide ground-truth for the remote-sensing components of the program.
ECOHAB MONTHLY CRUISES (Revised August 14, 1998) STATION LIST, SAMPLE DEPTHS, AND TYPES OF SAMPLES | |||||||||
SAMPLE TYPE | |||||||||
TRANSECT STATION NUMBER |
SAMPLE DEPTH |
CHL |
CHN |
PPO4 |
TDP |
TDN |
COUNT |
NUTRIENTS | |
(FANNING) | |||||||||
TAMPA BAY |
1 |
0 |
X |
X |
X |
X |
X |
X |
X |
3 |
X |
X | |||||||
2 |
CTD ONLY DEL N-15 | ||||||||
3 |
0 |
X |
X |
X |
X |
X |
X |
X | |
5 |
X |
X | |||||||
10 |
X |
X | |||||||
13 |
X |
X |
X |
X |
X |
X |
X | ||
4 |
CTD ONLY | ||||||||
5 |
0 |
X |
X |
X |
X |
X |
X |
X | |
10 |
X |
X | |||||||
20 |
X |
X | |||||||
25 |
X |
X |
X |
X |
X |
X |
X | ||
6 |
CTD ONLY DEL N-15 | ||||||||
7 |
0 |
X |
X |
X |
X |
X |
X |
X | |
10 |
X |
X | |||||||
20 |
X |
X | |||||||
30 |
X |
X |
X |
X |
X |
X |
X | ||
35 |
X |
X | |||||||
8 |
CTD ONLY | ||||||||
9 |
0 |
X |
X |
X |
X |
X |
X |
X | |
10 |
X |
X | |||||||
20 |
X |
X | |||||||
30 |
X |
X | |||||||
40 |
X |
X | |||||||
10 |
0 |
X |
X |
X |
X |
X |
X |
X | |
5 |
X |
X | |||||||
10 |
X |
DEL N-15 |
X | ||||||
15 |
X |
X | |||||||
20 |
X |
X | |||||||
25 |
X |
X | |||||||
30 |
X |
X | |||||||
35 |
X |
X | |||||||
40 m OR DCM DEPTH |
40 |
X |
X |
X |
X |
X |
X |
X | |
45 |
X |
X |
1998 G. breve Bloom. A significant (cell concentrations > 106 cells, with associated nearshore fish kills) bloom of G. breve was documented during the 1998 hydrography cruises. The 1998 G. breve bloom was first evident from live counts conducted during the November 1998 cruise, when concentrations of G. breve greater than 5.0 x 104 cells L-1 were found at site 50, located approximately 20 km off Sanibel Island, which is just south of Ft. Myers, FL. We modified our usual cruise track to include an alongshore transect at the 10 m isobath to determine the spatial extent of the bloom. Therefore, the normal cruise track for the remainder of the November 1998 cruise and subsequent cruises incorporated this transect with stations occupied at 5 nm intervals between Ft. Myers (site 51) and station 1 at the mouth of Tampa Bay. Both chlorophyll a and G. breve cell concentration surface maps (Figure 2) for the 1998 November survey showed that the bloom was extremely localized, covering a relatively small nearshore geographic area off Sanibel Island. One month later, this G. breve bloom had moved slightly north to include the region off Charlotte Harbor, with highest concentrations (1.12 x 106 cells L-1) found within a surface path approximately 10 km north of station 51 off Ft. Myers. The surface synoptic chlorophyll a map from the December 1998 cruise indicated both an increase in bloom size and concentration compared to the November 1998 data. The bloom extent is evident from G. breve cell counts, chlorophyll a measurements, station and underway fluorescence data, and SAFire backscattering data. Comparison with physical station data indicates that the outer edges of the bloom at the time of the December hydrography survey were confined by sharp gradients in the density field. The January hydrology cruise documented significant concentrations of G. breve cells within the Sanibel area where the bloom was initially documented. By February 1999, live G. breve cell concentrations at this site were close to background levels, while concentrations were elevated at sites (1, 80?83) near the mouth of Tampa Bay (Figure 3). Although this information might suggest that the bloom had traveled northward in the 17 days between the January and February cruises, a review of the current direction based on the slope of the isopycnal surfaces indicates that water movement during this time period should have been to the south. Therefore, we cannot be sure that the high cell concentrations off Sarasota and Tampa Bay in February were related to the populations seen off Sanibel Island in January. It is possible that a new, short-lived, bloom started in the Tampa Bay/Sarasota region. We say "short lived" because no significant concentrations of G. breve were counted in March, April, or May 1999 during our cruises nor were there any significant changes in physical parameters to account for the demise of that bloom. Further examination of additional physical processes and a model run are being conducted in an effort to explain the rapid changes that occurred in bloom status.
Near-Bottom Chlorophyll a Plume. A persistent feature of the ECOHAB hydrography survey area from June through December was a near-bottom chlorophyll a plume that extended from Tampa Bay to Ft. Myers along the approximately 30 m depth profile (Figure 4). Chlorophyll a concentrations within the plume were consistently greater than 2.5 g L-1, while concentrations within surrounding waters were < 1.0 g L-1. This feature corresponded with a lens of cold (19?C), high salinity (> 36.2 percent) water that was characterized by relatively high inorganic nutrient concentrations (September 1998, site 44, 35 m depth, 0.22 M PO4, 3.70 M SiO4, 2.00 M NO3).
Subcontract to Florida State University. Installation of our current meter at a site north of ECOHAB:Florida control volume has been completed by Drs. Sturges and Weatherby.
Future Activities:
Our scope of work for 1999?2000 has not changed, and there have been no changes in key personnel. We will continue to provide underway measurements, hydrography, and phytoplankton biomass measurements and population abundance (including G. breve) within the ECOHAB:Florida control volume. A second research vessel will be used for the alongshore section at the 10 m isobath of the control volume to allow the addition of an alongshore transect at the 50 m isobath and effectively "close" the control volume. Additional funds have been acquired for this purpose. The Florida Institute of Oceanography research vessel Bellows will be used for the cruises starting in October 1999.Both of the students supported by the ECOHAB:Florida program (NOAA funds) have designed M.S. thesis work that utilizes data collected by this component (EPA funded) of the overall study.
Journal Articles:
No journal articles submitted with this report: View all 31 publications for this projectSupplemental Keywords:
harmful algal blooms, ecosystem, habitat, marine science, ecology, oceanography, monitoring, satellite, Gulf of Mexico, tourist industry., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, State, Oceanography, algal blooms, Biochemistry, remote sensing, bloom dynamics, coastal resources, hydrography, marine biotoxins, brevetoxins, phytoplankton, remote sensing techniques, transport and concentration, bioindicator development, ECOHAB, Florida, FLARelevant Websites:
http://www.fmri.usf.edu/ecohab/ecofla.htm
http://www.fmri.usf.edu/ecohab/links.htm
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.