Algal Blooms on East and West Coasts of Florida—2002

Present Status: One species of dinoflagellate (= microscopic phytoplankton, Pyrodinium bahamense) is causing discoloration and depleting dissolved oxygen levels (thereby causing marine animal mortalities) in some parts of the Indian River near Melbourne. It is a common bloom organism and is being investigated for its potential to affect local marine animals.

Present Status: Since June, occasional reports of discolored coastal water have been received by various agencies. Discoloration due to higher-than-normal concentrations of microorganisms is common, especially in the summer. Because of the public interest that such phenomena presently generate, I will report information throughout the summer.

NOTE:   Because the "blackwater" event (January through April 2002) was poorly defined, it is the only event that FWC FMRI staff are referring to as "blackwater". Unfortunately, because it was studied only in the latter part of its existence, it is unlikely that investigators will determine an absolute cause for its appearance. Consequently, investigations of current water discolorations, marine mortalities, or other unusual events are being reported in this series of status reports on Algal Blooms, which is a very common cause of discoloration. Information associated strictly with the January-April event will continue to be reported under the "Blackwater Status Reports" that will be produced as results are available and as time permits.

Initial Report to FWC FMRI: This series of Florida West Coast status reports began with a June 23, 2002 bloom off Naples caused by a diatom in the genus Rhizosolenia. On July 3, 2002, Collier County Pollution Control received a report of discolored water that was observed June 28, 2002 by a boater offshore of the county. This latter discoloration was caused by a blue-green alga in the genus Trichodesmium.

Causes of Current Discolorations or Other Marine-Related Phenomena: The table below is a "running" list of the various discolorations or other marine phenomena that have been reported and sometimes investigated since June 2002. For details associated with these items, refer to Results Table below or to previous Algal Bloom Status Reports.

Sample Results:
NOTE:   Results from samples in which nothing unusual was observed are important for background reference. Therefore, samples are listed whether they contained blooms of interest or not.

* Ceratium sp., Dinophysis sp., Prorocentrum scutellum, Protoperidinium pellucidum, and Pyrophacus horologium = common dinoflagellates.
* Karenia brevis = a toxic dinoflagellate, common to the Gulf of Mexico, causes fish kills + respiratory irritation + occasional discoloration.
* Chaetoceros, Guinardia delicatula, Pseudo-nitschia, Rhizosolenia setigera, and Thalassionema nitzschoides = common diatoms.
* Trichodesmium = a common blue-green alga, often associated with large summertime blooms causing discoloration or an oily appearance.
* detritus = nonliving particulate matter = common, especially in inshore locations and when water is agitated.

West Coast Discolored Water Update for the Period June through August 2002:
Prepared August 28, 2002 by Merrie Beth Neely, FMRI Harmful Algal Blooms program staff

• Chlorophyll values are from C. Heil, USF Marine Science for period August 7–16
  
• Salinities and water temperature profiles are from P. Coble, USF Marine Science for period August 6–9
  
• Rainfall values for June and July are from the National Weather Service Web site with links to various other sites
  

Two separate algal blooms were noted on the southwest coast of Florida and were associated with discolored water. One was a diatom bloom in the Ten Thousand Islands area and the other was a cyanobacteria/diatom bloom near the entrance to the Caloosahatchee River south of Charlotte Harbor. The reported average chlorophyll values (extracted) range from 2.38–5.36 ug/L at the surface and 1.68–1.86 ug/L at the bottom for the Caloosahatchee/Charlotte Harbor area from early to mid-August. The chlorophyll values (extracted) from the Ten Thousand Islands area was 4.39 ug/L from early August. While these values are above normal for nonbloom conditions in this region, they are not equivalent to measurements from other blooms in this area, which can exceed 10–20 ug/L. Preliminary analyses of the chemical signatures of the discolored water found near the Ten Thousand Islands and Charlotte Harbor areas in early August point to a riverine source for the water, and they were associated with lower salinities. Rainfall in the southwest Florida region approached, and may have surpassed, record conditions in July, and rainfall during both June and July 2002 were 6–8 inches above normal. Diatom blooms and discolored water are common in this area, typical of southwest Florida estuaries, and are often associated with periods of high river discharge. Red tide, another type of algal bloom that is toxic to fish, also occurs along the west coast of Florida but was not detected in the most recent samples. Contrary to some reports, the discolored water encountered by researchers in mid-August and earlier this year was dominated by healthy living organisms typical to Florida waters ranging in size from microscopic to those readily seen by the unaided eye.

Comments:
PLEASE acknowledge the source of any data, images, or reports that are being e-mailed among all of us. Sharing information among the research community is essential. In an effort to ensure a spirit of cooperation, I'm reminding all of us that we should remember to provide the standard courtesy of referencing the source of any material that we may subsequently use. If I fail to acknowledge your work adequately, please let me know.

• August 20:   DEP reviewed river flow at various locks west of Lake Okeechobee in order to assess the effect of recent releases. DEP staff reported that flow rate attributable to Lake Okeechobee releases was insignificant by the time such water reached the lock near the Lee Co. line. Staff noted that rainfall may have increased the flow of many southwest Florida rivers. Specific data are available and will be forthcoming.
• August 18:   Chuanmin Hu (USF remote sensing) reported that satellite images suggest that water color on the southwest coast is nearly back to normal as of August 15.
• The most frequently asked question in recent weeks has been, "What are the results from either the earlier blackwater event or from the cruises and analyses being done on current samples?" When results are distributed, they will be reported here. Barring unusual circumstances, these reports will be generated about once per week and will incorporate whatever information has accumulated during the week. During research cruises, many samples are collected: time is needed to process, analyze, and interpret. Most of these samples are being done voluntarily and interspersed among other program responsibilities. Also, ship staff usually return very tired and need some rest. Please be patient.

Comments Relating to Previous "Blackwater Event":
August 30:   FMRI coral biologists are reviewing historical data relating to coral distribution in the Keys in order to evaluate IF and WHERE coral may have been affected by this event. There is presently some confusion about the possible effects of the blackwater event on coral abundance or lack thereof.

Comments Relating to Freshwater Blooms:
Just in case you thought only the marine environment was subject to algal blooms, here are two photos of discoloration caused by freshwater blue-green algae in Florida lakes: Apopka and Verona. These images are from John Burns, CyanoLab, Palatka who identified the species involved. John notes that Botryococcus produces oily compounds that can form thick surface scums.

Lake Apopka: A mixed bloom of Microcystis and Botryococcus

Lake Verona: A flask containing a bloom of Botryococcus

Anticipated Actions:
Continued accumulation and summarizing of information and data.

• Chuanmin Hu (USF) et al. published in the EOS newsletter, June 25, 2002: 83(26):281–285, entitled "Satellite images track 'black water' event off Florida coast", in which he reports about tracking the dark water in coastal water from fall 2001 off west central Florida through April 2002 off southwest Florida.
• Rick Stumpf (NOAA) spoke at a conference for remote sensing scientists. An abstract is available.
• Merrie Beth Neely (USF and FMRI) is compiling information for a poster relating to blackwater to be presented at the Xth International Conference on Harmful Algal Blooms in October. She is willing to extend co-authorship to those investigators who may want to present their information in this format to their peers.