SARASOTA -- Underwater robots “Waldo” from Mote Marine Laboratory and “Bass” from University of South Florida have been monitoring offshore Florida red tide and surrounding ocean conditions since being deployed Aug. 1.
It appears Manatee and Sarasota county Gulf coasts will be spared from this massive red-tide outbreak.
The bloom is reported to be 80 miles long and 50 miles wide, reaching from Dixie County to southern Pasco County, according to the Florida Fish and Wildlife Conservation Commission statewide update Aug. 1.
During the past few days, Waldo reported at 40 miles from the Pasco/Hernando border, red tide was detected at the surface and to depths of about 82 feet in areas where it was indicated by satellites.
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Bass: At the outer edge of the bloom, elevated chlorophyll associated with the red tide was present in waters as deep as 131 feet.
Bloom water is “stratified” (layered) with denser, cooler water below and lighter, warmer water on top.
Waldo will complete his mission this week or early next, while Bass will finish in two to three weeks.
The robot data is feeding into short-term forecasts of the red tide bloom developed by the Collaboration for Prediction of Red Tides, a partnership effort between the Florida Fish and Wildlife Conservation Commission and USF.
The latest three-day forecasts from USF and FWC, informed in part by the Mote-USF robot missions, show surface water in the bloom region is expected to move slightly south, but move little overall.
The deepwater in the bloom region is expected to move southeast slowly.
These south and southeast movements could bring the bloom close to southwest Florida’s coast in the coming weeks. However, there are many variables. For instance, large weather systems passing through can break up blooms.
According to the National Oceanic and Atmospheric Administration, no respiratory irritation is expected at southwest Florida beaches through Aug. 11.
FWC, Mote and USF scientists are collecting many kinds of data about the bloom during an FWC-led research cruise aboard the R/V Bellows, which is expected to wrap up Wednesday. The goal is to construct a 3-D picture of the red tide by measuring concentrations of red tide algae in surface and deepwaters offshore of Pinellas, Pasco, and Hernando counties.
Mote scientists on board are using state-of-the-art technology — including a Mote-developed red tide detector called an optical phytoplankton discriminator, nicknamed "BreveBuster" — to learn more about the red tide alga Karenia brevis and its relationship to the dynamic community of other microscopic algae found in Gulf waters.
The Mote researchers are studying phytoplankton pigments to study other species in addition to K. brevis. FWC is defining the nutrients present, and studying DNA and the phytoplankton community. USF scientists are studying optical properties of the bloom: ways that algae reflect the light. This is important for ground-truthing satellite images.
Mote also sampled waters between Sarasota and the bloom’s southern edge, finding many sites lacked red tide or only had background concentrations. However, sampling confirmed low and very low concentrations of red tide algae about 33 miles west of Caladesi Island in Pinellas County.
It’s important to note sampling is tricky: Red tide blooms can be very patchy, and areas with few red tide cells can be close to areas with lots of cells, according to a Mote press release. The cells can even swim and clump together. That means scientists must take multiple samples to get the best possible understanding of bloom intensity.