When good algae goes bad … NASA to help SFWMD and FAU study algal blooms

OKEECHOBEE — Algae is everywhere, and that’s a good thing because without it, there would be no life on planet Earth. Algae is the base of the food chain and produces about 75 percent of the oxygen in the atmosphere.

Under certain conditions, algae grows rapidly, forming a bloom.

A satellite photo from NASA on July 2, 2016, showed a massive algal bloom. Photo courtesy NASA/Joshua Stevens.

Algal blooms are not always harmful, explained James M. Sullivan, Ph.D., a research professor with Florida Atlantic University. “Most of the time, algal blooms are not harmful,” he said. Most often, algal blooms are beneficial to the ecosystem.

But under certain conditions, some kinds of algae produce toxins. These are referred to as Harmful Algae Blooms, or HABs.

What makes good algae go bad?

Researchers will have another tool to answer that question in June, thanks to NASA.

Due to a cooperative effort by NASA, Florida Atlantic University’s Harbor Branch Oceanographic Institute and the South Florida Water Management District, a SeaPRISM device will be installed on a tower in Lake Okeechobee the week of June 11.

“We need to understand what causes HABs,” Dr. Sullivan said. HABs are a worldwide problem, he explained.

The SeaPRISM is a solar-powered robotic device that will be installed on an existing SFWMD tower near the middle of the lake, he said. The SeaPRISM has a cell link so that data collected goes directly to NASA. The data will be available to researchers online.

The SeaPRISM device is about 2 feet long and about 8 to 10 inches wide. It will move with the sun so that the cameras can take clear photos of the sky and the water without glare.

Usually a SeaPRISM is set up to take photos every hour, but it can be programmed to take photos more frequently. The device uses filters to take photos at different wavelengths.
The color of the water will help researchers map the algae content and the turbidity of the water.

Cyanobacteria (sometimes called blue-green algae) has a unique color that the SeaPRISM can track, he explained.

NASA uses the SeaPRISM data to calibrate satellites. Satellite photos can be distorted by the atmosphere, he said. The SeaPRISM cameras, which take photos of the water and the sky, can be used for satellite “calibration validation,” he said.

While satellites take photos of Lake Okeechobee every few days, the SeaPRISM will take photos hourly or even more often.

Dr. Sullivan said Lake Okeechobee was chosen for a SeaPRISM device because of its size. “Lake Okeechbee is big enough to be seen from a satellite,” he said.

Researchers hope the additional data will help them understand the causes of toxic algal blooms. He said Harbor Branch will also do sampling on the lake.

Dr. Sullivan’s research interests range from the biological and physical mechanisms controlling the spatial-temporal dynamics of phytoplankton/zooplankton populations in the coastal oceans, Harmful Algal Bloom (red tide) dynamics, bioluminescence in the ocean, and the development and use of optical and autonomous sampling instrumentation and analytical techniques needed to study these complex processes.

Equipment he has developed or co-developed includes a moored autonomous vertical profiler, a bathyphotometer, an in situ hyperspectral spectrophotometer and an in situ holographic microscope for 3-D characterization of undisturbed particles in the ocean.

A SeaPRISM takes photos of the sky and water using a series of different filters. Photo courtesy NASA.

Dr. Sullivan earned his master’s and doctorate in biological oceanography with specializations in phytoplankton physiology and ecology, as well as bio-optics and biophysics, from the University of Rhode Island Graduate School of Oceanography (URI-GSO). Prior to joining Harbor Branch, he was research faculty at URI-GSO and a senior oceanographer for WET Labs Inc.


SeaPRISM to help scientists study algal blooms

OKEECHOBEE — Scientists have been using satellites to track Harmful Algal Blooms (HABs) from space for nearly 30 years, but new technology deployed by NASA could provide more detailed data on the growth of algal blooms not only in the ocean but also in Lake Okeechobee.

The new technology means those who follow HAB research have some new acronyms to learn.

AERONET-OC is the worldwide Aerosol Robotic Network, an international federation of sun- and sky-scanning radiometer networks that includes hundreds of instruments worldwide. OC stands for ocean color.

“Ocean color” refers to the various hues that ocean waters acquire in the presence of algae, bacteria, plankton, sediments or other organic material. Satellites can “see” these colors by measuring the wavelengths of light the Earth’s waters absorb and reflect, information that scientists can then use in several ways, including monitoring HABs, detecting the presence of phytoplankton and evaluating concentrations of organic carbon.

For the data from Earth-observing satellites to be accurate and credible, the influence of atmospheric characteristics on radiation measurements needs to be accounted for (i.e., an “atmospheric correction”). One way to do this is to validate satellite data by comparing it to data from in-situ or ground-based sensors.

AERONET-OC provides this validation through the installation of photometers — devices that can detect the wavelengths of light reflected by surface waters just like satellites — on offshore structures such as lighthouses, oceanographic research stations and oil platforms. By zeroing in on light reflected off the water, the SeaPRISM provides scientists with data about the conditions of the water. In addition, this data can be compared with ocean-color (or lake-color) data from Earth-observing satellite instruments such as the Visible Infrared Imager and Radiometer Suite (VIIRS) on the Joint Polar Satellite System’s Suomi NPP satellite.

PRISM stands for Portable Remote Imaging SpectroMeter. A SeaPrism instrument has specific filters and a scenario to measure the sea and sky radiance.

According to the National Oceanographic and Atmospheric Administration (NOAA) website, the SeaPRISM project is a federation of ground-based remote sensing networks established by NASA and PHOTONS (PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire) and expanded by networks and collaborators from national agencies, institutes, universities, individual scientists and partners. For more than 25 years, the project has provided a long-term, continuous and readily accessible public domain database of aerosol optical, microphysical and radiative properties for aerosol research and characterization, validation of satellite retrievals, and synergism with other databases. The network imposes standardization of instruments, calibration, processing and distribution

In 2016, Lake Erie became the first inland water body in the United States to have a SeaPRISM.

The SeaPRISM scheduled to be installed on Lake Okeechobee in June will be the first on inland water in Florida and the second on inland water in the United States.

Editor Katrina Elsken can be reached at kelsken@newszap.com

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