One day in late July, Donglai Gong was piloting his little quadcopter above his house when he noticed his drone camera picking up something odd in the York River below.
(From Daily Press/ by Tamara Dietrich) — “There were features, like, streaks of darkness,” Gong recalled Wednesday at the Virginia Institute of Marine Science in Gloucester Point. Gong is an assistant professor studying the physics of coastal and polar oceanography.
“And, being a physicist, I had no idea what biological processes could be causing that. So I took some pictures. They looked pretty.”
He emailed those pictures to VIMS colleagues, many of whom were biologists who knew exactly what was going on: a harmful algal bloom, or HAB.
Gong and a handful of colleagues who study HABs were soon teaming up to see just how effective drones like this can be in finding the troublesome blooms that pop up in the bay and its tributaries every summer.
When those blooms decay, they suck oxygen from the water column, endangering or killing marine life. Some algae can even be toxic, posing possible health concerns for fishermen and swimmers.
VIMS biologists were already seeking federal grants to expand their remote sensing capabilities for blooms. Even now, they use drones to observe marine features such as living shorelines and marshes. Gong uses his to track the underwater gliders he deploys for his ocean research.
The biologists have also been working with NASA to secure certain algorithms the space agency has been working on for several years that, once perfected, could help identify and differentiate between algal species — even determine the density of cells — by crunching spectral imagery data collected by satellite.
“Now that we know we have drone captains right here,” Anderson said.
Gong laughed. “Eye in the sky.”
The hunt for HABs
The traditional way to hunt for an algal bloom is rather straightforward, but hit or miss.
A small team will take a boat out to spot in a likely area, wearing sunglasses with polarized lenses that help them see the telltale mahogany or reddish hues of the bloom patches.
Once they find a patch, they drive the boat over and collect water samples for cell counts and other analyses.
Read the full story here: http://www.dailypress.com/news/science/dp-nws-drone-algal-blooms-20170825-story.html