VIMS uses drones to find, study algal blooms

[USA] 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.

“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.

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 Virginia Institute of Marine Science professor Dongli Gong, Chair of Aquatic Health Sciences Kimberly Reece and doctoral student Lydia Bienlien look at algae blooms in the York River via the feed from a drone Wednesday August 30, 2017. (Rob Ostermaier / Daily Press)

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, though, those scientists are wondering if such algorithms can be used by sensors mounted on drones to do pretty much the same thing, said Iris Anderson, professor and biologist, as she joined Gong and others in a VIMS lab.

“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.

The problem is, a HAB isn’t cohesive — it’s a shape-shifter at the mercy of wind and wave.

“It’s very disperse,” said Kimberly Reece, professor and molecular geneticist, gesturing at one of Gong’s bloom photos. “We’ve taken cell counts and we can get 40,000 cells here and we’ve taken a sample out here, it’s 40. I mean, really big differences in concentrations in those patches.”

When they can, VIMS researchers piggyback aboard survey planes operated by the Virginia Marine Resources Commission.

But while such aerial surveys can cover a wide area, they’re at such high elevation that photo resolution suffers.

A drone doesn’t have those same limitations, and VIMS is starting to recognize its potential in marine science — even offering a class to prepare students, like Lydia Bienlein, to become certified drone pilots.

“This is a new technique that’s coming on,” Bienlien said.

‘Let’s fly”

On Wednesday, she and Gong stood on the shore of the York with Anderson, Reece and associate professor B.K. Song, preparing to launch a quadcopter to search for a bloom.

The drone needs both a pilot and co-pilot — one handles the stick while watching the drone images transmitted to an iPad or iPhone mounted to the controller, and the other keeps an eye on the quadcopter in flight. The top legal cruising altitude is 400 feet.

The Virginia Institute of Marine Science has been using a drone to photograph algae blooms in the York River and to better place boats that are sampling the blooms. (Rob Ostermaier / Daily Press)

It had rained heavily the day before, with strong winds, so researchers felt sure the big bloom of Alexandrium monilatum they had surveyed and sampled the previous week would be long gone. They were so sure, they even passed on taking out the sampling boat that day, as planned.

“Let’s fly up and see whether we can see anything,” said Gong.

The peppy little drone took off fast and vertical, buzzing like a swarm of angry bees.

Song was staring across the river in the direction of the U.S. Coast Guard pier, murmuring that he thought he saw something in the water.

The drone sped toward the far shore.

When it was a mile and a half out, Gong piped up.

“I think I see something right there,” he said, watching the monitor. “I’m seeing a little bit of shade.” And, a moment later, “I’m definitely seeing something.”

Reece studied the screen.

“There it is,” she said. “That streak right there. Oh, so it is out there!”

The Virginia Institute of Marine Science has been using a drone to photograph algae blooms in the York River and to better place boats that are sampling the blooms. (Rob Ostermaier / Daily Press)

Immediately, she, Anderson and Song launched into an animated discussion on when they might take the boat out again for towing and sampling.

The drone returned before its battery ran down — the charge lasts for only 20 minutes — then launched again toward the Coleman Bridge just down the river next to the VIMS campus.

It found HAB patches at the bridge, too.

“That’s surprising, considering the rain that we’ve had,” said Bienlien. “I was not expecting it.”

About algae

The York has been a hot spot for harmful algal blooms for decades, said Reece. The algae are fed by nutrient runoff, mostly from agricultural lands, and nursed in warm, quiet water.

For years, the algal species that popped up in this region was the Cochlodinium polykrikoides. Then, in 2007, the Alexandrium showed up, blooming once Cochlodinium has run its course. Both can cause notorious red tides.

Alexandrium is also bioluminescent, glowing a stunning blue when disturbed by a fish or a boat or a hand trailing through the water.

Last year was a bad one for Alexandrium — spreading as far as Virginia Beach, the James River, the Rappahannock and the Piankatank, almost reaching the Eastern Shore.

“This year,” said Reece, “we have not seen any evidence yet of that kind of activity.”

Now that the weather is cooler, the HABs might even be petering out for the summer.

Even so, their cysts remain in the sediment wherever blooms have appeared.

And, when conditions are right again, they’ll be back.

“They’re dormant all winter, but they’re out there,” said Reece. “And that’s why, with the extension we’re seeing in so many different places, we have a concern that all of these areas are prone now to have blooms of these organisms.”

The Virginia Institute of Marine Science professor Dongli Gong pilots a drone over the York River looking for algae blooms in order to help research into the natural phenomenon. (Rob Ostermaier / Daily Press)

HABs are known to harm marine finfish and shellfish, and VIMS is studying their impact on larval fish and oysters. While human impacts are unknown, anecdotal accounts suggest the blooms can have an effect.

“When we sample in the middle of an intense bloom,” said Song, “we just get such a headache, we want to get out right away.”

Scientists are still trying to understand algae and their puzzling behavior, said VIMS spokesman David Malmquist.

“A single species might produce a toxin in California, but it’s not producing a toxin here,” Malmquist said. “And different species might produce the same toxin, and a single species might produce more than one toxin. And sometimes they don’t produce them at all.

“That’s why everything about these is just really hard to study, because they’re so variable — geographically and biologically and ecologically.”

VIMS is also studying how algal blooms might contribute to estuaries being a sink or a source for carbon dioxide, which can have larger environmental implications.

Next year, VIMS expects to receive a nearly $1 million, three-year grant from the National Science Foundation, in part to help learn how blooms might contribute to the release or uptake of CO2 in the Chesapeake Bay and other estuaries.

“That’s why everything about these is just really hard to study, because they’re so variable — geographically and biologically and ecologically.”

View original article at: VIMS uses drones to find, study algal blooms





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