May 21, 2018
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Coral farmer to teach Unity College students how to grow delicate saltwater organism

By Abigail Curtis, BDN Staff

UNITY, Maine — The small, sunny room at Unity College was clearly a work in progress, with boxes scattered around and a big, black plastic tank that now holds only tens of gallons of saltwater.

But Christian Carlson, a bearded, gregarious information technology employee at the college, said that within a few months the tank will be a lively repository for waving fronds of colorful coral which students will learn to grow in a semester-long marine ornamental aquaculture class.

“The coral project is really, really new,” the 26-year-old said. “I hope that this will be more than a resume builder. I’d love to get a student really interested in marine aquaculture. You can only get and understand so much from seeing it on the Discovery Channel.”

Coral, he said, is a sometimes-misunderstood organism that is gravely endangered around the world from pollution, sedimentation and global warming. One of the factors that can imperil coral is when it is harvested, improperly or over-enthusiastically, to be sold to decorate saltwater aquariums. When the Unity College students learn how to grow, or farm it, successfully, it will help to ease the pressure on fragile reefs.

“There’s tons of small reefs worldwide that have been just decimated … there are some species that have absolutely been over-harvested for the aquarium trade,” Carlson said. “I figured, if I can teach people how to grow coral in an effective manner, they’re the ones who will carry the torch to stop the degradation of the natural reefs.”

Coral polyps are tiny, translucent animals that are related to sea anemones and jellyfish, with a hard limestone skeleton at their base, according to the National Geographic. Coral polyps attach to a rock and divide into thousands of clones. Some of the oldest coral reefs on the planet began growing more than 50 million years ago. The reefs are found in tropical waters all over the planet, and although they cover less than one percent of the ocean, they support a quarter of all marine creatures. Scientists believe that almost a third of existing reefs could die in the next three decades.

Carlson has been an aquarium hobbyist for 17 years, and began experimenting with saltwater aquariums nine years ago. From that, he developed an aquarium service business from his home in Thorndike and began to work as a coral farmer. Two years ago, Carlson had a 750-gallon saltwater tank where he grew corals like the green sinularia coral, an organism that looks a little like an otherworldly tree and is found in the wild in the Indo-Pacific region of the world.

He showed a sinularia “mother colony” that the class’s 20 students will use as a root stock for their aquaculture efforts. Until recently, Carlson said, corals like this one had a 73 percent mortality rate when hobbyists tried to grow it at home. People didn’t understand know how to care for coral, he said, and the organisms would often weaken or die in the long transit from their home waters.

Coral is a photosynthetic organism and needs light in order to stay alive. Often people would keep their coral in tanks that were too far from light sources.

“It took us a while to break out of the freshwater system, the pink gravel and the bubbling pirates,” Carlson said. “Sometimes they were sold as an ornamental, and a week later, the thing’s an exoskeleton in your tank.”

But when grown by people who know what they’re doing, aquacultured coral has a much better survival rate in aquariums than coral that was wild-harvested, he said.

At Unity, the class will learn about a simple type of system that has been successful for Carlson. He’ll cover the bottom of the tank with a deep layer of sand, algae and what he calls “live rock:” aragonite that is covered with algae.

The students will learn how to take coral fragments from the mother colony and superglue them to the rock. Then, with light and time, the coral will grow. Carlson also will introduce fish to the tank, and the coral will consume some of the fish waste. The algae will take nitrites and nitrates out of the water and also is a salable product, he said.

“We’re really trying to create an ecosystem,” he said.

Students will need to be careful, always handling certain species with gloves when they use their knives to separate fragments from the mother colony. Corals can excrete toxins that can be deadly to fish and painful to people. Carlson said that when he once accidentally gave himself sinularia poisoning, he lost his sense of taste for 18 hours.

“It can hurt people,” he said of the toxin.

Students will also work on cultivating a species of bioluminescent invertebrate called renilla, which students use in other science classes. If students can grow this in the lab, Unity College can stop purchasing renilla that has been wild-collected in Florida, Carlson said.

That goal is right in line with the college’s focus on sustainability.

“I think it’s about respecting the resources that we have,” he said.

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