Oranges’ journeysyield scientific data Currents crucial to research on seaweed

Lost: 500 navel oranges. Distinguishing features include e-mail addresses and phone numbers written in permanent marker. Scientific value. Last seen being tossed overboard into the Gulf of Maine.

If you thought you saw small, round fruits bobbing around in the waters off Schoodic Point a few weeks back, you were right.

No, they weren’t missing freight from a cargo ship.

And no, they didn’t drift up from Florida citrus groves.

They were part of a research project by a University of Maine graduate student studying the genetic structure of seaweed.

Fucus vesiculosus, to be exact, the common brown algae that grow on rocks. It’s also known as rockweed or bladder wrack.

What do oranges have to do with seaweed? Absolutely nothing.

But the fruits are helping 25-year-old marine sciences student Jessica Muhlin learn about circulation patterns of water around Schoodic Point, which may yield information on the reproductive ecology of seaweed.

“I tried to think of inexpensive ways to find things out,” she said. “I chose oranges because they are biodegradable, they are buoyant, and they are visible.”

Muhlin, a phycology fanatic since she was 14, found that the genetic structures of rockweed growing in three spots along the Schoodic Peninsula were the same, but the structure of rockweed at a fourth site, Bucks Cove, was different.

Muhlin, who is originally from New York, is studying for her doctorate under Susan H. Brawley, a marine biology professor at the university in Orono. From her studies, Muhlin knows that Fucus vesiculosus reproduces by releasing its gametes, or sex cells, into the water when the sea is calm and the tide is high.

Normally, she said, the gametes don’t travel far. But she wondered how far they were traveling at Schoodic Point and whether the currents there were contributing to changes in the rockweed’s genetic structure.

Last fall, she bought 500 oranges and labeled each one with a letter and a digit, her e-mail address and her phone number. With help from a local fisherman and the Friends of Schoodic, she sent her fruit into the ocean.

Then she waited to see where, or if, they would be found.

“It’s like a message in a bottle that is just waiting, and I’d love to collect the information,” she said.

The Acadia National Park Service found two the next day. Shortly after that, four were spotted to the north in Wonsqueak Harbor. One was seen floating 41/2 miles south of Schoodic, and another was retrieved three weeks later – by a lobsterman in Frenchboro.

“He found it in his lobster trap 40 fathoms deep,” she said. That’s 240 feet of water. Frenchboro is near Swans Island, about 30 nautical miles from Schoodic Point.

“It was really weird,” she said. “I know there are a lot of lobster traps out there but the odds of an orange winding up in one is pretty foreign to me.”

In all, 54 of the oranges were accounted for. That’s a return rate of about 11 percent – a figure that pleases Muhlin.

“With the volume of ocean I put the oranges into, I was amazed that I got any information back,” she said.

She doubts there’ll be any more sightings of her oranges but plans to send out another batch or two in the spring. The orange experiment is really a test run for the bigger part of her research project: deploying two “drifters,” devices with global positioning equipment that can transmit steady streams of information about their travel patterns. The data will offer more definitive information on the circulation patterns at Schoodic, and her findings could give insight about genetic changes in seaweed in other locations, she said.

Brawley, her professor, has done extensive work on how environmental factors affect the reproduction patterns of seaweed, which she prefers to call sea vegetables. Only the English language, she said, refers to them as “weeds.”

Sea vegetables and their extracts are commonly used in medicines, fertilizers, cosmetics and foods, including ice cream. They are fascinating, useful and very hardy, Brawley said.

“It is remarkable that they live in such a wave-tossed habitat. You’d think they would have a hard time reproducing,” she said, “but they don’t.”

Brawley said she is happy with her student’s research.

“It’s wonderful. It’s simple,” she said. “And it is very, very informative.”