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USU undergrad finds no evidence of invasive organism spreading from Willard Bay By
Anna Brunson -- D. -- It stands for the organism's name, but a "D" in 12-point type also shows the space that one could fit in. Daphnia lumholtzi is a species of zooplankton, or small free-floating animals. It poses no direct danger to people or fish, but its appearance in Willard Bay is causing waves among the biology community. Quinn Cannon, a senior majoring in fisheries biology at Utah State University, spent his fall semester looking for Daphnia lumholtzi in lakes and reservoirs throughout Utah and southern Idaho. After more than 55 hours of sampling and research, Cannon was certain he would find it. He found nothing. But, that's a good thing. Daphnia are tiny, spineless cladocerans, often called water fleas, which live near the surface of bodies of water. Because many fish feed off Daphnia, they are a major part of the food web in lakes, rivers and ponds. Even a small imbalance of one organism can affect every other living thing in the ecosystem. "We don't know what the ultimate effect will be in Willard Bay, but we do know there have already been some changes there," says Cannon. Each lake and pond has its own native species of Daphnia, and Daphnia lumholtzi isn't native to any Utah lakes. In fact, it originates from Australia, Africa and India. But in the past decade, it has shown up in 56 lakes and reservoirs in the United States, says the United States Geological Survey. Chris Luecke, USU department head of the College of Natural Resources, discovered Daphnia lumholtzi in Willard Bay in 1999, which was the first sighting in the western states. "Actually, one of my classes found it in the fall of 1999," says Luecke. "The students had water samples from Willard Bay and a key [book with pictures] of North American zooplankton. There was one organism that they couldn't identify, but I was convinced they just weren't trying hard enough. But, finally, I looked at it and 'Oh my Lord!'" Cannon and Luecke believe it's only a matter of time before Daphnia lumholtzi spreads to other lakes and reservoirs in Utah. Cannon, who assisted Luecke's Willard Bay research in 1999, decided to apply for an Undergraduate Research & Creative Opportunities (URCO) grant to study the possible spread of Daphnia lumholtzi to neighboring lakes. "Anyone can apply for a grant," says Cannon. "I sent in a proposal with my plan and how it will benefit me and society, a letter of recommendation, a budget, and an application. They gave me $500, and the department matched it." Luecke has helped Quinn with the resources and study design for the project. Experts speculate that Daphnia lumholtzi was introduced when sport fish were transplanted from different lakes, and the Daphnia was in the water the fish were in. First, perch were transported from Lake Victoria in Africa to a reservoir in Texas. Some years later, wiper fish were transported from an infested lake in North Carolina to Willard Bay. "The fall of Communism was great for politics, but terrible for biology," says Luecke, in reference to the global trading of sport fish. If Daphnia lumholtzi spreads to other Utah lakes, however, Cannon believes it will be by boats or birds. "Water from Willard Bay may remain in the bilge system of boats, and then, when boaters take them to other lakes and reservoirs, they take the water, and the Daphnia too," says Cannon. "Resting eggs [eggs that may stay dormant for decades] may also stick to birds' feathers or be in bird feces, and then be transported to other places." To determine how Daphnia lumholtzi is spread, Cannon selected six bodies of water with frequent boating activity and six bodies of water with very few boaters. If the organism is spread by boaters, then it would likely be only at the six boating lakes. If it is spread by birds, the presence of Daphnia lumholtzi may depend on the lakes' proximity to Willard Bay. Cannon drove to the 12 locations, paddled a canoe out on the water, dangled over the edge of the boat with a zooplankton net (like a pool filter with a small bucket on the end), strained the water, and used a spray bottle to squirt the remaining silt into a zooplankton cup (like a hospital urine cup). "The other department boats were broken, so I had to just use a canoe," says Cannon. "It was very difficult. The wind also gave me logistical problems, because, to get an accurate sample, I want the net to go straight to the bottom of the lake and not get dragged." Cannon took three samples at each location and then examined each sample under a microscope. "They're really easy to pick out," he says. That's because Daphnia lumholtzi, unlike other Daphnia, has a unique shape. Most Daphnia are round, but Daphnia lumholtzi has sharp spines protruding from its head and tail that are each as long as its body length. Although millimeter-long spines are of little consequence to large fish, juvenile fish smaller than 3 inches may have a difficult time digesting them. Then Daphnia lumholtzi may be able to out-compete native Daphnia, and they may consume too much phosphorous and nitrogen nutrients, making it harder for the native Daphnia to survive. If native Daphnia die out, the fish may have a harder time as well. Still, research in Willard Bay has not shown any adverse effects. "It's not all that different from native Daphnia," says Luecke, "But we still want to control it because it's kind of like a weed, and we're still not sure what other factors it could affect." Reason for worry about Daphnia lumholtzi are caused by other exotic organisms introduced in the United States, such as the zebra mussel, which has been causing major problems in the Midwest. Also, red shiner, an exotic zooplankton, was introduced Zions National Park, and soon people found out it carried Asiatic tapeworm. After all his research, Cannon discovered no Daphnia lumholtzi in any of the locations he sampled. "There was no spread detected," says Cannon. "It may still be there, but it just hasn't established itself yet. There also may be resting eggs at the locations." On the other hand, Luecke says Quinn doesn't realize he sampled enough water that he can say for certain that Daphnia lumholtzi isn't in any of those lakes. "The state has actually been doing a good job of preventing spread, "says Luecke, "For example, whirling disease is a big problem in Utah, so the state has asked people to be aware of its possible spread by sticking on weighters and boats. Reducing the spread of whirling disease will also help reduce the spread of Daphnia lumholtzi.". "Of course it was a good thing [that I didn't find any Daphnia lumhotzi], but I was really expecting to find some," says Cannon. "It would have been more exciting if I did. The study will still help the monitoring process, and maybe even help find ways to stop the spread of lumholtzi. Hopefully, it will benefit society later on." Cannon will write a paper on his study an present a poster at the USU Student Showcase and at the American Society of Limnology and Oceanography (ASLO) Conference in Victoria, British Columbia. "It was a good experience for me. I didn't really have any 'A-ha!' moments, but it was all-around rewarding. It was a good opportunity to be involved in research, and it will prepare me for graduate school and my future career." Cannon, who is hoping to begin his masters degree program at Colorado State or Oregon State University, is done with Daphnia. "It was a good stepping stone, and I'm interested to see how it spreads, but I'm not planning on pursuing any more research on lumholtzi." It may not be a continuing interest for Cannon, "But it certainly will for me," says Luecke. The Division of Wildlife Resources also wants to know about any spread, so it will continue funding the research. "And, of course, we are still interested in (Daphnia lumholtzi) from the science perspective. There are few opportunities we get to observe an organism from the beginning of its introduction into an environment," says Luecke. Cannon's project is the beginning of a monitoring program that will be advised by Luecke. Every two to three years, another student will sample those 12 lakes and reservoirs hoping-and not hoping-to find Daphnia lumholtzi.
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