| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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| in pursuit of science On Mountain Lake The sun is out, the wind is low, and on this May day, the coming summer promises to deliver more than goosebumps to fogbound San Francisco. In the glare of the afternoon light, three lanky bodies stand silhouetted against the sparkling green wavelets of the Presidio’s Mountain Lake. They lean slightly forward in a delicate balancing act, moving only their eyes to rake the brush-covered banks and olive-drab waters. “Time’s up!” says Joe Kinyon, environmental educator for the California Academy of Sciences. “The two minutes are over. What’ve you found?” Six legs shift back together, three torsos straighten up, three heads turn shoreward, unconsciously mimicking the egrets that hunt these waters. These teenagers are counting turtles through spotting scopes. “Two soft-shelled, and eleven red-eared sliders,” reports Senayit Araya, a senior at Galileo Academy of Science and Technology. Her classmates, Carlos Berviz and Carlos Angel, agree—rafts of the reptiles are paddling through the murky water or basking on half-submerged branches along the shore adjacent to Highway 1. Kinyon and the students are here as part of the Mountain Lake Project of the California Academy of Sciences. For the last two years, Kinyon and Field Studies Manager Jack Laws have been teaching local students how to keep tabs on the health of one of the city’s few remaining natural freshwater lakes. As the first comprehensive biodiversity study ever conducted at the tiny wetland tucked into the corner of Park Presidio and Lake Street, the project will document the ailing lake’s responses to a five-year, $500,000 habitat improvement project slated to begin this summer. But the Academy educators have a second, equally important goal. By coaxing city kids to get their hands wet conducting their own research at the lake, Laws and Kinyon hope to inspire a new generation to appreciate the excitement and discovery of science. Student volunteers can be found doing research at the lake just about every day of the week during the school year. Some toss fine mesh nets resembling miniature parachutes into the water to sieve out zooplankton, then count and identify their transparent captives with the help of microscopes back at school. Others pour lake water the color of tea into tall beakers to determine clarity, and dunk meters to measure the water’s chemistry. And like the turtle teams, the birders scan sections of the lake and shoreline to estimate habitat usage and species diversity. Each group researches its own piece of the project, but being out at the edge of this living lake smelling, hearing, and looking means everyone learns much more. As the turtle surveyors move along the culvert road en route to another area of the lake, Kinyon notices a dog animatedly sniffing a rounded object on the side of the road. To everyone’s surprise, it’s a live turtle. “It must’ve taken it a year to walk up here,” Berviz says. “It may have come up here to lay eggs,” Kinyon says. After warning the students that reptiles carry diseases such as salmonella, Kinyon picks up the 10-inch-long red-eared slider to give the researchers their closest look yet at their study subject. “See how it shrinks its head most of the way into its shoulders? And how long its claws are?” The students nod wide-eyed, as the turtle tucks its limbs even further into its shell. Its green-and-yellow striped flesh looks both soft and vulnerable. Kinyon slips the turtle into his satchel for temporary safekeeping. The Academy’s Mountain Lake Program was born when community and parks groups, distressed after the death of a beloved swan by lead poisoning and mass fish kills during hot weather, banded together to hash out plans for a habitat improvement project at the lake. Seeing a chance to mesh science education with a real habitat restoration project, the Academy’s education department took on the task of monitoring conditions at the lake before, during, and after the project. Laws, who started the program, recruited Kinyon. The two of them researched, designed, and built the entire training program from the ground up. They had to do everything from assembling plankton identification pages tailored to the lake’s microscopic inhabitants to testing water quality meters for their ability to withstand hard use and abuse. Their next task was to find student volunteers. As the two traveled from school to school to gain the confidence of teachers, a combination of enthusiasm and dogged persistence earned them converts. “You can’t waste the kids’ valuable time,” Kinyon says. “This may be the one experience that turns them on to science, to show them that it is a possibility as a career, that it is important.” Once they had students, the pair had to teach each one the methodical techniques of science research. “It was like starting a whole new Academy from scratch, but having to teach the researchers everything from computer skills to water-testing techniques to species identification,” Kinyon says. This spring, the students showed just how much they had learned along the way. Each group analyzed its data, drew a conclusion, and created a poster or slide presentation of their work. And on April 25, just like professional scientists, the students presented its results to one another at the Mountain Lake Symposium held at the California Academy of Sciences. The young researchers’ observations are turning a much-needed spotlight on the cosmopolitan ecology known as urban parkland. “Every ecosystem has now been impacted by humans in some way. As human populations continue to grow, this situation will become increasingly the norm—there is no pristine out there,” Laws says. Yet a glance at Mountain Lake’s history shows just how resilient Mother Nature can be. Urban encroachment and debris from construction of the MacArthur Tunnel shrank the lake’s surface area by more than 40 percent, and its depth has been reduced to 9 feet—20 feet shallower than just 200 years ago. Lead from vehicle emissions, dating back to before leaded gasoline was phased out in 1976, continues to contaminate the bottom mud. Fertilizer runoff from the adjacent golf course chokes the lake with algae. And legions of former pets, including the carp, the bullfrogs, an occasional alligator, and both species of turtles have elbowed out native species. Yet some wild natives endure and could reclaim their former territory if given the right kind of human help. “If we want to preserve biodiversity, we must look at the impact humans have on the environment. This makes Mountain Lake a great teaching laboratory,” Laws says. The students’ research has already improved plans to enhance the lake’s habitat. Surveys by City College of San Francisco students showed that the eucalyptus, once thought to provide good habitat for birds, attracted fewer numbers and species of birds than the other trees along the lake. The data helped convince planners to fell the eucalyptus and replant with native willow, cypress, and wax myrtle. Spending so much time alongside the ailing lake has also made the fifth-period team better appreciate the effects people have on the environment. “They used to tell us in elementary school about recycling and stuff, but we didn’t think about it. Now that we’ve researched the lake, and see how things affect the environment, we realize we have to protect it,” Araya says. The lake and the environment have even become topics of dinner conversation at the students’ homes. “Our parents think what we are doing is good. They realize that we’ve got to protect the health of our environment, ‘for our future and our son’s future,’” Berviz says. Back at the lake, a slide down a steep bank to the water’s edge reveals another surprise. Alongside six-foot-tall bulrushes, Berviz and Angel find the scarlet remains of what looks like a half-eaten mini-lobster in the mud. “That’s a crawdad,” Kinyon says. “A raccoon probably caught it.” “Look—there’s another one,” Berviz says. “And another!” Though the group has tromped the lakeshore once a week for the past seven months, even splashing through the water in hip waders, this is the first sighting of the freshwater crustacean. “These studies only get better the more time you spend with them—just like a friend,” Kinyon observes. With the ease of long practice, Kinyon arches a hand over the water and makes a grab. A moment later, a live crayfish wriggles helplessly in his hand. He flips the animal over to show off its multitude of waving appendages. Then the science facts flow out naturally in Kinyon’s low-key, conversational style. “Under the tail, here,” Kinyon points, “it has smaller feet called swimmerets. If it’s a female, it will keep her eggs there.” “It’s only got one claw, the left one,” Berviz says. “When they get into fights, they escape predators and sometimes lose claws,” Kinyon says. The students marvel at the animal, but shrink from its sharp feet when asked if they want to touch it. A short hike through the dark eucalyptus grove, and the group enters the green-tinged light of the arroyo willows. Here, among red-winged blackbirds trilling in the branches, Kinyon takes the turtle from his satchel and places it in the water. To the astonished cheers of the students, it shoots off like a rocket and disappears into the depths of its beleaguered home. Kathleen Wong is Senior Editor of California Wild. |
Summer 2001
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