Photo exhibit explores local sea life
on September 24, 2011
How much life passes through a single one-foot by one-foot spot in the San Francisco Bay every day? Photographer David Liittschwager set out to answer that question over the course of 14 days this past spring. From a sailboat anchored in the shadow of the Golden Gate Bridge, he and an assistant used a 12-inch diameter plankton net to collect the microscopic plants and animals that were carried by the bay’s currents through a metal square-foot cube submerged in the upper water column.
What they found astounded them. In a single sample that consisted of the plants and animals collected in the plankton net over a two-minute troll at two knots they found an estimated 550,000 individual organisms. They calculated this number after counting the organisms in a smaller subsample of just ten drops of water. They found everything from juvenile jellyfish, crabs and shrimp to small crustaceans called copepods, and diatoms, which are algae encased in silica—tiny plants that live in glass houses.
Cataloguing every individual organism in the entire cube would have been impossible, but they estimated that up to 2.6 billion creatures would pass through the cube in a 24-hour period.
Liittschwager’s exhibit, “One Cubic Foot: miniature surveys in biodiversity,” opened last week at the David Brower Center in Berkeley. The walls of its gallery were filled with images of the creatures he found under the Golden Gate Bridge blown up to hundreds of times their real size. Enormous photographs of crab larvae and juvenile jellyfish, iridescent and alien-like against stark white backgrounds, hung beside hundreds of golden, glowing diatoms as seen in a magnified drop of water. One had to constantly be reminded that these plants and animals live right next door and not on some far-distant planet.
The largest portion of the exhibit is Liittschwager’s new work from underneath the Golden Gate Bridge, but there are also pieces from earlier surveys he did in other habitats such as a coral reef in French Polynesia and leaf litter in Central Park, as part of a project that was begun for National Geographic Magazine.
Liittschwager, who lives in San Francisco, called the bay “one of the most radically altered habitats in the world,” because of how human activity has drastically changed its landscape, hydrology and ecology. For example, he pointed out that hydraulic mining in the Sierras during the time of the Gold Rush deposited large amounts of sediment into the Bay via the San Joaquin and Sacramento Rivers, and the effects are still being felt today in reduced water quality and disruptions to the spawning and migration habits of a number of aquatic species.
Extensive filling has been done for residential and commercial building, including an extension to the San Francisco Airport runway fields, and in the South Bay estuaries have been converted to industrial salt ponds for the production of table salt—both of these activities have reduced important habitat areas for wildlife, he said. Non-native species such as crabs and clams have been introduced into the bay either in the ballast water of ocean-going ships, on the ships themselves, or intentional introductions by humans, he said.
“So many of these human activities taken together have a huge impact,” he said. Littschwager said he was pleasantly surprised to find such an abundance of creatures during his photography project. “It is inspiring to see that there’s a lot of life still there,” he said.“There are a lot of reasons to still work to fix the bay.”
Amy Tobin, the executive director of the Brower Center, who commissioned this work, said that after seeing Littschwager’s photographs, “I can now comprehend the currents of the bay in a different way,” referring to the sheer amount of life he captured that is not apparent to the naked eye. She said she hopes that the exhibit of super-sized photographs, which will be on display through January, will similarly surprise and inspire all those who get a chance to see them. “Looking at these creatures, you want to know how they live in the world,” she said.
The “One Cubic Foot” exhibit will be open and free to the public from September 15, 2011 through January 27, 2012, in the Hazel Wolf Gallery at the David Brower Center, 2150 Allston Way, Berkeley.
Corrections: A version of this article that was posted on Saturday incorrectly described the process by which Mr. Liittschwager collected and calculated the number of specimens he found during his survey in the San Francisco Bay. He calculated 550,000 organisms in one sample taken from a 12-inch diameter plankton net over the course of two minutes, not in ten drops of water as previously stated. On the boat he had one assistant not a team of scientists.
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