Reporting from San Francisco, California.
When pilings were sunk at Piers 15 and 17 for the Exploratorium’s new campus, it was only a matter of days before underwater organisms began claiming the pillars as their own.
“ I call it ‘dock schmutz,’” laughs Karen Kalumuck, Senior Biologist at the Exploratorium. “It’s the sea life that attaches itself to docks, piers, pilings, and boat hulls.” These life forms—which include barnacles, mussels, sea stars, and a host of barely visible creatures—plague boat owners and colonize structures built over water. For their invasive and potentially damaging behaviors, these organisms have also been dubbed the “fouling community.”
However foul, the life forms colonizing the very foundations of the new museum also present a gleaming opportunity: to conduct authentic scientific research onsite at the new bayside campus.
So where does “dock schmutz” come from, and what can we learn from it?
“Folks are generally well acquainted with ocean life – whales, dolphins, and fish, for example,” says Kalumuck. “But the vast majority of the ocean’s animals are invertebrates that spend their early life as tiny, planktonic larva,” swept along with the currents until they are eaten or morph into their adult forms.
In their planktonic stage, explains Kalumuck, these organisms can be carried in the bilge water of cargo ships, while their adult forms may cling to the ships’ undersides. “These unintentional hitchhikers can be transported thousands of miles from their native home. And without the normal checks on their growth in their native habitat (such as predators or environmental conditions) these newly introduced species can thrive and propagate dramatically, at times threatening native species.”
Invasions by sea are nothing new for the San Francisco Bay and Delta. In fact, the Bay/Delta is one of the world’s most invaded aquatic systems, with estimates that 80% of its biomass is non-native species. Some of these species end up clinging to any available underwater surface, from a pier piling to a plastic tile submerged for research purposes.
One person’s schmutz is another’s research nirvana
Not far from the Exploratorum’s old home near the yacht harbor, Kalumuck has submerged squares of PVC in order to mimic what happens on docks and pilings.
“By checking these settling plates periodically, photographing them and identifying species,” says Kalumuck, “we can detect the beginnings of invasions, monitor the seasonal fluxes of the various organisms’ abundance, study the effects of known contaminants on the normal populations, and even indicate that some natural or human-caused environmental change is leading to a shift in the normal complement and abundance of organisms.
Kalamuk has been working with Associate Professor Dr. Sarah Cohen, who studies the population biology of marine organisms and their ecological and evolutionary genetics. Cohen and other faculty members at the Romberg Tiburon Center for Environmental Studies (San Francisco State University’s marine laboratory) are also interested in collaborating on research at the Exploratorium’s new waterfront location.
The museum’s new home will span a variety of aquatic environments. The far end of the piers is “over relatively deep water, churning and full of oxygen,” says Kalumuck, while closer to the street, the piers are over shallow, calmer water that contains less oxygen. “These are ideal venues to research a host of environmental effects on the animals and plants of the bay,” says Kalumuck.
Photos of Kalamuk’s submerged PVC tiles reveal how rapidly organisms can colonize and grow on a settling plate. At three weeks, the orange blobs on one plate are the beginnings of colonial tunicate colonies; despite their appearance tunicates aren’t plants, but animals. At 8 weeks, those blobs have developed into extensive colonies. Interestingly, these types of colonial tunicates are being studied as a model for stem cell differentiation, and for insights into the “self/non-self” recognition that these colonies exhibit – a type of primitive immune system.
The clear bubbles visible on the 8-week plate Those are solitary tunicates. One of the common species used in research labs, Ciona intestinalis, has had its genome sequenced. It’s also been a model organism to study embryonic development, and is currently giving scientists insights into heart development and the mechanism of regeneration.