On a biological scale, 20 years is like the blink of an eye — if not faster.
But for San Francisco marine biology researchers, 20 years is priceless in what it can tell about the changing nature of the bay’s wildlife, especially in the face of a changing climate.
These long-term databases are rare for the region, but the Smithsonian Environmental Research Center in Tiburon has accomplished this milestone as of this year. The now 20-year-old study by the center’s Marine Invasions Lab has been tracking the presence of invasive and native species, mainly invertebrates, throughout the bay and delta, giving researchers like Andy Chang insights into how extremes such as droughts, heavy storms and warming waters can affect our backyard ecosystems.
“That gives us a good window into what might happen in these communities and possibly others in the future as we’re projected to see more frequent and severe extremes,” said Chang, who started the study and leads the lab.
Already the researchers have collected data on the shifts in marine life abundance during the recent historic drought and the abnormally warm waters sometimes referred to as “the blob” that disrupted marine ecosystems throughout the Pacific Ocean. With researchers warning of another “blob” appearing, the data could give insights into how this could impact San Francisco Bay. Last time around, the warmer waters caused tunicates — tube- or barrel-shaped invertebrates that siphon the water for food — from San Diego to appear in the bay.
However, Chang said what they observe cannot be automatically correlated to these climatic events. While the center has published studies on how wetter and drier years affect the bay’s invertebrates, more experiments must be performed to say for sure how the warming waters affect it.
“We’re scientists. We really want to nail it down,” he said.
How the data has been collected has been honed through time, Chang said, with the center in partnership with the Moss Landing Marine Laboratories now utilizing the improved DNA-sequencing technology to build genetic databases of the many invertebrates in the bay. At the same time, the researchers are also working to develop advanced methods that could allow researchers to collect this type of data by merely scooping water from the bay and sequencing it.
In Loch Lomond Marina on Friday, two of the center’s staff biologists, Katy Newcomer and Gail Ashton were pulling up one of the 14 algae-covered ropes that hung in the waters off several of the docks. Attached to each was a half-brick with a small square panel made of plastic on the underside. The plates had been sitting in the water for three months and once pulled up revealed an assortment of colorful creatures that had anchored themselves on, including tube worms, sea squirts, sea sponges and crustaceans.
This was but one of 10 marinas in the region where similar ropes where placed and will be collected for analysis. Once collected, the plates are put under a microscope and the creatures are counted back at the lab.
“As you get more data, you start being able to look at different questions and stitch together whether it’s looking by latitude or different wet years, dry years, freshwater influence,” Ashton said. “By studying native versus non-native on how that changes as well, you start to see what the non-native species are doing and if they’re a problem to local natives and if it’s worth trying to contain or eradicate or just adapting to the regular state of things.”
About 95 percent of the creatures that show up on the undersides of the plates are non-native species. Given the bay’s maritime history and the invasive creatures introduced by the many ships that have passed through, Ashton said that percentage is not surprising. But as invasive species spread further north, the data could provide insights into whether climatic changes could impact ecosystems in northern ocean waters.
The studies have been funded by the U.S. Coast Guard and the California Department of Fish and Wildlife, which uses the data as part of the department’s mandate to track invasive species.
“CDFW uses (the center’s) invasive species survey results to track the movements, distribution and spread of known invasive species populations and as a forewarning of any potential new invasive species that could be detrimental to the state’s ecosystems,” said Sharon Shiba, a senior biologist with the department. “The data also allows CDFW to analyze long-term trends.”
While the study is providing valuable insights, Chang said these types of long-term studies have their issues.
“Someone once said that there are two problems with doing a time series. One is starting one and the other is ending one. Once you’ve started it you feel like you have to keep going and once you end it then you say, “Oh no, I’ve stopped it. Now I’m not learning anything new,'” he said.
For now, Chang and his research team don’t plan on stopping.
