California's Coast Feeling The Heat - Part 1

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"An hour past dawn, the central California sun burns through the morning haze. The waters of Monterey Bay are rising after a 6:21 a.m. low tide. Rafe Sagarin, curly hair tousled by the unruly wind, gingerly crosses the exposed granite tidepools like a teenager negotiating a cluttered bedroom floor. This intertidal tangle is a library to Sagarin, who knows precisely where reefs of tube snails set their mucous nets, striped sunburst anemones open their tentacles to the tides, and barnaclelike limpets farm algae for their supper. Sagarin can also tell you that this tidal community is not what you would have seen in the 1930s. In fact, it looks a lot more like southern California. Sagarin knows because he has counted every critter along a line between two brass bolts in the rocks, and compared them to a similar count done 60 years earlier. That change is so big, so obvious, and so important that an article he and colleague Sarah Gilman wrote about it was published in the prestigious scientific journal Science while they were still undergraduates. That research, which used their counts combined with temperature and other measurements going back threequarters of a century, found that the most likely cause for the massive changes in the kinds of species there was warming temperature. It is exactly what one would expect to happen as the world's climate changes.

In 1993, Sagarin and Gilman were juniors at Stanford University, among two-dozen students who took a term away from the main campus to study marine biology at the university's Hopkins Marine Station on the Monterey Peninsula. Upon arrival, the undergraduates were treated to presentations about areas of research at the station, and projects they would have the opportunity to participate in.

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"Sometime in the early 1980s, the numbers began to pick up," Baxter says. "By the mid to late 1980s they were very abundant." The tube snails completely covered the rocks behind the Monterey Marina's breakwater, just as they had in southern California 40 years before. The new abundance of serpulorbus was not the only change Baxter had noticed in his decades at the station. Earlier researchers had documented the seaweed cover on the rocks; by the late 1980s much of that was completely gone or had shifted substantially, taking over what had been habitat for barnacles and other critters. Baxter also saw that one predatory snail in the whelk family, ocinebra, seemed to have increased; it was another species he knew from his southern California days.

While casual observations make interesting stories, they are not the same as rigorous science. They are, Baxter says, "anecdotes that you can't do much with." To turn his eyeballed observations into respectable research would take a concerted effort to actually measure any changes, compare them with other kinds of data about the physical environment, and then try to determine the factors that might have pushed the change forward. Baxter had a couple of starting points. He had found a small handful of older studies documenting all the plants and animals along specific sections of the rocky tide pools just downhill from the Hopkins station's lawn. The station had been collecting data including air and water temperature for decades; some statistics even went back as far as 1917. And the intertidal area between Hopkins and the open waters of Monterey Bay was California's first marine reserve, protected from fishing and other extraction since the 1930s, so the species found there would be essentially unaffected by human tastes. "For about five years it had become very obvious to me that some very dramatic changes had taken place and were continuing to take place in the intertidal off Hopkins," Baxter says. That was the source of his challenge to the students who came for the undergraduate research course each year. What had changed? How much had it changed? What factors were associated with those changes? And, did the changes in snails and the seaweed simply represent a shift in a few individual species, or was something broader and more significant happening?

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They started with a study done in the 1930s by a Stanford Ph.D. candidate named Willis Hewatt, who had pounded heavy-duty brass bolts into the slow-eroding granite and meticulously counted every anemone, whelk, snail, sea star, barnacle, limpet, and other critter along the 108 yards in between. The area where Hewatt did his work is a little triangle of pools made up of huge granite rock and ending at a bouldered point, streaked with white from the seabirds it hosts. The outer rocks provide some shelter from the more turbulent -- and cold -- waters of Monterey Bay, about 100 yards from shore. It is a perfect spot for looking at the creatures that thrive in the intertidal zone, the band along the rocks that is submerged at high tide, exposed at low tide, and wet by spray and waves in between. In the same way zones of life change as you climb a mountain -- or as you drive north or south along a coastline -- marine life varies by how often it is exposed to air and scalding sun, or how deeply it is covered by water."

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http://www.tidepool.org/original_content.cfm?articleid=138190