A classroom at the edge of the Sea of Cortez

One of the educational highlights of my life occurred during my senior year (late 1998) as an undergraduate at UC Santa Cruz. I enrolled in a wonderful quarter-long intensive course in marine ecology. The plan was to spend the first 5 weeks in Santa Cruz and the last five in the upper Gulf of California in northern Mexico. By this point in my education, I had been able to take a number of excellent courses in marine sciences – invertebrate zoology, marine botany – and I was ready to apply to graduate school. I didn’t know initially if I’d get into the class (an interview was required), but I had taken scientific diving the previous academic year so that I would be able to dive as part of the experience if I made it into the course.

I was reminded of this trip this part fall as I attended the annual Western Society of Naturalists meeting in Seaside, California. Per tradition, a naturalist of the year award is given at the meeting to a prominent ecologist or naturalist. This past year, it was given to Peter Raimondi and his long-time colleague at Santa Cruz, Mark Carr. Pete was one of the instructors for our class to the Gulf. In fact, our group of 20 or so eager undergraduates was the first cohort of the marine ecology field course that has since become an important part of the marine ecology curriculum on the Santa Cruz campus. From Pete’s remarks at the meeting, I learned that the inspiration for the course came from an earlier Santa Cruz course taught by the naturalist Ken Norris. In fact, Dr. Norris’s work led to the creation of the UC Natural Reserve System, a collection of research reserves throughout the state that sample the diversity of California’s ecosystems.

A unique aspect of the marine ecology field course – and a logistically challenging one to be sure – was the opportunity to dive in the subtropical waters of the Gulf of California. I logged about 9 dives during our stay in Mexico. The warmer diving in northern Mexico was a welcome change from the cold waters around Monterey where I had previously done all of my diving.



CEDO in Puerto Penasco, Sonora, MX.

Once we arrived in Mexico, we were required to participate in group research projects to get our feet wet in marine research, so to speak. My main project was conducted with a fellow student Derek Smith. Together we investigated whether shading impacted the abundance of zooxanthellae in a colonial anthozoan, Palythoa ignota. Zooxanthellae are symbiotic dinoflagellates that provide food for coral polyps. The idea was hatched at our first stop in Mexico, the Intercultural Center for the Study of Deserts and Oceans (CEDO) in Puerto Peñasco. If memory serves me correctly, we had had a hard time deciding on a project to conduct, but got a burst of inspiration (or some helpful prodding from course instructors) shortly before we were scheduled to leave for our next site farther south. With time running short, we had to quickly assemble some field gear and get out to the rocky intertidal to deploy the experiment.

The plan for the experiment was simple: we would construct cages with mesh coverings and cement these to the rocky substrate over colonies of Palythoa to reduce the amount of ambient light reaching the anthozoans. Palythoa isn’t a high intertidal species, so we needed a low tide to access the site and it happened that our window of opportunity occurred in the dark. With lamps and some assistance from other students, we went about the messy business of removing organisms from the rocks in order to secure our cages to the benthos. The experiment was set and we’d be back to Puerto Peñasco towards the end of our stay in Mexico to collect the data.


Left: A small colony of Palythoa polyps. Right: Our experimental manipulation
 of light level at the subtidal site. The cage in the middle is the classic cage control.

About a week later we found ourselves at Guyamas along the central coast of the Sea of Cortez.  Here, Palythoa only grew subtidally. We selected a second site to conduct a repeat experiment that was accessible only after a decent boat ride to a place removed from the city. We again placed our cages into colonies of Palythoa. Though our sites were admittedly very shallow, at least one of us needed to dive to make the clearings on the substrate, cement the cages to the rock, and later sample the animal tissue to count zooxanthellae cells.

We stayed in Guyamas for a week to ten days, and sampled the cnidarian tissues before leaving to count the density of zooxanthellae. Derek committed the needed manpower, doing all of the microscope work. As it turns out, we were fortunate to have conducted this repeat experiment. Once we returned to Puerto Peñasco for the second time, regrettably many of our cages in the intertidal had been lost. There were not enough surviving cages to really test our shading effects on cell counts.

My experiences in the outdoors classroom of Mexico were notable in several ways. To begin with, my work with Palythoa was the first manipulative experiment I had ever conducted. Manipulative experiments are the bread and butter of experimental ecology, the most conclusive way to infer causal mechanisms about ecological processes. During the course I was also exposed to new habitats and new organisms in northern Mexico. I saw my first mangroves, for instance. I also had a chance to conduct science in teams. The course was a wonderful opportunity to make some great friends. (Oh, and did I mention that real Mexican tortillas are amazing!?)

The value of field research for biologists can’t be overstated. To get it early in one’s career and in large doses is a blessing. While science inevitably involves background research in libraries, time pouring over data and statistics, and digestion of theory (and I enjoy each of these in respectable quantities), none of these other activities can compensate for observation and experimentation in the field. Natural history is not just a quaint discipline of the 1800s, it is the foundation of meaningful ecology. It is integral to the generation of hypotheses and the interpretation of the relevance of experimental results. It also goes beyond the role of science as a human endeavor– it connects us to our immeasurably rich natural heritage.


An urchin - one of my better underwater shots in Mexico.

Sunset at Punta Ingacio at Bahia Kino along the Gulf coast.