21 September 2012
Our stopover in London continues. This afternoon the team of Taranautes was expected at the Maritime Museum for a screening of the first in the series of 4 documentaries made during the Tara Oceans Expedition: “The Secret World”.
Chris Bowler, researcher at the ENS (Ecole Normale Supérieure) in Paris, specializing in diatoms, spent the day answering questions from the public. I decided to ask him some questions too.
Laëtitia Maltese: Chris, what are diatoms?
Chris Bowler: Diatoms are phytoplankton. Because of their relatively “large” size and weight, they play a significant role in the functioning of the oceans’ carbon pump, and therefore in climate balance – first through photosynthesis, and then when they die by “transporting” the carbon trapped in their cells to the ocean depths. They are also a vital link in the food chain since they’re the favorite food of copepods, the dominant species of zooplankton.
LM: How long did you spend on board and what was your job?
CB: I spent a total of 6 weeks, on 3 separate legs: Dubrovnik–Athens, Monte Puerto–Valparaiso, Bermuda–Azores. This last leg was particularly interesting because we were far away from the continental influence, and at the junction of waters from very different zones. Stations were defined in advance, based on satellite maps. As chief scientist, I had to decide the most appropriate zone to study.
In the oceans, waters are sometimes “separated”, vertically and horizontally. They are characterized by (among other things) different temperatures, salinity and density, and they don’t mix. Our goal is to compare the plankton of these different water masses. This analysis of biodiversity allows us to understand the relationship between the physico-chemical parameters and plankton. We can then make the connection between the natural phenomena of circulation and climate change.
LM: What are the first results of the expedition?
CB: Before Tara Oceans, there was little data on a planetary scale. Thanks to the expedition, we’re finding that diatoms are abundant in various oceans of the world, and there’s a great diversity of species. The first DNA analyses allow us to quantify: We thought there were 5,000 species of diatoms, but with the data from Tara, it looks like there are around 30,000 species! The results should be published in 2013.
Before the Tara expedition we were studying diatoms from cultures grown in our laboratory over several years. Now we can check a number of hypotheses using the wild diatoms collected in the samples of Tara Oceans. The samples we collected are so numerous (27,000) that 6 months after the expedition, taking into account all the laboratories, we’ve analyzed barely 1%. I’m convinced that the results of the expedition will serve as a reference in years to come, by the sheer mass of information provided.
LM: How did Tara change your life as a researcher?
CB: I have a better understanding of the issues of my research at the global level, a much more comprehensive vision, an openness to the world.
LM: In what way do you think Tara missions are essential today?
CB: With today’s advances, cutting-edge technologies can be easily miniaturized for use aboard ships of Tara’s size. So, at a lower cost, studies can be carried out on a large scale, accelerating collection of data and therefore scientific advances. The difficulty in oceanographic research is logistics, and the real problem is that we realize our ignorance of ocean life! Many doors are opening with this unique and exciting project.
After this exchange with Chris, I think of the story he told at the Maritime Museum about the epic explorers like Columbus and Vasco de Gama. And I go away reassured by the idea that mankind still has so much to discover! As for Chris, he will participate in the event “Science Museum Lates”, September 26th at 19.30, on the theme of climate change.