Setting sail for science

When the journal Science devoted a special issue to the renowned Tara ocean expedition a year ago, it declared: “The ocean is the largest ecosystem on Earth, and yet we know very little about it.”

It went on to say that the Paris-based nonprofit bearing that name and its scientific research schooner are changing that reality, having accomplished 10 successful research voyages since the Tara first set sail in 2003, traversing 300,000 kilometers across all the world’s oceans, the Arctic Circle, the Antarctic, the Mediterranean, and Patagonia.

On May 28, the 110-foot schooner embarked from the coast of France for its 11th voyage. On board are a half-dozen crew and a handful of scientists for the first leg of the journey, which docks in Miami at the end of June. One of the scientists, Dr. Michel Flores, is a postdoctoral fellow at the Weizmann Institute who works with Prof. Ilan Koren and Dr. Assaf Vardi. His goal: to learn about the effect of the ocean's ecosystem on the atmosphere, a key avenue of investigation in gaining a more refined understanding climate change and the environment.

This time, the Tara will be on the high seas for two-and-a-half years, mainly skirting around the islands of the South Pacific with a focus on coral reefs. The current expedition focuses on coral reefs and oceanic-atmospheric interaction - a main area of focus of Prof. Koren, a member of the Department of Earth and Planetary Sciences, and Dr. Vardi, of the Department of Plant and Environmental Sciences. Coral reefs harbor a quarter of the oceans’ biodiversity and provide a food supply to nearly a billion people, mainly in the region where the Tara will spend the bulk of its time.

It was no small matter getting a spot on the schooner: Scientists worldwide who are interested in biodiversity, climate change, the effects of pollution, and the ecology of the ocean vie for the few spots available on each expedition, and they must be fully funded and manage their own equipment. Its goal is both to advance scientific research and increase environmental awareness among the public. Tara even has a special “consultative status” in the United Nations, whereby it is spearheading an environmental advocacy plan to prevent environmental degradation and climate change. Hundreds of scientific publications have emerged from research done aboard the boat, and the project has generated resources such as an ocean microbial reference gene catalogue and a census of plankton diversity.

The duo received an invitation to join Tara following their previous studies on algae bloom demise, marine viruses, and marine aerosol formation.

Dr. Flores, who is from Mexico and did his PhD at the Max Planck Institute in Germany, completed a postdoctoral fellowship in the lab of Prof. Yinon Rudich of the Department of Earth and Planetary Sciences in January. He was considering returning to Mexico and even booked a month-long yoga vacation as he considered his future job prospects, when, in February, Prof. Koren and Dr. Vardi asked him to join the expedition. The task: to gather data on how the particles in the top layer of the ocean interact with the atmosphere.

“He was the right person at the right time,” says Prof. Koren. In the Rudich lab, Dr. Flores had investigated and measured the physical, chemical, and optical properties of aerosols, groups of solid or liquid particles suspended in air like haze, smoke, and other pollutants.

A "flagship" project

In addition to investigating how particles change when they go from water to air, he has other topics on his agenda. “One of the things we are interested in finding out is how plankton is often wiped out en masse in the ocean,” says Dr. Flores. “It seems that viruses that reach the interface between the water and the atmosphere are emitted into the air and, much like dust, are swept away in the wind and then drop onto other patches of plankton. In that way, viruses can efficiently eliminate hundreds of square miles of plankton.” Plankton provides a crucial source of food to many aquatic organisms like fish and whales.

In the last few months, Dr. Flores and Dr. Miri Trainic, a former postdoc who is now serving as a consultant on the project, built the instrumentation that will collect samples and measure the distribution of aerosols on board the Tara. In May, the duo installed the system on the schooner, and were trained in basic sailing techniques - “a lot of knot-tying,” remarks Dr. Flores, who said the only purchase he made for the journey was a pair of water shoes.

The installation involved adapting what they had created in the lab to nautical specifications and conditions on the boat, with the help of the captain and crew. One element was altogether too heavy, so it couldn’t be installed; another piece would have been destroyed by the wind, so the captain helped him attach it securely to a sail. Every day, Dr. Flores will filter and examine the water and air he collects to find microscopic particles. The materials will go back to the Koren and Vardi labs for future inspection, with Dr. Flores’ data and insights. After Dr. Flores disembarks in Miami, his research will be conducted by another scientist whom he will train during their journey across the Atlantic.

“This project is a dream come true for us,” says Prof. Koren. “The Tara expedition is a flagship project—no pun intended—in marine ecosystem research. Apart from the fact that being invited to join is a huge compliment, we will now have the much-needed micro-physical and genetic measurements to fuel our lab findings on links between marine ecosystems, aerosols, and clouds.”

“Tara has major potential for novel and far-reaching science,” says Dr. Vardi. “Having the ability to do atmospheric measurements on the ocean will double the scientific outcomes that would otherwise be done in the lab.”

Prof. Ilan Koren is supported by the Benoziyo Fund for the Advancement of Science and the Dr. Scholl Center for Water and Climate Research.

http://www.weizmann.ac.il/EPS/People/Ilan

Dr. Assaf Vardi is supported by the Benoziyo Fund for the Advancement of Science, the Angel Faivovich Foundation for Ecological Research, the Rothschild Caesarea Foundation, Dana and Yossie Hollander, Israel, Roberto and Renata Ruhman, Brazil, Selmo Nissenbaum, Brazil, the Brazil-Israel Energy Fund, Lord Sieff of Brimpton Memorial Fund, the European Research Council, the Estate of Samuel and Alwyn J. Weber, and the Germaine Hope Brennan Charitable Foundation. Dr. Vardi is the incumbent of the Edith and Nathan Goldenberg Career Development Chair.

http://www.weizmann.ac.il/plants/vardi