Like explorers, the scientists of the Weizmann Institute raised anchor, and set out to sea to seek new insights into man, and his place in the global ecosystem
On the swinging deck, at night, when the spray of the waves crashing against the side of the ship penetrates the eyes, thousands of kilometers away from the nearest shore, it is possible to understand that all the creatures on earth, from the microscopic algae to humans, we are all in the same boat. 30 scientists from five research groups, plus the same number of sailors and crew members, recently embarked on a journey following the mysterious life cycles of trillions of tiny, single-celled, plant-like creatures floating in seawater. These are the creatures called phytoplankton, on which the marine food web is based: without phytoplankton there would be no life in the oceans, and there would be no oxygen in the air.
The research ship that left Punta Delgada in the Azores turned north, and "cut" the Atlantic Ocean along its length, all the way to Reykjavik in Iceland. Among the scientists on board were Dr. Assaf Vardi, and several members of his group in the Department of Plant Sciences at the Weizmann Institute of Science. In a certain sense, the voyage, which was designed to examine the system of interrelationships between the phytoplankton and the marine environment and the atmosphere, was also a complex experiment in humans. Dr. Verdi: "Take a few dozen people from several countries, put them in a small, swaying, well-defined area in the heart of the ocean, add tension, scientific curiosity, drive for success. What did you get?".
Sometimes, for unknown reasons, the phytoplankton creatures multiply rapidly. As a result, blooms of algae are formed. covering hundreds and thousands of kilometers visible from satellites in space. But then a timed collapse takes place which results in the disappearance of the rash. The phytoplankton plays a central role in the production of oxygen in the world, absorbs considerable amounts of carbon dioxide, and its bloom is equivalent to the action of a rain forest. In doing so, it "extracts" the carbon dioxide from the air, reduces the rate of global warming, and provides a tremendous amount of food for the entire fabric of life in the sea.
Between algae and humans
Dr. Verdi and his research partners previously discovered that certain viruses are responsible for the collapse of algae blooms. It turns out that when the viruses attack the phytoplankton, they bring with them genes with which they force the marine creatures to produce enzymes in their bodies that create fat molecules (sphingolipids), very similar to those that cause various diseases in humans. Dr. Vardi: "It is interesting to see how well these production mechanisms are preserved in evolution, and exist in such a large variety of creatures."
Dr. Verdi and Dr. Freda with the daily spoils
Dr. Verdi discovered evidence of the existence of a cellular mechanism operating in phytoplankton, which in response to the accumulation of sphingolipids leads to the programmed death of cells (apoptosis). Apoptosis occurs in all types of multicellular organisms: damaged or old cells kill themselves, so that the entire organism can continue to live. But why would a single-celled organism - like the phytoplankton - kill itself? And what is the ecological significance of such suicide? How is communication between the cells carried out? What are the resistance mechanisms that allow some of them to survive? These are some of the questions that the scientists on the research ship sought to find out.
In fact, it turns out that the cells are not so enthusiastic about the idea of suicide, and they try to fight against the invading virus. This is how a real drama unfolds: an evolutionary, chemical arms race, which includes tricks, attack attempts, defense, evasion and braking, all at the molecular level, inside the cells of the phytoplankton. These processes have a decisive influence in determining bio-geo-chemical and climatic pathways. The fact that these are genes and biochemical pathways well conserved in evolution, allows scientists to learn from them about parallel processes in other biological systems. Therefore, a deep understanding of these processes and the identification of new natural substances from the marine environment may help develop ways to inhibit the penetration of viruses into various cells, including the penetration of disease-causing viruses into human cells. A better understanding of the processes of cell death may help in developing ways to purposely cause such "programmed" death, for example, in cancer cells.
A voyage to the blossom
The scientists on board the research vessel collected water samples at different depths. We tested these samples in laboratories installed on board. Dr. Vardi: "For two weeks we searched, and we did not find a rash. Then, in one sample we found it. It was an unforgettable moment, of a sense of well-being, on the one hand, and of starting research efforts that made us work 20 hours a day, on the other hand."
A unique collaboration, forged between the research group of Dr. Verdi and the research group of Prof. Ilan Koren from the Department of Environmental Sciences and Energy Research at the Weizmann Institute, led to a parallel examination of feedback processes between marine biological systems (mainly during the bloom phase) with the atmosphere and with aerosols carried in it, and influencing on the formation of clouds. This extended feedback loop affects climatic changes, and understanding it may solve several mysteries in this field.
"In fact," says Dr. Vardi, "here was the first attempt of its kind to simultaneously monitor processes occurring inside the cell, through cellular processes, and up to the behavior of cell populations spread over thousands of kilometers. The research work at a small distance from the surface of the sea, with whales accompanying us, was a unique experience. Every day we experienced a new sunset, different from the previous one. And then, when we were close to the Arctic Circle, white nights came. These are things that none of us will ever forget."
Meanwhile, in the laboratory at the Weizmann Institute of Science, thousands of samples are stored, and the scientists have already begun a series of experiments designed to discover more about the mechanisms of life, and the environmental feedback loops, and to obtain more insights regarding the "family ties" and the interrelationships between single-celled creatures and global natural cycles.
