Associate Professor Alex Leshansky and Professor John Dabiri

2012 Transformative Science Grant Awarded to Professor Alex Leshansky and Professor John Dabiri

This setup allows scientists to view movement of small water creatures through water.  It consists of an acrylic cylinder, water containers (that serve to deliver the layers of fluid), a spotlight (not pictured), a mirror and an iris. The spotlight generates a column of blue light that is reflected through the mirror.  The column’s diameter can be changed with the iris.

 

The BSF awarded its 2012 Transformative Science Grant to Alex Leshansky, Associate Professor of the Wolfson Department of Chemical Engineering at Technion, and John Dabiri, Professor in the Graduate Aeronautical Laboratories and the Option of Bioengineering at Caltech and a 2010 MacArthur Fellow for their research entitled, “Drift-mediated biogenic mixing in the ocean.”  The oceans are dominated by small species whose ‘drift-induced’ biogenic mixing mechanism may, if confirmed, have an enormous impact on our understanding of ocean circulation, transport of nutrients and dissolved matter and climate change. Leshansky and Dabiri plan to examine the provocative idea that small swimming organisms, such as krill and copepods, help to stir the ocean. This notion that strong mixing induced by small migratory organisms in the ocean can compete with that driven by winds, tides and currents is somewhat counter-intuitive.  Recent experimental findings suggest that small aquatic swimmers, such as jellyfish, krill and copepods, can generate fluid displacement, or ‘drift,’ on a scale considerably exceeding their own size and large enough for efficient mixing to occur in a typical marine environment.

Professor Leshansky and Professor Dabiri began discussing their mutual research in how organisms continue to transport in the ocean at an American Physical Society annual meeting.  Prof. Leshansky praised Prof. Dabiri’s surprising findings on drift-mediated mixing published in Nature in 2009.   “Later on,” said Prof. Leshansky, “my own paper on the subject was published presenting a theoretical model for biogenic mixing by organisms as they swim through the ocean and discussing its contribution towards global oceanic transport.  Knowing of our mutual interest, I suggested that we submit a collaborative BSF Transformative Science grant on the subject.”

BSF grants are considered highly prestigious in the United States scientific community albeit smaller than National Science Foundation or National Institutes of Health grants. For the Israeli researcher, the BSF is one of the two major granting agencies, along side the Israel Science Foundation.  Shared Prof. Leshansky, “I received a BSF grant right after arriving at Technion together with Professor John Brady from Caltech.  The support proved to be very fruitful, and since then I submit applications to the BSF on a regular basis.  The BSF is indeed unique. It is the only agency that I know supporting U.S.-Israeli collaboration in fundamental sciences. For me and many others,” continued Leshansky,  “the BSF is the leader in joint research with the United States collaborator.”

As the professors work together, one in Israel at the Technion and the other in the United States at Caltech, they combine both laboratory experiments and theoretical modeling.  On the experimental side, the efficiency of mixing small light-sensitive organisms through a density-stratified water column will be quantified using advanced experimental techniques. On theoretical side, they will develop a consistent hydrodynamic model of drift-induced mixing by using the powerful mathematical system of bio-locomotion.

Their project is driven by ideas that deviate considerably from the mainstream science and have potential to drastically change our understanding of important scientific concepts and lead to a paradigm shift in environmental science.  Stressing the BSF’s importance, Prof. Leshansky reports, “I am building a strong team on the Israeli side that will tackle the intriguing theoretical problems and collaborate efficiently with the American side already involved in the experimentation on the subject.  The BSF grant has a significant impact on my work and research directions. Winning the Transformative Science grant has shifted my research priorities.”

These two pictures depict mixing of water by brine shrimp (Artemia Salina). The shrimp swim in a box containing layers of different density.  The middle layer (2) is marked with fluorescent dye.  You can clearly see the Artemia mixing the fluid as it travels from one layer to another.