Tuesday, June 16, 2015

Looking below the surface

Looking below the surface is something I urge my students to do all the time. As a scientist I understand well the need to look beyond what appears at the surface in order to understand how things work. From a philosophical and critical thinking standpoint this makes sense too. Seeing beyond appearances makes us understand the world better. 

So it occurred to me as I was studying small irrigation tanks deep in the Sri Lankan countryside: if we want to understand how these complex systems work we have to look beneath the surface. During the wet season the tanks are shimmering lakes of beautiful, abundant, and mysterious water. Full of nature and promise, they sort of hypnotize us into thinking we understand them just by looking. 

But the thousands of tank ecosystems that cover a considerable portion of Sri Lanka with fresh water pose any number of problems. First, how did people form them and how have they lasted so long? Even though many of them fell into disrepair over the centuries cultivators in their wisdom managed to bring the tanks back into operation. So, what is it about tank design that allowed tanks either to persist or lend themselves to vital repairs? What makes them sustainable?

The second question goes a little deeper. We know that tanks have several more or less distinct regions that collect silt, salt, and alkaline water. We know as well that tanks have a complicated chemistry, hydrology, and ecology. As large bodies of water, we know that tanks experience varying pressure at various depths, that water flows through and out of them, and that certain aspects of their infrastructure need greater or lesser reinforcement depending on the position and purpose of a given part of the tank. 

Yet if we only look at the watery surface we have barely a clue as to the dynamics behind these phenomena. Having spent a couple of weeks studying tanks in a fair amount of detail, my objective now is to study the dry interior of some tanks, to walk or work along their dry bottoms, to detect curves, colors, and contours. Subtle distinctions in these features may lead us to a better understanding of the evolution, function, and longevity of these amazing man-made ecosystems. 

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