I wrote a couple more scientist profiles for the scientific journal Nature. Neuroscientist Leopoldo Petreanu published a paper describing a new technique for mapping neuronal connections in the brain (story by subscription). And Luke Harmon did a laboratory experiment modeling how different fish species can influence pond ecosystems (story by subscription). Both stories carry an element of surprise and seredipity, as is so often the case in science. In Petreanu's case, early experiments were useless because all the neurons were lighting up -- until he figured out a way to isolate only functional connections between neurons. In Harmon's case, early experiments clearly showed the effects of different fishes -- but a pattern of effects only emerged when researchers measured the physical properties of the water, such as light penetration and dissolved organic matter.