In a post on the Wired science blog Brandom Keim writes about efforts of biologists to monitor habitats with arrays of microphones spread through the ecosystem in order to analyze the balance of species and their relationships. Bioacousticians already study the sound of individual animals but research in a more holistic manner is rarely conducted. I had to think of the hydrophone array of the Alfred-Wegener-Institut that is transmitting live from the ocean below the antarctic ice and can be listened to here. I could imagine this would be nice for other ecosystems as well, but that is pie in the sky, I suppose.