1. Institute of Soil Science and Soil Geography; University of Bayreuth; D-95440 Bayreuth Germany
2. Covance Laboratories GmbH; Kesselfeld 29 48163 Münster Germany
3. Projeto Ecologia do Gran Pantanal; Instituto de Biociências, Universidade Federal de Mato Grosso; 78090-000 Cuiabá MT Brazil
4. Max-Planck Institute of Limnology; Tropical Ecology Working Group; D-24302 Plön Germany