Atmospheric nitrogen and carbon transformed by cyanobacteria contribute to productivity in pastoral rangelands

Abstract:

Cyanobacterial-dominated soil crusts are found worldwide in arid and savannah landscapes where the rainfall occurs mostly in summer (Büdel 2002). Cyanobacteria are single-celled, photosynthetic, blue-green bacteria (previously referred to as blue-green algae). They provide a protective, nutrient-rich layer closely integrated into the soil surface (Belnap et al. 2003). In addition they stabilise the surface soil, augment soil moisture and take up atmospheric carbon and nitrogen via photosynthesis. Cyanobacteria and biological crusts are responsible for around 45% of the world’s biologically fixed nitrogen (Elbert et al. 2012). The broad objective of this project was to quantify the importance of nitrogen fixation by cyanobacteria to grazing ecosystems in northern Australia’s pastoral rangelands. Figure 1 indicates the conceptual basis for the research.