Sampling locations in the Northern Territory, Australia. Map of the northern end of the Northern Territory, Australia, showing the river basins and locations of sampling sites. Shaded regions indicate the river basins included in this study. Numbers within shaded regions correspond to the basin names in the first column of Table 1, while numbers in circles correspond to the locations listed in the second column. The star indicates the location of Darwin, the largest city in this area. Image adapted from the Australian Bureau of Meteorology (http://www.bom.gov.au).