aquatic 33 terrestrial 26 alkaline 25 fresh water 25 anthropogenic 20 sludge 19 sediment 14 subsurface 14 benthic 14 groundwater 14 lentic 13 low salinity 12 anaerobic 11 high salinity 9 cropland 8 agriculture 8 very high salinity 7 lacustrine 6 medium temperature 6 high temperature 2 contaminated 2 host-associated 1 animal host 1 digestive tract 1 acidic 1 hot spring 1 intestine 1 lotic 1 low temperature 1 mine 1 spring 1