terrestrial 261 aquatic 193 soil 173 host-associated 99 lentic 86 paludal 79 wetland 79 animal host 78 digestive tract 76 anthropogenic 75 mammalian host 73 very low temperature 59 permafrost 58 forest 53 intestine 49 ice 44 low temperature 35 sludge 33 rumen 30 marine 27 child 26 acidic 24 contaminated 24 mine 23 fresh water 22 rhizosphere 21 human host 21 plant host 21 low salinity 21 anaerobic 20 medium temperature 14 non-industrialized 14 adult 14 rural 12 high salinity 12 grassland 11 hunter-gatherer 11 tundra 11 pelagic 10 agriculture 8 lotic 6 lacustrine 6 adolescent 5 cropland 5 hot spring 4 insect host 4 spring 4 wastewater 4 built environment 3 waste 2 sediment 2 sewage 2 subsurface 2 benthic 2 fluvial 2 infant 2 elderly 1 high temperature 1 groundwater 1 industrialized 1