Table 1.

Breakdown of node and edge attributes across extreme environmental networks.

Environment	Prevalence threshold in number of samples	Number of selected nodes [fraction from initial data]	Number of connected nodes [number of Unknown at genus]	Number of edges in network [K-K, K-U, U-U at genus]	Ratio of number edges vs. number nodes
Hot Springs	104	291 [4.4E − 4]	290 [133]	552 [167, 230, 155]	1.9
Hypersaline	85	193 [3.7E − 4]	191 [118]	516 [89, 125, 302]	2.7
Deep Sea	75	102 [1.6E − 4]	97 [51]	194 [59, 65, 70]	1.9
Polar	113	279 [9.6E − 4]	274 [171]	797 [112, 244, 441]	2.9

K-K: the edge connects two Known nodes at the genus level.

K-U: the edge connects one Known and one Unknown node at the genus level.

U-U: the edge connects two Unknown nodes at the genus level.