FIG. 3.

Unifrac statistics and P values for 16S rRNA (lower diagonal) and chitinase (upper diagonal) communities. The level of significance is indicated by shading (white, P < 0.01; light gray, P ≥ 0.01 and < 0.05; dark gray, P ≥ 0.05). (A) Salinity; (B) latitude; (C) proximity of the coastline; (D) geographic location. Abbreviations used: freshwater, fre; estuarine, est; marine, mar; hypersaline, hyp; tropics, tro; nontropics, ntr; coastal, coa; open ocean, ooc; Caribbean Sea, car; Galapagos Island, gal; Indian Ocean, ind; North American East Coast, nor; Sargasso Sea, sar.