This element’s namesake globules are studied in the model organism Allochromatium vinosum. Bacteria that reduce compounds of this element were likely displaced by vertical burrowers (-5[1])during the Cambrian substrate revolution. (10[1]-5[1])This element is enriched at the bottom of Winogradsky columns. (10[1]-5[1])Compounds of (10[2])this element are metabolized by endosymbionts (-5[2])in Alviniconcha mollusks and the trophosomes of Riftia (10[1])pachyptila. (10[1])Deep meromictic (-5[1])lakes are rich (10[1])in this element’s namesake “green” and “purple” bacteria (10[2]-5[1])that use it (-5[1])as a (10[1])non-oxygen electron acceptor. (10[2])According to Günter Wächtershäuser, (10[1])minerals of (10[1])iron and this element (10[1])were (10[1])the platform for early (10[1])organismal (10[1]-5[1])evolution near hydrothermal (10[1])vents. (10[3])For 10 points, (10[1])name (-5[1])this element (10[1])that often emits a rotten (10[3])smell. (10[1])■END■ (10[11])