Q. Do you treat a species as singular or plural? For example, would you say “Sporosarcina pasteurii cause” or “causes”?
A. Strictly speaking, a binomial species name, which refers collectively to a group of organisms, is grammatically singular. So you’d write (for example) that Sporosarcina pasteurii causes the phenomenon of microbially induced calcium carbonate precipitation.
Or, using a more well-known example, Musca domestica poses a threat to both humans and animals. This convention overlaps with the way common names are often referred to. For example, you might say that the housefly, Musca domestica, poses a threat to people and animals. But what you really mean is that houseflies (plural) pose this threat.
For a fascinating take on these conventions, see Kevin de Queiroz, “Plural versus Singular Common Names for Amphibian and Reptile Species,” Herpetological Review 42, no. 3 (2011): 339–42.
See also Scientific Style and Format, 8th ed. (Council of Science Editors and University of Chicago Press, 2014), 22.2.1.