[3] Alphaproteobacteria is a type of proteobacteria, and it can be divided into several different orders, including Rhodobacterales, Rhodospirillales, and Caulobacterales.
OpenStax Biology 2e defines clades as “groups of organisms that descended from a single ancestor” (Clark, Douglas, & Choi 2018).
FEMS Microbiology Ecology notes that “SAR11 was first observed in the Sargasso Sea, and subsequent findings show that the clade is widespread in both marine and freshwater environments” (Ortmann & Santos, 2016).
Ocean-dwelling organisms often rely on specific nutrient levels, such as phosphate and nitrate, for survival.
“One reason for the success of Pelagibacteraceae might be its ability to thrive under nutrient-limited conditions, like those in the open ocean, possibly due to adaptive genome streamlining” (Ortmann & Santos, 2016).