Microorganisms
In biology, a test is the hard shell of some spherical marine animals and protists, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae.
Recent review conceptualizes how soil fauna can alter the stability of carbon in soil via processes such as tranformation/translocation of organic matter or grazing on microorganisms. Better understanding of the quantitative contribution of these processes could aid in managing soils as carbon sinks