I think Matt Cooper takes a too narrow definition of “metabolism” as a rather dull process of material exchange that occurs within a cell. From my reading, as a non-specialist, Marx was using the term in a broader sense as the material and ultimately purposeless means by which complex order emerges from disordered matter.
‘Karl Marx’s Ecosocialism: Capital, Nature, and the Unfinished Critique of Political Economy’ (2017)
This guide is designed to help understand the central ideas in Kohei Saito, Karl Marx’s Ecosocialism: Capital, Nature, and the Unfinished Critique of Political Economy. New York: Monthly Review, (2017)