( ( Of ( particular relevance ) ) ( ( is ( ( the role ) ( of ( ( terrestrial ecosystems ) ( in ( the ( global ( carbon cycle ) ) ) ) ) ) ) ) . ) )
(ROOT (SINV (PP (IN Of) (NP (JJ particular) (NN relevance))) (VP (VBZ is)) (NP (NP (DT the) (NN role)) (PP (IN of) (NP (NP (JJ terrestrial) (NNS ecosystems)) (PP (IN in) (NP (DT the) (JJ global) (NN carbon) (NN cycle)))))) (. .)))
Of particular relevance is the role of terrestrial ecosystems in the global carbon cycle.
(ROOT (S (NP (NP (DT A) (JJ primary) (NN role)) (PP (IN of) (NP (NP (NNS decomposers)) (PP (IN in) (NP (DT an) (NN ecosystem)))))) (VP (VBZ is) (SBAR (IN that) (S (NP (PRP they)) (VP (VBZ cycle) (NP (NN matter)) (PP (IN by) (S (VP (VBG returning) (NP (NN carbon) (CC and) (JJ other) (NN matter)) (PP (TO to) (NP (DT the) (NN ecosystem)))))))))) (. .)))
A primary role of decomposers in an ecosystem is that they cycle matter by returning carbon and other matter to the ecosystem.