( ( ( ( ( A ( primary ( greenhouse gas ) ) ) , ) ( carbon dioxide ) ) , ) ( ( ( is intimately ) ( ( linked ( with ( ecosystem processes ) ) ) ( through ( the ( ecosystem ( carbon cycle ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (JJ primary) (NN greenhouse) (NN gas)) (, ,) (NP (NN carbon) (NN dioxide)) (, ,)) (VP (VBZ is) (ADVP (RB intimately)) (VP (VBN linked) (PP (IN with) (NP (NN ecosystem) (NNS processes))) (PP (IN through) (NP (DT the) (NN ecosystem) (NN carbon) (NN cycle))))) (. .)))
A primary greenhouse gas, carbon dioxide, is intimately linked with ecosystem processes through the ecosystem 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.