Increased concentrations of atmospheric CO 2 induced a lower nitrogen concentration in sweet chestnut litter. The C:N ratio was about 35 at a 350 μl l -1 CO 2 concentration and about 70 at 700 μl 1 -1 . The CO 2 enrichment increased the proportion of hemicelluloses and cellulose and decreased the proportion of lignin. Both litters were decomposed in microcosms with animal food webs of different complexities. The chemical composition of the decomposed litter (nitrogen, water-soluble compounds, cellulose, hemicelluloses and lignin) was related to the initial composition and to the mass loss. Rates of hemicelluloses and lignin decomposition and nitrogen dynamics were the most affected by the change in litter quality due to atmospheric CO 2 enrichment. In N-rich litter, hemicelluloses were almost completely decomposed and lignin remained intact without effect of animal grazing. In N-poor litter derived from CO 2 -enriched atmosphere, increased complexity of invertebrates food webs significantly enhanced decomposition of all the chemical components. By adding different groups of animals, some limiting factors were overcome and new substrates were liberated for microbial decomposition. It was hypothesized that the decomposition process was controlled by the interaction between lignin and nitrogen.
No takes yet. Share an insight, caveat, or question.
Coûteaux et al. (1996) studied this question.