Decomposition in salt marsh ecosystems: phenolic dynamics during decay of litter of Spartina alterniflora

Abstract

Loss of weight and change in concentration of soluble phenolics, bound phenolics, lignins, and cell wall material were followed over 2 yr of decay in 4 types of litter of Spartina alterniflora. The pattern of weight loss showed rapid leaching during the first month, temperature- dependent decay during the first year, and little further loss during the second year. Soluble phenolics were lost throughout decomposition. Initially some soluble phenolics may become attached to cell walls; absolute increases in bound phenolics were observed in low marsh litters during the first 2 wk of decay. Lignins were lost at the slowest rate from litter material and increased in relative concentration during decay. Intraspecific differences in litter quality were small, and did not alter the pattern of decomposition among the 4 types of litter. Changes in chemical composition of litter during decay, however, were major controls of decay rates during the second and third phases of decomposition. Decreasing weight loss correlated with increasing lignin and nitrogen content. The increase in nitrogen presumably reflected synthesis of refractory nitrogen-enriched complexes. As decay con- tinued, the litter became progressively enriched in recalcitrant lignin and nitrogen-enriched com- plexes and little further loss of organic matter occurred.