In situ experimental study of reed leaf decomposition along a full salinity gradient

摘要: Abstract An experimental study on Phragmites australis leaf litter decomposition was conducted in the estuarine environment, Ria de Aveiro, Western Portugal, using leaf-bag technique, with fine- (1 mm) and coarse-mesh (5 mm) bags. The bags were placed field sites at day 0, covering a complete salinity gradient, replicates collected over time, days 3 (leaching), 7, 15, 30 60. biomass loss through leaching phase, about 20% of initial mass, independent both bag mesh size. decay pattern along gradient varied time presented strong similarities between two sizes, remaining always lower 5 mm mesh-size At 7 lowest observed head estuary, preferential distribution area P. australis. 30, higher marine diminished under direct relationship salinity, reaching value freshwater values ranging from 66% to 44% weight bags, 79% 51% 1 mm largest heterogeneity among areas positioned found close 40 (1 mm). overall results indicate that rate depends considered (k15, k30 or k60) and, for later stages (k60), also This implies use rates as functional indicator transitional waters will need take into consideration factor location stage which is determined. differences size acted mainly level absolute k not gradient. Even so, data obtained mouth closest fully indicated after leaching, P. australis decayed either very slowly, 5 mm, all,