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The effect of hydrostatic pressure on the decomposition of inundated terrestrial plant detritus of different quality in simulated reservoir formation
Author(s) -
Fonseca André Luiz dos S.,
Bianchini Irineu,
Pimenta Cristiane M.M.,
Soares Cássio B.P.,
Mangiavacchi Norberto
Publication year - 2016
Publication title -
lakes and reservoirs: research and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.296
H-Index - 39
eISSN - 1440-1770
pISSN - 1320-5331
DOI - 10.1111/lre.12139
Subject(s) - detritus , decomposition , hydrostatic pressure , eutrophication , environmental chemistry , carbon fibers , organic matter , total organic carbon , dissolved organic carbon , chemistry , environmental science , nutrient , ecology , materials science , biology , organic chemistry , physics , composite number , composite material , thermodynamics
The formation of reservoirs usually incorporates the inundation of terrestrial vegetation in the basin. The decomposition of organic matter from the flooded vegetation may have several implications for reservoir functioning, including eutrophication and dissolved oxygen depletion. The hydrostatic pressure increases with depth in a reservoir, and its influence on the decomposition process has not previously been evaluated. This study was undertaken to evaluate the decomposition of terrestrial plant detritus of different qualities (leaves and branches) under different hydrostatic pressure conditions. Detritus were placed separately in glass bottles in the laboratory and incubated in tight stainless steel pressure vessels, simulating three different depths (surface, 30 and 100 m). The masses (mg) of particulate organic carbon ( POC ), dissolved organic carbon ( DOC ) and inorganic carbon ( IC ) were determined for the 4 months of the detritus decomposition simulated in this study. The mass values were transformed in percentages of the initial detritus carbon. The results of temporal variations of the compounds studied were fitted to a first‐order biphasic decay model. The hydrostatic pressure exhibited no significant effects on litter decomposition. On the other hand, the detritus chemical composition (i.e. the presence of labile and refractory compounds) was the determining factor for the decomposition curve shape and for the differences observed between the leaves and branches. The greatest POC loss from leaves, and resulting larger DOC mass, indicated the leaves were more labile than the branches. The results also indicated the branches are the main detritus remaining in a reservoir over time.