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Nutrient Retention Associated with Phenological Features in Sparganium Erectum Stands in a Lowland Stream
Author(s) -
Asaeda T.,
Rashid M. H.
Publication year - 2015
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.2733
Subject(s) - macrophyte , sediment , phosphorus , nutrient , organic matter , environmental science , nitrogen , total organic carbon , phenology , hydrology (agriculture) , ecology , environmental chemistry , chemistry , biology , geology , paleontology , geotechnical engineering , organic chemistry
Abstract In a previous study, we found that Sparganium erectum , an emergent macrophyte, accumulates sediment inside the stand because of its phenological features. Because this species usually grows in a nutrient‐rich environment, we hypothesize that a high trophic level is maintained in the accumulated sediment. To test this hypothesis, we intensively studied flow velocity, nutrient budget and nutrient flux in and outside of S. erectum stands along the Moto‐Arakawa River, Saitama, Japan and found that the growth stages of S. erectum substantially affected the flow conditions inside the stand. The growth stages of this plant also controlled the depositional rate of sediment and organic particles. After the collapse of each cohort, a substantial amount of organic matter accumulated on the stand bed. Because the accumulated organic matter mineralized very fast, the concentration of total carbon (TC), total nitrogen (TN) and total phosphorus (TP) increased substantially after the collapse of the shoots. While the concentrations of TC, TN and TP within the stand's sediment varied seasonally, the concentrations of these elements were always higher inside than outside of the stand. More than five times the amount of carbon and twice the amount of nitrogen and phosphorus were physically retained in the stand for 1 year compared with the amounts assimilated by the plants. The ratio of carbon to nitrogen in the stand's sediment also remained constant throughout the growing period. Conversely, the nitrogen to phosphorus ratio of the accumulated sediment was much lower than that of other plant tissues. The main flow contains suspended organic solids that constantly supply the stand and partially occupy the channel where they eventually settle. Copyright © 2014 John Wiley & Sons, Ltd.