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Impact of Hurricane Irene and Tropical Storm Lee on riparian zone hydrology and biogeochemistry
Author(s) -
Vidon Philippe,
Marchese Sara,
Rook Stephen
Publication year - 2016
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.11045
Subject(s) - hydrology (agriculture) , environmental science , biogeochemistry , surface runoff , biogeochemical cycle , riparian zone , storm , oceanography , geology , environmental chemistry , ecology , chemistry , geotechnical engineering , habitat , biology
Although riparian zones are well known to reduce nitrogen (N) and phosphorus (P) runoff to streams, they also have the potential to affect greenhouse gas (CO 2 , N 2 O, and CH 4 ) fluxes to the atmosphere. Following large storms, soil biogeochemical conditions often become more reduced, especially in oxbow depressions and side channels, which can lead to hot moments of greenhouse gas production. Here, we investigate the impact of the remnants of Hurricane Irene and Tropical Storm Lee on riparian zone hydrology (water table: WT), and biogeochemistry (oxidation‐reduction potential [ORP], dissolved oxygen [DO], NO 3 − , PO 4 3 − , CO 2 , N 2 O, CH 4 ). Results indicate that large storms have the potential to reset WT levels for weeks to months. Overbank flooding at our site following Irene and Lee led to the infiltration of well‐oxygenated water at depth (higher DO and ORP) while promoting the development of anoxic conditions within soil aggregates near the soil surface (increased N 2 O and CH 4 fluxes). A short‐term increase in CO 2 emission was observed following Irene at our site where aerobic respiration was water‐limited. Over a 2‐year period, an oxbow depression exhibited higher WT, higher N 2 O and CH 4 fluxes (hot moment), higher CO 2 fluxes (seasonal), and lower NO 3 − concentrations (seasonal) than the rest of the riparian zone. However, neither Irene, nor Lee, nor the oxbow depression significantly impacted PO 4 3 − . Dissolved organic carbon, ORP, and DO data illustrate the time‐lag (>20 years) between the creation of an oxbow depression and the development of reducing conditions despite clear differences in riparian zone and oxbow WT dynamics.