TY - JOUR
T1 - Controls on nitrogen transformation rates on restored floodplains along the Cosumnes River, California
AU - Hoagland, B.
AU - Schmidt, C.
AU - Russo, T. A.
AU - Adams, R.
AU - Kaye, J.
N1 - Funding Information:
Financial support for this research was provided by the National Science Foundation Graduate Research Fellowship Program [grant no. DGE1255832 ]. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Additional funding was provided by the Richard R. Parizek grant from the Department of Geosciences at The Pennsylvania State University, United States . Special thanks to Laura Liermann, Brosi Bradley, and Karol Confer at The Pennsylvania State University, as well as Richard Doucett, Katherine Pecsok-Ewert, and Emily Schick at the University of California-Davis Stable Isotope Facility for assistance with nutrient and isotope analyses. Further thanks to undergraduate students at Penn State and University of San Francisco for support with field sampling and preliminary tests, as well as graduate students at The Pennsylvania State University for thoughtful discussions prior to submission. Finally, we would like to acknowledge Sara Sweet and the Cosumnes River Preserve for providing access to and background information for the floodplain sites.
Funding Information:
Financial support for this research was provided by the National Science Foundation Graduate Research Fellowship Program [grant no. DGE1255832]. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Additional funding was provided by the Richard R. Parizek grant from the Department of Geosciences at The Pennsylvania State University, United States. Special thanks to Laura Liermann, Brosi Bradley, and Karol Confer at The Pennsylvania State University, as well as Richard Doucett, Katherine Pecsok-Ewert, and Emily Schick at the University of California-Davis Stable Isotope Facility for assistance with nutrient and isotope analyses. Further thanks to undergraduate students at Penn State and University of San Francisco for support with field sampling and preliminary tests, as well as graduate students at The Pennsylvania State University for thoughtful discussions prior to submission. Finally, we would like to acknowledge Sara Sweet and the Cosumnes River Preserve for providing access to and background information for the floodplain sites.
Publisher Copyright:
© 2018
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Levee construction results in the systematic replumbing of river systems and reduces the frequency of floodplain inundation, which impacts nutrient delivery and transformations in floodplains. Floodplain restoration via levee removal affects downstream water quality by restoring soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA). Although these metabolisms are important for the nitrogen cycle, few studies have quantified the contribution of all three pathways to nitrate retention or loss in restored floodplains. The objectives of this study were to quantify the relevance of denitrification, anammox and DNRA to nitrogen retention, characterize the hydrologic conditions most favorable to each pathway, and estimate the potential for floodplain restoration to improve nitrogen cycling in the Cosumnes River watershed. To address these goals, we simulated flood conditions in soil mesocosms collected from two floodplains where levees were breached in 1997 and 2014 along the Lower Cosumnes River in the San Joaquin Basin of California. River water enriched with K15NO3 tracer was pumped into each mesocosm at a constant rate for a period of 3 months. Samples were collected from the surface water and soil pore water for measurements of NO3 −, NO2 −, and NH4 + concentrations, and δ15N of dissolved gases (N2 and N2O). To the best of our knowledge, this study reports the highest relative contribution to N2 production due to anammox for freshwater systems (41 to 84%) to date. High anammox rates were associated with heterogeneous grain size distribution across depth and high nitrification rates. We quantify the capacity of restored floodplain soils with distinct textural and chemical characteristics to retain or release nitrogen during large and small floods in a particular water year.
AB - Levee construction results in the systematic replumbing of river systems and reduces the frequency of floodplain inundation, which impacts nutrient delivery and transformations in floodplains. Floodplain restoration via levee removal affects downstream water quality by restoring soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA). Although these metabolisms are important for the nitrogen cycle, few studies have quantified the contribution of all three pathways to nitrate retention or loss in restored floodplains. The objectives of this study were to quantify the relevance of denitrification, anammox and DNRA to nitrogen retention, characterize the hydrologic conditions most favorable to each pathway, and estimate the potential for floodplain restoration to improve nitrogen cycling in the Cosumnes River watershed. To address these goals, we simulated flood conditions in soil mesocosms collected from two floodplains where levees were breached in 1997 and 2014 along the Lower Cosumnes River in the San Joaquin Basin of California. River water enriched with K15NO3 tracer was pumped into each mesocosm at a constant rate for a period of 3 months. Samples were collected from the surface water and soil pore water for measurements of NO3 −, NO2 −, and NH4 + concentrations, and δ15N of dissolved gases (N2 and N2O). To the best of our knowledge, this study reports the highest relative contribution to N2 production due to anammox for freshwater systems (41 to 84%) to date. High anammox rates were associated with heterogeneous grain size distribution across depth and high nitrification rates. We quantify the capacity of restored floodplain soils with distinct textural and chemical characteristics to retain or release nitrogen during large and small floods in a particular water year.
UR - http://www.scopus.com/inward/record.url?scp=85052650710&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85052650710&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2018.08.379
DO - 10.1016/j.scitotenv.2018.08.379
M3 - Article
C2 - 30179826
AN - SCOPUS:85052650710
VL - 649
SP - 979
EP - 994
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
ER -