Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Nitrate loss from a restored floodplain in the Lower Cosumnes River, California

Nitrate loss from a restored floodplain in the Lower Cosumnes River, California Floodplain restoration has been advocated as a means to restore several ecological services associated with floodplains: water quality improvement, fish rearing habitat, wildlife habitat, flood control, and groundwater recharge. A history of agricultural encroachment on the lower Cosumnes River has resulted in extensive channelization and levee construction. In fall 1998, an experimental floodplain was established by breaching a levee in order to restore the connection between the main channel and its historic floodplain. In this study, we examined how effective this newly restored floodplain was at processing nitrate (NO 3 − ) before reentering the main channel downstream. Two methods were used to examine nitrate loss. In December 2001, we determined denitrification potentials of the floodplain soils before seasonal flooding inundated the floodplain. Next, we conducted a series of field soil column (mesocosm) experiments from March to June 2002 to study NO 3 − -N loss from the overlying water in both sandy and clayey soils and at three levels of NO 3 − -N (ambient, +1 mg N l−1, +5 mg N l−1). In addition, we examined NO 3 − -N loss from mesocosms with water only to determine if loss was related primarily to soil or water column processes. Denitrification potentials were highly variable ranging from 1.6 to 769 ng N2O–N cm−3 h−1. In addition, the denitrification potential was highly correlated with the amount of bioavailable carbon indicating that carbon was a limiting factor for denitrification. Nitrate-N loss rates from mesocosms ranged from 2.9 to 21.0 μg N l−1 h−1 over all treatments and all 3 months examined. Significant loss of NO 3 − -N (60–93%) from the water only treatment only occurred in June when warmer temperatures and solar radiation most likely increased NO 3 − -N uptake by phytoplankton. When scaled up, potential NO 3 − -N loss from the restored floodplain represented 0.6–4.4% of the annual N load from the Lower Cosumnes River during a typical wet year and ~24% during a dry year. During dry water years, the effectiveness of the floodplain for reducing nitrate is limited by the amount of N supplied to the floodplain. Results from this study suggest that restored floodplains can be an effective NO 3 − sink. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Hydrobiologia Springer Journals

Nitrate loss from a restored floodplain in the Lower Cosumnes River, California

Sheibley, Richard; Ahearn, Dylan; Dahlgren, Randy
Hydrobiologia , Volume 571 (1) – Jul 29, 2006
Download PDF
12 pages

Loading next page...
 
/lp/springer-journals/nitrate-loss-from-a-restored-floodplain-in-the-lower-cosumnes-river-0dYY8y460K

References (52)

Publisher
Springer Journals
Copyright
Copyright © 2006 by Springer
Subject
Life Sciences; Freshwater & Marine Ecology; Ecology; Zoology
ISSN
0018-8158
eISSN
1573-5117
DOI
10.1007/s10750-006-0249-2
Publisher site
See Article on Publisher Site

Abstract

Floodplain restoration has been advocated as a means to restore several ecological services associated with floodplains: water quality improvement, fish rearing habitat, wildlife habitat, flood control, and groundwater recharge. A history of agricultural encroachment on the lower Cosumnes River has resulted in extensive channelization and levee construction. In fall 1998, an experimental floodplain was established by breaching a levee in order to restore the connection between the main channel and its historic floodplain. In this study, we examined how effective this newly restored floodplain was at processing nitrate (NO 3 − ) before reentering the main channel downstream. Two methods were used to examine nitrate loss. In December 2001, we determined denitrification potentials of the floodplain soils before seasonal flooding inundated the floodplain. Next, we conducted a series of field soil column (mesocosm) experiments from March to June 2002 to study NO 3 − -N loss from the overlying water in both sandy and clayey soils and at three levels of NO 3 − -N (ambient, +1 mg N l−1, +5 mg N l−1). In addition, we examined NO 3 − -N loss from mesocosms with water only to determine if loss was related primarily to soil or water column processes. Denitrification potentials were highly variable ranging from 1.6 to 769 ng N2O–N cm−3 h−1. In addition, the denitrification potential was highly correlated with the amount of bioavailable carbon indicating that carbon was a limiting factor for denitrification. Nitrate-N loss rates from mesocosms ranged from 2.9 to 21.0 μg N l−1 h−1 over all treatments and all 3 months examined. Significant loss of NO 3 − -N (60–93%) from the water only treatment only occurred in June when warmer temperatures and solar radiation most likely increased NO 3 − -N uptake by phytoplankton. When scaled up, potential NO 3 − -N loss from the restored floodplain represented 0.6–4.4% of the annual N load from the Lower Cosumnes River during a typical wet year and ~24% during a dry year. During dry water years, the effectiveness of the floodplain for reducing nitrate is limited by the amount of N supplied to the floodplain. Results from this study suggest that restored floodplains can be an effective NO 3 − sink.

Journal

Hydrobiologia – Springer Journals

Published: Jul 29, 2006

There are no references for this article.