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Review ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Environ. Sci. | doi: 10.3389/fenvs.2019.00181

LINX I and II: lessons learned and emerging questions

 Adam S. Wymore1*, Bianca M. Rodriguez-Cardona1,  Allison Herreid1 and  William H. McDowell1
  • 1University of New Hampshire, United States

Anthropogenic nitrogen (N) loading has had widespread effects on the integrity of aquatic ecosystems. Headwater streams play a central role in controlling watershed N budgets by serving as a final environmental filter for excess nutrient inputs before they are exported to downstream receiving waters. Understanding the controls on in-stream N cycling has direct implications for water quality; however, in-stream nitrogen cycling is also a source of greenhouse gas production including nitrous oxide (N2O). Here we review some lessons learned from the Lotic Intersite Nitrogen eXperiments (LINX I and II), which were a series of replicated 15N in situ manipulations across biomes and land-uses designed to provide insight into the controls and fate of inorganic nitrogen in stream ecosystems. We highlight six unique insights gained from these continental- scale projects and discuss their implications for predicting fluxes and concentrations of N2O through a series of emerging questions to motivate future work. Our objective in this review is to present both retrospective and forward-looking perspectives on the N cycle in headwater streams and river networks.

Keywords: LINX, Nitrogen, Dissolved Organic Nitrogen (DON), stream ecology, Nitrous oxide - N2O

Received: 23 May 2019; Accepted: 31 Oct 2019.

Copyright: © 2019 Wymore, Rodriguez-Cardona, Herreid and McDowell. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Adam S. Wymore, University of New Hampshire, Durham, United States, adam.wymore@unh.edu