The Lotic Inter-site Nitrogen eXperiment (LINX) consisted of two consecutive, large inter-site studies involving 15N-tracer additions to streams to determine rates and mechanisms of nitrogen cycling at the scale of entire stream reaches. These studies, referred to as LINX I and II, involved about 20 senior PI’s at different institutions. The studies were highly successful, resulting in publications in Science and Nature as well as many other peer-reviewed journal papers. Results showed that streams are important sites for uptake and retention of nitrogen in the landscape and that both autotrophic and heterotrophic processes are important in nitrogen cycling. The work also demonstrated the value of field 15N-tracer additions for studying nitrogen cycling in streams, and protocols have been shared with a number of other research groups.
This network of experimental research sites was the product of a long history of informal collaboration among stream ecologists interested in nutrient dynamics beginning at meetings in the 1980’s. A workshop held in 1995 at Coweeta Hydrologic Laboratory, organized by Donna Morrall and Judy Meyer, resulted in the LINX I proposal to NSF which included 12 sites. The NSF IRCEB competition provided the opportunity to expand the network to 72 streams for LINX II which focused on nitrate uptake and retention. In LINX II we also added a landscape component to the network by developing a model of nitrogen transport and retention in 8 large river basins across the