naa a22 4500 510737900 CHVBK 20180411083017.0 cr unu---uuuuu 180411e20130901xx s 000 0 eng 10.1007/s11284-012-0939-3 doi (NATIONALLICENCE)springer-10.1007/s11284-012-0939-3 Ohte Nobuhito Department of Forest Science, Graduate School of Agricultural and Life Sciences, University of Tokyo, 113-8657, Tokyo, Japan aut Tracing sources and pathways of dissolved nitrate in forest and river ecosystems using high-resolution isotopic techniques: a review [Elektronische Daten] [Nobuhito Ohte] Nitrogen inputs into stream and river ecosystems, and the factors influencing those inputs, are important for various ecological and environmental concerns. Reliable information on where and how nitrogen compounds flow into aquatic ecosystems is indispensable to understanding the nutrient status of these ecosystems. Such information should include the biogeochemical mechanisms and hydrological controls of nutrient leaching into rivers from terrestrial systems such as forests, agricultural fields, and urbanized areas. Advancements in stable isotopomer measurements over the past two decades have expanded the variety of target substances and the precision with which they can be investigated. The high-throughput microbial denitrifier method allows for simultaneous measurement of nitrogen and oxygen isotope ratios and can provide high-resolution spatiotemporal information on both nitrate sources and biogeochemical processes. Although advanced techniques of stable isotope analysis have been used extensively to detect sources and estimate the relative contributions of multi-source systems in various rivers, there are still new horizons in investigating nitrogen transformations. For example, stable isotopes of oxygen (18O and 17O) occurring in nitrate due to atmospheric deposition can be used as natural tracers for evaluating internal nitrogen cycling; these isotopes are distinct from the oxygen within microbially generated nitrate in soils and water bodies. Another future challenge is improved use of nitrous oxide isotopomers in evaluating the relative contributions of nitrification and denitrification. Such analysis could provide insight into the nitrogen transformation that occurs under redox conditions at the boundary between terrestrial and aquatic systems, where nitrification and denitrification often occur simultaneously in soil and aquatic environments. The Ecological Society of Japan, 2012 Nitrate isotope nationallicence Denitrifier method nationallicence Anthropogenic nitrogen source nationallicence Nitrogen transformation nationallicence Hydrological process nationallicence Ecological Research Springer Japan 28/5(2013-09-01), 749-757 0912-3814 28:5<749 2013 28 11284 https://doi.org/10.1007/s11284-012-0939-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11284-012-0939-3 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Ohte Nobuhito Department of Forest Science, Graduate School of Agricultural and Life Sciences, University of Tokyo, 113-8657, Tokyo, Japan aut NATIONALLICENCE 773 0- Ecological Research Springer Japan 28/5(2013-09-01), 749-757 0912-3814 28:5<749 2013 28 11284 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer