Stable isotopes of nitrate reveal different nitrogen processing mechanisms in streams across a land use gradient during wet and dry periods
| Autor: | Fiona Y. Warry, Paul Reich, Jesse Pottage, Perran L. M. Cook, Keryn L. Roberts, Wei Wen Wong, Michael R. Grace |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Hydrology Denitrification 010504 meteorology & atmospheric sciences lcsh:QE1-996.5 lcsh:Life STREAMS 010501 environmental sciences 01 natural sciences Manure lcsh:Geology chemistry.chemical_compound lcsh:QH501-531 Nitrate chemistry lcsh:QH540-549.5 Dominance (ecology) Environmental science Organic matter Ecosystem lcsh:Ecology Surface water Ecology Evolution Behavior and Systematics 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Biogeosciences, Vol 15, Pp 3953-3965 (2018) |
| ISSN: | 1726-4189 1726-4170 |
| Popis: | Understanding the relationship between land use and the dynamics of nitrate (NO3-) is the key to constrain sources of NO3- export in order to aid effective management of waterways. In this study, isotopic compositions of NO3- (δ15N–NO3- and δ18O–NO3-) were used to elucidate the effects of land use (agriculture in particular) and rainfall on the major sources and sinks of NO3- within the Western Port catchment, Victoria, Australia. This study is one of the very few studies carried out in temperate regions with highly stochastic rainfall patterns, enabling a more comprehensive understanding of the applications of NO3- isotopes in catchment ecosystems with different climatic conditions. Longitudinal samples were collected from five streams with different agriculture land use intensities on five occasions – three during dry periods and two during wet periods. At the catchment scale, we observed significant positive relationships between NO3- concentrations (p δ15N–NO3- (p NO3- in our study sites. Artificial fertiliser was the dominant source of NO3- during the wet periods. In addition to artificial fertiliser, nitrified organic matter in sediment was also an apparent source of NO3- to the surface water during the dry periods. Denitrification was prevalent during the wet periods, while uptake of NO3- by plants or algae was only observed during the dry periods in two streams. The outcome of this study suggests that effective reduction of NO3- load to the streams can only be achieved by prioritising management strategies based on different rainfall conditions. |
| Databáze: | OpenAIRE |
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