
%0 Journal Article
%A Udy, James White 
%A Bunn, Stuart Edward 
%T <emph type="2">Short Communication</emph>: Elevated &#948;<emph type="7">15</emph>N values in aquatic plants from cleared catchments: why?
%J Marine and Freshwater Research
%D 2001/05/23
%V 52
%N 3
%P 347-351
%K nitrogen, stable isotopes, denitrification, catchment disturbance, riparian vegetation, sediment
%R https://doi.org/10.1071/MF00002
%U https://www.publish.csiro.au/paper/MF00002 
%X &#948;15N values of plants and animals are being increasingly used to identify the flow of nitrogen through aquatic ecosystems. The &#948;15N values of crops, riparian trees, emergent and submerged aquatic vegetation in streams from both cleared (agricultural) and forested (rainforest) catchments were sampled. Riparian and aquatic plants had similar &#948;15N values in forested streams,suggesting a similar source of inorganic nitrogen.In cleared catchments, however, aquatic plants had &#948;15N values 4&#8211;8&#8240; higher than adjacent riparian vegetation and aquatic plants from streams in forested catchments. The elevated &#948;15N values of aquatic vegetation in streams with cleared catchments suggest that these plants either have access to a different source of N than those in undisturbed catchments or that high rates of microbial decomposition and nutrient cycling in the cleared catchments influence the &#948;15N value of available N. This also suggests that the aquatic plants in disturbed catchments are incorporating a different source of nitrogen than the adjacent riparian vegetation. This supports the proposal that in-stream processing of N affects the &#948;15N value of available N in streams with cleared catchments. These results begin to identify potential pathways for nitrogen transport to streams and the effect that internal cycling may have on a stream&#8217;s nitrogen load. 
