Longitudinal trends in river functioning: Patterns of nutrient and carbon processing in three Australian rivers

Hadwen, WL; Fellows, CS; Westhorpe, DP; Rees, GN; Mitrovic, SM; Taylor, B; Baldwin, DS; Silvester, E; Croome, R

Longitudinal trends in river functioning: Patterns of nutrient and carbon processing in three Australian rivers

Hadwen, WL Fellows, CS Westhorpe, DP Rees, GN Mitrovic, SM

Taylor, B Baldwin, DS Silvester, E Croome, R

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Publication Type:: Journal Article
Citation:: River Research and Applications, 2010, 26 (9), pp. 1129 - 1152
Issue Date:: 2010-11-01

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Field	Value	Language
dc.contributor.author	Hadwen, WL	en_US
dc.contributor.author	Fellows, CS	en_US
dc.contributor.author	Westhorpe, DP	en_US
dc.contributor.author	Rees, GN	en_US
dc.contributor.author	Mitrovic, SM https://orcid.org/0000-0002-5528-2215	en_US
dc.contributor.author	Taylor, B	en_US
dc.contributor.author	Baldwin, DS	en_US
dc.contributor.author	Silvester, E	en_US
dc.contributor.author	Croome, R	en_US
dc.date.issued	2010-11-01	en_US
dc.identifier.citation	River Research and Applications, 2010, 26 (9), pp. 1129 - 1152	en_US
dc.identifier.issn	1535-1459	en_US
dc.identifier.uri	http://hdl.handle.net/10453/14748
dc.description.abstract	Understanding longitudinal trends in the processing of carbon in rivers represents a much conceptualised, but infrequently tested, issue in aquatic ecology. In this study, we conducted concurrent longitudinal examinations of three very different rivers in eastern Australia to determine whether general principles in river functioning exist across broad geographic and hydrologic scales. Specifically, we examined trends in ambient basic water chemistry, nutrient concentrations, dissolved organic carbon (DOC), extracellular enzymes and food web structure and functioning and conducted bioassays to examine the degree to which DOC and nutrients limit heterotrophic bacterial respiration. These parameters revealed striking similarities across all sites. For metazoan communities, stable isotope analysis showed that algal carbon was the dominant basal resource utilised by consumers in all three rivers, suggesting that in-stream primary producers strongly underpin trophic pathways regardless of the position within a catchment or catchment condition. Analyses of extracellular enzymes revealed that microbial communities are actively utilising DOC at all sites. In fact, heterotrophic microbial respiration was strongly limited by DOC at all sites, with nutrient additions resulting in only relatively minor increases in respiration. Ultimately, this study demonstrates that DOC and algal carbon are critically important drivers of ecosystem processes in Australian riverine ecosystems. Furthermore, across all of our sites and rivers, ambient nutrient concentrations did not influence carbon processing. The consistent longitudinal trends in river function identified in this study provide useful insights for catchment managers and modellers with respect to identifiying key principles that underpin ecosystem functioning in Australian rivers. Copyright © 2009 John Wiley & Sons, Ltd. Copyright © 2009 John Wiley & Sons, Ltd.	en_US
dc.relation.ispartof	River Research and Applications	en_US
dc.relation.isbasedon	10.1002/rra.1321	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Longitudinal trends in river functioning: Patterns of nutrient and carbon processing in three Australian rivers	en_US
dc.type	Journal Article
utslib.citation.volume	9	en_US
utslib.citation.volume	26	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0502 Environmental Science and Management	en_US
utslib.for	0907 Environmental Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	9	en_US
pubs.publication-status	Published	en_US
pubs.volume	26	en_US

Abstract:

Understanding longitudinal trends in the processing of carbon in rivers represents a much conceptualised, but infrequently tested, issue in aquatic ecology. In this study, we conducted concurrent longitudinal examinations of three very different rivers in eastern Australia to determine whether general principles in river functioning exist across broad geographic and hydrologic scales. Specifically, we examined trends in ambient basic water chemistry, nutrient concentrations, dissolved organic carbon (DOC), extracellular enzymes and food web structure and functioning and conducted bioassays to examine the degree to which DOC and nutrients limit heterotrophic bacterial respiration. These parameters revealed striking similarities across all sites. For metazoan communities, stable isotope analysis showed that algal carbon was the dominant basal resource utilised by consumers in all three rivers, suggesting that in-stream primary producers strongly underpin trophic pathways regardless of the position within a catchment or catchment condition. Analyses of extracellular enzymes revealed that microbial communities are actively utilising DOC at all sites. In fact, heterotrophic microbial respiration was strongly limited by DOC at all sites, with nutrient additions resulting in only relatively minor increases in respiration. Ultimately, this study demonstrates that DOC and algal carbon are critically important drivers of ecosystem processes in Australian riverine ecosystems. Furthermore, across all of our sites and rivers, ambient nutrient concentrations did not influence carbon processing. The consistent longitudinal trends in river function identified in this study provide useful insights for catchment managers and modellers with respect to identifiying key principles that underpin ecosystem functioning in Australian rivers. Copyright © 2009 John Wiley & Sons, Ltd. Copyright © 2009 John Wiley & Sons, Ltd.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/14748