SPECIAL ISSUE
How network structure can affect nitrogen removal by streams
Abstract
- Streams and rivers can be highly reactive sites for nitrogen (N) transformation and removal. Empirical and model‐based research show how location in a stream network affects rates of N removal. Because the structure of stream networks can vary widely and N cycling in headwater streams may affect N cycling in downstream reaches, we hypothesised that network structure may affect whole stream network processing of N.
- We generated three stream networks with the same catchment area but differing shapes, based on optimal channel network theory. We applied a model of nitrate (
) transport and denitrification, and implemented model scenarios to examine how network shape affects 
removal with (1) increased 
loading from the catchment, (2) altered spatial distributions of 
loading and (3) decreased drainage density (i.e. loss of headwater streams).
- For all stream networks, the fraction of total
removed decreased with increasing 
loading from the catchment. Stream networks in narrow catchments removed a higher fraction of 
, particularly at intermediate 
loading rates. Network shape also controlled the distribution of removal in small versus large streams, with larger streams removing a higher fraction of the total 
load in narrower networks.
- The effects of network shape on
removal when the spatial distribution of 
loading was altered varied with the magnitude of 
loading. At low loads, 
was entirely removed when added to distal parts of the stream network, and about 50% removed when added near the outlet; there was no effect of network shape. At intermediate and high loads, the fraction of total 
load removed by the narrow stream network was 1.5× higher than the rectangular and square networks when 
was added to distal parts of the networks. Network shape did not have an effect when 
load occurred near the outlet, regardless of the magnitude of the 
load.
- The fraction of total
removed by the stream network was up to 5% lower when drainage density was reduced from 1.0 to 0.74 km−1, with the least change for the narrow network. Reducing the drainage density also altered the role of small relative to large streams, with the net effect of moving the location of 
removal downstream.
- Overall, effects of network shape contributed up to 20% of the variation in the fraction of
removed by stream networks. Network shape was most important at intermediate to high 
loads and when 
was loaded to distal parts of the catchment. The narrow network removed more 
across model scenarios, with elevated removal in larger streams explaining most of the difference. We suggest the shape of the catchment may modulate the degree to which large streams contribute to whole network 
removal.
Citing Literature
Number of times cited according to CrossRef: 19
- Luca Carraro, Enrico Bertuzzo, Emanuel A. Fronhofer, Reinhard Furrer, Isabelle Gounand, Andrea Rinaldo, Florian Altermatt, Generation and application of river network analogues for use in ecology and evolution, Ecology and Evolution, 10.1002/ece3.6479, 10, 14, (7537-7550), (2020).
- N. Durighetto, F. Vingiani, L. E. Bertassello, M. Camporese, G. Botter, Intraseasonal Drainage Network Dynamics in a Headwater Catchment of the Italian Alps, Water Resources Research, 10.1029/2019WR025563, 56, 4, (2020).
- Ellen Wohl, References, Rivers in the Landscape, 10.1002/9781119535409, (361-490), (2020).
- Sheng Ye, Murugesu Sivapalan, Qihua Ran, Synergistic Impacts of Rainfall Variability and Land Use Heterogeneity on Nitrate Retention in River Networks: Exacerbation or Compensation?, Water Resources Research, 10.1029/2018WR024226, 56, 8, (2020).
- Andrea Rinaldo, Marino Gatto, Ignacio Rodriguez-Iturbe, , River Networks as Ecological Corridors, 10.1017/9781108775014, (2020).
- Rebecca J. Frei, Benjamin W. Abbott, Remi Dupas, Sen Gu, Gerard Gruau, Zahra Thomas, Tamara Kolbe, Luc Aquilina, Thierry Labasque, Anniet Laverman, Ophelie Fovet, Florentina Moatar, Gilles Pinay, Predicting Nutrient Incontinence in the Anthropocene at Watershed Scales, Frontiers in Environmental Science, 10.3389/fenvs.2019.00200, 7, (2020).
- Kamila Tichá, Ondřej P. Simon, Jakub Houška, Lucie Peláková, Karel Douda, Helocrenic springs as sources of nutrient rich fine particulate organic matter in small foothill watershed, PLOS ONE, 10.1371/journal.pone.0230750, 15, 4, (e0230750), (2020).
- Seema Karki, Michael J. Stewardson, James Angus Webb, Keirnan Fowler, Giri Raj Kattel, David J. Gilvear, Does the topology of the river network influence the delivery of riverine ecosystem services?, River Research and Applications, 10.1002/rra.3720, 0, 0, (2020).
- Suning Liu, Ting Fong May Chui, Numerical modelling to evaluate the nitrogen removal rate in hyporheic zone and its implications for stream management, Hydrological Processes, 10.1002/hyp.13548, 33, 24, (3084-3097), (2019).
- Xiaojing Shao, Yu Fang, James W. Jawitz, Jiaguo Yan, Baoshan Cui, River network connectivity and fish diversity, Science of The Total Environment, 10.1016/j.scitotenv.2019.06.340, 689, (21-30), (2019).
- Brandon C. Goeller, Lee F. Burbery, Catherine M. Febria, Kathryn E. Collins, Nikki J. Burrows, Kevin S. Simon, Jon S. Harding, Angus R. McIntosh, Capacity for bioreactors and riparian rehabilitation to enhance nitrate attenuation in agricultural streams, Ecological Engineering, 10.1016/j.ecoleng.2019.03.014, 134, (65-77), (2019).
- Rémi Dupas, Benjamin W. Abbott, Camille Minaudo, Ophélie Fovet, Distribution of Landscape Units Within Catchments Influences Nutrient Export Dynamics, Frontiers in Environmental Science, 10.3389/fenvs.2019.00043, 7, (2019).
- Zahra Thomas, Pauline Rousseau-Gueutin, Benjamin W. Abbott, Tamara Kolbe, Hugo Le Lay, Jean Marçais, François Rouault, Christophe Petton, Pascal Pichelin, Geneviève Le Hennaff, Hervé Squividant, Thierry Labasque, Jean-Raynald de Dreuzy, Luc Aquilina, Jacques Baudry, Gilles Pinay, Long-term ecological observatories needed to understand ecohydrological systems in the Anthropocene: a catchment-scale case study in Brittany, France, Regional Environmental Change, 10.1007/s10113-018-1444-1, (2019).
- Adam S. Ward, Steven M. Wondzell, Noah M. Schmadel, Skuyler Herzog, Jay P. Zarnetske, Viktor Baranov, Phillip J. Blaen, Nicolai Brekenfeld, Rosalie Chu, Romain Derelle, Jennifer Drummond, Jan H. Fleckenstein, Vanessa Garayburu-Caruso, Emily Graham, David Hannah, Ciaran J. Harman, Jase Hixson, Julia L. A. Knapp, Stefan Krause, Marie J. Kurz, Jörg Lewandowski, Angang Li, Eugènia Martí, Melinda Miller, Alexander M. Milner, Kerry Neil, Luisa Orsini, Aaron I. Packman, Stephen Plont, Lupita Renteria, Kevin Roche, Todd Royer, Catalina Segura, James Stegen, Jason Toyoda, Jacqueline Wells, Nathan I. Wisnoski, Spatial and temporal variation in river corridor exchange across a 5th-order mountain stream network, Hydrology and Earth System Sciences, 10.5194/hess-23-5199-2019, 23, 12, (5199-5225), (2019).
- John R. Gardner, Martin W. Doyle, Sediment–Water Surface Area Along Rivers: Water Column Versus Benthic, Ecosystems, 10.1007/s10021-018-0236-2, (2018).
- W. M. Wollheim, S. Bernal, D. A. Burns, J. A. Czuba, C. T. Driscoll, A. T. Hansen, R. T. Hensley, J. D. Hosen, S. Inamdar, S. S. Kaushal, L. E. Koenig, Y. H. Lu, A. Marzadri, P. A. Raymond, D. Scott, R. J. Stewart, P. G. Vidon, E. Wohl, River network saturation concept: factors influencing the balance of biogeochemical supply and demand of river networks, Biogeochemistry, 10.1007/s10533-018-0488-0, (2018).
- Jonathan D. Tonkin, Jani Heino, Florian Altermatt, Metacommunities in river networks: The importance of network structure and connectivity on patterns and processes, Freshwater Biology, 10.1111/fwb.13045, 63, 1, (1-5), (2017).
- Jonathan D. Tonkin, Florian Altermatt, Debra S. Finn, Jani Heino, Julian D. Olden, Steffen U. Pauls, David. A. Lytle, The role of dispersal in river network metacommunities: Patterns, processes, and pathways, Freshwater Biology, 10.1111/fwb.13037, 63, 1, (141-163), (2017).
- Enrico Bertuzzo, Ashley M. Helton, Robert O. Hall,, Tom J. Battin, Scaling of dissolved organic carbon removal in river networks, Advances in Water Resources, 10.1016/j.advwatres.2017.10.009, 110, (136-146), (2017).
