caa a22 4500 605517576 CHVBK 20210128100720.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s10533-015-0118-z doi (NATIONALLICENCE)springer-10.1007/s10533-015-0118-z The varying role of water column nutrient uptake along river continua in contrasting landscapes [Elektronische Daten] [Alexander Reisinger, Jennifer Tank, Emma Rosi-Marshall, Robert Hall Jr., Michelle Baker] Nutrient transformation processes such as assimilation, dissimilatory transformation, and sorption to sediments are prevalent in benthic zones of headwater streams, but may also occur in the water column. The river continuum concept (RCC) predicts that water column processes become increasingly important with increasing stream size. We predicted that water column nutrient uptake increases with stream size, mirroring carbon/energy dynamics predicted by the RCC. We measured water column uptake of ammonium ( $${\text{NH}}_{4}^{ + }$$ NH 4 + ), nitrate ( $${\text{NO}}_{3}^{ - }$$ NO 3 - ), and soluble reactive phosphorus (SRP) in 1st through 5th order stream and river reaches (discharge: 50-68,000Ls−1) in three watersheds ranging from <1 to >70% developed lands. We found that water column volumetric uptake (U vol ) of $${\text{NH}}_{4}^{ + }$$ NH 4 + , $${\text{NO}}_{3}^{ - }$$ NO 3 - , and SRP did not significantly differ among watersheds and we did not find any longitudinal patterns for U vol . Uptake velocity (v f ) of $${\text{NH}}_{4}^{ + }$$ NH 4 + increased with stream size, whereas $${\text{NO}}_{3}^{ - }$$ NO 3 - and SRP v f did not differ with stream size or among watersheds. Both U vol and v f were related to water column metabolism and material suspended in the water column, but specific relationships differed among solutes and uptake metrics. Median water column v f across 15 sites was 4, 9, and 19% of median whole-stream $${\text{NH}}_{4}^{ + }$$ NH 4 + , $${\text{NO}}_{3}^{ - }$$ NO 3 - , and SRP v f based upon a previous meta-analysis. Thus, although we could not demonstrate a generalized longitudinal pattern in water column nutrient uptake, water column processes can be important. An improved mechanistic understanding of the controls on uptake and the ultimate fate of nutrients will facilitate effective management and restoration for mitigating downstream nutrient export. Springer International Publishing Switzerland, 2015 Water column nationallicence River continuum nationallicence Nutrient uptake nationallicence Nitrogen nationallicence Phosphorus nationallicence Reisinger Alexander Department of Biological Sciences, University of Notre Dame, 46556, Notre Dame, IN, USA aut Tank Jennifer Department of Biological Sciences, University of Notre Dame, 46556, Notre Dame, IN, USA aut Rosi-Marshall Emma Cary Institute of Ecosystem Studies, 12545, Millbrook, NY, USA aut Hall Jr. Robert Department of Zoology and Physiology, University of Wyoming, 82071, Laramie, WY, USA aut Baker Michelle Department of Biology and the Ecology Center, Utah State University, 84322, Logan, UT, USA aut Biogeochemistry Springer International Publishing 125/1(2015-08-01), 115-131 0168-2563 125:1<115 2015 125 10533 https://doi.org/10.1007/s10533-015-0118-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0118-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Reisinger Alexander Department of Biological Sciences, University of Notre Dame, 46556, Notre Dame, IN, USA aut NATIONALLICENCE 700 1- Tank Jennifer Department of Biological Sciences, University of Notre Dame, 46556, Notre Dame, IN, USA aut NATIONALLICENCE 700 1- Rosi-Marshall Emma Cary Institute of Ecosystem Studies, 12545, Millbrook, NY, USA aut NATIONALLICENCE 700 1- Hall Jr Robert Department of Zoology and Physiology, University of Wyoming, 82071, Laramie, WY, USA aut NATIONALLICENCE 700 1- Baker Michelle Department of Biology and the Ecology Center, Utah State University, 84322, Logan, UT, USA aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 125/1(2015-08-01), 115-131 0168-2563 125:1<115 2015 125 10533