Different morphology of Nuphar lutea in two contrasting aquatic environments and its effect on ecosystem engineering |
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| Authors: | Jonas Schoelynck Kris Bal Veerle Verschoren Ellis Penning Eric Struyf Tjeerd Bouma Dieter Meire Patrick Meire Stijn Temmerman |
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| Affiliation: | 1. Department of Biology, Ecosystem Management Research Group, University of Antwerp, Wilrijk, Belgium;2. Department of Biodiversity, School of Molecular and Life Sciences, University of Limpopo, Limpopo, South Africa;3. Deltares, Delft, The Netherlands;4. Netherlands Institute of Ecology, Wageningen, The Netherlands;5. Netherlands Institute of Ecology, Centre for Estuarine and Marine Ecology, Yerseke, The Netherlands;6. Department of Civil Engineering, Labo voor Hydraulica, University of Ghent, Ghent, Belgium |
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| Abstract: | Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Though, the extent to how plant morphological plasticity actively influences these feedbacks has received little scientific attention. The nymphaeid macrophyte species Nuphar lutea (L.) Smith is characterized by a distinct leaf duality. Floating leaves shade most of the submerged leaves thereby limiting light penetration in the water. Despite their apparent negligible photosynthetic role, submerged leaves of N. lutea remain intact during summer and contribute a significant part to the total biomass. Our results indicate that the submerged leaves are crucial in plant–flow interactions and hence in the engineering potential of the plant, i.e. the capacity to locally reduce flow velocities and to promote sedimentation, including organic matter deposition. Plant individuals growing in running river water were compared to individuals from adjacent oxbow lake water. The number and size of submerged leaves were significantly higher for river standing individuals and the accumulated sediment contained significantly more organic matter, total nitrogen and total phosphorus, and was characterized by a lower carbon/nitrogen ratio and a finer grain size. We therefore argue that the submerged N. lutea canopy in rivers has the ability to create a high‐nutrient, low hydrodynamic environment, resembling the conditions found in oxbow lakes. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | Biebrza scale‐dependent feedbacks morphological plasticity bio‐geomorphology aquatic vegetation nutrient dynamics organic matter accumulation |
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