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Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment

One prominent effect of nutrient pollution of surface waters is the mass invasion of floating plants, which can clog waterways, disrupting human use of aquatic systems. These plants are widely vilified and motivate expensive control campaigns, but their presence may be providing a poorly recognized...

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Autores principales: Winton, R. Scott, Kleinschroth, Fritz, Calamita, Elisa, Botter, Martina, Teodoru, Cristian R., Nyambe, Imasiku, Wehrli, Bernhard
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508817/
https://www.ncbi.nlm.nih.gov/pubmed/32963306
http://dx.doi.org/10.1038/s41598-020-72499-1
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author Winton, R. Scott
Kleinschroth, Fritz
Calamita, Elisa
Botter, Martina
Teodoru, Cristian R.
Nyambe, Imasiku
Wehrli, Bernhard
author_facet Winton, R. Scott
Kleinschroth, Fritz
Calamita, Elisa
Botter, Martina
Teodoru, Cristian R.
Nyambe, Imasiku
Wehrli, Bernhard
author_sort Winton, R. Scott
collection PubMed
description One prominent effect of nutrient pollution of surface waters is the mass invasion of floating plants, which can clog waterways, disrupting human use of aquatic systems. These plants are widely vilified and motivate expensive control campaigns, but their presence may be providing a poorly recognized function in the cycling of excess nutrients. The capacity for floating plants to absorb nutrients from surface water has been understood for decades, primarily from their use in constructed wetlands for wastewater treatment. Yet, in natural settings, there has not been to date any effort to quantify whether floating plant invasions represent important pools or fluxes of nutrients relative to those of the river catchments in which they occur. We found that seasonal hydrologic cycles in the Zambezi trap and flush floating plants from river choke points, such as dams and river confluences, on an annual basis. Peak plant biomass at such choke points constitutes a proxy for estimating annual plant-bound nutrient loads. We assessed the significance of floating vegetation as nutrient sinks by comparing annual plant-bound nutrient loading to conventional river nutrient loading (dissolved and particulate) for four tributaries of the Zambezi River in Zambia. We found that the relative importance of floating vegetation was greatest in the more urbanized catchments, such as the Maramba River draining the city of Livingstone, representing approximately 30% and 9% of annual digestible phosphorus and nitrogen flux respectively. We also found plant-bound phosphorus to be important in the Kafue River (19%), draining the industrial town of Kafue and extensive sugarcane plantations. These results demonstrate the great potential of floating plants to take up excess nutrients from natural river systems. Given the importance of hydrology in the life cycle of floating vegetation, controlled dam discharges may have an important role in managing them and their water quality treatment functions.
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spelling pubmed-75088172020-09-24 Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment Winton, R. Scott Kleinschroth, Fritz Calamita, Elisa Botter, Martina Teodoru, Cristian R. Nyambe, Imasiku Wehrli, Bernhard Sci Rep Article One prominent effect of nutrient pollution of surface waters is the mass invasion of floating plants, which can clog waterways, disrupting human use of aquatic systems. These plants are widely vilified and motivate expensive control campaigns, but their presence may be providing a poorly recognized function in the cycling of excess nutrients. The capacity for floating plants to absorb nutrients from surface water has been understood for decades, primarily from their use in constructed wetlands for wastewater treatment. Yet, in natural settings, there has not been to date any effort to quantify whether floating plant invasions represent important pools or fluxes of nutrients relative to those of the river catchments in which they occur. We found that seasonal hydrologic cycles in the Zambezi trap and flush floating plants from river choke points, such as dams and river confluences, on an annual basis. Peak plant biomass at such choke points constitutes a proxy for estimating annual plant-bound nutrient loads. We assessed the significance of floating vegetation as nutrient sinks by comparing annual plant-bound nutrient loading to conventional river nutrient loading (dissolved and particulate) for four tributaries of the Zambezi River in Zambia. We found that the relative importance of floating vegetation was greatest in the more urbanized catchments, such as the Maramba River draining the city of Livingstone, representing approximately 30% and 9% of annual digestible phosphorus and nitrogen flux respectively. We also found plant-bound phosphorus to be important in the Kafue River (19%), draining the industrial town of Kafue and extensive sugarcane plantations. These results demonstrate the great potential of floating plants to take up excess nutrients from natural river systems. Given the importance of hydrology in the life cycle of floating vegetation, controlled dam discharges may have an important role in managing them and their water quality treatment functions. Nature Publishing Group UK 2020-09-22 /pmc/articles/PMC7508817/ /pubmed/32963306 http://dx.doi.org/10.1038/s41598-020-72499-1 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Winton, R. Scott
Kleinschroth, Fritz
Calamita, Elisa
Botter, Martina
Teodoru, Cristian R.
Nyambe, Imasiku
Wehrli, Bernhard
Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment
title Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment
title_full Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment
title_fullStr Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment
title_full_unstemmed Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment
title_short Potential of aquatic weeds to improve water quality in natural waterways of the Zambezi catchment
title_sort potential of aquatic weeds to improve water quality in natural waterways of the zambezi catchment
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508817/
https://www.ncbi.nlm.nih.gov/pubmed/32963306
http://dx.doi.org/10.1038/s41598-020-72499-1
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