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High resolution in situ nutrient mapping of large rivers and reservoir systems

Gesuchsteller/in Wehrli Bernhard
Nummer 128707
Förderungsinstrument R'EQUIP
Forschungseinrichtung Abteilung Oberflächengewässer EAWAG
Hochschule Eidg. Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz - EAWAG
Hauptdisziplin Hydrologie, Limnologie, Glaziologie
Beginn/Ende 01.04.2010 - 31.03.2011
Bewilligter Betrag 127'974.00
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Alle Disziplinen (2)

Disziplin
Hydrologie, Limnologie, Glaziologie
Geochemie

Keywords (9)

in-situ analysis; real-time; nutrients; river systems; lakes; biogeochemistry; fluxes; rivers; reservoirs

Lay Summary (Englisch)

Lead
Lay summary
The natural cycles of nitrogen and phosphorus have been severely disturbed in many rivers and lakes worldwide. Pressure on these aquatic systems will increase in the coming decades due to growing urbanization. In Africa, Asia and South America there is a lack of baseline data in order to analyze how aquatic systems respond to changing conditions. The goal of this proposal is to assemble an integrated system of field instruments for the analysis of nutrients (nitrate, ammonium, and phosphate), chlorophyll, and other key parameters in-situ, at high-frequency, and with low detection limits. In conventional field campaigns samples for nutrient analysis have to be transported to a laboratory for individual analysis. At the core of the new analytical instrument is an automated chemical analysis module capable of generating nutrient concentration data at the point of measurement with a frequency of up to one sample per second. The instrument will have profiling capabilities with a depth range up to 200 meters. The nutrient module will work together with a conductivity-temperature-depth (CTD) profiler with additional sensors. The instrument will have high-resolution sampling capabilities for individual analysis of trace components, microorganisms and for isotopic analysis. The equipment will be tested and optimized in Switzerland for profiling studies in lakes and reservoirs. For the analysis of biogeochemical nutrient fluxes in river systems the module will be used together with an acoustic doppler current profiler (ADCP) which provides runoff data. In this configuration a large-scale field campaign is planned for the Zambezi River in the framework of an interdisciplinary project on integrated water resource management.
Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Publikationen

Publikation
Organic carbon and nitrogen export from a tropical dam-impacted floodplain system
Zurbruegg R., Suter S., Lehmann M. F., Wehrli B., Senn D. B. (2013), Organic carbon and nitrogen export from a tropical dam-impacted floodplain system, in BIOGEOSCIENCES, 10(1), 23-38.
River-floodplain exchange and its effects on the fluvial oxygen regime in a large tropical river system (Kafue Flats, Zambia)
Zurbruegg Roland, Wamulume Jason, Kamanga Romas, Wehrli Bernhard, Senn David B. (2012), River-floodplain exchange and its effects on the fluvial oxygen regime in a large tropical river system (Kafue Flats, Zambia), in JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 117(G03008), 1-12.

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
Universität Basel, Prof. Moritz Lehmann Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
- Forschungsinfrastrukturen
- Austausch von Mitarbeitern
Eawag, Dr. Carsten Schubert Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
- Forschungsinfrastrukturen
- Austausch von Mitarbeitern
Eawag, CCES Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
- Forschungsinfrastrukturen
- Austausch von Mitarbeitern
ETH, CCES Sambia (Afrika)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
- Forschungsinfrastrukturen

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153091 Factors governing methane oxidation pathways at redox boundaries in lakes 01.04.2014 Projektförderung (Abt. I-III)
120112 The role of lake sediments in the carbon cycle: organic carbon preservation and methane emission 01.06.2008 Projektförderung (Abt. I-III)
135299 Methane oxidation pathways at oxic-anoxic boundaries in lakes 01.04.2011 Projektförderung (Abt. I-III)

Abstract

Anthropogenic activities have severely disturbed the natural cycling of nitrogen and phosphorous in aquatic ecosystems, both by dramatically increasing bioavailable N and P loadings, and through construction of dams that remove nutrients in upstream reservoirs and also alter natural cycling in downstream systems by disturbing hydrology. These pressures will increase over the coming decades due to growing world population, and will be exerted on ecosystems in in Africa, Asia and South America, where high population growth coincides with severe lack of data about baseline conditions and how river systems will respond to changes. In order to best manage these pressures, there is an urgent need for high-quality data sets with sufficient spatial and temporal resolution to calibrate predictive biogeochemical models for water quality under tropical to arid conditions.The goal of this proposal is to assemble an integrated system of field instruments that will enable real-time, in situ, and high-spatial-resolution measurement of nutrients (nitrate, ammonium, phosphate), chlorophyll, cyanobacteria fluorescence (to quantify abundance of N-fixing plankton), and other key parameters (dissolved O2, pH, T, conductivity) rivers, lakes, and reservoirs. At the core of the instrument is an automated wet-chemical analysis module for high-frequency nutrient analyses with low detection limit. This analytical equipment package will be combined with a lightweight acoustic doppler velocity profiling system for measuring river flow rates to quantify nutrient fluxes in river systems.The proposed instrument package will first be field-tested in Switzerland and then be used intensively within the CCES-funded interdisciplinary African Dams Project (ADAPT) to map river nutrient fluxes and reservoir concentration profiles in the Zambezi River Basin (ZRB), the fourth largest river basin in Africa. The ZRB supports multiple valuable yet fragile wetland ecosystems, is heavily fragmented by several major dams with numerous others planned, and hosts a large (30 million) and rapidly growing (3% per year) population, and is thus an ideal river basin for urgent and intense study. A main goal of ADAPT is to characterize the impacts of large dams on nutrient and carbon cycling in the Zambezi River Basin, and use this improved understanding to identify dam operation strategies that minimize impacts to downstream ecosystems. The data from field expeditions will be used to develop coupled hydrological-biogeochemical-ecological models from the regional to the basin scale to characterize nutrient cycling under current conditions in the ZRB and predict cycling under future conditions (different hydrological regimes, increased nutrient loadings from anthropogenic pressures). To undertake the necessary sampling intensity under the prevailing conditions (i.e., low nutrient concentrations, extended field trips to remote locations and difficulties preserving samples), in situ field measurements are essential. In addition, real-time data acquisition will allow us to identify important transformation zones or nutrient sources while in the field, and then probe these zones in sufficient detail to elucidate the main drivers. In addition to opening a new analytical window for large-scale river biogeochemistry the instrumental package will allow nutrient profiling of stratified lake and reservoir systems in real-time and open the opportunity for precise sampling of redox boundaries in the water column. Several research partners expressed their interest to use these greatly enhanced field capabilities for studying nutrient cycling in pristine and disturbed aquatic ecosystems.
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