Droevendaalsesteeg 10
6708 PB Wageningen
The Netherlands
Netwerk
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Hi there, my research focuses on the interrelationships between eutrophication, climate change, and ecosystem service. Follow my Twitter @QingZhan2 for the latest updates about my science journey.
Biografie
Qing has a background in mathematics and studied Ecological Engineering at the Magdeburg-Stendal University of Applied Sciences for his master, where he focused on water quality modelling and reservoir management. In his second year, he worked as a student assistant handling high-frequency monitoring data of a reservoir observatory system (RRO) at the Helmholtz Central for Environmental Research, Magdeburg (UFZ). Later on, he continued his master thesis at UFZ investigating the dissolved organic carbon (DOC) dynamics in a drinking water reservoir in the Harz Mountains, Central Germany. For mitigating the DOC loading from this reservoir, he has constructed an optimization model including a decision-making module and a DOC dynamics simulation module, and then interpolated the high-frequency data into this model. Qing's reservoir operation model has been recognized with great interest in a presentation at the responsible reservoir authority (Talsperrenbetrieb Sachsen-Anhalt), and he has been awarded Otto-von-Guericke Scholarship during the last year of his master program (see news). Since July 10, 2020, Qing started to work at the AqE department of NIOO as a PhD candidate on the project titled "management of extreme events in lakes and catchments" (MANTEL-project), supervised by Dr. Lisette De Sernopont Domis of the working group "Aquatic Knowledge Centre Wageningen" (AKWA).
CV
Employment
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2019–PresentPh.D. candidate
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2018–2019Student assistant at Helmholtz Centre for Environmental Research - UFZ
Education
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2019–PresentPh.D.
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2016–2019Master of Science at Magdeburg-Stendal University of Applied Sciences, Germany
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2012–2016Bachelor of Science at Nanjing Agricultral University, China
Publicaties
Belangrijkste publicaties
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High frequency data provide new insights into evaluating and modeling nitrogen retention in reservoirs
Freshwater ecosystems including lakes and reservoirs are hot spots for retention of excess nitrogen (N) from anthropogenic sources, providing valuable ecological services for downstream and coastal ecosystems. Despite previous investigations, current quantitative understanding on the influential factors and underlying mechanisms of N retention in lentic freshwater systems is insufficient due to data paucity and limitation of modeling techniques. Our ability to reliably predict N retention for these systems therefore remains uncertain. Emerging high frequency monitoring techniques and well-developed ecosystem modeling shed light on this issue. In the present study, we explored the retention of NO3–N during a five-year period (2013–2017) in both annual and weekly scales in a highly flushed reservoir in Germany. We found that annual-averaged NO3–N retention efficiency could be up to 17% with an overall retention efficiency of ∼4% in such a system characterized by a water residence time (WRT) of ∼4 days. On the weekly scale, the reservoir displayed negative retention in winter (i.e. a source of NO3–N) and high positive retention in summer (i.e. a sink for NO3–N). We further identified the critical role of Chl-a concentration together with the well-recognized effects from WRT in dictating NO3–N retention efficiency, implying the significance of biological processes including phytoplankton dynamics in driving NO3–N retention. Furthermore, our modeling approach showed that an established process-based ecosystem model (PCLake) accounted for 58.0% of the variance in NO3–N retention efficiency, whereas statistical models obtained a lower value (40.5%). This finding exemplified the superior predictive power of process-based models over statistical models whenever ecological processes were at play. Overall, our study highlights the importance of high frequency data in providing new insights into evaluating and modeling N retention in reservoirs. -
Cyanobacterial blooms in oligotrophic lakes: Shifting the high‐nutrient paradigm
Freshwater cyanobacterial blooms have become ubiquitous, posing major threats to ecological and public health. Decades of research have focused on understanding drivers of these blooms with a primary focus on eutrophic systems; however, cyanobacterial blooms also occur in oligotrophic systems, but have received far less attention, resulting in a gap in our understanding of cyanobacterial blooms overall. In this review, we explore evidence of cyanobacterial blooms in oligotrophic freshwater systems and provide explanations for those occurrences. We show that through their unique physiological adaptations, cyanobacteria are able to thrive under a wide range of environmental conditions, including low-nutrient waterbodies. We contend that to fully understand cyanobacterial blooms, and thereby mitigate and manage them, we must expand our inquiries to consider systems along the trophic gradient, and not solely focus on eutrophic systems, thus shifting the high-nutrient paradigm to a trophic-gradient paradigm. -
Effectiveness of phosphorus control under extreme heatwaves: implications for sediment nutrient releases and greenhouse gas emis
Eutrophication has been identified as the primary cause of water quality deterioration in inland waters worldwide, often associated with algal blooms or fish kills. Eutrophication can be controlled through watershed management and in-lake measures. An extreme heatwave event, through its impact on mineralization rates and internal nutrient loading (phosphorus—P, and nitrogen—N), could counteract eutrophication control measures. We investigated how the effectiveness of a nutrient abatement technique is impacted by an extreme heatwave, and to what extent biogeochemical processes are modulated by exposure to heatwaves. To this end, we carried out a sediment-incubation experiment, testing the effectiveness of lanthanum-modified bentonite (LMB) in reducing nutrients and greenhouse gas emissions from eutrophic sediments, with and without exposure to an extreme heatwave. Our results indicate that the effectiveness of LMB may be compromised upon exposure to an extreme heatwave event. This was evidenced by an increase in concentration of 0.08 ± 0.03 mg P/L with an overlying water volume of 863 ± 21 mL, equalling an 11% increase, with effects lasting to the end of the experiment. LMB application generally showed no effect on nitrogen species, while the heatwave stimulated nitrification, resulting in ammonium loss and accumulation of dissolved oxidized nitrogen species as well as increased dissolved nitrous oxide concentrations. In addition, carbon dioxide (CO2)-equivalent was more than doubled during the heatwave relative to the reference temperature, and LMB application had no effect on mitigating them. Our sediment incubation experiment indicates that the rates of biogeochemical processes can be significantly accelerated upon heatwave exposure, resulting in a change in fluxes of nutrient and greenhouse gas between sediment and water. The current efforts in eutrophication control will face more challenges under future climate scenarios with more frequent and intense extreme events as predicted by the IPCC. -
Spatial and Temporal Variability in Concentration‐Discharge Relationships at the Event Scale
The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.
Peer-reviewed publicaties
High-frequency monitoring enables operational opportunities to reduce the dissolved organic carbon (DOC) load in Germany’s largest drinking water reservoir
https://doi.org/10.1080/20442041.2021.1987796Rising dissolved organic carbon (DOC) is interfering with drinking water production. While strategies for DOC removal during water treatment have been successfully implemented, the potential for DOC load reduction by optimized reservoir operation is not yet fully explored, mainly constrained by data paucity on real-time DOC dynamics. In this study, we utilized the emerging in situ high-frequency (HF) monitoring technique for DOC and developed a simulation–operation framework that promotes DOC mitigation in Germany’s largest drinking water reservoir. Rappbode Reservoir is embedded in a network of smaller upstream reservoirs from which Königshütte Reservoir delivers the most water but can also be operated as a bypass system. Using high-frequency monitoring of DOC concentrations and discharge at the inflows and outflows, we constructed a mass balance model that simulated the DOC dynamics in the reservoir, allowing us to explore alternative operation regimes that deliver the same amount of water but a lower DOC load. Our results show that, through rapid decision-making that enables bypassing of water with high DOC concentrations around the drinking water reservoir, the optimized operation regime is able to reduce DOC load of the drinking water reservoir by 25 ± 3%. Therefore, our proposed operational strategy to minimize DOC loading to reservoirs is promising.
Towards climate-robust water quality management: Testing the efficacy of different eutrophication control measures during a heatwave in an urban canal
Harmful algal blooms are symptomatic of eutrophication and lead to deterioration of water quality and ecosystem services. Extreme climatic events could enhance eutrophication resulting in more severe nuisance algal blooms, while they also may hamper current restoration efforts aimed to reduce nutrient loads. Evaluation of restoration measures on their efficacy under climate change is essential for effective water management. We conducted a two-month mesocosm experiment in a hypertrophic urban canal focussing on the reduction of sediment phosphorus (P)-release. We tested the efficacy of four interventions, measuring phytoplankton biomass, nutrients in water and sediment. The measures included sediment dredging, water column aeration and application of P-sorbents (lanthanum-modified bentonite - Phoslock® and iron-lime sludge, a by-product from drinking water production). An extreme heatwave (with the highest daily maximum air temperature up to 40.7 °C) was recorded in the middle of our experiment. This extreme heatwave was used for the evaluation of heatwave-induced impacts. Dredging and lanthanum modified bentonite exhibited the largest efficacy in reducing phytoplankton and cyanobacteria biomass and improving water clarity, followed by iron-lime sludge, whereas aeration did not show an effect. The heatwave negatively impacted all four measures, with increased nutrient releases and consequently increased phytoplankton biomass and decreased water clarity compared to the pre-heatwave phase. We propose a conceptual model suggesting that the heatwave locks nutrients within the biological P loop, which is the exchange between labile P and organic P, while the P fraction in the chemical P loop will be decreased. As a consequence, the efficacy of chemical agents targeting P-reduction by chemical binding will be hampered by heatwaves. Our study indicates that current restoration measures might be challenged in a future with more frequent and intense heatwaves.https://doi.org/10.1016/j.scitotenv.2022.154421Cyanobacterial blooms in oligotrophic lakes
Freshwater cyanobacterial blooms have become ubiquitous, posing major threats to ecological and public health.https://doi.org/10.1111/fwb.13791
Decades of research have focused on understanding drivers of these blooms with a primary focus on eutrophic systems; however, cyanobacterial blooms also occur in oligotrophic systems, but have received far less attention, resulting in a gap in our understanding of cyanobacterial blooms overall.
In this review, we explore evidence of cyanobacterial blooms in oligotrophic freshwater systems and provide explanations for those occurrences.
We show that through their unique physiological adaptations, cyanobacteria are able to thrive under a wide range of environmental conditions, including low-nutrient waterbodies.
We contend that to fully understand cyanobacterial blooms, and thereby mitigate and manage them, we must expand our inquiries to consider systems along the trophic gradient, and not solely focus on eutrophic systems, thus shifting the high-nutrient paradigm to a trophic-gradient paradigm.Effectiveness of phosphorus control under extreme heatwaves
https://doi.org/10.1007/s10533-021-00854-zEutrophication has been identified as the primary cause of water quality deterioration in inland waters worldwide, often associated with algal blooms or fish kills. Eutrophication can be controlled through watershed management and in-lake measures. An extreme heatwave event, through its impact on mineralization rates and internal nutrient loading (phosphorus—P, and nitrogen—N), could counteract eutrophication control measures. We investigated how the effectiveness of a nutrient abatement technique is impacted by an extreme heatwave, and to what extent biogeochemical processes are modulated by exposure to heatwaves. To this end, we carried out a sediment-incubation experiment, testing the effectiveness of lanthanum-modified bentonite (LMB) in reducing nutrients and greenhouse gas emissions from eutrophic sediments, with and without exposure to an extreme heatwave. Our results indicate that the effectiveness of LMB may be compromised upon exposure to an extreme heatwave event. This was evidenced by an increase in concentration of 0.08 ± 0.03 mg P/L with an overlying water volume of 863 ± 21 mL, equalling an 11% increase, with effects lasting to the end of the experiment. LMB application generally showed no effect on nitrogen species, while the heatwave stimulated nitrification, resulting in ammonium loss and accumulation of dissolved oxidized nitrogen species as well as increased dissolved nitrous oxide concentrations. In addition, carbon dioxide (CO2)-equivalent was more than doubled during the heatwave relative to the reference temperature, and LMB application had no effect on mitigating them. Our sediment incubation experiment indicates that the rates of biogeochemical processes can be significantly accelerated upon heatwave exposure, resulting in a change in fluxes of nutrient and greenhouse gas between sediment and water. The current efforts in eutrophication control will face more challenges under future climate scenarios with more frequent and intense extreme events as predicted by the IPCC.
Spatial and Temporal Variability in Concentration-Discharge Relationships at the Event Scale
The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.https://doi.org/10.1029/2020WR029442
Projecten & samenwerkingen
Projecten
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Securing biodiversity, functional integrity and ecosystem services in DRYing rivER networks (Dryver)
Securing biodiversity, functional integrity and ecosystem services in DRYing rivER networks (Dryver)
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Functioning and ecosystem services provisioning of quarry lakes
Functioning and ecosystem services provisioning of quarry lakes
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Global Lake Ecological Observatory Network-GLEON projects
At the AKWA group we are involved in numerous GLEON projects
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Management of Extreme events in Lakes and Reservoirs (MANTEL)
MANTEL (Management of Climatic Extreme Events in Lakes & Reservoirs for the protection of Ecosystem Services) is a Marie Sklodowska-Curie European Joint Doctorate Innovative Training Network that trained a cohort of Early Stage Researchers (ESRs) to investigate the effects of extreme climatic events on water quality. As one of 12 ESRs, Qing's MANTEL project focus on mitigating negative impacts of extreme events on the sustained provision of lake ecosystem services.
The outputs will support stakeholders through development of measures that mitigate the negative consequences of extreme events, including toxic cyanobacterial blooms, and runoff induced high nutrient loads. Lowering the trophic status of surface waters is expected to increase resilience against predicted global warming and therewith reduce problematic cyanobacterial blooms. Cost-efficient mitigation calls for a tailor made benefit oriented restoration plan, building on an arsenal of restoration techniques, combined with innovative techniques (e.g. geo-engineering techniques).
Qing will be primarily based in the Netherlands Institute of Ecology, Netherlands, supervised by Dr Lisette de Senerpont Domis, and will be co-supervised by and spend study time with Dr Miquel Lurling, Wageningen University, and Dr. Rafa Marcé, Catalan Institute for Water Research, Spain. The PhD will be awarded by Wageningen University.
More information about this project can be found: https://www.mantel-itn.org/
Additionele Projecten
Management of Climatic Extreme Events in Lakes and Reservoirs for the Protection and Ecosystem Services
2019–2021
Qing Zhan is involved in Project 10, one of 12 MANTEL Projects. This project will support stakeholders through development of measures that mitigate the negative consequences of extreme events, including toxic cyanobacterial blooms, and runoff induced high nutrient loads. Lowering the trophic status of surface waters is expected to increase resilience against predicted global warming and therewith reduce problematic cyanobacterial blooms. Cost-efficient mitigation calls for a tailor made benefit oriented restoration plan, building on an arsenal of restoration techniques, combined with innovative techniques.
A very promising way of moving lakes to an oligo/mesotrophic state is by using geo-engineering techniques that reduce cyanobacterial biomass and bioavailable phosphorus. The overall objective of the project is to test the hypothesis that such rehabilitated waters are not only more resilient to increased water temperatures, but also to pulsed inflows of nutrients. Experiments will be conducted in highly controlled indoor mesocosms – so called “Limnotrons” – that all will start eutrophic, including nutrient rich sediments: half will be treated (rehabilitated) and exposed to four temperatures ranging from low summer (20°C), normal (23°C), warm (26°C) and extreme (29°C). Effects of heat wave events and pulsed summer rain events (dilution and nutrient enrichments) will be studied. In addition, to gain a better understanding of cost-efficient mitigation, the early stage researcher will have access to HFM data of the catchment area Mark-Vliet-Dintel, and Volkerakzoommeer-Binnenschelde, two areas where rehabilitation projects are ongoing. To detect the negative impacts of episodic events on these degraded systems, a modelling framework will be developed. The results will give a much needed management perspective of both the Dutch water board Brabantse Delta as well as the drinking water company ATLL.
Qing Zhan is the ESR for Project 10. Qing will be primarily based in the Netherlands Institute of Ecology, Netherlands, supervised by Dr Lisette de Senerpont Domis, and will be co-supervised by and spend study time with Dr Miquel Lurling, Wageningen University, and Dr. Rafa Marcé, Catalan Institute for Water Research, Spain. The PhD will be co-awarded by University of Girona and Wageningen University.