Siyue Li

Wuhan Institute of Technology, Wuhan 430205, China · Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering

Freshwaters are important sources of greenhouse gases (GHGs) to the atmosphere that may partially offset the terrestrial carbon sink. However, current emission estimates from inland waters remain uncertain due to data paucity in key regions with a large freshwater surface area, such as China. Here, we show that the areal fluxes of GHGs (carbon diox...

River damming and reservoir operation alter hydrological process, raising concerns over far-reaching influence on fluvial water, biogeochemistry and sediment fluxes due to the common occurrence of fragmented river landscapes around the world. Here, we investigated carbon, nutrients, and geochemical conditions in the world's largest reservoir, the T...

Rivers and streams play a central role in global carbon budget, but our knowledge is limited on the magnitude and extent of urbanization influence on riverine methane (CH4) dynamics. In this study, we investigated dissolved CH4 (dCH4) concentration and CH4 diffusive fluxes in 27 river segments of two 4th-order and three 3rd-order tributary rivers t...

The large variability in the emissions of carbon dioxide (CO2) from urban lakes remains a challenge for partitioning these sources at meaningful spatial and temporal scales. Dissolved organic matter (DOM) governs the spatial and temporal variations in CO2, yet relationships of the CO2 concentration (cCO2) and emission flux (FCO2) with DOM in urban...

Aquaculture systems contribute to atmospheric N2O, but the magnitude of this N2O source is largely uncertain. Here, we synthesized data from 139 aquaculture sites based on 59 peer-reviewed publications, and estimated that China's aquaculture systems emitted 9.68 Gg N yr−1 (4.12 Tg CO2-eq yr−1). N2O emission varied significantly according to system...

Soils in the aquatic-terrestrial zone undergo periodic flooding and act as significant carbon sinks. However, the mechanisms governing soil organic carbon (SOC) formation in these zones are not well understood. This study elucidates the effects of periodic flooding on SOC accumulation at the water level drawdown zone of the Three Gorges Reservoir,...

Flash droughts, as sub-seasonal phenomena, are characterized by their rapid onset and significant impact on terrestrial ecosystems. However, understanding how vegetation responds to flash droughts and the mechanisms governing vegetation recovery remains elusive. Here, we analysed the response of vegetation productivity to flash droughts and identif...

The study investigated the leaching and biodegradation of dissolved organic carbon in leaf leachates from typical fresh leaves in the Wuhan Urban Forest Park, Central China. The fresh leaf-leached dissolved organic carbon quality and biodegradability, as well as their potential determinants, were examined for 12 major tree species, including decidu...

Terrestrial ecosystems are increasingly being exposed to metallic nanoparticles (MNPs). However, the global‐scale impact of MNPs on soil carbon dioxide (CO 2 ) emission remains unknown, limiting our understanding of the role of MNPs in global carbon cycle. We compiled a dataset comprising 1764 pairs of experimental observations to investigate the e...

Shallow lake ecosystems are highly sensitive to temperature fluctuation because of their high water surface-to-volume ratios. Shallow lakes have been increasingly identified as a hotspot of CO2 and CH4 emissions, but their response to temperature variation remains unclear. Here, we report from a 5-month outdoor mesocosm experiment where we investig...

Eutrophication is prevalent in urban lakes; however, a knowledge gap exists regarding eutrophication influences on carbon dynamics in these ecosystems. In the present study, we investigated the carbon dioxide (CO2) and methane (CH4) concentration and diffusion fluxes in Lake Tangxun (the largest shallow Chinese urban lake) in the autumn and winter...

Accurately quantifying the carbon dioxide (CO2) emissions from lakes, especially in urban areas, remains challenging due to constrained temporal resolution in field monitoring. Current lake CO2 flux estimates primarily rely on daylight measurements, yet nighttime emissions is normally overlooked. In this study, a non-dispersive infrared CO2 sensor...

Urban lakes are numerous in the world, but their role in carbon storage and emission is not well understood. This study aimed to answer the critical questions: How does algal growing season influence carbon dioxide concentration (pCO2) and exchange flux (FCO2) in eutrophic urban lakes? We investigated trophic state, seasonality of algal productivit...

Urban lakes are hotspots of methane (CH4) emissions. Yet, actual field measurements of CH4 in these lakes are rather limited and our understanding of CH4 response to urban lake eutrophication is still incomplete. In this study, we measured dissolved CH4 concentrations and quantified CH4 diffusion from four urban lakes in subtropical China during we...

Shallow lakes are numerous in all climate zones, but our knowledge about their dissolved carbon dioxide (CO2) response to future climate change and nutrient enrichment is rather limited. Here we performed a mesocosm experiment with four treatments to investigate how warming and nitrogen addition will impact the partial pressure of CO2 (pCO2) and ph...

Agricultural ditches are pervasive in agricultural areas and are potential greenhouse gas (GHG) hotspots, since they directly receive abundant nutrients from neighboring farmlands. However, few studies measure GHG concentrations or fluxes in this particular water course, likely resulting in underestimations of GHG emissions from agricultural region...

Urban riverine networks are hotspots of CO2 and CH4 emissions, due to river impoundment and pollution. The river–lake connection is considered to be an important way to improve the ecological environment of urban rivers; however, its impact on CO2 and CH4 emissions from urban rivers and regulatory mechanisms are still unclear. Rivers and lakes have...

The disturbance of reactive nitrogen (N) on ecosystems and biogeochemical cycles is now one of the most severe environmental problems worldwide. Nitrate (NO3−) is usually a dominant reactive N species in river ecosystems. Excessive NO3− concentrations in rivers have led to eutrophication and consequent ecological and environmental damages. Quantify...

The disturbance of reactive nitrogen (N) on ecosystems and biogeochemical cycles is now one of the most severe environmental problems worldwide. Nitrate (NO 3-) is usually a dominant reactive N species in river ecosystems. Excessive NO 3-concentrations in rivers have led to eutrophication and consequent ecological and environmental damages. Quantif...

Underscoring how crop mulching changes the dissolved organic carbon (DOC) in runoff is essential to understanding the sustainable application of cornstalk mulching. This study examined the runoff DOC quantity and quality in plots with and without cornstalk mulching under various rainfall intensities in a representative steep fallow land of southwes...

We analyzed the impacts of land use/land cover types on carbon dioxide (CO2) and methane (CH4) concentration and diffusion in 1st to 4th Strahler order tributaries of the Longchuan River to the upper Yangtze River in China by using headspace equilibration method and CO2SYS program. Field sampling and measurements were conducted during the dry and w...

Biological degradation of dissolved organic matter (DOM) regulates its structure and fate in river ecosystems. Previous views suggested that labile components were dominantly consumed by microbial metabolism. Here we provide new observations that a part of recalcitrant compounds largely contribute to riverine DOM biodegradation. The excitation-emis...

A mixed land use/land cover (LULC) catchment increases the complexity of sources and transformations of nitrate in rivers. Spatial paucity of sampling particularly low-resolution sampling in tributaries can result in a bias for identifying nitrate sources and transformations. In this study, high spatial resolution sampling campaigns covering mainst...

Exploring linkages between riverine water quality and land use is of great importance for catchment management and water quality conservation. Relationships between them are complex and site-specific. Therefore, land-use/landscape effects on water quality remain to be investigated. Multivariate statistics and empirical models are used to examine th...

Sources and quality of dissolved organic matter (DOM) in streams may be largely controlled by the landscape and season. In this study, we attempted to answer three critical questions: 1) Do land use/land cover (LULC) types affect DOM characteristics? 2) Is there seasonal fluctuation in DOM components? 3) How do DOM quality and LULC types influence...

Dissolved carbon (DC) deciphers biotic and abiotic processes in aquatic ecosystems, representing a critical component of global carbon cycling. However, underlying drivers of riverine DC dynamics and internal links have yet to be studied. Here, we investigated fluvial physicochemical characteristics, dissolved inorganic carbon (DIC) species, carbon...

Land use and seasonal changes in environmental conditions influence biological communities and their trophic interactions in riverine ecosystems. However, how land use and the seasonality of environmental conditions jointly influence the food web structure of riverine ecosystems remains unclear. Here, we conducted a comparative study on basal resou...

Headwater streams make the majority of commutative stream length in a river basin, carbon dioxide (CO2) emission from headwater (low order) streams is thus an essential component. Anthropogenic activities in headwater areas such as land use change and land use practices can strongly modify terrestrial carbon and nutrient input, which could affect t...

Rapid urbanization has considerably altered carbon biogeochemical cycle and river hydrology. However, the influences of urban land use and urban-induced nutrient increase on dissolved organic matter (DOM) characteristics are poorly understood. Here we hypothesize that the alterations significantly change sources and levels of DOM in river systems t...

Nitrate (NO3⁻) is a major trigger for river eutrophication. While efforts have been made to understand the anthropogenic NO3⁻ pollution in rivers, the role of background NO3⁻ in determining NO3⁻ loads remains to be studied. In this study, we used dual-isotopes (δ¹⁵N/δ¹⁸O-NO3⁻) and an isotope-mixing model to reveal the natural and anthropogenic proc...

Dissolved organic matter (DOM) is a diverse and highly complex mixture of organic macromolecules, and thus plays a central role in aquatic ecosystems. However, responses of components and sources of DOM to hydrological processes and trophic levels (nutrient stoichiometric ratios) are poorly understood, particularly in monsoonal headwater streams of...

Carbon dioxide (CO2) emissions from inland waters to the atmosphere are a pivotal component of the global carbon budget. Anthropogenic land use can influence riverine CO2 emissions, but empirical data exploring cause-effect relationships remain limited. Here, we investigated CO2 partial pressures (pCO2) and degassing in a monsoonal river (Yue River...

Rapid urbanization has been reported to affect carbon biogeochemical cycle of waterways, contributing to even higher carbon dioxide (CO2) outgassing from rivers to the atmosphere. However, knowledge on the magnitude and extent of the urbanization influence on riverine CO2 dynamics is still limited. In this study, we investigated partial pressure of...

Dissolved organic matter (DOM) chemodiversity shows spatial and temporal variations in aquatic systems due to different biogeochemical process and complex sources. However, there remains a large gap on DOM compositions and source proportion, as well as factors driving DOM chemical compositions and source variations in monsoonal rivers of China. Her...

The urbanization process of the Three Gorges Reservoir area (TGRA) shows important impacts on the formation, migration, and transportation of dissolved organic matter (DOM) in rivers. In this study, a high-urbanized river (Taohuaxi) and low-urbanized river (Pulihe) in the TGRA were selected and water samples were collected in spring (April) and sum...

Forest land affected by deforestation contributes with high soil and water losses. There is a need to find managements to reduce the soil losses and achieve sustainability. Mulches were found very suitable to control the soil losses, and straw mulches are easy to apply, contribute with organic matter and are efficient since the day of application....

Trophic state index (TSI) can assess lake trophic status and trace in-situ metabolism, exhibiting a high potential in explaining autochthonous carbon dioxide (CO 2) in aquatic environments. However, there remains a knowledge gap in how TSI links to the partial pressure of CO 2 (pCO 2) generated and consumed in lakes. Here we explored the temporal v...

River acts as a continuum of dissolved organic matter (DOM) transport and transformation. However, underlying controls of fluvial DOM spatiotemporal variability has yet to be revealed. Here, we explored the DOM component, molecular weight and source in the Longchuan River, a headwater tributary of the Yangtze with Karst characteristic. Concentrated...

Dissolved organic matter plays a fundamental geochemical role in aquatic systems. However, not much is known about interactions of dissolved organic matter characteristics, source, and partial pressure of carbon dioxide in the monsoonal streams of Asia. The ultraviolet visible and fluorescence spectroscopic indices were used as proxies for dissolve...

Understanding optical characteristics, composition and source of dissolved organic matter (DOM) in rivers of the Three Gorges Reservoir (TGR) region is important for region and global carbon cycle. However, chemical compositions and source of DOM from the tributary to mainstream in the TGR region are not well studied. Consequently, 126 water sample...

Water quality is important for domestic, industrial, agricultural and environmental purposes, and is reported to be strongly affected by land use including land use composition, configuration and intensity, whereas, the linkages are highly variable at multiple spatial and seasonal scales. We evaluated the land use effects on water quality in a typi...

Inland waters frequently exhibit carbon dioxide (CO2) supersaturation and potentially serve as CO2 emitters to the atmosphere. However, study on water–air interface CO2 exchange from small rivers remains limited, which causes large uncertainty of local and global carbon budgets. Based on seasonal field measurements, carbonate equilibria (CO2SYS pro...

Studying the influences of urbanization on the composition, chemical structure, source and migration of dissolved organic matter (DOM) in rivers is of great significance for aquatic ecosystem protection and biogeochemical carbon (C) cycling. The DOM spectroscopic characteristics of the three typical rivers (Taohuaxi, Nanhe, and Puli) with different...

The optical properties can characterize the chemical composition, bioavailability and origins of dissolved organic matter (DOM), and thus indicate its biodegradability in natural waters. However, there remains a large gap in how DOM optical properties (UV–visible and fluorescence spectra) trace and predict the dissolved organic carbon biodegradatio...

The mineralization of dissolved organic matter (DOM) can partially explain riverine carbon dioxide (CO2) emissions to the atmosphere. However, little is known about how the DOM origin and composition drive CO2 partial pressures (pCO2). Here, we reveal links between aquatic pCO2, DOM optical parameters (a254, a350 and S275-295 and S350-400) and nutr...

The removal of antibiotic residues in the aquatic environment is still a big challenge in environmental protection. Here, we developed NaYF4:Yb,Tm@TiO2 as a highly efficient photocatalyst for photocatalytic degradation of ciprofloxacin (CIP), a representative antibiotic in water under simulated solar irradiation. NaYF4:Yb,Tm@TiO2 can efficiently ut...

Carbon dioxide (CO2) emission via water-air interface from fluvial networks plays a central role in the global carbon budget. Large uncertainties, however, exist because field measurements are often spatially and temporally biased, while aqueous carbon (C) processing can be strongly affected by anthropogenic activities in rapidly urbanizing areas....

Carbon dioxide (CO2) emissions from rivers are a vital part of the global carbon budget. However, data from subtropical areas, especially in the headwater streams, are scare. Spatiotemporal dynamics and drives of partial pressure of CO2 (pCO2) and water-air CO2 fluxes (FCO2) in a monsoonal headwater stream Jinshui River of the Yangtze were unravele...

Carbon (C) in riverine ecosystems play an important role in regulating terrestrial carbon reservoir to the oceans and atmosphere, thus, understanding C dynamics in riverine ecosystem are essential for understanding global carbon cycle. Here, we investigated the seasonal and spatial variations in concentrations of dissolved inorganic carbon (DIC), p...

Aquatic carbon (C) loss is mostly driven by in-situ mineralization of dissolved organic carbon (DOC) and leads to autonomous carbon dioxide (CO2) emissions to the atmosphere. However, limited studies have examined the biodegradability of riverine DOC, especially for the initial trophic controls of DOC biodegradation (%BDOC) and variations in dissol...

The high reproducibility of trace detection in complex systems is very hard but crucial to analytical technology and science. Here, we present a surface-enhanced Raman scattering (SERS) platform made by large-scale self-assembly of Au nanoparticle (NP) arrays at the cyclohexane/water interface and its use for pesticides residues trace detection. Th...

Soil detachment capacity (Dc) is a key parameter in many soil erosion models and is typically estimated using hydraulic parameters. However, the accuracy of predicting Dc and its relationship to hydraulic characteristics remains poorly understood for many soil types. This study investigates the predictability of Dc with hydraulics by simulated scou...

CO2 outgassing from rivers is a critical component for evaluating riverine carbon cycle, but it is poorly quantified largely due to limited measurements and modeling of gas transfer velocity in subtropical streams and rivers. We measured CO2 flux rates and calculated k and partial pressure (pCO2) in 60 river networks of the Three Gorges Reservoir (...

To examine the mountainous lake CO2 evasion in Southwest China, partial pressures of carbon dioxide[p(CO2)] and the CO2 exchange flux[F(CO2)] via the water-air interface of nine mountainous lakes in Chongqing, China, have been studied in summer using the thin boundary layer model (TBL) and floating chambers. Key water quality parameters were concom...

Dissolved carbon plays a pivotal role in carbon cycles and potentially affects ecological processes of water body. While stalk mulch can regulate soil and water losses, its effects on the export of dissolved carbon from soils are poorly understood. The main objective of this study was to determine the effects of rainfall intensity and downslope cor...

Rivers and streams are important agents for global and regional carbon cycle, which represent a nonnegligible carbon source to the atmosphere. However, carbon dioxide (CO2) degassing via water-air interface from inland waters currently has a large uncertainty in estimation. Here we examined the CO2 partial pressure (pCO2) and CO2 degassing in the D...

Diurnal and seasonal characterization of CO2 partial pressure p(CO2) and CO2 areal flux F(CO2) at the water-air interface in an anthropogenic river in the Three Gorges Reservoir area was studied. A tributary of the Jialing River in Chongqing Municipality was chosen, and daily and seasonal samples were taken in summer and autumn, focusing on riverin...

Reservoirs are considered as important carbon source of the atmosphere, whilst, regional and global reservoir CO2 quantification is hampered by data limitation and bias in spatial and temporal sampling. By deploying chamber measurements and employing the newly developed model of gas transfer velocity, CO2 partial pressure (pCO2) and evasion in the...

Dissolved organic carbon (DOC) plays an indispensable role in biogeochemical cycles and ecosystem services in rivers. However, little is known about the seasonal variations of DOC biodegradation in subtropical rivers. Here, we investigated the concentrations of DOC, dissolved total nitrogen (DTN), and dissolved total phosphorus (DTP), humification...

Silicon and carbon geochemical linkages were usually regulated by chemical weathering and organism activity, but had not been investigated under the drought condition, and the magnitude and extent of drought effects remain poorly understood. We collected a comprehensive data set from a total of 13 sampling sites covering the main water body of the...

An extensive investigation on the main tributaries of the Three Gorges Reservoir (TGR) region was conducted in autumn (Oct. 2015), with focuses on riverine CO2 partial pressure (pCO2) and its associated controls. Our results indicated that pCO2 in the main rivers of the TGR region ranged from 18.75 to 296.31 Pa, with a mean value of (141.06±77.51)...

TiO₂ nanoparticles with surface porosity were prepared by a simple and efficient method and presented for the removal of malachite green (MG), a representative organic pollutant, from aqueous solution. Photocatalytic degradation experiments were systematically conducted to investigate the influence of TiO₂ dosage, pH value, and initial concentratio...

CO2 outgassing from rivers is a critical component for evaluating riverine carbon cycle, but it is poorly quantified largely due to limited measurements and modeling of gas transfer velocity (k) in subtropical streams and rivers. We measured CO2 flux rates, k and partial pressure (pCO2) in river networks of the Three Gorges Reservoir (TGR) region,...

The leaching behaviour of Cu and Zn from contaminated soils at a copper mine was investigated using four extractants: citric acid (CA), oxalic acid (OA), ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA). Six soil samples were characterized for the distribution of four chemical fractions of Cu or Zn (acid-soluble, reducible, ox...

The Three Gorges Reservoir (TGR) is one of the largest hydropower reservoirs in the world. However, changes of the important physical characteristics of the reservoir covering pre-, during-, and post- dam have not been well studied. This study analyzed the lengths and water surface areas of the TGR using advanced support vector machine method (SVM)...

Biodegradable dissolved organic carbon (BDOC) plays a key role in C cycle in inland waters. However, the magnitude of temperature sensitivity (Q10 value) of BDOC is still unclear, and the effect of DOC quality on Q10 value of BDOC is not well verified in these aquatic systems. Here, we used a laboratory incubation experiment to determine the Q10 va...

Soil heavy metal pollution now is a major environmental concern in China particularly in some rapidly developing areas with intensified agricultural practices. High-spatial-resolution sampling (1664 surface (0–20 cm) and 416 deep (150–200 cm) soil samples) was undertaken in four typical agricultural Counties of Municipality Chongqing (SW China) and...

Soil pollution with heavy metals (HMs) has been attracting more and more interests, however, assessment of eco-environmental and human risks particularly in a rapidly urbanization area (the upper Yangtze) remains limited. Multiple modern indices were firstly performed for complete risk assessment of eco-environment and human health based on a high-...

Rivers are an important source of CO2 to the atmosphere, however, mountainous rivers and streams with high emission rates are not well studied particularly in China. We report the first detailed investigation on monsoonal mountainous rivers in the Three Gorges Reservoir (TGR) region, with a focus on the riverine CO2 partial pressure (pCO2), CO2 deg...

Phosphorus (P) enrichment is expected to strongly influence dissolved organic carbon (DOC) biodegradation. However, the relationship between P availability and DOC biodegradation is largely unknown in nitrogen (N)-limited ecosystems. Here, we investigated the changes in the ratio of DOC to dissolved total nitrogen (DTN), specific UV absorbance at 2...

In order to assess heavy metals (HMs) in soils of the upper Yangtze Basin, a very high-spatial-resolution sampling (582 soil samples) was conducted from Hechuan County, an important agricultural practice area in the Southwest China. Multiple indices including geoaccumulation index (Igeo), enrichment factor (EF), sediment pollution index (SPI) and r...

Eight heavy metals (HMs: As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were measured from 337 top and 80 deep soil samples in Tongliang District (Chongqing, SW China), and consequently multiple statistics and indices (PI — pollution index; Igeo — geoaccumulation index; EF — enrichment factor, and RI — potential ecological risk index) were employed for risk ev...

Uncertainty is recognized as a critical consideration for accurately predicting stream water nitrogen (N) loading, but identifying the relative contribution of individual uncertainty sources within the total uncertainty remains unclear. In this study, a powerful method, referred to as the Bayesian inference combined with analysis of variance (BayeA...