Eutrophication decreased CO2 but increased CH4 emissions from lake: A case study of a shallow Lake Ulansuhai
Graphical abstract
Introduction
Inland waters play a critical role in the storage and emission of greenhouse gases (GHGs), and they are extremely active components of the local and global carbon cycles (Butman et al., 2016; Davidson et al., 2015; Saunois et al., 2020; Vachon et al., 2010). Global inland waters emitted 0.13 Pg C yr−1 of methane (CH4) (Stanley et al., 2016) and 2.1 Pg C yr−1 of carbon dioxide (CO2) (DelSontro et al., 2018; Raymond et al., 2013). Lakes are a vital component of the inland water system concerning carbon cycle and climate regulation because they store, transport, and transform carbon (Tranvik et al., 2009). Global lakes only cover 3.7% of the non-glaciated land area on Earth (Verpoorter et al., 2014); however, they emit large amounts of CO2 and CH4. While previous research has estimated global GHG emissions from lakes, certain differences have been observed between the studies (Raymond et al., 2013; Holgerson and Raymond, 2016; Li et al., 2018; Bastviken et al., 2011; Wik et al., 2016; Saunois et al., 2020).
Shallow lakes (average depth of less than 3 m) are the water bodies that account for the largest area globally (Downing et al., 2006; Verpoorter et al., 2014), while functioning as important sources of carbon efflux (Bastviken et al., 2011; Tranvik et al., 2009). Low water levels lead to reduced water hydrostatic pressure and shorter gas transport pathways (DelSontro et al., 2011). This can reduce CH4 oxidation and lead to rapid CH4 emission into the atmosphere, thereby resulting in greater proportions of GHG emissions from shallow lakes than those observed from deep lakes (Li et al., 2020). Furthermore, shallow lakes are affected by turbulence (Margalef, 1997; Zhu et al., 2018). Wind-driven turbulence can lead to thermal destratification and hypoxia reduction, thereby enhancing organic matter aerobic decomposition and inhibiting CH4 production. Thus, turbulence can increase CO2 emissions and decrease CH4 emissions (Jalil et al., 2018; Jung et al., 2014; Zhu et al., 2018). Compared to deep lakes, shallow lakes are more vulnerable to eutrophication due to high nutrient loadings and poor self-cleaning capacity (Havens et al., 2001; Li et al., 2020). In addition, their nutrient levels and biotic interactions can affect GHG production and biogeochemical processes (Davidson et al., 2015). The high nutrient loadings in shallow lakes stimulate mineralisation and provided more liable organic substrates to enhance CH4 production, causing an increase in GHG emissions (Li et al., 2020; Xiao et al., 2020). In contrast, nutrient enrichment can enhance primary production to promote the carbon fixation efficiency of lake sediments (Gu et al., 2011), resulting in a decrease in CO2 emissions. Additionally, aquatic plants and phytoplankton drive the primary production in shallow lakes and therefore reduce CO2 emissions due to their CO2 uptake from the water (Engel et al., 2019). However, the dynamics of CO2 and CH4 under different eutrophication levels in a lake remain unclear. Therefore, it is necessary to study the impact of eutrophication on GHG emissions in shallow lakes.
Eutrophication is a serious environmental problem in inland lakes (Anderson et al., 2014; Sinha et al., 2017), and the eutrophic status plays a critical role in influencing the amount of GHG emissions from inland lakes (Davidson et al., 2015; Xiao et al., 2017). Studies have found that eutrophication can stimulate GHGs emissions. For example, a laboratory incubation experiment demonstrated that hypereutrophic lakes exhibited higher CH4 emissions than those of oligotrophic lakes (Sepulveda-Jauregui et al., 2015). Studies on GHG emissions from continuous eutrophication lakes and impoundments illustrated that higher levels of eutrophication can increase GHG emissions into the atmosphere (DelSontro et al., 2018). In contrast, Balmer and Downing found that eutrophication enhanced primary production, thereby decreasing CO2 emissions (Balmer and Downing, 2011). Although the impact of eutrophication on GHG emissions has been investigated, the results of previous studies have been contradictory (Davidson et al., 2015; Sepulveda-Jauregui et al., 2015; Xiao et al., 2020). Furthermore, it is not clear how different levels of eutrophication affect GHG dynamics. In China, there are approximately 185,000 lakes, that exhibit a total surface area of approximately 82,232 km2 (Yang and Lu, 2014). Eutrophication has become one of the most prominent problems faced by freshwater shallow lakes (Zhao et al., 2012). Therefore, more studies are required to study the impact of eutrophication on GHG emissions.
Here, we conducted a field study to explore the effect of eutrophication on GHG dynamics in an arid shallow lake. The specific objectives of this study were (1) to evaluate the spatial and seasonal variations and possible influence factors associated with the partial pressures and emissions of CO2 and CH4, and (2) to clarify the impact of eutrophication on CO2 and CH4 emissions in shallow lakes.
Section snippets
Study area and sampling sites
Lake Ulansuhai (40°46′–41°08′N, 108°40′–108°57′E) is located in Urad Qianqi, Bayannaoer City of the Inner Mongolia Autonomous Region, China (Fig. 1). It is a typical furiotile lake with a total area of 293 km2 and a storage capacity of 2.5–3 × 108 m3 (Ma et al., 2013). The depth of the lake ranges from 0.5 to 3 m, with an average depth of 0.7 m (Köbbing et al., 2014). It lies in a temperate continental climate with four distinct seasons, and the ice-free period of the lake is from April to
Temporal and spatial variation of environmental variables and trophic states
Lake Ulansuhai exhibited significant temporal variations in its biological and chemical properties (Fig. 2, Fig. 3). Furthermore, there were significant differences in mean value of pH, DO, DOC, TN and NO3− amongst the seven sites; however, there were no significant spatial variations in the mean water temperature, Chl-a, DIC, TP, DTP and NH4+. The pH value changed from 7.05 to 10.00 with a mean value of 8.82±0.13; the pH value at S1 was slightly lower than that of the other sites (Fig. 2b).
CO2
Water environments affect the balance of aquatic CO2 production and consumption. pCO2 exhibited spatial and temporal variations in Lake Ulansuhai, suggesting that the CO2 dynamics were affected by ambient parameters that also demonstrated spatial and temporal variations. The correlation analysis results demonstrated that pCO2 was negatively correlated with water temperature (R2=0.31, p<0.01) and pH (R2=0.26, p<0.01) (Fig. 8a and b), which was similar to the results reported in previous studies (
Conclusions
In this study, we investigated GHG (CO2 and CH4) emissions and environmental parameters in Lake Ulansuhai from January 2019 to October 2019 by conducting trimestral sampling campaigns. This study explored the dynamics of CO2 and CH4 in a hypereutrophic lake, demonstrating large spatial and temporal variations in the partial pressures and emissions of CO2 and CH4. Our results indicate that the lake is a source of CO2 but a stronger source of CH4, and that an increase in the trophic state (e.g.
CRediT authorship contribution statement
Heyang Sun: Visualization, Methodology, Formal analysis, Writing – original draft, Writing – review & editing. Xixi Lu: Visualization, Writing – original draft, Writing – review & editing. Ruihong Yu: Visualization, Writing – original draft, Writing – review & editing. Jie Yang: Visualization, Writing – original draft. Xinyu Liu: Writing – review & editing. Zhengxu Cao: Methodology, Formal analysis. Zhuangzhuang Zhang: Methodology, Formal analysis. Meixia Li: Methodology, Formal analysis. Yue
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper.
Acknowledgments
This study was funded by the Major Science and Technology Projects of Inner Mongolia Autonomous Region (grant nos. 2020ZD0009 and ZDZX2018054), National Natural Science Foundation of China (grant no. 51869014), Key Scientific and Technological Project of Inner Mongolia (grant no. 2019GG019), National Key Research and Development Program of China (grant no. 2016YFC0500508), and Open Project Program of the Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau
References (109)
- et al.
Methane emissions from wastewater management
Environ. Pollut.
(2001) - et al.
Gas transfer velocities of CO2 and CH4 in a tropical reservoir and its river downstream
J. Mar. Syst.
(2007) - et al.
Nutrient dynamics and the eutrophication of shallow lakes Kasumigaura (Japan), Donghu (PR China), and Okeechobee (USA)
Environ. Pollut.
(2001) - et al.
Fluxes of methane, carbon dioxide and nitrous oxide in boreal lakes and potential anthropogenic effects on the aquatic greenhouse gas emissions
Chemosphere
(2003) - et al.
The role of wind field induced flow velocities in destratification and hypoxia reduction at meiling bay of large shallow Lake Taihu, China
Environ. Pollut.
(2018) - et al.
Two-step accelerated mineral carbonation and decomposition analysis for the reduction of CO2 emission in the eco-industrial parks
J. Environ. Sci.
(2014) - et al.
Effects of seasonality, trophic state and landscape properties on CO2 saturation in low-latitude lakes and reservoirs
Sci. Total Environ.
(2019) - et al.
Economic evaluation of common reed potential for energy production: a case study in Wuliangsuhai Lake (Inner Mongolia, China)
Biomass Bioenerg.
(2014) - et al.
Large greenhouse gases emissions from China’s lakes and reservoirs
Water Research
(2018) - et al.
The significant contribution of lake depth in regulating global lake diffusive methane emissions
Water Res.
(2020)
Geochemical evidence of the anthropogenic alteration of element composition in lacustrine sediments from Wuliangsu Lake, North China
Quat. Int.
Uncertainty analysis of gas flux measurements at air-water interface using floating chambers
Ecohydrol. Hydrobiol.
Methane emissions in two small shallow neotropical lakes: the role of temperature and trophic level
Atmospheric Environment
Eutrophication exacerbates the impact of climate warming on lake methane emission
Sci. Total Environ.
Water velocity and irradiance effects on internal transport and metabolism of methane in submerged Isoetes alpinus and Potamogeton crispus
Aquatic Botany
Effects of water depth and substrate on growth and morphology of Eleocharis sphacelata: implications for culm support and internal gas transport
Aquatic Botany
Carbon dioxide and methane supersaturation in lakes of semi-humid/semi-arid region, Northeastern China
Atmos. Environ.
Fluxes of carbon dioxide and methane across the water–atmosphere interface of aquaculture shrimp ponds in two subtropical estuaries: the effect of temperature, substrate, salinity and nitrate
Sci. Total Environ.
Daily pCO2 and CO2 flux variations in a subtropical mesotrophic shallow lake
Water Res.
Methane and carbon dioxide fluxes from a shallow hypereutrophic subtropical Lake in China
Atmospheric Environmen
Physical controls on carbon dioxide transfer velocity and flux in low-gradient river systems and implications for regional carbon budgets
J. Geophys. Res. Biogeosci.
Lake eutrophication and its implications for organic carbon sequestration in Europe
Glob. Change Biol.
Carbon dioxide concentrations in eutrophic lakes: undersaturation implies atmospheric uptake
Inland Waters
Methane emissions from lakes: dependence of lake characteristics, two regional assessments, and a global estimate
Glob. Biogeochem. Cycles
Heat-wave effects on oxygen, nutrients, and phytoplankton can alter global warming potential of gases emitted from a small shallow lake
Environ. Sci. Technol.
Freshwater methane emissions offset the continental carbon sink
Science
Eutrophication will increase methane emissions from lakes and impoundments during the 21st century
Nat. Commun.
Aquatic carbon cycling in the conterminous United States and implications for terrestrial carbon accounting
Proc. Natl. Acad. Sci. U. S. A.
A trophic state index for lakes 1
Limnol. Oceanogr.
Seasonal dynamics of dissolved methane in lakes of the Mackenzie Delta and the role of carbon substrate quality
J. Geophys.Res. Biogeosci.
Synergy between nutrients and warming enhances methane ebullition from experimental lakes
Nat. Clim. Change
Eutrophication effects on greenhouse gas fluxes from shallow-lake mesocosms override those of climate warming
Glob. Change Biol.
Greenhouse gas emissions from lakes and impoundments: upscaling in the face of global change
Limnol. Oceanogr. Lett.
Spatial heterogeneity of methane ebullition in a large tropical reservoir
Environ. Sci. Technol.
The global abundance and size distribution of lakes, ponds, and impoundments
Limnol. Oceanogr.
Environmental conditions for phytoplankton influenced carbon dynamics in boreal lakes
Aquat. Sci
Spatio-temporal variability of lake CH4 fluxes and its influence on annual whole lake emission estimates
Limnology and Oceanography
Eutrophication reverses whole-lake carbon budgets
Inland Waters
Long-term C accumulation and total C stocks in boreal lakes in northern Québec
Glob. Biogeochem. Cycles
Magnitudes and controls of organic and inorganic carbon flux through a chain of hard-water lakes on the northern Great Plains
Limnology and Oceanography
Regulation of spatial and temporal variability of carbon flux in six hard-water lakes of the northern great plains
Limnol. Oceanogr.
Extreme13 C enrichments in a shallow hypereutrophic lake: implications for carbon cycling
Limnol. Oceanogr.
Low carbon dioxide partial pressure in a productive subtropical lake
Aquat. Sci.
Biovolume calculation for pelagic and benthic microalgae
J. Phycol.
Large contribution to inland water CO2 and CH4 emissions from very small ponds
Nat. Geosci.
Fluxes of CH4, CO2, and N2O in hydroelectric reservoirs Lokka and Porttipahta in the northern boreal zone in Finland
Glob, Biogeochem. Cycles
Lake Environment in China
Terrestrial organic matter support of lake food webs: evidence from lake metabolism and stable hydrogen isotopes of consumers
Limnol. Oceanogr.
Geographical and environmental drivers of regional differences in the lake pCO2 versus DOC relationship across northern landscapes
J. Geophys. Res. Biogeosci.
Continental-scale variation in controls of summer CO2 in United States lakes
J. Geophys. Res. Biogeosci.
Cited by (69)
Re-estimating China's lake CO<inf>2</inf> flux considering spatiotemporal variability
2024, Environmental Science and EcotechnologyQuantifying the contribution of methane diffusion and ebullition from agricultural ditches
2024, Science of the Total EnvironmentSpatio-temporal patterns and drivers of CH<inf>4</inf> and CO<inf>2</inf> fluxes from rivers and lakes in highly urbanized areas
2024, Science of the Total EnvironmentDiel variability of carbon dioxide concentrations and emissions in a largest urban lake, Central China: Insights from continuous measurements
2024, Science of the Total EnvironmentClimatic zone effects of non-native plant invasion on CH<inf>4</inf> and N<inf>2</inf>O emissions from natural wetland ecosystems
2024, Science of the Total Environment