Lake metabolic processes and their effects on the carbonate weathering CO2 sink: Insights from diel variations in the hydrochemistry of a typical karst lake in SW China

Metabolic processes and their effects on carbon cycling in a karst reservoir, south China

Metabolic processes of aquatic photosynthetic organisms significantly influence the multi-time scale cycle of dissolved inorganic carbon (DIC) in aquatic environments. Running karst water characterized by high DIC content are becoming lentic water body due to damming activities around the world, which could benefit for aquatic metabolic processes and change initial carbon cycle processes. However, despite the availability of high-resolution monitoring data, there is a lack of comprehensive studies examining the characteristics of the metabolic processes of aquatic photosynthetic organisms, controlling factors, and their relationship with changes in reservoir thermal structure and carbon cycling. Based on this, this study selected the Dalongdong (DLD) reservoir, a typical karst reservoir located in Southwest China, as the research area for multi-parameter high-resolution continuous monitoring conducted in 2021. Seasonal sampling of relevant indicators was conducted in June, August, and December. The results indicate that the average net ecosystem production (NEP) of surface-layer during mixing period was 0.40 mg L-1 d-1, significantly lower than the thermal stratification period (4.65 mg L-1 d-1). The reservoir demonstrated a net autotrophic state, with the estimated carbon sink of approximately 81.54 t C km-2 y-1. Seasonal and diurnal variations in metabolic processes were primarily influenced by photosynthetically active radiation, which subsequently affected the hydrochemical characteristics. During the thermal stratification period, high temperatures and significant DIC fertilization effect sustained high production efficiency among aquatic photosynthetic organisms. In contrast, during the mixing period, biological growth was more dependent on upwelling nutrient inputs from the reservoir bottom. Through physical disturbances and the inhibition of biological photosynthesis, CO2 emissions increased during rainfall, while NEP rose following the rainfall. Combining high-resolution continuous data with seasonal sampling data, the multi-scale effects of aquatic photosynthetic metabolism on the carbon cycle in aquatic systems are elucidated, which is essential for accurately calculating the carbon budget in reservoir basins.

Biogeochemical Mechanisms of HCO3-Ca Water and NO3- Pollution in a Typical Piedmont Agricultural Area: Insights from Nitrification and Carbonate Weathering

Water hardening and NO3- pollution have affected water quality globally. These environmental problems threaten social sustainability and human health, especially in piedmont agricultural areas. The aim of this study is to determine the biogeochemical mechanisms of HCO3-Ca water and NO3- pollution in a typical piedmont agricultural area (Qingshui River, Zhangjiakou, China). Here, an extensive biogeochemical investigation was conducted in a typical piedmont agricultural area (Qingshui River, China) using multiple hydrochemical, isotopic (δ2H-H2O, δ18O-H2O and δ13C-DIC) and molecular-biological proxies in combination with a forward model. In the region upstream of the Qingshui River, riverine hydrochemistry was dominated by HCO3-Ca water, with only NO3- concentrations (3.08-52.8 mg/L) exceeding the acceptable limit (10 mg/L as N) for drinking water quality. The riverine hydrochemistry responsible for the formation of HCO3-Ca water was mainly driven by carbonate dissolution, with a contribution rate of 49.8 ± 3.96%. Riverine NO3- was mainly derived from agricultural NH4+ emissions rather than NO3- emissions, originating from sources such as manure, domestic sewage, soil nitrogen and NH4+-synthetic fertilizer. Under the rapid hydrodynamic conditions and aerobic water environment of the piedmont area, NH4+-containing pollutants were converted to HNO3 by nitrifying bacteria (e.g., Flavobacterium and Fluviimonas). Carbonate (especially calcite) was preferentially and rapidly dissolved by the produced HNO3, which was attributed to the strong acidity of HNO3. Therefore, higher levels of Ca2+, Mg2+, HCO3- and NO3- were simultaneously released into river water, causing riverine HCO3-Ca water and NO3- pollution in the A-RW. In contrast, these biogeochemical mechanisms did not occur significantly in the downstream region of the river due to the cement-hardened river channels and strict discharge management. These findings highlight the influence of agricultural HNO3 on HCO3-Ca water and NO3- pollution in the Qingshui River and further improve the understanding of riverine hydrochemical evolution and water pollution in piedmont agricultural areas.

Effects of land use and dissolved organic matter on pCO2 are dependent on stream orders and hydrological seasonality in a low-order karst river

Human activities and stream accumulation influence carbon loadings, altering the distributions and characteristics of dissolved inorganic and organic carbon in rivers. It is widely recognized that such alterations affect dissolved organic matter (DOM) components, water environment and river carbon dioxide (CO2) degassing, however, the control factors by which land use/land cover (LULC) and DOM components regulate the partial pressure of CO2 (pCO2) are unclear. Here, in the Daning karst river system, an extensive investigation was presented to investigate the role of LULC and DOM components in influencing the spatial and temporal variability of pCO2, as well as to investigate the regulating effect of stream order and hydrological rhythm on this influence. DOM quality and pCO2 levels exhibited significant spatial and temporal variations. In the 3rd - 4th order streams, pCO2 was correlated with protein and lignin compounds in the wet period and with DOM molecular weight in the dry period. Relatively high protein-like components (54.83 % ∼ 71.84 %, on average) and biological index (0.86-0.90, on average) indicated notable autochthonous processes. Significant relationships between pCO2 and water quality parameters were observed in the 3rd - 4th order streams in the wet period, demonstrating the role of runoff and upstream accumulation. Farmland increased pCO2 levels in the 3rd - 4th order streams, whereas forests could potentially mitigate river CO2 saturation. River pCO2 was well predicted by LULC under extended circular buffers (1000 and 2000 m in diameter). This study demonstrated that DOM and LULC directly or indirectly affect pCO2 and that the influences are largely regulated by hydrological seasonality and stream orders, which is better for understanding aquatic CO2 drivers.

Metabolic processes drive spatio-temporal variations of carbon sink/source in a karst river

Riverine carbon dioxide (CO2) exchange is a crucial component of the global carbon cycle. However, the changes in the CO2 sink/source in karst rivers caused by differences in lithological features and climate, hindered the resolution of the spatio-temporal heterogeneity of global inland water carbon emissions. Here, we use hydrochemical data and CO2 gas isotopic data to reveal the spatio-temporal variations of CO2 sink/source in karst rivers and their controlling mechanisms. Fifty-two monitoring transects were set up in the subtropical Lijiang River in southwest China in June and December 2019. Our results indicated that the CO2 flux across the water-air interface (FCO2) in the Lijiang River basin ranged from -43.77 to 519.67 mmol/(m2·d). In June, the Lijiang River acted as an atmospheric carbon source due to higher water temperatures (Twater). However, driven by hydrodynamic conditions and the metabolism of aquatic photosynthesis, the river shifts from being an atmospheric carbon source in June to an atmospheric carbon sink in December. The stable isotopes of CO2 (δ13C-CO2) show significant differences in the spatio-temporal variations of CO2 sink/source. In December, the transects of the Lijiang River basin with a negative CO2 flux are significantly negatively correlated with dissolved oxygen (DO) and chlorophyll-a (Chl-a) concentration (p < 0.05). This confirms that the enhancement of aquatic photosynthesis efficiency increased water DO concentrations, which resulted in the positive movement of water δ13C-CO2 and a decrease in the partial pressure of CO2 (pCO2) and FCO2. Comparative analysis with global river FCO2 indicates that under the combined driving forces of metabolic processes of aquatic photosynthetic organisms and hydrodynamic conditions, rivers tend to act more frequently as CO2 sinks, particularly in subtropical and temperate rivers. In conclusion, this study represents a new example focusing on CO2 dynamics to address the spatio-temporal heterogeneity of carbon emissions in inland waters on a global scale.

Variations and driving factors for concentrations and carbon isotopes of dissolved CO2 in lake water across different Chinese lakes

Carbon dioxide (CO2) stands as the primary driver of Earth's greenhouse effect, and it's suggested that the global contribution of CO2 emissions from lakes cannot be ignored. Despite the numerous estimations of CO2 fluxes from lakes, limited focus has been directed towards the carbon isotopes (δ13C) of dissolved CO2 in lake water. Particularly, the potential use of δ13C values in tracing the CO2 concentrations in lake water remains as an understudied area, warranting further exploration and investigation. In this study, we conducted an analysis of the concentrations and δ13C values of dissolved CO2 in 33 lakes located at the Tibetan Plateau, Chinese Loess Plateau, and Yangtze Plain (among which high-resolution spatial investigations were performed in 6 lakes through in-situ continuous monitoring). Our findings revealed spatial variations in both the CO2 concentrations and δ13C values in lakes. Additionally, notable differences are observed among lakes in different regions of China, with lakes in the Yangtze Plain exhibiting considerably higher CO2 concentrations, and the overall CO2 δ13C values in lakes on the Tibetan Plateau tend to be more positive, while those in lakes on the Chinese Loess Plateau tend to be more negative. The pH values, dissolved oxygen, and dissolved organic carbon are likely crucial factors influencing the CO2 concentrations and δ13C values in the lakes. Furthermore, lake water CO2 concentrations are negatively correlated with δ13C values of CO2 and dissolved inorganic carbon (DIC) both within a single lake with high spatial resolutions or in lake groups across different regions. These results highlight that the CO2/DIC δ13C values can be applied to trace the concentration variations of dissolved CO2 in lakes.

Reducing CO2 emissions from rivers around bare land contributes to improving the carbon sink function of the Qinghai-Tibetan Plateau

River CO2 fluxes (FCO2) play an important role in the carbon cycle of the Qinghai‒Tibet Plateau (QTP). However, the carbon budget of river water is ignored in the assessment of the carbon sources and sinks of ecosystems on the QTP, which makes the assessment of the carbon sinks of ecosystems uncertain on the QTP. Here, we selected rivers around alpine steppe, alpine meadow, forestland and bare land areas on the QTP to determine their FCO2 values and control factors during thaw, rainy and freezing periods. The results revealed that river water around the alpine steppe absorbed CO2 during the thaw and freezing periods, making it a carbon sink. The influencing factors of FCO2 around different ecosystems significantly differed across the different periods. The pCO2 was the most direct factor affecting the FCO2 of river water. During the thaw period, the FCO2 of rivers around the alpine steppe and bare land was affected mainly by dissolved organic carbon (DOC) and precipitation, respectively. The FCO2 of rivers around the alpine meadow and forestland was affected by dissolved inorganic carbon (DIC). During the rainy period, the FCO2 of the rivers around the alpine steppe and bare land was affected mainly by total nitrogen (TN) and salinity, respectively. The FCO2 of rivers around the alpine meadow and forestland was affected by dissolved oxygen (DO) and DOC. During the freezing period, the FCO2 of the rivers around the alpine steppe and bare land was affected mainly by TN and pCO2, respectively. The FCO2 of rivers around the forestland and alpine meadow was affected by precipitation, runoff and DIC. The FCO2 in rivers around vegetated areas were affected by rock weathering, aquatic ecosystem biology and hydrological processes to varying degrees at different times. However, rivers around bare ground were less affected by these processes. The FCO2 values around the alpine steppe, alpine meadow, forestland and bare land were 1.40 g C/m2/d, 1.12 g C/m2/d, 2.29 g C/m2/d and 4.20 g C/m2/d, respectively. The river water around bare land released a large amount of CO2. Therefore, to reduce the CO2 emissions of rivers on the QTP, it is urgent that we restore bare-land vegetation and promote the transfer of bare land to steppe, which is an effective way to increase the carbon sink of the ecosystems on the QTP.

The shifting pattern of CO2 source sink in a subtropical urbanizing lightly eutrophic lake

Globally, numerous freshwater lakes exist, and rapid urbanization has impacted carbon biogeochemical cycling at the interface where water meets air in these bodies. However, there is still a limited understanding of CO2 absorption/emission in eutrophic urbanizing lakes. This study therefore involved biweekly in-situ monitoring to evaluate fluctuations in the partial pressure (pCO2) and flux (fCO2) of CO2 and associated parameters from January to September 2020 (7:00-17:00 CST) in an urbanizing lake in southwestern China. Our study revealed that during the daylight hours of the 11 sampling days, both pCO2 and fCO2 consistently demonstrated decreasing trends from the early morning period to the late afternoon period, with notable increases on May 7th and August 15th, respectively. Interestingly, unlike our previous findings, an nonsignificant difference (p > 0.05) in mean pCO2 and fCO2 was observed between the morning period and the afternoon period (n = 22). Furthermore, the mean pCO2 in January (~105 μatm; n = 4) and April (133-212 μatm; n = 8) was below the typical atmospheric CO2 level (C-sink), while that in the other months surpassed 410 μatm (C-source), although the average values (n = 44) of pCO2 and fCO2 were 960 ± 841 μatm and 57 ± 85 mmol m-2 h-1, respectively. Moreover, the pCO2 concentration was significantly greater in summer (May to August, locally reaching 1087 μatm) than in spring (January to April at 112 μatm), indicating a seasonal shift between the C-sink (spring) and the C-source (summer). In addition, a significant positive correlation in pCO2/fCO2 with chlorophyll-a/nitrate but a negative correlation in dissolved oxygen and total phosphorus were recorded, suggesting that photosynthesis and respiration were identified as the main drivers of CO2 absorption/emissions, while changes in nitrate and phosphorus may be attributed to urbanization. Overall, our investigations indicated that this lightly eutrophic lake demonstrated a distinct shifting pattern of CO2 source-sink variability at daily and seasonal scales.

Effects of carbon limitation and carbon fertilization on karst lake-reservoir productivity

Nitrogen and phosphorus are universally recognized as limiting elements in the eutrophication processes affecting the majority of the world's lakes, reservoirs, and coastal ecosystems. However, despite extensive research spanning several decades, critical questions in eutrophication science remain unanswered. For example, there is still much to understand about the interactions between carbon limitation and ecosystem stability, and the availability of carbon components adds significant complexity to aquatic resource management. Mounting evidence suggests that aqueous CO2 could be a limiting factor, influencing the structure and succession of aquatic plant communities, especially in karstic lake and reservoir ecosystems. Moreover, the fertilization effect of aqueous CO2 has the potential to enhance carbon sequestration and phosphorus removal. Therefore, it is important to address these uncertainties to achieve multiple positive outcomes, including improved water quality and increased carbon sinks in karst lakes and reservoirs.

Plant-microbe involvement: How manganese achieves harmonious nitrogen-removal and carbon-reduction in constructed wetlands

Carbon deficits in inflow frequently lead to inefficient nitrogen removal in constructed wetlands (CWs) treating tailwater. Solid carbon sources, commonly employed to enhance denitrification in CWs, increase carbon emissions. In this study, MnO2 was incorporated into polycaprolactone substrates within CWs, significantly enhancing NH4+-N and NO3--N removal efficiencies by 48.26-59.78 % and 96.84-137.23 %, respectively. These improvements were attributed to enriched nitrogen-removal-related enzymes and increased plant absorption. Under high nitrogen loads (9.55 ± 0.34 g/m3/d), emissions of greenhouse gases (CO2, CH4, and N2O) decreased by 147.23-202.51 %, 14.53-86.76 %, and 63.36-87.36 %, respectively. N2O emissions were reduced through bolstered microbial nitrogen removal pathways by polycaprolactone and MnO2. CH4 accumulation was mitigated by the increased methanotrophs and dampened methanogenesis, modulated by manganese. Additionally, manganese-induced increases in photosynthetic pigment contents (21.28-64.65 %) fostered CO2 sequestration through plant photosynthesis. This research provides innovative perspectives on enhancing nitrogen removal and reducing greenhouse gas emissions in constructed wetlands with polymeric substrates.

Algal-bacterial consortium promotes carbon sink formation in saline environment

INTRODUCTION

The level of atmospheric CO2 has continuously been increasing and the resulting greenhouse effects are receiving attention globally. Carbon removal from the atmosphere occurs naturally in various ecosystems. Among them, saline environments contribute significantly to the global carbon cycle. Carbonate deposits in the sediments of salt lakes are omnipresent, and the biological effects, especially driven by halophilic microalgae and bacteria, on carbonate formation remain to be elucidated.

OBJECTIVES

The present study aims to characterize the carbonates formed in saline environments and demonstrate the mechanisms underlying biological-driven CO2 removal via microalgal-bacterial consortium.

METHODS

The carbonates naturally formed in saline environments were collected and analyzed. Two saline representative organisms, the photosynthetic microalga Dunaliella salina and its mutualistic halophilic bacteria Nesterenkonia sp. were isolated from the inhabiting saline environment and co-cultivated to study their biological effects on carbonates precipitation and isotopic composition. During this process, electrochemical parameters and Ca2+ flux, and expression of genes related to CaCO3 formation were analyzed. Genome sequencing and metagenomic analysis were conducted to provide molecular evidence.

RESULTS

The results showed that natural saline sediments are enriched with CaCO3 and enrichment of genes related to photosynthesis and ureolysis. The co-cultivation stimulated 54.54% increase in CaCO3 precipitation and significantly promoted the absorption of external CO2 by 49.63%. A pH gradient was formed between the bacteria and algae culture, creating 150.22 mV of electronic potential, which might promote Ca2+ movement toward D. salina cells. Based on the results of lab-scale induction and 13C analysis, a theoretical calculation indicates a non-negligible amount of 0.16 and 2.3 Tg C/year carbon sequestration in China and global saline lakes, respectively.

CONCLUSION

The combined effects of these two typical representative species have contributed to the carbon sequestration in saline environments, by promoting Ca2+ influx and increase of pH via microalgal and bacterial metabolic processes.

Control of carbon dioxide exchange fluxes by rainfall and biological carbon pump in karst river-lake systems

As an important component of inland water, the primary factors affecting the carbon cycle in karst river-lake systems require further investigation. In particular, the impacts of climatic factors and the biological carbon pump (BCP) on carbon dioxide (CO2) exchange fluxes in karst rivers and lakes deserve considerable attention. Using quarterly sampling, field monitoring, and meteorological data collection, the spatiotemporal characteristics of CO2 exchange fluxes in Erhai Lake (a typical karst lake in Yunnan, SW China) and its inflow rivers were investigated and the primary influencing factors were analyzed. The average river CO2 exchange flux reached 346.80 mg m-2 h-1, compared to -6.93 mg m-2 h-1 for the lake. The carbon cycle in rivers was strongly influenced by land use within the basin; cultivated and construction land were the main contributors to organic carbon (OC) in the river (r = 0.66, p < 0.01) and the mineralization of OC was a major factor in CO2 oversaturation in most rivers (r = 0.76, p < 0.01). In addition, the BCP effect of aquatic plants and the high pH in karst river-lake systems enhance the ability of water body to absorb CO2, resulting in undersaturated CO2 levels in the lake. Notably, under rainfall regulation, riverine OC and dissolved inorganic carbon (DIC) flux inputs controlled the level of CO2 exchange fluxes in the lake (rOC = 0.78, p < 0.05; rDIC = 0.97, p < 0.01). We speculate that under future climate and human activity scenarios, the DIC and OC input from rivers may alleviate the CO2 limitation of BCP effects in karst eutrophication lakes, possibly enabling aquatic plants to convert more CO2 into OC for burial. The results of this research can help advance our understanding of CO2 emissions and absorption mechanisms in karst river-lake systems.

Fine-scale spatiotemporal variations in bacterial community diversity in agricultural pond water

Microbial communities in surface waters are affected by environmental conditions and can influence changes in water quality. To explore the hypothesis that the microbiome in agricultural waters associates with spatiotemporal variations in overall water quality and, in turn, has implications for resource monitoring and management, we characterized the relationships between the microbiota and physicochemical properties in a model irrigation pond as a factor of sampling time (i.e., 9:00, 12:00, 15:00) and location within the pond (i.e., bank vs. interior sites and cross-sectional depths at 0, 1, and 2 m). The microbial communities, which were defined by 16S rRNA gene sequencing analysis, significantly varied based on all sampling factors (PERMANOVA P < 0.05 for each). While the relative abundances of dominant phyla (e.g., Proteobacteria and Bacteroidetes) were relatively stable throughout the pond, subtle yet significant increases in α-diversity were observed as the day progressed (ANOVA P < 0.001). Key water quality properties that also increased between the morning and afternoon (i.e., pH, dissolved oxygen, and temperature) positively associated with relative abundances of Cyanobacteria, though were inversely proportional to Verrucomicrobia. These properties, among additional parameters such as bioavailable nutrients (e.g., NH3, NO3, PO4), chlorophyll, phycocyanin, conductivity, and colored dissolved organic matter, exhibited significant relationships with relative abundances of various bacterial genera as well. Further investigation of the microbiota in underlying sediments revealed significant differences between the bank and interior sites of the pond (P < 0.05 for α- and β-diversity). Overall, our findings emphasize the importance of accounting for time of day and water sampling location and depth when surveying the microbiomes of irrigation ponds and other small freshwater sources.

The dual roles of dissimilatory iron reduction in the carbon cycle: The "iron mesh" effect can increase inorganic carbon sequestration

Dissimilatory iron reduction (DIR) can drive the release of organic carbon (OC) as carbon dioxide (CO2 ) by mediating electron transfer between organic compounds and microbes. However, DIR is also crucial for carbon sequestration, which can affect inorganic-carbon redistribution via iron abiotic-phase transformation. The formation conditions of modern carbonate-bearing iron minerals (ICFe ) and their potential as a CO2 sink are still unclear. A natural environment with modern ICFe , such as karst lake sediment, could be a good analog to explore the regulation of microbial iron reduction and sequential mineral formation. We find that high porosity is conducive to electron transport and dissimilatory iron-reducing bacteria activity, which can increase the iron reduction rate. The iron-rich environment with high calcium and OC can form a large sediment pore structure to support rapid DIR, which is conducive to the formation and growth of ICFe . Our results further demonstrate that the minimum DIR threshold suitable for ICFe formation is 6.65 μmol g-1  dw day-1 . DIR is the dominant pathway (average 66.93%) of organic anaerobic mineralization, and the abiotic-phase transformation of Fe2+ reduces CO2 emissions by ~41.79%. Our findings indicate that as part of the carbon cycle, DIR not only drives mineralization reactions but also traps carbon, increasing the stability of carbon sinks. Considering the wide geographic distribution of DIR and ICFe , our findings suggest that the "iron mesh" effect may become an increasingly important vector of carbon sequestration.

Impact of ecosystem metabolism on CO2 emissions: Insights from high-resolution time series of pH measured in situ

Lakes and reservoirs are important sources/sinks of atmospheric CO2. Primary production and respiration transforming inorganic to organic carbon and vice versa alter CO2 concentrations in the surface waters and thus affect CO2 emissions. Here we investigate the link between net-production (NEP) and CO2 concentrations and emissions at high temporal resolution over more than two months in a German pump storage reservoir. Continuous in-situ pH measurements in combination with few alkalinity measurements provided concentrations of CO2 and dissolved inorganic carbon (DIC) at high temporal resolution over more than 75 days. Time series of metabolic rates of carbon were determined with an open-water diel pH technique, which utilizes the diel changes in DIC obtained from the observed diel changes in pH and data on alkalinity. During the measuring period, average NEP was positive and CO2 concentrations were typically substantially under-saturated. On average, the reservoir acted as a sink for CO2, whereby CO2 uptake was 39% larger in the evening than in the morning. Only few consecutive days with negative NEP were sufficient to turn the reservoir temporally into a source of CO2. Therefore, the average CO2 uptake determined from continuous data can be 80% larger to 30% smaller than estimates of average uptake based on bi-weekly data. Daily mean NEP explained only 9% and 4% of the variance of daily mean DIC and CO2. Note that NEP is proportional to the time derivative of DIC and therefore not expected to correlate well with DIC in general. Because CO2 changes nonlinearly with DIC, NEP explains less variance of CO2 than of DIC. Numerical experiments confirmed the arguments above and revealed that at positive average NEP the total CO2 uptake over several weeks is not well predicted by average NEP but depends on the detailed temporal pattern of NEP. However, if average NEP is negative, average NEP may be a good predictor of total CO2 emissions. Similar conclusions apply for high and low alkalinity waters, but uptake rates and temporal variability of CO2 emissions are smaller in high than in low alkalinity waters. Assessment of the link between NEP and CO2 emissions requires differentiation between lakes with different alkalinity and, because of the non-linear relationship between NEP and CO2, strongly benefits from data with high temporal resolution especially during time-periods with positive net-production.

The Carbon Emission Characteristics and Reduction Potential in Developing Areas: Case Study from Anhui Province, China

Global warming and world-wide climate change caused by increasing carbon emissions have attracted a widespread public attention, while anthropogenic activities account for most of these problems generated in the social economy. In order to comprehensively measure the levels of carbon emissions and carbon sinks in Anhui Province, the study adopted some specific carbon accounting methods to analyze and explore datasets from the following suggested five carbon emission sources of energy consumption, food consumption, cultivated land, ruminants and waste, and three carbon sink sources of forest, grassland and crops to compile the carbon emission inventory in Anhui Province. Based on the compiled carbon emission inventory, carbon emissions and carbon sink capacity were calculated from 2000 to 2019 in Anhui Province, China. Combined with ridge regression and scenario analysis, the STIRPAT model was used to evaluate and predict the regional carbon emission from 2020 to 2040 to explore the provincial low-carbon development pathways, and carbon emissions of various industrial sectors were systematically compared and analyzed. Results showed that carbon emissions increased rapidly from 2000 to 2019 and regional energy consumption was the primary source of carbon emissions in Anhui Province. There were significant differences found in the increasing carbon emissions among various industries. The consumption proportion of coal in the provincial energy consumption continued to decline, while the consumption of oil and electricity proceeded to increase. Furthermore, there were significant differences among different urban and rural energy structures, and the carbon emissions from waste incineration were increasing. Additionally, there is an inverted "U"-shape curve of correlation between carbon emission and economic development in line with the environmental Kuznets curve, whereas it indicated a "positive U"-shaped curve of correlation between carbon emission and urbanization rate. The local government should strengthen environmental governance, actively promote industrial transformation, and increase the proportion of clean energy in the energy production and consumption structures in Anhui Province. These also suggested a great potential of emission reduction with carbon sink in Anhui Province.