Persistence of fertilization effects on soil organic carbon in degraded alpine wetlands in the Yellow River source region

In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are sustainable.This study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics,soil physicochemical properties,and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen,phosphorus,and organic mixed fertilizer.The following results were obtained:The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded wetlands.Three months after fertilization,nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands,whereas after 15 months,organic compost enhanced the soil organic carbon level in severely degraded wetlands.Structural equation modeling indicates that fertilization decreases the soil pH and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of vegetation.Three months after fertilization,nitrogen fertilizer showed a direct positive effect on soil organic carbon.However,organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil moisture.After 15 months,none of the fertilizers significantly affected the soil organic carbon level.In summary,it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.

One-pot degradation of cellulose into carbon dots and organic acids in its homogeneous aqueous solution

As the abundant biopolymer, cellulose can be used as a feedstock for chemicals and materials. Effective conversion of cellulose by simple processes is a key point. Degradation of cellulose in its homogeneous solution is attractive for the molecular chains are free and spread. Here,microcrystalline cellulose was first dissolved in aqueous solution of Na OH and urea, and then hydrothermal reaction was carried out at various temperature and time. Fluorescence carbon dots(CDs) were generated accompanied with six organic acids: oxalic acid, formic acid, malonic acid, lactic acid, acetic acid, and fumaric acid. The yields of all organic acids and CDs, and the fluorescence quantum yield(QY) of CDs were studied at different reaction conditions. It was found that the maximum yield of organic acids and CDs are 80.1% and 6.03%, respectively, and the highest QY of the CDs is 10.9%. Fluorescence studies reveal that the as-prepared CDs has efficient selectivity and sensitivity toward iron ions in acidic condition, indicating it is a potential fluorescent sensor to the detection of Fe3+. Importantly, it provides a panorama to summary the degradation routes of cellulose in its homogeneous aqueous solution with both organic molecules and CDs as products.

Effects of degradation succession of alpine wetland on soil organic carbon and total nitrogen in the Yellow River source zone,west China

Wetland is an important carbon pool,and the degradation of wetlands causes the loss of organic carbon and total nitrogen.This study aims to explore how wetland degradation succession affects soil organic carbon(SOC)and total nitrogen(TN)contents in alpine wetland.A field survey of 180 soilsampling profiles was conducted in an alpine wetland that has been classified into three degradation succession stages.The SOC and TN contents of soil layers from 0 to 200 cm depth were studied,including their distribution characteristics and the relationship between microtopography.The results showed that SOC and TN of different degradation succession gradients followed the ranked order of Non Degradation(ND)>Light Degradation(LD)>Heavy Degradation(HD).SWC was positively correlated with SOC and TN(p<0.05).As the degree of degradation succession worsened,SOC and TN became more sensitive to the SWC.Microtopography was closely related to the degree of wetland degradation succession,SWC,SOC and TN,especially in the topsoil(0-30 cm).This result showed that SWC was an important indicator of SOC/TN in alpine wetland.It is highly recommended to strengthen water injection into the wetland as a means of effective restoration to reverse alpine meadow back to marsh alpine wetland.

Dissolved organic carbon and nitrogen in precipitation, throughfall and stemflow from Schima superba and Cunninghamia lanceolata plantations in subtropical China

Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two planta- tions of Schima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO3 -N, NH4 -N and total dissolved N (TDN). DON was calculated by subtracting NO3 -N and NH4 -N from TDN. The results - + - + showed that the precipitation had a mean DOC concentration of 1.7 mg·L-1 and DON concentration of 0.13 mg·L-1. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L-1 in the SS and 10.3 and 0.19 mg·L-1 in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L-1 respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L-1 respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipita- tion tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September-November period.

Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain,Northeast China

Overwhelming evidence reveals that concentrations of dissolved organic carbon （DOC） have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland （R^2 = 0.3122 and R^2 = 0.443）. The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon （TOC）, total carbon （TC） and Fe（II）, DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe（II） were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain.

Concentrations and seasonal dynamics of dissolved organic carbon in forest floors of two plantations （Castanopsis kawakamii and Cunninghamia lanceolata） in subtropical China

The concentrations and seasonal dynamics of DOC in forest floors of monoculture plantations of Castanopsis kawakamii and Chinese fir （Cunninghamia lanceolata） were assessed in Sanming, Fujian, China （26°11′30″N, 117°26′00″E）. Forest floor samples were taken in January, April, July and October in 2002 and divided into undecomposed material （horizon Oi）, partially decomposed organic material （horizon Oe）, and fully decomposed organic material （horizon Oa）. Upon collection. DOC concentrations of samples were analyzed by a High Temperature TOC. The results showed that the annual average DOC concentration of Chinese fir （1341.7 mg·kg^-1） in the forest floor was higher than that of Castanopsis kawakamii （ 1178.9 mg·kg^-1）. Difference in DOC concentrations was observed among three horizons of the forest floor. DOC concentration of forest floor in the two forests was the highest in horizon Oe. Seasonal trends of DOC concentrations in different horizons of forest floors were similar and the maximal value occurred in autumn （or winter）. The concentration and temporal change of DOC in studied forests were probably related to the variation in moisture, temperature, biological activity and quantity of organic matter in the forest floor.

Spatial Variation of Dissolved Organic Carbon in Soils of Riparian Wetlands and Responses to Hydro-geomorphologic Changes in Sanjiang Plain, China

Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli River and the Bielahong River. The results showed that the average contents of DOC for soil layer of 0–100 cm were 730.6 mg/kg, 250.9 mg/kg, 423.0 mg/kg and 333.1 mg/kg respectively from riverbed to river terrace along the transverse directions of the Naoli watershed. The content of the soil DOC was the highest in the riverbed, lower in the high floodplain and much lower in the river terrace, and it was the lowest in the low floodplain. The difference in the content and vertical distribution of DOC between the riverbed and the three riparian wetlands was significant, while it was not significant among the low floodplain, the high floodplain and the river terrace. The variability of soil DOC was related to the hydrological connectivity between different landscape position of the riparian wetlands and the adjacent stream. Extremely significant correlations were observed between DOC and total organic carbon(TOC), total iron(TFe), ferrous iron(Fe(II)) whose correlation coefficients were 0.819, –0.544 and –0.709 in riparian wetlands of the Naoli River. With the increase of wetland destruction, soil p H increased and soil DOC content changed. The correlation coefficients between soil DOC and TOC, TFe, Fe(II) also changed into 0.759, –0.686 and –0.575 respectively in the Bielahong River. Under the impact of drainage ditches, the correlations between soil DOC and TFe, Fe(II) were not obvious, while the soil p H was weakly alkaline and was negatively correlated with soil DOC in the previous high floodplain. It indicates that riparian hydro-geomorphology is the main factor that could well explain this spatial variability of soil DOC, and the agricultural environmental hydraulic works like ditching also must be considered.

Bioturbation coefficients and organic carbon degradation rates of deep-sea sediments in the central-eastern tropical Pacific

The biogeochemical processes of marine sediments are influenced by bioturbation and organic carbon decomposition,which is crucial for understanding global element cycles and climate change.Two sediment cores were acquired in 2017 from abyssal basins in the central-eastern tropical Pacific to determine the bioturbation and organic carbon degradation processes.The radioactivity concentrations of 210Pb and 226Ra in the sediment cores were measured,indicating the presence of significant excess 210Pb(210Pbex)signals in the sediment cores.Besides,a manganese nodule was discovered in one core,which had a substantial influence on the distribution of 210Pbex.With the exception of this anomalous finding,the bioturbation coefficients in the remaining core were estimated to be 10.6 cm^(2)/a using a steady-state diffusion model,greater than most of the deep-sea sediments from the equatorial eastern Pacific.By using a bio-diffusion model,we further calculated the degradation rates of organic carbon(8.02 ka-1),which is also higher than other areas of the Pacific.Our findings displayed the presence of a biologically active benthic ecosystem in the central-eastern tropical Pacific.

Magnetic porous carbon composites for rapid and highly efficient degradation of organic pollutants in water

A magnetic porous carbon composite(MPC)was prepared from metal-organic frameworks(MOFs)by the onestep calcination method.The MPC was characterized by SEM,TEM,TG,DTG,Raman and XPS.The adsorption and degradation performance of MPC towards four organic dyes were investigated.The maximum adsorption amount of magenta on MPC was 191.94 mg g^(-1) at 25℃.Furthermore,the MPC showed remarkable stability for it can be recycled 5 times through the facile magnetic separation without obvious loss of activity.The degradation efficiency of MPC toward four kinds of organic pollutants was nearly 100%within 36 min,which was much higher than that previously reported.

Chemical properties of colored dissolved organic matter in the sea-surface microlayer and subsurface water of Jiaozhou Bay, China in autumn and winter

The distribution and chemical properties of chromophoric dissolved organic matter （CDOM） in the Jiaozhou Bay, China were examined during four cruises in 2010-2011. The influence of freshwater and industrial and municipal sewage along the eastern coast of the bay was clearly evident as CDOM level- s （defined as a30s）, and dissolved organic carbon （DOC） concentrations were well correlated with salinity during all the cruises. Moreover, DOC concentrations were significantly correlated with chlorophyll a con- centrations in the surface microlayer as well as in the subsurface water. The concentrations of DOC and CDOM displayed a gradually decreasing trend from the northwestern and eastern coast to the central hay, and the values and gradients of their concentrations on the eastern coast were generally higher than those on the western coast. In addition, CDOM and DOC levels were generally higher in the surface microlayer than in the subsurface water. In comparison with DOC, CDOM exhibited a greater extent of enrichment in the microlayer in each cruise, with average enrichment factor （EF） values of 1.38 and 1.84, respectively. Four fluorescent components were identified from the surface microlayer and subsurface water samples and could be distinguished as peak A, peak T, peak B and peak M. For all the cruises, peak A levels were higher in the surface microlayer than in the subsurface water. This pattern of variation might be attributed to the terrestrial input.

原位土壤溶液采样及可溶性有机碳(DOC)的紫外吸收光谱直接测定探讨

首次采用管壁过滤孔径为微米级(0.1～O.3 μm)的水处理用多孔聚丙烯(腈)空心纤维细管,与注射器或真空管相连,自制成土壤溶液采样器,将空心纤维管埋置或插入土壤中抽取层面土壤溶液,所得溶液无须过滤即可进行各种理化分析和测定,且可连续采样,提出了一种价廉实用的原位土壤溶液取样方法.并根据可溶性有机碳(DOC)在紫外光区的吸收特征,将土壤溶液在254 nm波长处的吸光度(UVA254)与DOC浓度(TOC仪法)进行比较,发现两者有较好的相关性(DOC=38.84×UVA254,n=37,R2=O.82),即直接测定土壤溶液的UVA254,再乘以系数38.84可以估算DOC浓度.与复杂的氧化-比色和昂贵的TOC仪测定法对比,UVA254能快速便捷地估计土壤溶液中DOC的浓度.UVA254也适用于水体DOC的估计.

海水中溶解有机碳(DOC)的测定

本文论述了海水中溶解有机碳(DOC)的测定方法,对DOC的测定原理及氧化方法进行了讨论,并提出了妨碍海水中DOC测定准确度提高的因素,这对于建立高准确度和精密度的新分析方法具有重要的意义。

基于荧光分析的不同有机碳水平水稻土添加外源有机物培养对DOC的影响

以江西省红壤研究所内的水稻土有机肥长期定位试验(始于1981年)为研究对象,基于三维荧光技术,在室内培养条件下,研究外源有机物(葡萄糖和秸秆,分别代表易分解和难降解碳)对不同碳水平水稻土可溶性有机碳含量与结构的影响。结果表明:添加葡萄糖对高碳和低碳水稻土可溶性有机碳(DOC)含量均无显著影响(p>0.05),但可以促进DOC结构中类溶性微生物代谢产物的增加与类胡敏酸类富里酸的减少。添加秸秆则对高碳和低碳水稻土DOC有不同的影响:低碳土壤中,在培养末期(60d),添加秸秆处理的DOC含量显著提高(p<0.05),而高碳土壤处理则无显著变化。在DOC结构方面,秸秆可以促进低碳土壤中类蛋白物质转化为更稳定的类胡敏酸和类富里酸物质;对于高碳土壤,则可以促进类溶性微生物代谢产物的积累,促进类胡敏酸与类富里酸的分解利用。低碳土壤DOC含量相对稳定,结构受外源有机碳影响较大;高碳土壤DOC结构相对稳定,但含量变化较大。

DOC遥感研究进展——基于全球大河DOC与CDOM保守性特征

目前,溶解有机碳(DOC)遥感反演研究主要集中在河口及陆源影响较大的边缘海区,大多数是利用DOC与有色溶解有机物(CDOM)或DOC与盐度的经验关系获取。为了较好的理解DOC的遥感反演机理,收集了全球主要大河(流量排名前25中16条)及边缘海DOC与CDOM浓度与保守性分布状况,发现大多数河口CDOM呈现保守性分布,DOC呈现非保守性分布。基于DOC与CDOM保守性行为的主要影响因素分析以及研究海区的生物地球化学特征,论述了DOC遥感反演算法的研究进展,提出了DOC遥感反演需要考虑DOC受不同主要控制因素(如保守混合与生物作用等)的影响,并对这些控制因素进行量化。

三江平原典型岛状林湿地土壤水DOC质量浓度分布特征

以三江平原典型岛状林湿地作为研究对象,分别在6、8和10月下旬分层采集土壤水溶液(0-60cm),测定土壤水可溶性有机碳(DOC)和其他几种元素的质量浓度,研究三江平原典型岛状林湿地土壤水DOC质量浓度分布特征。结果表明,岛状林湿地土壤水DOC质量浓度具有明显的季节变化规律,6月份土壤水DOC质量浓度最高,10月份次之,8月份最低。土壤水DOC质量浓度还具有明显的垂直分布规律,从土壤表层向下,随深度增加,土壤水DOC质量浓度先减小后增加,剖面层次之间土壤水DOC质量浓度差异显著(P<0.05)。不同月份之间土壤水DOC质量浓度的垂直分布特征存在差异性,但差异不显著(P=0.061)。土壤有机质数量和分布、土壤的冻融作用、土壤矿物吸附作用是引起土壤水DOC质量浓度分布的主要原因,采样点的排水状况也对土壤水DOC的分布有重要影响。另外,岛状林湿地土壤水DOC质量浓度与TOC、TC、Fe2+、TP、NO3-呈显著相关关系,与NH4+、PO43-、TN、pH存在一定相关关系,说明土壤水DOC质量浓度的分布还与其他各种元素迁移、转化紧密相关,尤其营养元素。

梯级水电开发下黄河上游龙-刘河段DOC时空分布特征及通量研究

针对梯级水电开发影响下河流生源物质循环的科学问题,选取黄河上游梯级开发河段(龙羊峡-刘家峡段,共5个水库)为研究区域,以溶解性有机碳(DOC)为主要研究对象,采用采样监测方法分析DOC以及理化指标的时空分布特征,并且基于静态箱式算法模型估算各水库DOC的输移通量。结果表明:DOC及常规理化指标存在明显的时空异质性,DOC浓度呈现汛期(5.37~7.00 mg/L)高于非汛期(2.90~5.56 mg/L)的特征,汛期由于水库出现垂向水温分层现象,DOC在沿水深垂直方向上呈波动变化。在采样年里,龙羊峡-刘家峡段DOC的年输入通量为258.53 kt,年输出通量为192.23 kt,拦截率为25.6%,具有拦截效应的水库为龙羊峡、公伯峡和刘家峡,其余水库为输送效应。

一种DOC在线分析仪光电信号处理方法

目前在海洋生态环境监测领域,国内尚无快速、稳定、在线的溶解性有机碳(DOC)自动化测量方法。为此,提出了一种专门针对海水DOC在线分析的光电信号处理方法。首先,确保氧化发光产生的微弱光信号能够通过光电倍增管探测到,之后信号经过锁相放大、带通滤波等电路模块进行前期处理,并且在CPU中采用复合数字滤波算法进一步平滑降噪处理,最终该方法解决了DOC在线分析方法中微弱光电信号处理的难题。长期的海试比对试验数据表明:该方法的测量数据的平行度能够达到实验室方法的测量数据的85%,证明其具备在线分析的能力,而且该方法测量速度更快,因此具有很好的实用性。

基于CDOM吸收特性的东北地区水库DOC浓度遥感估算

有色溶解性有机物(CDOM)广泛存在于水体中,占溶解有机碳(DOC)10%~90%,其浓度影响水环境碳循环过程、污染物质迁移以及水生生物群落的结构和功能。为分析东北地区水库DOC碳循环情况,本文于2015—2020年对第二松花江流域典型水库白山水库和丰满水库进行5次现场观测和室内实验,在分析CDOM吸收特性的基础上,基于Landsat系列卫星利用波段比值法建立CDOM浓度反演模型(R^(2)=0.82),根据实测值CDOM与DOC的强相关性(R^(2)=0.78),进而估算水库DOC浓度。结果表明:①利用野外实测数据和Landsat系列卫星能够对东北内陆水库CDOM浓度进行良好反演,②2000—2020年白山水库和丰满水库年际CDOM和DOC浓度变化不大,在2010年之后表现出轻微上升趋势,CDOM浓度从支流和干流的汇入到主库区呈现逐渐减少趋势,③白山水库和丰满水库M值(CDOM在250和365 nm处吸收系数比值)和S _(275~295)(CDOM在275~295 nm波段处的吸收光谱的斜率)较小、SUVA _(254)(CDOM在波长254 nm处的吸收系数与DOC浓度的比值)较大,表明其CDOM组分中腐殖质含量较高,倾向于陆源大分子,④利用多元回归分析方法分析水库CDOM变化主要受到降水、化肥施用量和污水排放量的影响。综上,本研究丰富了对东北典型水库CDOM浓度变化的认识,为构建东北地区水库CDOM反演模型和DOC储量估算提供了数据基础。

Soil organic carbon and nitrogen content of density fractions and effect of meadow degradation to soil carbon and nitrogen of fractions in alpine Kobresia meadow

This research was conducted on the non-disturbed native alpine Kobresia meadow(YF) and the severely degraded meadow(SDL) of Dari County of Qinghai Province.By a density fractionation approach,each soil sample was divided into two fractions:light fraction(LF) and heavy fraction(HF).The obtained fractions were analyzed for organic carbon(OC) and nitrogen(N) concentrations.The results showed:(1) the OC concentration in HF and LF was 3.84% and 28.63% respectively while the nitrogen concentration in HF and LF was 0.362% and 1.192% respectively in 0-10 cm depth.C:N ratio was 10.6 in HF and 23.8 in LF respectively.(2) As far as the ratio of OC in given fraction to that in gross sample was concerned,dominance of OC in HF was obvious in the whole soil profile.OC in HF increased from 78.95% to 90.33%,while OC in LF decreased from 21.05% to 9.68% with depths.(3) Soil total OC amounted to 47.47 in YF while 17.63 g.kg-1 in SDL,in which the OC content in HF decreased from 37.31 to 16.01 g.kg-1 while OC content in LF decreased from 10.01 to 1.62 g.kg-1.In other words,results of OC and N content show meadow degradation led to the loss of 57% OC in HF and 84% OC in LF from originally native ecosystem on alpine meadow.In addition,meadow degradation led to the loss of 43% N in HF and 79% N in LF from originally native ecosystem on alpine meadow.(4) The main reason for loss of C and N in LF during meadow degradation was not attributed to the decrease of OC and N concentration in LF and LF,but to the decrease in LF dry weight.Loss of N was far lower than loss of C in HF.This may suggest that there is difference in protection mode of C and N in HF.

Bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalysts toward artificial carbon cycling

Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combining these carbon-involved photocatalytic oxidation-reduction processes together,by which an artificial photocatalytic carbon cycling process can be established.The key challenge lies in the exploitation of efficient bifunctional photocatalysts,capable of triggering both aerobic oxidation and anaerobic reduction reactions.In this work,a bifunctional ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst is successfully constructed,which not only demonstrates superior aerobic photocatalytic oxidation performance in degrading an organic pollutant(using the dye,Rhodamine B as a model),but also exhibits impressive photocatalytic CO2 reduction performance under anaerobic conditions.Moreover,a direct conversion of Rhodamine B to solar fuels in a one-pot anaerobic reactor can be achieved with the as-prepared ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst.The excellent bifunctional photocatalytic performance of the g-C3N4/Bi/BiVO4 photocatalyst is associated with the formation of efficient S-scheme hybrid junctions,which contribute to promoting the appropriate charge dynamics,and sustaining favorable charge potentials.The formation of the S-scheme heterojunction is supported by scavenger studies and density functional theory calculations.Moreover,the in-situ formed plasmonic metallic Bi nanoparticles in the S-scheme hybrid g-C3N4/Bi/BiVO4 photocatalyst enhances vectorial interfacial electron transfer.This novel bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalyst system provides new insights for the further development of an integrated aerobic-anaerobic reaction system for photocatalytic carbon cycling.