Rising demand for aquatic products has expanded aquaculture, significantly elevating greenhouse gas (GHG) emissions from the aquaculture ponds. However, the emission estimation shows huge uncertainty. This study employed a meta-analysis of 1060 datasets of CO2, 2 , CH4 4 and N2O 2 O fluxes to examine how temporal variability affects GHG emissions from China's aquaculture ponds and to identify key environmental drivers. The results reveal that China's aquaculture ponds are significant sources of GHGs to the atmosphere, with fluxes of CO2, 2 , CH4, 4 , and N2O 2 O from coastal pond systems at 5.50, 7.41 mg m2 2 h-1,- 1 , and 16.72 mu g m2 2 h-1- 1 during the farming period, and-8.96, 4.33 mg m2 2 h-1,- 1 , and 44.98 mu g m2 2 h-1- 1 during the non-farming period, respectively. Regarding inland pond systems, the fluxes of CO2, 2 , CH4, 4 , and N2O 2 O were 50.48, 5.19 mg m2 2 h-1,- 1 , and 36.35 mu g m2 2 h-1- 1 during farming period, and 0.90, 1.03 mg m2 2 h-1,- 1 , and 51.46 mu g m2 2 h-1- 1 during non-farming period, respectively. Total GHG annual emissions were 42.17 Tg CO2-eq 2-eq over a 100-year time scale, predominantly from CH4 4 at 74.11 %, with CO2 2 contributing to 9.63 %, and N2O 2 O to 6.63 %. Post-cultivation drainage significantly shifts biogeochemical conditions and emission patterns, reducing total GHG emissions. Ignoring the non-farming period leads to overestimated CO2 2 and CH4 4 emissions, and underestimated N2O 2 O emissions. Our study provides new insights into GHG estimation from aquaculture ponds, highlighting the importance of considering temporal variability in GHG inventories, and supporting the development of management-based mitigation strategies.

Shallow-water ponds represent the hotspots of greenhouse gas (GHG) emissions. Most current studies focus on the temporal dynamics for GHGs in water, with little consideration given to the effects of weather changes. In this study, we measured and compared the concentrations and fluxes of CO2, CH4, and N2O from a pond in Northeast China under different meteorological conditions. Results showed that the rates of CO2, CH4, and N2O emissions from pond into the atmosphere during strong winds were 85.85 +/- 7.55 mmol m- 2 d-1, 22.05 +/- 6.80 mmol m- 2 d-1, and 10.87 +/- 0.72 mu mol m- 2 d-1, respectively, significantly higher than those measured during non-rain weather. Among which, over 88 % of CH4 emissions were contributed by ebullition. Meanwhile, the CO2 and N2O flux were also significantly higher during heavy rainfall, reaching 100.05 +/- 19.76 mmol m- 2 d-1 and 5.90 +/- 1.03 mu mol m- 2 d-1, respectively. Strong winds and precipitation induced sediment disturbances, high gas transport coefficients, reduced photosynthesis and oxygen greatly promoted the GHGs escape evasion. Wind speed, air pressure, solar radiation, and dissolved oxygen in water were important influencing factors. Our results

Aquaculture ponds are potential hotspots for carbon cycling and emission of greenhouse gases (GHGs) like CO2 and CH4, but they are often poorly assessed in the global GHG budget. This study determined the temporal variations of CO2 and CH4 concentrations and diffusive fluxes and their environmental drivers in coastal aquaculture ponds in southeastern China over a five-year period (2017-2021). The findings indicated that CH4 flux from aquaculture ponds fluctuated markedly year-to-year, and CO2 flux varied between positive and negative between years. The coefficient of inter-annual variation of CO2 and CH4 diffusive fluxes was 168% and 127%, respectively, highlighting the importance of long-term observations to improve GHG assessment from aquaculture ponds. In addition to chlorophyll-a and dissolved oxygen as the common environmental drivers, CO2 was further regulated by total dissolved phosphorus and CH4 by dissolved organic carbon. Feed conversion ratio correlated positively with both CO2 and CH4 concentrations and fluxes, showing that unconsumed feeds fueled microbial GHG production. A linear regression based on binned (averaged) monthly CO2 diffusive flux data, calculated from CO2 concentrations, can be used to estimate CH4 diffusive flux with a fair degree of confidence (r(2) = 0.66; p < 0.001). This algorithm provides a simple and practical way to assess the total carbon diffusive flux from aquaculture ponds. Overall, this study provides new insights into mitigating the carbon footprint of aquaculture production and assessing the impact of aquaculture ponds on the regional and global scales.

Understanding synchronous vegetation changes are crucial to assess the impact of carbon cycle on climate warming in peatlands. We established a mesocosm system to monitor ecosystem respiration (Re) and methane (CH4) fluxes in the growing season from 2020 to 2021 under different scenarios, including warming and ma-nipulations of species diversity. Overall, the mean Re and CH4 fluxes varied in the ranges of 1.38 +/- 0.18 to 46.25 +/- 6.62 mg CO2-C m(-2) h(-1) and 2.72 +/- 2.36 to 319.55 +/- 96.22 mu g CH4-C m(-2) h(-1), respectively, with the highest values appearing in the middle of growing season. The Re and CH4 fluxes in L-III and L-IV mesocosms showed significant increases of 38.86% and 54.28%, and 56.38% and 107.54%, respectively, compared to the mono-culture treatment. The primary controls for this phenomenon were the plant biomass and the concentrations of dissolved organic carbon and phenolics. Warming significantly increased the emissions of CO2 by similar to 40% during the study period, but it reduced the fluxes of CH4 in 2021. Sustained warming and soil water loss may destroy the original anaerobic environment, which plays a role in inhibiting the generation and emission of CH4 in the long term. Interestingly, although warming has reduced CH4 emissions, a mixture of three and four species seems to buffer more than 50% of this impact, further demonstrating the positive contribution of species diversity. Our results indicate that an increase in species diversity, specifically manifested in the expansion of vascular plants as a community process adapting to warming, can strongly affect carbon fluxes in peatlands and create potential feedback on future climate environments.

Since the 1990s, the climate in the Amur River Basin (ARB) has changed, and large-scale wetlands in the region have been reclaimed for paddy fields. The study of the influence of climate change and agricultural expansion on groundwater storage is of great significance to the evaluation of regional water resource balance and the promotion of ecological protection and agricultural development. In this work, the groundwater storage anomaly (GWSA) in the ARB and its drivers were analyzed for the period 2003–2016 using Gravity Recovery and Climate Experiment (GRACE) satellite data, a Global Land Data Assimilation System model, and in situ observations of groundwater levels. Results indicated that 1) the GWSA in the ARB increased at a rate of 2.0–2.4 mm/yr from 2003 to 2016; the GWSA in the upper reaches of the ARB increased, whereas the GWSA in the middle and lower reaches decreased during the study period. 2) The GWSA in the middle and lower reaches of the ARB was greatly influenced by temperature (Tmp) and evapotranspiration (ET). Tmp was positively correlated with GWSA, whereas ET was negatively correlated with GWSA (p < 0.05). 3) Extreme rainfall had a delayed effect on groundwater recharge. Wetland degradation and agricultural development were the main factors causing the decrease of the GWSA in the middle and lower reaches of the ARB. In summary, temperature and evapotranspiration affect groundwater storage by regulating the water–heat balance, wetland reclamation reduces the regional storage capacity, and the irrigation required for reclaimed farmland is the main source of groundwater loss.

Recent studies have reported worldwide vegetation suppression in response to increasing atmospheric vapor pressure deficit (VPD). Here, we integrate multisource datasets to show that increasing VPD caused by warming alone does not suppress vegetation growth in northern peatlands. A site-level manipulation experiment and a multiple-site synthesis find a neutral impact of rising VPD on vegetation growth; regional analysis manifests a strong declining gradient of VPD suppression impacts from sparsely distributed peatland to densely distributed peatland. The major mechanism adopted by plants in response to rising VPD is the "open" water-use strategy, where stomatal regulation is relaxed to maximize carbon uptake. These unique surface characteristics evolve in the wet soil‒air environment in the northern peatlands. The neutral VPD impacts observed in northern peatlands contrast with the vegetation suppression reported in global nonpeatland areas under rising VPD caused by concurrent warming and decreasing relative humidity, suggesting model improvement for representing VPD impacts in northern peatlands remains necessary.

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 was applied to measure dissolved CO2 concentrations over a 24-h period in a largest urban lake (Tangxun Lake) in Wuhan City, Central China, yielding extensive data on diel variability of CO2 concentrations and emissions. We showed the practicality and efficiency of the sensor for real-time continuous measurements in lakes. Our findings revealed distinct diurnal variations in CO2 concentrations (Day: 38.58 ± 23.8 μmol L-1; Night: 42.01 ± 20.2 μmol L-1) and fluxes (Day: 7.68 ± 10.34 mmol m-2 d-1; Night: 9.68 ± 9.19 mmol m-2 d-1) in the Tangxun Lake. The balance of photosynthesis and respiration is of utmost importance in modulating diurnal CO2 dynamics and can be influenced by nutrient loadings and temperature. A diel variability correction factor of 1.14 was proposed, suggesting that daytime-only measurements could underestimate CO2 emissions in urban lakes. Our data suggested that samplings between 11:00 and 12:00 could better represent the average diel CO2 fluxes. This study offered valuable insights on the diel variability of CO2 fluxes, emphasizing the importance of in situ continuous measurements to accurately quantify CO2 emissions, facilitating selections of sampling strategies and formulation of management strategies for urban lakes.

Land reclamation is a major threat to the world's coastal wetlands, and it may influence the biogeochemical cycling of nitrogen in coastal regions. Conversion of coastal marshes into aquaculture ponds is common in the Asian Pacific region, but its impacts on the production and emission of nitrogen greenhouse gases remain poorly understood. In this study, we compared N2O emission from a brackish marsh and converted shrimp aquaculture ponds in the Shanyutan wetland, the Min River Estuary in Southeast China over a three-year period. We also measured sediment and porewater properties, relevant functional gene abundance, sediment N2O production potential and denitrification potential in the two habitats. Results indicated that the pond sediment had lower N-substrate availability, lower ammonia oxidation (AOA and comammox Nitrospira amoA), nitrite reduction (nirK and nirS) and nitrous oxide reduction (nosZ Ⅰ and nosZ Ⅱ) gene abundance and lower N2O production and denitrification potentials than in marsh sediments. Consequently, N2O emission fluxes from the aquaculture ponds (range 5.4–251.8 μg m–2 h–1) were significantly lower than those from the marsh (12.6–570.7 μg m–2 h–1). Overall, our results show that conversion from marsh to shrimp aquaculture ponds in the Shanyutan wetland may have diminished nutrient input from the catchment, impacted the N-cycling microbial community and lowered N2O production capacity of the sediment, leading to lower N2O emissions. Better post-harvesting management of pond water and sediment may further mitigate N2O emissions caused by the aquaculture operation.

Aquaculture is one of the fastest growing food production sectors in the world, but many of the small-hold operations are poorly assessed for their climate impact. We analyzed the literature data on CO2 and CH4 fluxes from various aquaculture systems in China. The mean fluxes varied in the ranges of 382.45-551.88 g CO2-C m (2) yr (1) and 0.03-565.09 g CH4-C m (2) yr (1). Aquaculture system reclaimed from mudflat had the highest CH4 emission (54.92 +/- 21.00 g C m (2) yr (1)) but lowest CO2 emission. Shrimp aquaculture and semiintensive farming tended to yield higher CH4 emission. Small and shallow systems had significantly higher CO2 and CH4 emissions, with chlorophyll a and dissolved oxygen concentrations as the main environmental drivers. Management practice such as drainage, exposure and desilting during the non-farming period significantly decreased CH4 emission. We estimated that aquaculture systems in China emitted 181.66 Tg CO2-eq yr (1), offsetting similar to 7% of the national terrestrial carbon sink, with most of the emission concentrated in coastal provinces and along the major rivers in the southeastern quadrant. This study highlights the importance of accounting for greenhouse gas emissions from aquaculture to improve the accuracy of the regional and national carbon budgets.

甲烷(CH4)是一种重要的温室气体,在全球气候变化中扮演着重要角色.水库作为大气库中CH4的重要来源而备受关注.为探究亚热带河口区水库溶存CH4浓度时空变化特征及其影响因素,于2018年11月(秋季)、2019年3月(春季)和6月(夏季)分别对文武砂水库表层水进行高精度多空间点位采样分析.结果表明,文武砂水库表层水体CH4浓度在研究期间的变化范围为0.03～27.35 μmol·L-1,呈现春、夏季显著高于秋季的时间变化特征(p＜0.01);在空间变化上,外源输入强度大的库区水体溶存CH4浓度显著较高,且呈现出由库区沿海区向中心区递减的趋势.相关分析结果显示,水库表层水体CH4浓度与水温、DOC浓度呈显著正相关关系(p＜0.05或p＜0.01),与水体盐度和溶解氧呈显著负相关关系(p＜0.01).本研究结果证实亚热带水库是一个重要的CH4排放源,库区周边的废水排入等因素影响了CH4的排放.

Peatlands in northeast China are experiencing severe climate warming. Most studies on peatlands focus on the responses of CH4 dynamics to temperature. However, they rarely consider the synchronous changes in the composition of plant communities caused by the expansion of vascular plants. In this study, an experiment combined warming with the manipulation of plants to examine the concentrations of CH4 porewater and its fluxes in the mesocosm. We found that warming increased the concentration of CH4 and its fluxes relative to the control treatments, and it was strongly modulated by plant richness and functional types. The average CH4 fluxes in the warming and non-warming mesocosms varied from 72.10 to 119.44 and 97.95 to 194.43 mg m-2 h-1, respectively. Plant species richness significantly increased CH4 flux at the warming level of 3.2 degrees C (P < 0.01). The presence of vascular plants, such as Carex globularis and Vaccinium uliginosum, significantly increased the CH4 fluxes after warming had occurred. Our results suggest that the distinct response of CH4 to richness and species primarily stemmed from the direct or indirect effects of plant biomass and functional characteristics. Therefore, more consideration should be given to the diversity changes caused by vascular plant expansion when estimating CH4 flux in boreal peatland, especially in the context of future climate warming. (c) 2021 Elsevier B.V. All rights reserved.

Carbon dioxide(CO2)emissions from aquatic ecosystems are important components of the global carbon cycle,yet the CO2 emissions from coastal reservoirs,especially in developing countries where urbanization and rapid land use change occur,are still poorly understood.In this study,the spatiotemporal variations in CO2 concentrations and fluxes were inves-tigated in Wenwusha Reservoir located in the southeast coast of China.Overall,the mean CO2 concentration and flux across the whole reservoir were 41.85±2.03 μmol/L and 2.87±0.29 mmol/m2/h,respectively,and the reservoir was a consistent net CO2 source over the entire year.The land use types and urbanization levels in the reservoir catchment signifi-cantly affected the input of exogenous carbon to water.The mean CO2 flux was much higher from waters adjacent to the urban land(5.05±0.87 mmol/m2/hr)than other land use types.Sites with larger input of exogenous substance via sewage discharge and upstream runoff were often the hotspots of CO2 emission in the reservoir.Our results suggested that ur-banization process,agricultural activities,and large input of exogenous carbon could result in large spatial heterogeneity of CO2 emissions and alter the CO2 biogeochemical cycling in coastal reservoirs.Further studies should characterize the diurnal variations,microbial mechanisms,and impact of meteorological conditions on reservoir CO2 emissions to ex-pand our understanding of the carbon cycle in aquatic ecosystems.

Static floating chambers (FCs) are the conventional method to measure CH4 fluxes across the water-air interface in ponds, while thin boundary layer (TBL) modelling is increasingly used to estimate CH4 fluxes. In this study, both FCs measurements and TBL models of gas transfer velocity were used to determine CH4 evasion from aquaculture ponds in southeastern China. The surface water CH4 concentrations ranged from 0.4 to 9.1 ?mol L-1 with an average of 4.8 ? 0.8 ?mol L-1. CH4 flux was always positive, indicating the ponds as a persistent CH4 source to air. Mean CH4 flux based on different TBL models showed large variations, ranging between 19 and 316 ?mol m- 2 h-1. Compared against the direct measurement FCs, three TBL models developed for the open sea, flowing estuarine system and lentic ecosystem (TBLW92a, TBLRC01, and TBLCL98, respectively) overestimated CH4 emission by 40?200%, while the wind tunnel-based TBL model (TBLLM86) underestimated CH4 emission. Two TBL models developed for lakes (TBLW92b and TBLCW03) gave estimates similar to FCs.

为揭示河口区陆基养虾塘从养殖期到非养殖期一年间的CO2通量变化,以福建省闽江河口鳝鱼滩陆基养虾塘为研究对象,于2016年5月-2017年3月采用悬浮箱/静态箱-气相色谱法对养虾塘养殖期水-大气界面和非养殖期沉积物-大气界面白天CO2垂直通量进行原位观测.结果表明:①养虾塘在整个研究期间CO2通量变化范围为-62.87～ 162.81 mg/(m2 ·h),平均值为(42.66±18.12) mg/(m2 ·h),总体上表现为大气CO2的释放源,且呈非养殖期CO2通量平均值[(78.51±16.61) mg/(m2·h)]显著高于养殖期[(17.98-± 18.26)mg/(m2·h)]的特征.②养殖期间,养虾塘CO2通量呈“排放-吸收”交替变化的特征,而非养殖期养虾塘一直是大气CO2的净排放源.③养虾塘养殖期CO2通量时间变化特征主要受到ρ(DOC)(DOC为总溶解有机碳)、ρ(SO42-)、ρ(Cl-)、盐度、pH、ρ(Chla)(Chla为叶绿素a)的影响,其中,pH和ρ(SO42-)是其主要影响因子,而ρ(TDN)(TDN为总溶解氮)、ρ(TDP)(TDP为总溶解磷)、ρ(SO42-)对非养殖期CO2通量时间变化影响较大.研究显示,滨海陆基养殖塘是大气CO2的重要来源,其排放通量多低于河流、水库等水生生态系统,但高于湖泊生态系统;养殖塘CO2通量受人为影响明显,其较高的变异性与养殖生物、饲料投放以及浮游藻类有关.

Aquaculture ponds are hotspots of carbon cycling and important anthropogenic sources of the potent greenhouse gas methane (CH4). Despite the importance of CH4 ebullition in aquatic ecosystems, its magnitude and spatiotemporal variations in aquaculture ponds remain poorly understood. In this study, we determined the rates and spatiotemporal variations of ebullitive CH4 emissions from three mariculture ponds during the aquaculture period of two years at a subtropical estuary in southeast China. Our results showed that the mean ebullitive CH4 flux from the studied ponds was 14.9 mg CH4 m(-2) h(-1) during the aquaculture period and accounted for over 90% of the total CH4 emission, indicating the importance of ebullition as a major CH4 transport mechanism. Ebullitive CH4 emission demonstrated a clear seasonal pattern, with a peak value during the middle stage of aquaculture. Sediment temperature was found to be an important factor influencing the seasonal variations in CH4 ebullition. Ebullitive CH4 fluxes also exhibited considerable spatial variations within the ponds, with 49.7-71.8% of the whole pond CH4 ebullition being detected in the feeding zone where the large loading of sediment organic matter fueled CH4 production. Aquaculture ponds have much higher ebullitive CH4 effluxes than other aquatic ecosystems, which indicated the urgency to mitigate CH4 emission from aquaculture activities. Our findings highlighted that the importance of considering the large spatiotemporal variations in ebullitive CH4 flux in improving the accuracy of large-scale estimation of CH4 fluxes in aquatic ecosystems. Future studies should be conducted to characterize CH4 ebullitive fluxes over a greater number and diversity of aqua culture ponds and examine the mechanisms controlling CH4 ebullition in aquatic ecosystems. (c) 2020 Published by Elsevier Ltd.

While aquaculture ponds are potentially important sources of atmospheric N2O, the magnitude and variability of N2O concentrations and fluxes both within and across the ponds remain poorly understood. In this study, we examined the small-scale spatial variations of dissolved N2O concentrations in water and N2O fluxes across the water-air interface from three mariculture ponds in a subtropical estuary in southeast China. Our results showed that the dissolved concentrations and diffusive fluxes of N2O in the shrimp ponds ranged between 2.3-19.2 nM and 16.4-589.7 nmol m(-2) hr(-1), respectively, over the culture period. Significant variations of N2O concentrations and fluxes were observed within the ponds, with higher values being observed in the aeration area that could be attributed to the high rates of nitrification in the water column, as well as sediment N2O production and diffusive flux into the overlying water. Also, N2O concentrations and fluxes varied significantly among the three ponds as a result of the difference in N-NO(3)(-)and N-NH(4)(+)concentrations in the water column. The large fine-scale spatial variations of N2O concentrations and fluxes observed in our aquaculture ponds suggested that management practices such as aeration and bait feeding could largely affect the extent that aquaculture activities have on N2O emissions and climate change through their influence on the physicochemical environment (e.g., oxygen and N-NH(4)(+)concentrations) of the ponds.

Diffusion model methods are frequently applied in monitoring water-atmosphere methane (CH4) fluxes. To explore the variation character and influence factors of CH4 transfer velocity (kx) and diffusive fluxes across the water-atmosphere interface from aquaculture shrimp ponds, this study chooses six different model methods for estimating kxand CH4 diffusive fluxes in the Min River estuary (MRE) and Jiulong River estuary (JRE) on the southeast coast of China. For each estuary, water samples were collected using a hydrophore sampler from three shrimp ponds in June, August, and October 2015, respectively. Meanwhile, meteorological parameter (air temperature, wind speed and atmospheric pressure) and water-quality indicators (water temperature, pH, dissolved oxygen and salinity) were measured in situ using a portable instrument. A headspace equilibration technique was used for the measurement of dissolved CH4 concentration. The mean kxat MRE and JRE ponds during the study period ranged between1.60±0.75 and 6.29±1.30 cm/h, and 0.89±0.19 and 6.07± 0.61 cm/h, respectively. The mean CH4 diffusive fluxes in the MRE and JRE ponds over the study period ranged between 9.19±2.67 and 30.64±6.28 μmol/ (m2·h), and 3.18±0.48 and 21.03±2.13μmol/ (m2·h), respectively. The results showed that kxand CH4 diffusive fluxes across the water-atmosphere interface from the estuaries of shrimp ponds greatly varied in spatial and seasonal dynamics. The CH4 diffusive fluxes were significantly higher from the shrimp ponds in the Min River estuary than in the Jiulong River estuary (P＜0.05). Average seasonal kx (or CH4 diffusive fluxes) in MRE and JRE shows an increasing trend over time. The wind speed, water dissolved CH4 concentration and salinity are important factors that drive the changes in CH4 diffusive fluxes emission. There are differences in CH4 transfer velocity across the water-atmosphere interface from aquaculture shrimp ponds between the different model methods, indicating that the CH4 diffusive fluxes from the model-based estimation has a certain degree of uncertainty.

Freshwater aquatic ecosystems are important sources of greenhouse gases, such as CO2. However, few studies have presented data on the greenhouse gas flux from coastal aquaculture ponds. Diffusion models are important tools for estimating the CO2 exchange flux across the water-air interface of aquatic ecosystems. Several different parameterized means were selected to estimate the CO2 gas exchange rate (kx) and CO2 diffusive flux across the water-air interface of shrimp ponds in the Minjiang River Estuary. The results indicated that:① the CO2 gas exchange rate and diffusive flux over the culture period all presented significant temporal variation. This variation showed a dynamic trend:October > September > November > July > August and November > July > August > September > October. ② Wind speed, kx, CO2 concentration, pH, DOC concentration, and Chl-a concentration were important factors affecting the temporal variation of CO2 diffusive flux. ③ There were differences in the estimated value of CO2 diffusive flux across the water-air interface of the culture ponds in the Minjiang River Estuary among different parameterized approaches (P<0.01). This indicates that the model method has some uncertainties in estimating the CO2 diffusive flux in culture ponds. Our results suggest that the models RC01 and CW03 are more suitable methods for estimating the CO2 diffusive flux at the water-air interface of estuarine reclaimed aquaculture ponds in the Minjiang River Estuary, after comprehensive analysis of the water environment and the different estimation results.

Human activities have increased anthropogenic CO2 emissions, which are believed to play important roles in global warming. The spatiotemporal variations of CO2 concentration and flux at fine spatial scales in aquaculture ponds remain unclear, particularly in China, the country with the largest aquaculture. In this study, the plot-scale spatiotemporal variations of water CO2 concentration and flux, both within and among ponds, were researched in shrimp ponds in Shanyutan Wetland, Min River Estuary, Southeast China. The average water CO2 concentration and flux across the water–air interface in the shrimp ponds over the shrimp farming period varied from 22.79 ± 0.54 to 186.66 ± 8.71 μmol L−1 and from − 0.50 ± 0.04 to 2.87 ± 0.78 mol m−2 day−1, respectively. There was no remarkable difference in CO2 concentration and flux within the ponds, but significantly spatiotemporal differences in CO2 flux were observed between shrimp ponds. Chlorophyll a, pH, salinity, air temperature, and morphometry were the important factors driving the spatiotemporal patterns of CO2 flux in the shrimp ponds. Our findings highlighted the importance and spatiotemporal variations of CO2 flux in the important coastal ecosystems.

以闽江河口塔礁洲感潮淡水野慈姑(Sagittaria trifolia Linn.)湿地为研究对象,于2016年2、4、7和9月每月均在连续2个小潮日内向研究样地施加人造海水和Fe(OH)3溶液,研究短期的盐水入侵及Fe(Ⅲ)浓度增强对河口感潮淡水湿地土壤反硝化速率及理化特征的影响.结果表明,短期的盐水入侵、Fe(Ⅲ)浓度增强对河口感潮淡水沼泽湿地土壤反硝化速率的影响不显著,然而,盐水和Fe(Ⅲ)共同施加会显著提高湿地土壤反硝化速率,与对照(CK)相比,盐水和Fe(Ⅲ)共同施加可使土壤反硝化速率提高270.9％.盐水入侵、盐水和Fe(Ⅲ)共同施加均可显著提高湿地土壤、间隙水的电导率及Cl-、SO42-的含量;Fe(Ⅲ)浓度增强可显著降低土壤和间隙水pH值,同时显著提高土壤三价铁含量.