Seasonal dynamics of 13C-labeled methanotrophic communities in constructed wetlands of different ages in Taiwan.

Dynamic changes of microbial community and Pb speciation distribution in rain sewage alternating constructed wetlands in winter and summer

Summary Birds show considerable spatial and temporal fluctuations in their abundance due to variations in habitat conditions. The lowland wetlands of the Pampas region in Argentina are key wintering areas for two flamingo species. The Chilean Flamingo Phoenicopterus chilensis is a year-round resident, while the Andean Flamingo Phoenicoparrus andinus is a partial altitudinal migrant that uses these wetlands in winter when some of the wetlands in the high Andes freeze over. We studied the association between the annual abundance of both flamingo species, wetland condition (water surface area and water salinity), and environmental conditions (flooding) driven by the El Niño Southern Oscillation (ENSO) over 15 consecutive winters (July–August 2008–2022) in 24 lowland wetlands in central Argentina. There were notable differences in wetland surface area and water conductivity between years, with some wetlands ranging from flooded to almost dried out. For any given year, there were also large differences in water surface area and water conductivity between wetlands. Both flamingo species showed marked fluctuations in abundance over the study period. Each year, the Chilean Flamingo was more abundant than the Andean Flamingo. The Chilean Flamingo was recorded at least once in every wetland, while the Andean Flamingo was absent from three wetlands and was not observed in two years during the study. The Chilean Flamingo was recorded in wetlands covering a larger range of water conductivity values than the Andean Flamingo (2.53–58.23 ms/cm vs 2.94–16.20 ms/cm, respectively). The abundance of both flamingo species was higher at intermediate water conductivity values and decreased at higher or lower values. These results show that these lowland wetlands are subjected to strong interannual variation in climatic conditions which affect lake conditions, and thus the abundance of both flamingo species, highlighting the importance of conserving wetlands encompassing a broad range of environmental conditions.

Abstract Freshwater turtles are important consumers in Australian freshwater ecosystems. They serve as scavengers, nutrient regulators, and as food sources and Totems for Traditional Owners throughout Australia. Despite their importance, most Australian freshwater turtle species are declining. The impact of winter wetland drying on turtle populations remains unknown, and winter exposure of hibernating turtles may be an important additional source of mortality. We aimed to examine turtle responses to seasonal and episodic wetland drying in wetlands using acoustic telemetry and active trapping. Wetlands were chosen that spanned a range of hydrological connectivity to the adjacent Edward/Kolety‐Wakool River. We found that tagged Emydura macquarii typically exit wetlands disconnected from the adjacent permanent river prior to winter, and overwinter in the river. Female E. macquarii rapidly re‐entered ‘home’ wetlands (wetlands in which they were initially tagged) the following spring, whereas males tended to leave the study area, returning occasionally. Although we were not able to evaluate a winter drying event, one of the wetlands experienced partial summer drying. All three local turtle species (E. macquarii, Chelodina expansa, C. longicollis) exited the wetland long before winter drying would have become a potential threat. Our results suggest that turtles in this system may be protected from winter wetland drying because they move to the adjacent permanent river prior to winter. Spending the winter in the river channel reduces the risks of being trapped in a drying wetland as temperatures drop in winter.

N deposition is a key factor affecting the composition and function of soil microbial communities in wetland ecosystems. Previous studies mainly focused on the effects of N deposition in the soil during the growing season (summer and autumn). Here, we focused on the response of the soil microbial community structure and function in winter. Soil from the Sanjiang Plain wetland, China, that had been treated for the past 11 years by using artificial N deposition at three levels (no intervention in N0, N deposition with 4 g N m-2 yr-1 in N1, and with 8 g N m-2 yr-1 in N2). Soil characteristics were determined and the bacterial composition and function was characterized using high-throughput sequence technology. The N deposition significantly reduced the soil bacterial diversity detected in winter compared with the control N0, and it significantly changed the composition of the bacterial community. At the phylum level, the high N deposition (N2) increased the relative abundance of Acidobacteria and decreased that of Myxococcota and Gemmatimonadota compared with N0. In soil from N2, the relative abundance of the general Candidatus_Solibacter and Bryobacter was significantly increased compared with N0. Soil pH, soil organic carbon (SOC), and total nitrogen (TN) were the key factors affecting the soil bacterial diversity and composition in winter. Soil pH was correlated with soil carbon cycling, probably due to its significant correlation with aerobic_chemoheterotrophy. The results show that a long-term N deposition reduces soil nutrients in winter wetlands and decreases soil bacterial diversity, resulting in a negative impact on the Sanjiang plain wetland. This study contributes to a better understanding of the winter responses of soil microbial community composition and function to the N deposition in temperate wetland ecosystems.

Abstract Aquatic plants are the main primary producers and an important part of the aquatic ecosystem. Seasonal flooding broke out in July 2020 in the middle and lower reaches of the Yangtze River, resulting in continued high water levels in lakes connected to the Yangtze River. To study the impact of extreme flooding on aquatic vegetation cover, we utilized two methods (surveying and remote sensing image data) to determine the changes in the aquatic vegetation cover of Shengjin Lake, one of the lakes connected to the Yangtze River, during the wet season from 2018 to 2020. The results showed that the dominant aquatic plant species before the flood in July 2020 were the emergent plantZizania caduciflora, the floating plantTrapa incisa, the submerged plantCeratophyllum demersumandVallisineria natans. The area covered by aquatic vegetation in 2018–2019 showed a slight upward trend, increasing from 24.94 to 25.94 km2. In April 2020, the aquatic vegetation cover was 25.53 km2, and after the flooding in July 2020, the aquatic vegetation cover decreased sharply to 1.36 km2, which was mainly composed of emergent plantZ. caduciflorain the nearshore. No recovery of the dominant aquatic plant species, the floating plantT. incisaand other submerged plants, was seen during the monitoring of water level decline from September to December 2020. Winter wetland plants were not significantly affected by flooding. The results of the study provide a theoretical basis for the maintenance mechanism of aquatic vegetation and lake management in Shengjin Lake.

鄱阳湖是我国最大的淡水湖，也是具有国际意义的候鸟越冬地. 近年来，鄱阳湖水文情势异常使得候鸟越冬环境更加复杂. 本文以2020年鄱阳湖出现夏季极端水位为背景，基于2019和2020年鄱阳湖越冬水鸟同步调查数据，探讨了夏季极端水位对越冬水鸟丰富度和空间分布的影响. 研究结果表明：夏季极端水位条件下鄱阳湖越冬水鸟的总数量、群落结构和优势物种组成相对稳定，水鸟数量由597307只下降至572358只，主要是鸭科、鸥科、鹳科、鸬鹚科和鹮科鸟类数量明显下降；食块茎、食种子和食鱼集团水鸟数量均有所下降. 水鸟的整体空间分布格局变化不大，主要栖息地仍为鄱阳湖保护区和上饶湿地的碟形湖及人控湖汊，越冬水鸟向人工湿地扩散加剧. 2019年在人工湿地主要记录到灰鹤926只、白鹤3只；2020年则记录到白鹤2215只、灰鹤7294只、白头鹤88只、白枕鹤378只、豆雁550只、鸿雁3100只、灰雁3200只和小天鹅1543只. 2020年冬季人工湿地中的越冬水鸟数量比2019年增加显著. 鄱阳湖夏季极端水位导致沉水植物群落崩溃，造成植食性水鸟在天然湿地中的越冬食物短缺，从而导致种群空间分布格局出现明显变化，这也是鹤类和雁类水鸟前往人工湿地觅食的主要原因. 因此，在夏季洪水频发的背景下加强人工湿地管理，是当前解决越冬水鸟天然湿地食物资源短缺的重要措施.;Lake Poyang is the largest freshwater lake in China and has been an important wintering ground for migratory birds. In recent years, the abnormal hydrological regime of Lake Poyang deteriorated the quality of this wintering ground for migratory birds. In summer of 2020, Lake Poyang experienced extreme water level, which maybe affect the waterbird community structure and waterbird distribution. We compared the wintering waterbird species diversity, abundance and spatial distribution between winter of 2019 and 2020 to understand the impact of extreme water level on wintering waterbirds. The results showed that the total number, community structure and dominant species composition of wintering waterbirds were relatively stable after extreme summer water level. The total number of waterbirds decreased from 597307 to 572358, among which the number of Anatidae, Laridae, Ciconiidae, Phalacrocoracidae and Threskiornithidae obviously decreased. The abundances of tuber eaters, seed eaters and fish eaters were declined. The overall spatial distribution pattern of waterbirds showed little change. Waterbirds mainly inhabited the sub-lakes and controlled lake branches in the Lake Poyang National Nature Reserve and Shangrao wetland. However, waterbirds spread more severely from Lake Poyang nature wetlands to artificial wetlands nearby Lake Poyang. In 2019, 926 common cranes and 3 Siberian cranes were recorded in rice paddies and lotus ponds; In 2020, 2215 Siberian cranes, 7294 common cranes, 88 hooded cranes, 378 white-napped cranes, 550 bean geese, 3100 swan geese, 3200 greylag geese and 1543 tundra swans occurred in these artificial wetlands. The wintering waterbirds in artificial wetlands in winter of 2020 was significantly more abundant than that in winter of 2019. The extreme water level in summer led to the collapse of submerged plant community, resulting in the shortage of wintering food for herbivorous waterbirds in the natural wetlands, which drove cranes and geese dispersed into the artificial wetlands. Therefore, it is necessary to strengthen the management of artificial wetlands under the condition of frequently higher flood in Lake Poyang for wintering waterbirds conservation.

In this study, based on the regional land-use risk space division (regional ecological risk source/receptor space identification) using production–living–ecology analysis, three spatial function indexes, i.e., production, living, and ecology function indexes, were proposed for regional ecological risk assessment (RERA) with respect to human disturbance. The first two indexes can be regarded as regional ecological risk source indexes, whereas the final index can be regarded as a regional ecological risk receptor index. Using an artificial assignment method based on the land-use types and Defense Meteorological Program Operational Line-Scan System (DMSP/OLS) nighttime light intensity data, these three spatial function indexes were effectively manifested. By incorporating these indexes with eco-environmental vulnerability proxies, an RERA framework was established and applied in the Poyang Lake Eco-economic Zone (PLEZ), which is an ecological-protection and economic-development coordination-oriented region in China. The results suggest that (1) the DMSP/OLS nighttime light intensity data correlated well with the spatial distribution of regional urban/town areas; consequently, it was reasonable to use this dataset for representing regional production-living function space (urban/town area). (2) Overall, the forestlands and winter waterbodies of Poyang Lake were in the high-risk grade, and so did the Nanchang City construction land area; in contrast, the final risk levels of winter wetlands and croplands were relatively low. (3) Owing to the highest human disturbance (including both production and consumption human activities) and eco-environmental vulnerability level, urban/town areas such as Nanchang City had the highest final risk grade. (4) The low, medium, high, and very high-risk grades accounted for 21.22%, 39.53%, 36.31%, and 2.94% of the region, respectively. I believe that the proposed land use function indexes will be helpful in conducting human-caused RERA research in the future. Furthermore, the assessment results can provide a scientific basis for regional ecological risk management within the PLEZ.

Assessing wetland nitrogen removal and reed (Phragmites australis) nutrient responses for the selection of optimal harvest time

New solution to build constructed wetland in cold climatic region

Due to the influence of low temperature in winter, the removal effect of pollutants in constructed wetlands in winter is greatly reduced. In order to improve the removal effect of wetland on pollutants such as nitrogen and phosphorus, this paper proposes a new insulation method that uses the residual heat of bathroom bath waste water to supply heat to the constructed wetland. In the proposed new wetland system, the average removal rates of TN, TP and NH4 +-N in wetlands reached 61.09%, 85.03% and 33.85%, respectively. The application of residual heat energy to the construction of constructed wetland can realize the recovery and utilization of energy, which is conducive to the promotion and application of constructed wetland in the cold regions of the north. A post-publication change was made to this article on 29 May 2020 to correct an author name on the webpage.

In this study, plant growth and nitrogen and phosphorus removal efficiency in lab-scale CWs by five plants (H. vulgaris, N. peltatum, N. tetragona, N. pumilum, S. trifolia) in winter in Sichuan basin was evaluated. H. vulgaris and N. tetragona would well adapt to the winter wetland environment, and the relative growth at the end of the experiment was 89.83% and 66.85%, respectively. In winter, H. vulgaris kept growing with accumulated stems and leaves, while growth of N. tetragona was mainly caused by the growth of roots and stems underwater. In addition, during the winter, removal efficiencies were 66.29%, 57.47%, 54.78%, 55.47%, 41.66% of TN and 62.40%, 69.75%, 69.97%, 65.65%, 76.55% of TP for each planted CWs respectively. The results indicated that the removal of nitrogen and phosphorus from CWs was mainly achieved by substrate, while a small portion was attributed by plant. However, plants like H. vulgaris and N. tetragona, in the CWs in winter can play the role of landscaping. Thus, H. vulgaris could be considered as a suitable and effective nutrient removal plant for treatment of nitrogen and phosphorus water in winter wetlands in Sichuan basin.

Constructed wetlands (CWs) have been widely used as an ecological technology for removing nutrients from aquatic ecosystems. However, the treatment efficiency of surface flow constructed wetlands (SFCWs) in winter is generally low. To enhance the nutrient removal performance of SFCWs in winter, we developed a novel hardy submerged plant-benthic fauna system by adding Chironomus riparius (C. riparius) larvae and planting Potamogeton crispus L. in SFCWs. Compared to a system without C. riparius, the paired system greatly enhanced TN and TP removal with the average removal efficiencies of 54.73% and 94.76%, respectively. Furthermore, the paired system improved NO3−–N removal efficiency by 29.51% and reached NH4+–N removal efficiency as high as 86.20% simultaneously. The mass balance analysis indicated that C. riparius larvae enhanced substrate absorption and plant uptake in the CWs. The results of microbial analysis agreed with the nutrient removal performance, showing that C. riparius larvae influence the abundance and community structure of microbes related to N removal. As a whole, this study provides a promising ecological strategy for performance intensification of SFCWs in winter.

The plants effect in subsurface flow constructed wetlands (SSF-CWs) is controversial, especially at low temperatures. Consequently, several SSF-CWs planted with Iris pseudacorus (CWI) or Typha orientalis Presl. (CWT) and several unplanted ones (CWC) were set up and fed with secondary effluent of sewage treatment plant during the winter in Eastern China. The 16S rDNA Illumina Miseq sequencing analysis indicated the positive effects of I. pseudacorus on the bacterial community richness and diversity in the substrate. Moreover, the community compositions of the bacteria involved with denitrification presented a significant difference in the three systems. Additionally, higher relative abundances of nitrifying bacteria (0.4140%, 0.2402% and 0.4318% for Nitrosomonas, Nitrosospira and Nitrospira, respectively) were recorded in CWI compared with CWT (0.2074%, 0.0648% and 0.0181%, respectively) and CWC (0.3013%, 0.1107% and 0.1185%, respectively). Meanwhile, the average removal rates of NH4+-N and TN in CWI showed a prominent advantage compared to CWC, but no distinct advantage was found in CWT. The hardy plant I. pseudacorus, which still had active root oxygen release in cold temperatures, positively affected the abundance of nitrifying bacteria in the substrate, and accordingly was supposed to contribute to a comparatively high nitrogen removal efficiency of the system during the winter.

Intensively managed restored wetlands and flooded croplands of California’s Central Valley support millions of wintering waterbirds. While the benefits to wintering waterfowl are well documented, the effect of intensive management on birds at other times of the year is less clear. Practices such as drainage, mowing, disking and burning may be a nuisance to these nontarget birds at best or life threatening at worst. Alternatively, irrigation over the summer may create habitat that might otherwise be lacking in the dry season. Our objective was to assess the influence of management, adjacent land use, and habitat characteristics on the richness, diversity, and occupancy of birds other than waterfowl in the spring and summer. We conducted 640 bird surveys on restored wetlands managed at varying levels in 2008 (4 April–30 July) and 2009 (19 April–16 July) and used likelihood-based modeling to evaluate occupancy and the relative importance of intensity of management and various environmental factors. Management was not the most important predictor of the richness, diversity, or occupancy of nontarget birds in the summer; rather, variables such as wetland size, vegetation composition, and landscape characteristics were more important for most bird guilds. Contrary to the commonly held view that restored wetlands in California’s Central Valley support only wintering waterfowl, they also support a diverse avifauna year round regardless of how they are managed. Bird occupancy and diversity in restored wetlands may be enhanced by creating and maintaining large, complex mosaics of vegetation. Each year California’s Central Valley hosts the majority of the Pacific Flyway’s wintering waterfowl (Gilmer et al. 1982). Restored wetlands provide critical food and habitat for winter visitors, and there is broad support for programs and initiatives geared toward increasing the extent of wetlands in winter (CVJV 2006). Far less emphasis is placed on the role restored wetlands play in supporting summer breeders, migrants, and year-round residents. Greater than 95% of all depressional wetlands and 98% of riparian wetlands in California were destroyed between 1800 and 1980 (Dahl 1990, CVJV 2006, Garone 2011, Duffy et al. 2016). The passage of the Swamplands Act in 1850 and subsequent revisions led to extensive alterations to natural hydrology through the creation of reservoirs and channelization of the Central Valley’s main rivers. Restoration has been intended to replace the thousands of acres of wetland lost to agriculture and human settlement. Most managed restored wetlands target wintering waterfowl and therefore receive most of their water in the fall and winter. Historically, however, much of the

Abstract. This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E). The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS) and the CSIRO Conformal-Cubic Atmospheric Model (CCAM). Radon is also simulated and used to reduce the impact of transport differences between the models and observations. Comparisons are made for air samples that have traversed the Australian continent. All six emission scenarios give modelled concentrations that are broadly consistent with those observed. There are three notable mismatches, however. Firstly, scenarios that incorporate interannually varying biomass burning emissions produce anomalously high methane concentrations at Cape Grim at times of large fire events in southeastern Australia, most likely due to the fire methane emissions being unrealistically input into the lowest model level. Secondly, scenarios with wetland methane emissions in the austral winter overestimate methane concentrations at Cape Grim during wintertime while scenarios without winter wetland emissions perform better. Finally, all scenarios fail to represent a~methane source in austral spring implied by the observations. It is possible that the timing of wetland emissions in the scenarios is incorrect with recent satellite measurements suggesting an austral spring (September–October–November), rather than winter, maximum for wetland emissions.

Recently, constructed wetland was applied for sewage treatment globally due to its high efficiency and relatively low investment. However, operation of many constructed wetlands in cold winter is quite difficult due to the inhibition effect of low temperature. The objective of this experiment is to study the sewage treatment efficiency of Pseudomonas flava WD-3 in the integrated vertical-flow constructed wetland (IVCW) during winter with different dosages (bacterial suspension concentration: 4.575 × 108 mL−1). Two treatments were designed, inoculation of P. flava WD-3 with different dosages and the control without bacterium incubation. A simplified Monod model was applied to simulate and evaluate the pollutant removal efficiency of this bacterial strain with respect to its dosages. Results indicated that P. flava WD-3 could degrade organic pollutants, nitrogen, and phosphorus nutrients from wastewater effectively. The optimal dosage of this strain was 6.0%, and the removal rates of chemical oxygen demand (COD), ammonium nitrogen (), and total phosphorous (TP) were 85.82–87.00%, 73.91–84.18%, and 82.04–87.00%, respectively. Furthermore, the average removal efficiencies of COD, , and TP were 1.46, 1.49, and 1.76 times, respectively, than the control. The simplified Monod model accurately predicted the pollutant removal efficiency of P. flava WD-3 in the IVCW system in winter.

Four decades of winter wetland changes in Poyang Lake based on Landsat observations between 1973 and 2013

Nutrient removal capability and growth characteristics of Iris sibirica in subsurface vertical flow constructed wetlands in winter

Modeling seasonal variation in bacteriophage removal in constructed wetlands using convection–dispersion equation