Photosynthetic metabolism and antioxidant in Ormosia arborea are modulated by abscisic acid under water deficit?

The aim of this research was to evaluate the effect of abscisic acid (ABA) on gas exchange and the activity of antioxidant enzymes of Ormosia arborea (Vell.) Harms seedlings under water deficit and its influence on the recovery potential of the seedlings. The experiment was conducted using four treatments, being daily irrigation or water restriction without and with 10 μM ABA. Seedlings under water deficit + ABA showed greater adjustment to drought, and when re-irrigated, they restored photosynthetic metabolism and water potential. ABA minimizes the reduction in the photosynthetic metabolism and water potential of the leaf, however, it does not increase the antioxidant activity of the O. arborea seedlings under water deficit. These results suggest that this species exhibits plasticity, which enables it to survive also in environments subjected to temporary water deficit regardless of the supplementation of ABA. We suggest that other doses of ABA be researched to expand the beneficial effect of ABA on this species.

Diversity of Silica-Scaled Chrysophytes in Central Vietnam

This paper focuses on the flora of scale-bearing chrysophytes from eight provinces located in the central part of Vietnam. Khanh Hoa, Phu Yen, Binh Dinh, Thua Thien Hue, Quang Tri, and Quang Binh provinces are located in the coastal area of Vietnam. Lam Dong and Dak Lak provinces represent mountain territories with an elevation of 500–2000 metres above sea level. In total, 212 water bodies of different origins were studied. Samples were obtained from swamp areas, lakes, rivers, reservoirs, ponds, and small temporary water bodies. In total, 76 taxa were identified by electron microscopic observations of samples. A total of 54 taxa were found in the mountainous provinces, while 73 were found in the coastal provinces. Of these, 51 species are common for both areas. The most diverse was the genus Mallomonas with 66 species, varieties, and forms; followed by Synura with 7 taxa; Chrysosphaerella with 2; and Spiniferomonas with 1. Seven taxa of the genus Mallomonas were not identified to the lower rank. All these unidentified specimens may potentially represent new species for science. Ten taxa are reported for the first time in Vietnam.

HCH Removal in a Biochar-Amended Biofilter

This study evaluated the efficiency of two biofilter systems, with and without biochar chambers installed, at degrading and removing HCH and its isomers in natural drainage water. The biochar biofilter proved to be 96% efficient at cleaning HCH and its transformation products from drainage water, a significant improvement over classic biofilter that remove, on average, 68% of HCH. Although iron- and sulfur-oxidizing bacteria, such as Gallionella and Sulfuricurvum, were dominant in the biochar bed outflows, they were absent in sediments, which were rich in Simplicispira, Rhodoluna, Rhodoferax, and Flavobacterium. The presence of functional genes involved in the biodegradation of HCH isomers and their byproducts was confirmed in both systems. The high effectiveness of the biochar biofilter displayed in this study should further encourage the use of biochar in water treatment solutions, e.g., for temporary water purification installations during the construction of other long-term wastewater treatment technologies, or even as final solutions at contaminated sites.

Studies on Algae from the Order Synurales (Chrysophyceae) in Northern Vietnam

The present paper focuses on the flora of synuralean algae from four northern provinces in Vietnam: Bac Kan, Hanoi, Ninh Binh, and Thanh Hoa. Fifty-five water bodies were studied, including territories within national parks Ba Be, Ba Vi, Cuc Phuong, Ben En, and Trang An Wetland—The World Cultural and Natural Heritage and Van Long Wetland Nature Reserve. Samples were obtained from natural lakes and wetlands, artificial reservoirs and ponds, and small temporary water bodies. Electron microscopy allowed for the discovery of 39 taxa, 37 of which belonged to the genus Mallomonas and two to the genus Synura. Six taxa of the genus Mallomonas and two taxa from the genus Synura were not identified to the lower rank. Five taxa are reported for the first time in Vietnam. The most diverse flora was observed in natural protected water bodies. Eutrophic and hypereutrophic water bodies, which were prevalent in the study area, had a reduced number of selected species.

Ant Rafting in an Extreme Ecosystem

Ants are among the most abundant organisms on Earth, being adapted for living on different solid surfaces. However, in some habitats, like riparian forests and flooded plains, water can be a constant obstacle, and overcoming this obstacle can be essential to determine the persistence of ants in such habitats. While most ant species avoid the water during a flood by foraging at higher elevations or climbing on trees, a few species developed ways to overcome this obstacle by swimming. Here, we report, for the first time, ants of the species Linepthema micans (Forel 1908) performing rafts. We observed 14 rafts in three consecutive days at approximately 1400 meters a.s.l. in Serra do Cipó, Brazil. Notably, this is the first record of ant rafting in tropical mountaintop grasslands, which are extreme habitats with shallow and sandy soils, and where small temporary water pools are extremely common in the wet season.

Tadpoles Inhabiting Natural and Anthropogenic Temporary Water Bodies: Which Are the Environmental Factors that Affect the Diversity of the Assemblages?

The study of tadpole assemblages allows inferring habitat availability and using their occupation as a means of proxy for the effective reproduction of the species, contributing to complementary information for the study of their adult forms. Environmental variables, represented by abiotic variables, vegetation structure, matrix management, and landscape elements, affect species having reproductive modes associated with oviposition and development in bodies of water. In the Orinoco region, most amphibians have complex life cycles and deposit their eggs in highly dynamic lentic bodies of water. Therefore, it is important to know how larval assemblages change over short periods of water accumulation and their relationship with environmental variables. Fieldwork was conducted during 9 weeks of larval sampling, from the beginning of the rainy season. We evaluate changes in anuran assemblages associated with water accumulation in five temporary water bodies of anthropogenic (road or pasture) and natural (savanna or gallery forest) origin. Twenty environmental variables were evaluated and measured in the center of each water body. Of these, nine landscape variables were measured only once during the study. The other eleven variables, representing management practices, physicochemical and structural characteristics of the water bodies, were measured weekly during the 3 months of sampling. We explored differences in the structure and diversity of larval-stage anuran assemblages using statistical tests suitable for small sample sizes (i.e., permutational multivariate analysis of variance PERMANOVA and the distance-based linear modeling DistLM). Of the 14 species found, two species had remarkedly high abundances from which Rhinella humboldti (19% of the total tadpole abundance) was a generalist inhabiting the natural and anthropogenic water bodies, while Leptodactylus insularum (18% of the total tadpole abundance) was a specialist at a natural pond in the savanna. The natural water bodies contained the highest number of species (between 10 and 12) and a total abundance of larvae (between 847 and 485 individuals). In contrast, the anthropogenic water body tracks generated by tractors were only occupied by two species with 50 individuals in total, while the water body generated by the trampling of cattle in pastures had three species with 474 individuals. These three species that inhabited the anthropogenic puddles were also found in the natural ponds and none of the eight species of hylids inhabited the puddles. In each field trip, all the tadpoles were collected from the sampled bodies of water. However, a week later, we found that each of the water bodies had been recolonized by four species (Leptodactylus fuscus, Leptodactylus fragilis, Elachistocleis ovalis, and R. humbolti). The variables with the highest explanatory power on the variation of anuran assemblage structure throughout all the water bodies were height of plants, number of cattle, distance to the nearest native forest edge, distance to an anthropic lentic body of water, distance to a natural lentic body of water, and pH. The bodies of water immersed in the natural cover were more diverse and had a greater degree of spatial and temporal species turnover. Our study calls for the importance of understanding the turnover of larval stage anurans over short periods, associated with water accumulation, in highly dynamic systems such as natural ponds and anthropogenic puddles. The importance of species traits and local processes is also highlighted, from environmental variables to human management activities, in the conservation of amphibian assemblages.

MANIFESTATIONS OF UNFAVORABLE GEOGRAPHICAL PROCESSES WITHIN THE SMOTRICH CANYON OF KAMENETS-PODOLSKY

The research allowed the authors to identify various types of adverse, destructive and erosion processes in the canyon of the Smotrych River. Now the ecological situation within the Smotrytsya canyon is quite difficult. The main factor in the deterioration of the situation is anthropogenic and man-made load: quarrying, garbage accumulation, unauthorized agriculture on the slopes of the canyon. Within the Smotric canyon, natural water and wind erosion are manifested, which in most cases are combined and the processes of destruction as a result of their action are intensified. Studies of erosion processes in the canyon of the Smotrich River have revealed a great variety of their manifestations. Karst processes are a typical manifestation of water erosion in the study area. Among the surface forms of karst, microforms (crates of various types) predominate. Individual karst funnels are less common. We discovered a karst cave located near Bilanivska embankment. Its area is 6 m2. The walls are covered with cracks, dominated by horizontal, less vertical, but they are larger. Turfed, covered type of karst can be found on the section where the river Smotrich encircles the Old Town in the direction of the village. Poodles. Lateral erosion is due to slope processes and erosion of the riverbed. It causes the migration of the riverbed, watercourse, the formation of river meanders, widens the river valley. Within the Smotric canyon, this type of erosion occurs in places where the shoreline is formed of clay soil. Inflows and outflows of water masses during the season also change the structure of the soil. Wind deflation and weathering within the canyon are manifested in those areas where rock remains and leads to the formation of various forms, are evidence of long-term wind erosion. Over the centuries, these forms can change, collapse. Linear erosion includes slope processes under the influence of anthropogenic activity and temporary water flows, which form furrows, ravines, ravines. Bilanivska embankment is characterized by the development of a system of ravines that descend to the river floodplain as a result of temporary water flows, during heavy rainfall, heavy rains, melting snow. They are small, but descend to the river. There are ravines as a result of concentrated storm currents, which are formed during heavy rainfall Transport erosion occurs throughout the study area. The result of such erosion is narrow and wide paths, dirt and hard roads made of limestone and artificially covered and filled with rubble. Zoogenic (pasture) erosion is quite common in Smotrich canyon. Grazing of cattle (cows), horses or small animals (goats, sheep) is carried out everywhere. The lack of special pastures, the inability to keep animals in a tethered way, leads to the fact that animals graze on the slopes of the canyon, in the coastal zone, in parks, and goats graze even on steep terraces. During the last few years, the recreational service in the form of walks along the riverbed on the BRDM-2 vehicle has been causing a destructive impact on the ecosystem of the Smotrich River. Summarizing the results of our research, we should point out other negative impacts from tourism activities using military equipment: gradual destruction of the river bottom, acceleration of erosion processes on rocky and silty slopes, increasing turbidity, changing water circulation in the river, changing gorge, near Novoplan the bridge actually washes its supports, introduces fuel and lubricants into the water and with the wheels of the car feces of large animals, the noise scares away birds that nest in the coastal zone of the river. Key words: unfavorable geographical processes, ecological condition, Smotrich canyon, Smotrich river, erosion, pollution, sewage, landscape complexes, anthropogenization.

Enhancement of Detecting Permanent Water and Temporary Water in Flood Disasters by Fusing Sentinel-1 and Sentinel-2 Imagery Using Deep Learning Algorithms: Demonstration of Sen1Floods11 Benchmark Datasets

Identifying permanent water and temporary water in flood disasters efficiently has mainly relied on change detection method from multi-temporal remote sensing imageries, but estimating the water type in flood disaster events from only post-flood remote sensing imageries still remains challenging. Research progress in recent years has demonstrated the excellent potential of multi-source data fusion and deep learning algorithms in improving flood detection, while this field has only been studied initially due to the lack of large-scale labelled remote sensing images of flood events. Here, we present new deep learning algorithms and a multi-source data fusion driven flood inundation mapping approach by leveraging a large-scale publicly available Sen1Flood11 dataset consisting of roughly 4831 labelled Sentinel-1 SAR and Sentinel-2 optical imagery gathered from flood events worldwide in recent years. Specifically, we proposed an automatic segmentation method for surface water, permanent water, and temporary water identification, and all tasks share the same convolutional neural network architecture. We utilize focal loss to deal with the class (water/non-water) imbalance problem. Thorough ablation experiments and analysis confirmed the effectiveness of various proposed designs. In comparison experiments, the method proposed in this paper is superior to other classical models. Our model achieves a mean Intersection over Union (mIoU) of 52.99%, Intersection over Union (IoU) of 52.30%, and Overall Accuracy (OA) of 92.81% on the Sen1Flood11 test set. On the Sen1Flood11 Bolivia test set, our model also achieves very high mIoU (47.88%), IoU (76.74%), and OA (95.59%) and shows good generalization ability.