Spatiotemporal change analysis of long time series inland water in Sri Lanka based on remote sensing cloud computing

Sri Lanka is an important hub connecting Asia-Africa-Europe maritime routes. It receives abundant but uneven spatiotemporal distribution of rainfall and has evident seasonal water shortages. Monitoring water area changes in inland lakes and reservoirs plays an important role in guiding the development and utilisation of water resources. In this study, a rapid surface water extraction model based on the Google Earth Engine remote sensing cloud computing platform was constructed. By evaluating the optimal spectral water index method, the spatiotemporal variations of reservoirs and inland lakes in Sri Lanka were analysed. The results showed that Automated Water Extraction Index (AWEIsh) could accurately identify the water boundary with an overall accuracy of 99.14%, which was suitable for surface water extraction in Sri Lanka. The area of the Maduru Oya Reservoir showed an overall increasing trend based on small fluctuations from 1988 to 2018, and the monthly area of the reservoir fluctuated significantly in 2017. Thus, water resource management in the dry zone should focus more on seasonal regulation and control. From 1995 to 2015, the number and area of lakes and reservoirs in Sri Lanka increased to different degrees, mainly concentrated in arid provinces including Northern, North Central, and Western Provinces. Overall, the amount of surface water resources have increased.

Pile Dwellings in the Circum-Baltic Area

The phenomenon of northern pile dwellings has been found in different geographical zones and landscapes of the Circum-Baltic region: in sea landscapes and on the shores of inland lakes and rivers. Inland sites were established in specific lacustrine landscapes, appearing within former post-glacial basins. The pile dwellings revealed here are characterized by different types of wooden buildings, including structures with raised floors. They are dated to the 4th millennium BC to 4th century BC in Central Europe and the Baltics, and to the end of the 4th to end of the 3rd millennium BC – in NW Russia and Belarus. They appeared in major cases independently and followed different cultural trajectories. The article presents an overview of a number of sites which can be attributed to pile dwelling settlements distributed in the Circum-Baltic area. It discusses particular features of their construction, traits of material culture, and site location patterns.

Microplastic Pollution in the Surface Waters from Plain and Mountainous Lakes in Siberia, Russia

Microplastics (MPs) contaminations of freshwater and marine environments has become a global issue. Lakes in southern Siberia provide a wide range of ecosystem services and are essential elements in the annual and interannual runoff distribution of the Great Siberian Rivers. However, the extent of their MPs pollution remains unknown. In this paper, for the first time, we analyze the concentrations, composition, and spatial distribution of MPs in six lakes in southern Siberia. The studied lakes are located both in the Altai mountains and the West Siberian plain. Some of them are significantly impacted by human activities, while others are located in protected areas with no permanent population. Nevertheless, MPs were detected in all of the studied lakes. MPs concentrations ranged from 4 to 26 MPs L−1. Comparing with other inland lakes, South Siberian lakes presented moderate MPs concentrations. Among the registered MPs forms, fragments and films were dominant, with a size range between 31 and 60 nm. The MPs’ sources depend on local human activities (fishing, transport, landfilling). Therefore, sufficiently high concentrations were observed even in remote lakes. The present study set a baseline that emphasizes the need for increased attention to waste management and sustainable water use in Siberian freshwater environments.

Early presence of Bythotrephes cederströmii (Cladocera: Cercopagidae) in lake sediments in North America: evidence or artifact?

The spiny water flea (Bythotrephes cederströmii), a freshwater crustacean considered to be the world’s best-studied invasive zooplankter, was first recorded in North America in the Laurentian Great Lakes during the 1980s. Its arrival is widely considered to be the result of ocean-going cargo ships that translocated contaminated ballast water from Eurasia to the Great Lakes during the 1970–1980s. The subsequent first discovery of the species in inland lakes is consistent with the hypothesis that propagules dispersed initially from established Great Lakes populations. Here we present evidence of exoskeletal remains, including mandibles, tail spines, and resting eggs, in 210Pb-dated lake sediment cores, which suggests that B. cederströmii was already resident in four inland North American lakes (two in Minnesota, USA; two in Ontario, Canada) by at least the early 1900s. Densities of exoskeletal remains were low and relatively steady from first appearance until about 1990, after which time they increased in all cores. The earliest evidence that we found was a mandible at 33-cm depth (pre-1650) in the sediments of Three Mile Lake, Ontario, Canada. These unexpected findings challenge the current paradigm of B. cederströmii invasion, renew uncertainty about the timing and sequence of its colonization of North American lakes, and potentially question our ability to detect invasive species with traditional sampling methods. We attempted to eliminate errors in the dated stratigraphies of the exoskeletal remains that might have been introduced either methodologically (e.g., core-wall smearing) or naturally (e.g., bioturbation). Nonetheless, given the very low numbers of subfossils encountered, questions remain about the possible artifactual nature of our observations and therefore we regard our results as ‘preliminary findings’ at this time.

Spatiotemporal Change Analysis of Long Time Series Inland Water in Sri Lanka Based on Remote Sensing Cloud Computing

Sri Lanka is an important hub connecting Asia-Africa-Europe maritime routes, with abundant rainfall but uneven spatiotemporal distribution, and obvious seasonal water shortage. Monitoring water area change in its inland lakes and reservoirs plays an important role in guiding the development and utilization of water resources. In this study, a rapid extraction model of surface water based on Google Earth Engine remote sensing cloud computing platform was constructed. On the basis of evaluating the optimal spectral water index method, the spatiotemporal variation of typical reservoir and inland lakes and reservoirs in Sri Lanka were analyzed. The results showed that AWEIsh can accurately identify the water boundary, with an overall accuracy of 99.14%, which was suitable for the extraction of surface water in Sri Lanka. The area of Maduru Oya Reservoir showed an overall increasing trend on the basis of small fluctuations from 1988 to 2018, and the monthly area of reservoir fluctuated greatly in 2017, thus water resources management in dry zone should pay more attention to seasonal regulation and control. From 1995 to 2015, the number and area of lakes and reservoirs in Sri Lanka increased in different degrees, mainly concentrated in arid provinces such as Northern Province, North Central Province, Western Province, etc., and the amount of surface water resources increased as a whole.

Examining the spread of Aquatic Invasive Species, Bythothephes longimanus, In Inland Lakes Across Ontario

The purpose of this study is to is to examine the secondary spread of Bythothephes longimanus, commonly known as spiny water flea, across inland lakes in Ontario, and potentially determine predictors for the its invasion. Data for 190 inland lakes across 84 quaternary watersheds in Ontario were included in the database. Global Moran's I was used to analyze the spatial autocorrelation of the variables, and McFadden's Rho-Squared was used to determine if a variable was a predictor of invasion. Three independent variables, out of 28, were found to be good predictors of invasion: (1) mean temperature of watersheds during summer (MNTMPWSSU), (2) mean precipitation for watersheds during spring (MNPCPWSSP), and (3) mean precipitation for watersheds during summer (MNPCPWSSU). Of the three, mean precipitation for watersheds during summer was determined to be the best predictor.

Examining the spread of Aquatic Invasive Species, Bythothephes longimanus, In Inland Lakes Across Ontario

The purpose of this study is to is to examine the secondary spread of Bythothephes longimanus, commonly known as spiny water flea, across inland lakes in Ontario, and potentially determine predictors for the its invasion. Data for 190 inland lakes across 84 quaternary watersheds in Ontario were included in the database. Global Moran's I was used to analyze the spatial autocorrelation of the variables, and McFadden's Rho-Squared was used to determine if a variable was a predictor of invasion. Three independent variables, out of 28, were found to be good predictors of invasion: (1) mean temperature of watersheds during summer (MNTMPWSSU), (2) mean precipitation for watersheds during spring (MNPCPWSSP), and (3) mean precipitation for watersheds during summer (MNPCPWSSU). Of the three, mean precipitation for watersheds during summer was determined to be the best predictor.