Analysis of Climate Change Effects on Surface Temperature in Central-Italy Lakes Using Satellite Data Time-Series

Evaluation of the impact of climate change on water bodies has been one of the most discussed open issues of recent years. The exploitation of satellite data for the monitoring of water surface temperatures, combined with ground measurements where available, has already been shown in several previous studies, but these studies mainly focused on large lakes around the world. In this work the water surface temperature characterization during the last few decades of two small–medium Italian lakes, Lake Bracciano and Lake Martignano, using satellite data is addressed. The study also takes advantage of the last space-borne platforms, such as Sentinel-3. Long time series of clear sky conditions and atmospherically calibrated (using a simplified Planck’s Law-based algorithm) images were processed in order to derive the lakes surface temperature trends from 1984 to 2019. The results show an overall increase in water surface temperatures which is more evident on the smallest and shallowest of the two test sites. In particular, it was observed that, since the year 2000, the surface temperature of both lakes has risen by about 0.106 °C/year on average, which doubles the rate that can be retrieved by considering the whole period 1984–2019 (0.053 °C/year on average).

Non-Equilibrium Uranium as an Indicator of Global Climate Variations—The World Ocean and Large Lakes

In natural water, as a rule, there is a violation of radioactive equilibrium in the chain 238U … → 234U → 230Th →. Groundwater usually has a 234U/238U ratio in the range of 0.8–3.0 (by activity). However, in some regions, the 234U/238U ratio reaches >10 and up to 50. Ultrahigh excesses of 234U can be explained by climatic variations. During a cold period, minerals accumulate 234U as a normal component of the radioactive chain, and after the melting of permafrost, it is lost from the mineral lattice faster than 238U due to its higher geochemical mobility. This hypothesis was tested using data on the isotopic composition of uranium in the chemo- and bio-genic formations of the World Ocean and large lakes, which are reservoirs that accumulate continental runoff. The World Ocean has the most significant 234U enrichments in the polar and inland seas during periods of climatic warming in the Late Pleistocene and Holocene. In the bottom sediments of Lake Baikal, the 234U/238U ratio also increases during warm periods and significantly exceeds the 234U excess of the World Ocean. Furthermore, the 234U/238U ratio in the water of Lake Baikal and its tributaries increases from north to south following a decrease in the area of the continuous permafrost and has a seasonal variation with a maximum 234U/238U ratio in summer. The behavior of 234U in large water reservoirs is consistent with the hypothesis about the decisive influence of permafrost degradation on the anomalies in 234U/238U ratios in groundwater.

Feasibility study of floating solar panels over lakes in Bengaluru City

Sustainable energy production has become an issue of prime concern for regions across the globe. With all the global bodies urging nations to explore and adopt clean sources of energy, India’s enormous solar potential provides a sustainable source of energy, replacing conventional sources that are both polluting and rapidly depleting. To produce large amounts of solar energy, solar parks spanning across large areas are required, making it impossible to serve in highly populated cities like Bengaluru, where spacious lands are not available. The rooftop solutions contribute very minimally towards the city’s energy demand because of the dense urban cover and congested planning. But the city has a large number of water bodies including tanks, large lakes and reservoirs. This paper studies the floating solar photovoltaic (FSPV) technology to provide an alternative solar route to harness sustainable energy. In this study, 32 lakes within the city limits were considered spanning across 3294 ac of lake area and analysed for the climatic suitability of FSPV systems, solar output assessment and estimation of evaporation losses. The study found that the FSPV systems adopted on lakes with a coverage ratio of 0.5–0.6 could meet an average of 26% of the city’s annual power demand.

Ovipleistophora mirandellae. [Descriptions of Fungi and Bacteria].

A description is provided for Ovipleistophora mirandellae, a parasite of various freshwater fish, and as such is found in the same habitats (large lakes, and medium to large rivers, etc.) as its hosts. Some information on its associated organisms and substrata, dispersal and transmission, habitats and conservation status is given, along with details of its geographical distribution (Europe (Austria, Czech Republic, Denmark, Finland, France, Germany)).

SPATIAL STRUCTURE OF VEGETATION OF LARGE LAKES OF THE ONEGA PENINSULA (ON THE EXAMPLE OF MURAKANSKOE AND BOLSHOE VYGOZERO LAKE)

Studying the vegetation of freshwater lakes remains a topical subject in the national parks of the Arkhangelsk Region. It is in particular important for the Onega Pomorie National Park, which is located along the coasts of the Onega and Dvinskoy bays (of the White Sea) in the northern part of the Onega Peninsula. This article examines the spatial structure of aquatic and coastal-aquatic vegetation of Murakanskoye and Bolshoye Vygozero – two large lakes of the Onega Peninsula. The spatial structure is presented in the form of ecological series of associations of plant communities. A comparative characteristic of the lakes’ vegetation is given in the discussion of the article. The littoral zone is poorly developed in both lakes mentioned above. It depends on the openness of the water areas to the winds from the north. It is indicated that the species composition and vegetation structure of the Bolshoye Vygozero Lake mostly depends on water transparency and high acidity; these factors determine the development of the Phragmitetum australis fontinaliosum dalecarlicae, Phragmitetum australis caricosum aquatilis, Caricetum aquatilis associations. In the Murakanskoe Lake, high water transparency and slightly alkaline pH values contribute to the development of communities of pondweeds – such as Potamogeton alpinus, Potamogeton praelongus, and communities of the Lobelietum dortmannae isoëtosum echinosporae association.

ZOOINDICATION OF WATER BODIES WITHIN PETROLEUM INDUSTRIAL TERRITORIES OF THE BOLSHEZEMELSKAYA TUNDRA

Intensive development of the oil and gas industry and accidents on oil pipelines become the reason of the environmental tension in the Pechora River basin (Nenets Autonomous District). Data on changes in water quality in five lakes and a small watercourse in the territory of oil fields of the Bolshezemelskaya tundra are presented. The bioindication indices (Berger-Parker (D), Shannon biodiversity (H '), Woodiwiss (W), Pantle-Buck (S), Balushkina (Kch)) were applied. The assessment of the state of water bodies in the Kolva River Basin (large lakes - Kolvaty and Nercheity), in the Laya River Basin (shallow lakes - Krugloye, Bezymyannoe 1, Bezymyannoe 2, stream) was done. The 28 samples of zoobenthos was processed by the standard method in July 2012 and 2019. A low diversity of benthic invertebrates was revealed for 5–20 taxa of the rank of families and orders. During the considered period, the changes have occurred in the structure and composition of the zoobenthos of water bodies. In 2019, the species diversity decreased in Kolvaty Lake (H'<2). There are no species of the crustacean complex (Monoporeia affinis, Mesocyclops leuckarti, Heterocope borealis) and larvae of Trichoptera. Only Sphaeriidae and Chironomidae with a predominance of Psectrocladius psilopterus (D = 55%) were recorded. The species diversity in Nercheity Lake increased (H'> 2) with a change in the dominant taxa: the larvae of the chironomids Ablabesmyia monilis (D = 44%) were found in 2012, the lower crustaceans (D = 47–51%) - in 2019. However, according to the totality of hydrobiological indicators, the quality of water in the lakes of the Kolva River Basin in 2019 compared to 2012 did not change significantly. The quality of water in the Krugloye and Bezymyannoe 1, Bezymyannoe 2 lakes (the Laya River Basin) has improved that is confirmed by a significant increase of species diversity. The most characteristic groups of benthic communities in these lakes are lower crustaceans (Cladocera, Copepoda, Ostracoda) and Chironomidae. The indicators of clean waters are o-β-mesosaprobic species Cladocera, Copepoda Heterocope appendiculata, Heterocope borealis (in the oligotrophic lakes), caddisfly Limnephilus stigma (in the Krugloe Lake), rotifer Polyarthra euryptera (in the Bezymyannoe 2 Lake), mayfly larvae Centroptilum luteolum. More resistant to organic pollution Copepoda began to prevail in abundance and diversity in Bezymyannoe 1 and Bezymyannoe 2 lakes, with a decrease in the taxonomic composition of Cladocera, which indicates the eutrophication of these water bodies. In most lakes, the water corresponds to the III quality class ("moderate pollution"), but in the Kolvaty lake and in the Bezymyanny stream (the Laya River basin) was recorded the biogenic pollution. Totally, insignificant taxonomic changes in zoobenthos structure took place in the lakes and the state of water bodies of the surveyed tundra remains relatively stable.

Seasonal flow forecasting in Africa; exploratory studies for large lakes

For many applications, it would be extremely useful to have insights into river flows at timescales of a few weeks to months ahead. However, seasonal predictions of this type are necessarily probabilistic which raises challenges both in generating forecasts and their interpretation. Despite this, an increasing number of studies have shown promising results and this is an active area for research. In this paper, we discuss insights gained from previous studies using a novel combined water balance and data-driven approach for two of Africa's largest lakes, Lake Victoria and Lake Malawi. Factors which increased predictability included the unusually long hydrological response times and statistically significant links to ocean-atmosphere processes such as the Indian Ocean Dipole. Other lessons learned included the benefits of data assimilation and the need for care in the choice of performance metrics.