Limnol. Rev., Volume 23, Issue 3 (December 2023) – 5 articles

Global warming is an essential factor to consider when studying tidal wetlands. The Río Piedras and Flecha de El Rompido salt marsh is one of the main wetlands in Andalusia, Spain. From the mid-1950s to the present day, Land Use Changes (LUCs) have caused significant alterations to the landscape. These changes, along with the effects of climatic variables and human activity, have led to an unprecedented impact on the environment. In this study, a patented method is used to obtain the total cubic meters of eroded soil and the average erosion prediction between 2015 and 2021 in the marshland area. Additionally, the various factors contributing to this phenomenon and the influence of intertidal processes are discussed. The results demonstrate how the enhanced integration of LIDAR technologies, digital elevation models, and Geographic Information Systems (GIS), in conjunction with regression models, has proven highly useful in describing, analyzing, and predicting the volumetric change process in the study area. In conclusion, the methodology used is helpful for any type of coastal marshes influenced by tidal processes and climate change. Full article

The complete climatic courses of the parameters of stable thermal stratification for the central part of Lake Ladoga, the largest European lake, are presented on the basis of empirical relationships, taking into account the physical processes governing water temperature variations. For the first time, the seasonal cycle of the surface water temperature, the temperature and the depth of the thermocline, and the hypolimnion temperature are calculated using the vertical profiles of the temperature obtained from the central area of Lake Ladoga. Temperature data are used for the period of in situ observations from 1897 to the present. The proposed functional forms of the temporal temperature cycle and the course of thermocline’s boundaries deepening are useful for examination and simulation of the heat vertical transport from air to water. Approximation curves for the parameters of heating and cooling periods were developed with high significant determination coefficients. Time dependencies of the climatic rates of change in water temperature and the depth of the thermocline boundaries were determined from the onset of stable stratification to its dissipation. The highest rate of water temperature change in the heating stage takes place in late June–early July, which at the water surface, is 0.32 °C/day, while in the thermocline layer, it is 0.18 °C/day. The peak velocity during the cooling stage at the surface occurs in late August–early September and is 0.14 °C/day, whereas in the thermocline, it is 0.08 °C/day and takes place between September and early October. During the period of heating, the deepening parameters of the thermocline layer do not fluctuate very much, only within the range of 0.1–0.3 m/day. During the cooling period, under the influence of free convection, rates increase drastically. The maximum rates of deepening during the period of full autumn mixing reach 1.8 m/day. When the autumn overturn occurs, the epilimnion thickness equals the bottom depth, and the bottom temperature reaches its maximum during the annual cycle. Climatic norms of the stratification parameters against which it is necessary to assess climate change are calculated. Full article

Increasing global pollution of water resources undermines the efforts invested in the realisation of Sustainable Development Goals. In developing countries, for example, water pollution is exacerbated by poor regulatory structures and improper waste disposal. This study, for the first time, investigated the physicochemical and microbial parameters of surface water from the Ugandan stretch of the Kagera transboundary river. Surface water (n = 135) from downstream, midstream and upstream of the river was sampled between February 2021 and June 2021, and analysed following standard methods for the examination of water and wastewater. Further, the samples were analysed using flame atomic absorption spectroscopy for the presence of heavy metals: nickel, lead, chromium, cadmium and copper. The obtained results showed that turbidity (24.77 ± 5.5–43.99 ± 6.87 mg/L), colour (118 ± 8.90–145.2 ± 30.58 Pt-co units), Escherichia coli (4.96 ± 7.01 CFU/100 mL), lead (23.0 ± 11.0–43.0 ± 12.0 µg/L) and cadmium (3.3 ± 1.0–10.1 ± 10.0 µg/L) were at levels that surpassed their permissible limits as per World Health Organization guidelines for potable water. These results are lower than previously reported for the Rwandese stretch of this river, but still present potential health risks to the population whose livelihoods depend on the river. Measures should therefore be instituted by the East African Community member states to mitigate riverine pollution and ensure sustainable use of the Kagera transboundary river. Full article

This paper presents the results of the calculation of black ice thickness, as well as conductive heat fluxes inside the ice and at the water–ice boundary during the winter in the shallow boreal Lake Vendyurskoe (Russia). The calculation was carried out on the basis of experimental data obtained from a thermistor chain with nine sensors, five of which were successively frozen into the black ice during the winter of 1995–1996. Data processing was carried out by two methods, whose novelty lay in the simultaneous use of the temperature series of two sensors frozen into the ice and those that were in the water column directly under the lower ice boundary. The resulting estimates of black ice growth rates varied widely: maximum values (up to 8.5 mm/day) were observed in December during first month of ice period, with an average growth rate of 3.4 mm/day from December to the end of February. The heat flux in the black ice sheet varied significantly over synoptic time intervals; the highest values (up to 40 W/m²) were observed during the first two weeks of measurements, then a downward trend was noted, to values of ~10 W/m². Black ice was isothermal from the end of February to the end of April due to the release of water on the ice surface after heavy snowfall. During this period the heat flux inside the black ice was zero, and there was no increase in black ice thickness. The calculation of the water–ice heat flux gives results that are very sensitive to both measurement limitations and the variability of external parameters. However, the estimates of this flux for moments in time when the sensors were frozen in the ice are values 1–2 W/m², which are quite close to the previous estimates for Lake Vendyurskoe. The limitations of the presented method are related to the thermal inertia of black ice and make it possible to calculate of ice thickness with a time delay of several days. To quantify the effects of thermal inertia of ice, a model problem of heat propagation in the ice sheet is considered for the case of periodic temperature changes at its upper boundary. The attenuation of the amplitude and the delay of a heat wave during its propagation in the ice are estimated, and accordingly, the conditions, under which the temperature profile in the ice sheet is close to linear, are analyzed. Full article

The COVID-19 pandemic affected nearly all strata of life, including scientific activities. Implementation of nationwide lockdowns, closures of universities, and other measures significantly limiting social mobility precluded field and laboratory research from being pursued at a pre-pandemic pace. On the other hand, working from home could translate into higher productivity of researchers in terms of publication output, ultimately affecting the journals’ metrics. This effect has been well evidenced in the biomedical field, but whether it also occurred in aquatic sciences has not been explored. Therefore, this study aimed to analyze and compare various metrics of journals classified in the Scopus evaluations in 2019 (encompassing 2016–2019, the pre-pandemic period) and 2022 (covering 2019–2022, the pandemic period) within three subjects: aquatic science, oceanography, and water science and technology. In general, the number of journals classified into the considered categories increased in 2022 by 12%, and the majority (78%) experienced an increase in the CiteScore metric. The total published articles and received citations also significantly increased in 2022 by 17.5% and 63.5%, respectively, and were even higher in the case of open access journals—69% and 145%, respectively. The overall share of cited articles in the considered period was higher by 5% than in the 2019 Scopus evaluation and by 7% in the case of open access periodicals. However, source normalized impact per paper (SNIP) and the SCImago journal rank (SJR) values decreased by 7% and 8%, respectively. The highest share of citations was generated by Water Research, Water, and the Journal of Hydrology, and the highest number of articles was published by Water, Frontiers in Marine Science, and Desalination and Water Treatment. Only five of the COVID-19-related papers published in journals with the highest CiteScore and total number of citations received more than 200 citations, but their contribution to citations received by the journals was not high. In summary, the present study’s findings indicate the high potential of the field dedicated to water sciences to adapt in a period challenged by an infectious disease pandemic. However, they do not exclude the adverse effect that this period could have on the activities of individual scientists and research teams. Full article