Response of a Small River Plume on Wind Forcing

Wind forcing is the main driver of river plume dynamics. Direction and magnitude of wind determine position, shape, and size of a river plume. The response of river plumes on wind forcing was simulated in many numerical modeling studies; however, in situ measurements of this process are still very scarce. In this study, we report the first direct measurements of frontal movement of a small river plume under variable wind forcing conditions. Using quadcopters, we performed nearly continuous daytime aerial observations of the Bzyb river plume located in the non-tidal Black Sea. The aerial remote sensing was accompanied by synchronous in situ measurements of wind forcing. We assessed spreading patterns of the plume and evaluated movement velocity of its outer border with unprecedentedly high spatial (∼10 m) and temporal (∼1 min) resolution, which was not available in previous studies based on in situ measurements and satellite observations. Based on the collected data, we evaluated the time of response of plume spreading dynamics on changes in wind forcing conditions. The advection velocity of the outer plume border shows linear relation to wind speed with very small response time (10–20 min). The reversal between upstream/downstream plume spreading occurs during several hours under moderate wind forcing conditions. These reversals involve only near-field part of the plume, which cause detachment of the far-field part of the plume. The obtained results are crucial for understanding and simulating spreading dynamics of small river plumes worldwide.

Basin-centric approach to the sustainable development of agriculture in the context of climate change

The aim is to develop conceptual principles of sustainable development of the agrosphere and reproduction of degraded riverbeds of small rivers under climate change. Methods. Methodology and methods of system approach, monitoring, statistical analysis, and synthesis of scientific data. Results. It has been determined the ecological condition in Ukraine and the world has been by the manifestations of degradation processes in terrestrial ecosystems and small river basins on the principle of causation. It has been suggested the conceptual bases of restoration of channels of small rivers and their basins by carrying out engineering, culture-technical works in channels and floodplains of small rivers, the organization of adaptive landscaping of the territory, and also carrying out agro-, chemo-, bio- and phyto-meliorations in their basins without disturbance the basis of erosion and giving impetus to self-renewal of natural fauna and flora. In the processes of nature restoration, the leading role of domestic science in the methodological and methodological support of projects has been identified, and importance is attached to the restoration of natural biodiversity and biologization in agricultural systems. We proposed to create a state mortgage land bank with a concentration in it of land fees of ecological funds with the involvement of domestic and foreign investment. It is recommended to test the idea in several model pools of soil-climatic zones with further replication in Ukraine and the spread of technology beyond its borders. Conclusions. А systematic approach is needed to carry out reclamation works in the basins of small rivers is to implement the basin approach. To implement the program, the Verkhovna Rada of Ukraine must adopt the Law of Ukraine “On Agriculture, Sustainable Development of the Biosphere and Ecological Nature Management”, the project of which was developed at the NSC “Institute of Agriculture of NAAS”. The NSC “Institute of Agriculture of NAAS” with appropriate financial and personnel support on a multifunctional basis can perform the functions of a methodological center for the development of methodology and techniques of land management and reclamation in the process of restoring small river basins.

Ovipleistophora ovariae. [Descriptions of Fungi and Bacteria].

A description is provided for Ovipleistophora ovariae. There are only two records of this species in the wild (both on feral fish), from a pond and a small river in Oklahoma. It may, however, be expected in the same freshwater habitats as its known 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 (North America (USA (Alabama, Arkansas, California, Illinois, Kansas, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, Tennessee, Texas))).

Wild Populations Of Medicago Falcata L. In Small River Basins Of European Russia As A Source Material For Breeding

The genetic resources of wild populations of Medicago falcate L. of the Cretaceous South of the Srednerussky Upland in ecotopic conditions of chalky slopes and floodplain meadows in the basins of small rivers Tikhaya Sosna and Manjokha were studied to find the source material for breeding work to create varieties for different cultivation conditions. Evaluation of phytocenotic features, density of cenopopulations, forage and seed species was carried out. The species M. falcata forms, both on meadows in floodplains and on chalk slopes, full-membered normal cenopopulations, which have a continual (continuous) distribution of individuals by age groups, stable in time and in space. The centralized ontogenetic spectrum indicates the stable status of M. falcata cenopopulations in plant communities in various ecotopes of small river basins. The density of individuals of M. falcata was on average 18.9 % higher in cenopopulations of floodplains than in chalk slopes. The density of generative individuals in all studied cenopopulations was on average close and varied within 81.2-83.7 %, which indicates their stability in time and high adaptive potential. The weight of one fruiting model plant of floodplain meadows was 2.28 times higher than on chalky slopes. Seed yield on floodplain meadows was 2.02 times higher than on chalky slopes. Valuable source material for breeding M. falcatum varieties adapted to different ecotopic conditions was obtained.

Internal Waves as a Source of Concentric Rings within Small River Plumes

This study is focused on concentric rings, which are regularly observed by remote sensing of small river plumes located in different regions worldwide. We report new aerial observations of these features obtained by quadcopters and supported by synchronous in situ measurements, which were collected during the recent field survey at the Bzyb river plume in the eastern part of the Black Sea. Joint analysis of remote sensing imagery and in situ data suggest that the observed concentric rings are surface manifestations of high-frequency internal waves generated in the vicinity of the river mouth. The obtained results demonstrate that the propagation of these waves does not induce offshore material transport within the plume induced by shear instability, which was hypothesized in a recent numerical modeling study of this process. We provide an explanation for the appearance of misleading material features in the numerical simulations discussed above. Finally, we discuss directions for future research of high-frequency internal waves generated in small river plumes.