Distinct Seasonal Primary Production Patterns in the Sub-Polar Gyre and Surrounding Seas

Primary production (PP) in the sub-polar region appears to be important for ocean carbon uptake but how the different water masses contribute to the PP occurring here has not yet been described. Using two models based on satellite observations of surface chlorophyll, light and temperature, seasonal patterns in the distribution of PP are shown here to differ in the sub-polar gyre south of the Greenland-Scotland Ridge (GSR) and surrounding water masses. Monthly averages of PP (2003–2013) were determined. Total and seasonal PP were similar in both models. Average PP in five of the domains (0.47–0.77 g C m–2 d–1) was well above the global average (0.37 g C m–2 d–1). Over the East Greenland shelf, however, total annual PP was estimated to be only 0.19 g C m–2 d–1. The Norwegian shelf was the most productive of the regions studied. “Spring blooms” appear sporadically as spikes in the annual distribution of PP in some regions/years, but do not emerge as a dominant feature in the average annual development of PP in any of the domains. For all regions, ∼25% of the annual PP takes place in the period January-May. PP peaked over most of the study area at or around maximum insolation or temperature. PP in the study region as a whole appears to be more related to latitude or water masses than to bathymetry. In waters over the East Greenland shelf, the Norwegian shelf, and north of the GSR up to 50% of annual PP had taken place when ∼50% of the annual flux of light has reached the surface. In contrast, only about 35% of annual PP had taken place in the sub-polar gyre and waters over the southern open shelf by this time. Light-use efficiency differences may be explained by differences in mixed layer depth (MLD). Multi-model Earth System model studies have indicated that climate change may decrease the MLD in the sub-polar gyre and suggest this may lead to a decrease in the PP occurring here. The results presented here, however, suggest that a shallower MLD could lead to an increase in PP.

INFLUENCE OF ATMOSPHERIC PRECIPITATIONS ON THE RUN OF THE PUTIL RIVER

Research of precipitation, water balance of river basins, and the impact of precipitation on river runoff remain relevant in the context of global and regional climate change. Nowadays, many scientific research all over the world are devoted to the research of the problem of river runoff change under the influence of climatic factors. This kind of research has been developing strongly in Ukraine in recent decades. In particular, they concern the rivers of the Ukrainian Carpathians. The basin of the river Putyla to the line of the village of Putyla has an area of 181 km2. It is located in the south-eastern part of the Carpathian and characterized by a significant influence of warm rains on the formation of water runoff. The average annual runoff is characterized by rather complex patterns of change both in time and space. There are periodic, cyclical and unidirectional changes that occur under the influence of a complex system of factors. Climate is a major factor of the water change. Thus, the research of the average runoff of the Putila River has different aspects.To determine the effect of precipitation on river runoff, the method of comparing difference-integral curves of annual runoff and precipitation, as well as water-balance methods are used. Long-term changes and intra-annual distribution of precipitation, in particular rainfall, according to the observations of the meteorological station Selyatyn were analyzed. We constructed a differential integrated curve of modular coefficients of the average annual precipitation in the Putil district. It clearly reflects the cyclical changes in precipitation. Long-term changes and intra-annual distribution of water runoff in the Putyla River also were analyzed. During the observation period, periods of long-term fluctuations of the average annual precipitation were revealed. The average annual rainfall is 842.9 mm. The annual course is stable, ie the greatest amount of precipitation falls in the summer, when there are intense thunderstorms and showers, the least – in winter. Based on the data of hydrological observations, the average long-term value of water consumption according to GP Putila is 2.47 m3/s. We calculated the coefficient of variability (variation). The coefficient of variation for average costs is 0.21 (21%), and for precipitation – 0.7 (7%). The connection between precipitation and runoff was established. We have built a comprehensive schedule of annual distribution of precipitation and costs of the Putyla River for 2010. You can see that in the spring due to snowmelt there is an influx of water and there is a spring flood. It is known that 2010 in Putilsky district was full of water. The reduction of water consumption in the Putyla River in the cold period of the year with a decrease in precipitation is also observed. Graph of the dependence of the runoff of the Putyla River on precipitation in the village of Selyatyn showed a fairly clear relationship between the variable values of runoff and precipitation (the coefficient of variation is 0,66). The feeding structure of the Putyla River is mixed. The main share is occupied by rain, less - snow and groundwater. Key words: climate change, precipitation, runoff, rivers, long-term changes in runoff, intra-annual distribution of precipitation and runoff, Putyla river.

On eco-evolutionary dynamics of phenologies in competitive communities and their robustness to climate change

Global changes currently cause temporal shifts in the favourable conditions for different phases of species life cycles. Phenologies characterizing temporal presence, may adapt through heritable evolution in response to these changes. Given a community context, this evolution may cause a change in the phenology overlap and thus a change of interspecific interactions such as competition. Using a model in which phenologies compete and coevolve, we study the conditions under which diversity emerges, as well as their annual distribution. We find that the environment richness (food quantity, light, pollinators, etc) and competition constrain the diversity and spread of phenologies. A robust pattern of phenologies distribution emerges consistent with Swedish flowering observations. Once a stable community is reached, we apply a progressive change in environmental conditions. We found that adaptation eventually restored diversity, but that the simulated change often led to numerous extinctions due to increased competition. The percentage of diversity lost depends on the speed of change and on the initial diversity. Phenologies already pre-adapted to the new environmental conditions drive the restoration of diversity after the change. We finally study a spatial version of the model in which local communities are organized along an environmental gradient. Pre-change, allowing dispersal decreases the local adaptation of phenologies to their local fixed environmental conditions. Dispersal however largely enhances the maintenance of biodiversity in changing environments, though its benefits are not homogeneous in space. Evolution remains the only rescue mechanism for southern phenotypes.

Origin and Route of Severe Dust Storms in West Asia (with Horizontal Visibility Less Than 1000 Meters)

Storms are intensified atmospheric phenomena which are sometimes accompanied by heavy rainfall and sometimes by dust. Dust storms, especially storms with horizontal visibility of fewer than 1000 meters, have always been harmful and detrimental to human comfort and health. In recent decades, the worrisome phenomena of conflict, climate change, and droughts have increased the frequency of dust storms in West Asia. Identifying the source and route of dust storms is the first step in limiting the harm they inflict. To investigate this phenomenon, using the daily data of the Meteorological Organization of Iran, storms with horizontal visibility of less than 1000 meters in the southwestern region of Iran, as one of the destination areas of these storms, in a statistical period of 33 years (1987 to 2019) was extracted. First, the monthly, seasonal and annual distribution of dust storms in 13 synoptic stations in this area was investigated. Then, using the site https://www.ready.noaa.gov/HYSPLIT by backward method from the GDAS data system with a step of 0.5 degrees, the origin and path of the storms were identified. Finally, maps of each route were drawn in ArcGIS 10.6. The findings of this study revealed that the biggest number of dust storms occurred in the winter, in terms of temporal distribution (38% of storms). With 23% of storms, spring is in second position. In terms of monthly distribution, the month of January has the most storms, followed by February and December. Storms decrease in intensity as they move from the south to the north, and from the west to the east of the region. The central region of Iraq ranks first in terms of storm origin, accounting for 25% of all storms. If dust storms originating in western Iraq are added to this number, about 35% of storms in west Asia originate in western and central Iraq. Regarding the pattern of large-scale atmospheric circulation prevailing in the middle layer of the atmosphere in this region, most of these dust storms in the west-east direction, after passing through the center and south of Iraq, enter Iran. The study also shows that storms in Syria، Jordan or northwestern Saudi Arabia, are very thick. These storms cover the middle layer of the troposphere and then affect high stations such as Shahrekord and Yasuj with an altitude of more than 2000 meters.

JUSTIFICATION OF HYDROPOWER POTENTIAL OF THE VOVCHA RIVER FOR CONSTRUCTION OF SMALL HPP IN THE SITE OF GAVRYLIVKA RESERVOIR

The article presents the research results of the hydropower potential of the Vovcha River in the site of Gavrilivka Reservoir for construction of a small hydropower plant. During the research, statistical methods were used to analyze the homogeneity of long-term fluctuations of river flow. Estimation of parameters of analytical distribution curves (average long-term value Q, coefficient of variation СV, ratio of asymmetry coefficient to variation coefficient CS/CV) was performed by the maximum likelihood method. Determination of the estimated annual distribution of the flow in the site is carried out by the real year method. Methods for calculating the hydropower potential are based on the results of hydrological investigation. To achieve stated objective, the following tasks are solved: 1) the water resources of the Vovcha River in the Gavrilivka Reservoir were quantified; 2) the hydropower potential of the Gavrilivka Reservoir is estimated according to model years; 3) the value of technically achievable, guaranteed and ecologically justified hydropower potential is established; 4) technical and economic indicators of project practicability are assessed. The provision of HPP capacity has been determined both for the whole series of observations and for the distinctive model years. In particular, the provision capacity of N = 50 kW will amount on average 57% (208 days per year), and for the guaranteed component of N = 44 kW it will amount 62% (226 days per year). According to the research results, it is established that the optimal capacity of the hydropower plant is 50÷75 kW with a designed capacity utilization of 80÷70%, respectively. The approximate payback period will be 7-9 years with a 10% amortization rate, and accordingly a possible replacement of equipment in 10 years.

Dynamics of Aedes albopictus invasion. Insights from a spatio-temporal model

France displays a latitudinal range for the expansion of Aedes albopictus invasive populations that is not yet completely colonized providing a critical opportunity to address key invasion processes. We propose a spatio-temporal model (DISTIGRI) to describe and predict current and future expansion at both intra- and inter-annual scales of Aedes albopictus. This process-based model integrates mechanistic descriptions of the developmental cycle and the dispersal process of Aedes albopictus within a reaction-diffusion framework, depending on climatic suitability and photoperiod with a high spatio-temporal resolution. Using this model coupled with a climatic database, we propose several maps describing the current intra-annual distribution of Aedes albopictus, including the date of first emergence and the length of the period with significant adult presence. We also compute its future distribution over the next 10 years under several climatic scenarios, which shows a range expansion with a strong dependence on the climatic scenario. The outputs of the model may constitute a valuable asset for designing control and avoidance strategies, and to anticipate the biting nuisance with a high spatio-temporal resolution. These outputs also emphasize the importance of taking both dispersal and life cycle into account to obtain accurate descriptions of out-of-equilibrium processes such as ongoing invasions.

Studies of meteorological elements and climate change in the Uruçuí river basin/Brazil

The objective is to show the variability of meteorological elements in the hydrographic basin area of the hydrographic basin of the Uruçuí Preto River–PI/Brazil, aiming to contribute to sustainable development in the productive areas of agriculture, laser, and hydrology. The meteorological elements studied are air temperature and relative humidity and their fluctuations, thermal amplitude, wind (intensity and direction), total insolation, cloud cover, evaporation, evapotranspiration, and rainfall. The data were from the 1960-1990 series, acquired by the Superintendency of the Development of the Northeast and by the Technical Assistance and Rural Extension Company of Piauí. The maximum annual temperature is 32.1°C, its minimum 20.0°C, with an average annual temperature of 26.1°C. A climatic classification was used according to the KÖPPEN systems, where two climatic types are distinguished in the Uruçuí Preto/PI river basin, the Aw, tropical hot and humid, with rain in summer and dry in winter; Bsh, warm semi-arid, with summer rains and dry winter. The variation of the thermal amplitude is from 11.9 to 14.9ºC. The average relative humidity of the air was 47 to 79%; the average annual precipitation was 937.7 mm; it was observed that the annual march of relative humidity follows the annual distribution of precipitation because the precipitation was the feeding process from natural sources of water vapor and moisture. Total Sunstroke in the BHRUP area ranges from 2520 to 2750 hours. It is concluded that the maximum annual temperatures increased during the period, which can cause several socioeconomic problems, and human health.

Abundance and annual distribution of freshwater snails and some trematode cercariae at Damietta Governorate, Egypt

Summary In addition to being a good food source, freshwater snails are considered one of the positively and negatively influencing invertebrates on the environment. Several biotic and abiotic factors are thought to affect the distribution and the dynamics of these snails. Freshwater snails are the most dominant and conspicuous individuals of the freshwater biota in Damietta Governorate. In this study, freshwater snails were collected monthly from 5 geographically and environmentally different sites at Damietta Governorate at the north of Egypt during June 2017-May 2018. Seven snail species; Lanistes carinatus, Lanistes varicus, Pila wernei, Segmentorbis angustus, Melanoides tuberculata, Biomphalaria alexandrina, and Gabbiella senoriansis, were identified. Lanistes carinatus was the most abundant species (56.4%) in the collection sites. Besides, Al-Inaniyyah village had the highest snail species abundance and variety. The abundance of the most recorded species varied seasonally; the highest abundance was recorded during summer while the lowest was during winter. The abundance of some snail species correlated positively or negatively with some physico-chemical parameters; water temperature, dissolved oxygen, conductivity, total dissolved salts, and electrical conductivity. Two types of trematode cercariae; gymnocephalus cercariae and xiphidiocercariae, were harvested from Lanistes carinatus. The highest prevalence of both cercarial types was detected during summer. The correlation between the prevalence of both cercarial types and the physico-chemical parameters were determined. Xiphidiocercariae were the most predominant cercarial type in Damietta Governorate. Our findings suggest that the invasion of some freshwater snails is likely to be the cause of the low prevalence or complete absence of some medically important intermediate snail hosts. We recommend further characterization of the distribution of freshwater snails and the interrelationships among them in Egypt, and suggest a controlled use of selected snail species to combat their medically important analogues.

Effects of Organic Additives on Chemical, Microbiological and Plant Pathogen Suppressive Properties of Aerated Municipal Waste Compost Teas

The aim of the present study was to characterize the physical-chemical and microbiological features of aerated compost teas (CTs) extracted with dechlorinated tap water and with two different additives, molasses and whey, in increasing doses. Plant pathogen suppression properties of CTs were also taken into account. Total nitrogen in CTs increased with rising doses of the additives used. In spite of this, nitrogen and mineral element contributions were limited but complementary for plant mineral nutrition. Although total heavy metal contents in CTs were low, an increase of their bioavailable forms (ionic and chelated forms, presence in microorganisms) should be taken into account. In addition, the distribution on soil of acid and/or chelating products by CTs could increase the bioavailability of heavy metals, especially in the case of several annual distribution cycles and of medium–long term treatments. Additives modulated the structure and composition of microbial communities and CTs, exhibiting a broad spectrum of suppressive properties against plant pathogens, especially when they were used in a raw form.