Southern Branch Research Articles

Comparative Rainfall-Runoff analysis of the Upper Murat River Basin in Turkey in context of Hydro-Meteorological variables

This study was carried out to examine rainfall-runoff relationship in the Upper Murat River Basin in Turkey. Murat River Basin, which forms the study area, includes Tunceli, Muş regions and Upper Murat within the Upper Euphrates in Eastern Anatolia, forms the southern branch of the upper basin of the Euphrates River and corresponds to the Middle Euphrates section. Previous studies were carried out for entire Murat River Basin. The novelty of this study is that it focuses on Upper Murat Basin, and gives a different perspective to rainfall-runoff relationship by considering precipitation elasticity in addition to the existing studies. To figure out the basin characteristics, geographic information system based on digital elevation model was used. Annual mean flow records of four flow observation stations (1969–2019), annual total precipitation records and mean temperature records of seventeen meteorological observation stations (1964–2019) were used in the analyses. Rainfall-runoff and temperature-runoff relationship are shown on the graph. Trend analyses were performed by linear regression and Mann-Kendall trend test. Flow parameters were determined for all sub-basins and entire Upper Murat River Basin. The rational method and Thiessen polygons were used to determine flow coefficients. Besides, precipitation elasticities were determined by using elasticity equation to determine the sensitivity of streamflow to climate changes. Determining trends in precipitation, streamflow and temperature values, determination of flow coefficients and precipitation elasticities enabled a comparative rainfall-runoff analysis of the basin. Although there is no exact correlation between the results compared, a new perspective on the basin is presented. Runoff coefficients of sub-basins change between 0.42 and 0.72. Runoff coefficient for entire upper basin is 0.49. In precipitation elasticities, the values calculated for relevant sub-basins for last forty years change between 0.24 and 0.56. Precipitation elasticity for entire upper basin is 0.66. According to the results of the trend analysis, an upward trend was detected in precipitation at 2 stations, a downward trend at 3 stations, an upward trend was detected at 9 stations in temperatures, and a downward trend at 1 station in flows.

Seasonal overturning variability in the eastern North Atlantic subpolar gyre: a Lagrangian perspective

Abstract. Both observations and ocean reanalyses show a pronounced seasonality in the strength of the Atlantic meridional overturning circulation (MOC) within the eastern North Atlantic subpolar gyre (eSPG). However, attributing this overturning seasonality to seasonal dense water formation remains challenging owing to the wide distribution of recirculation timescales within the Iceland and Irminger basins. Here, we investigate the nature of seasonal overturning variability using Lagrangian water parcel trajectories initialised across the Overturning in the Subpolar North Atlantic Program (OSNAP) East section within an eddy-permitting ocean sea ice hindcast. By adopting a Lagrangian perspective, we show that the seasonal minimum of the Eulerian overturning at OSNAP East in autumn results from a combination of enhanced stratification and increased southward transport within the upper East Greenland Current. This convergence of southward transport within the MOC upper limb is explained by decreasing water parcel recirculation times in the upper Irminger Sea, consistent with a gyre-scale response to seasonal wind forcing. To account for the diversity of recirculation times within the eSPG, we also quantify the Lagrangian overturning (LMOC) as the total dense water formation along water parcel trajectories. The majority of water parcels, sourced from the central and southern branches of the North Atlantic Current, fail to return to OSNAP East prior to experiencing wintertime diapycnal transformation into the lower limb, and thus they determine the mean strength of the LMOC within the eSPG (8.9 ± 2.2 Sv). The strong seasonality of the LMOC is explained by a small collection of upper-limb water parcels, circulating rapidly (≤ 8.5 months) in the upper Irminger and central Iceland basins, whose along-stream transformation is determined by their month of arrival at OSNAP East.

Future Drying Subtropical East Asia in Winter: Mechanism and Observational Constraint

Abstract Coupled climate models project robust wintertime wetting trend over midlatitude East Asia under global warming scenarios, but the projected change in precipitation shows large intermodel uncertainty over subtropical East Asia from southern China to southwestern Japan. Based on an ensemble of climate models participating in CMIP6, this study shows that the weakened southern branch westerly jet (SWJ) on the southern side of Tibetan Plateau (TP) plays a key role in suppressing subtropical East Asian precipitation. The SWJ is deflected into southwesterly wind on the southeastern side of TP, bringing ascent and precipitation to subtropical East Asia primarily through isentropic gliding. As a result of the poleward and upward shift of the planetary-scale westerly jet under global warming, the SWJ becomes weaker and it acts to suppress subtropical East Asian precipitation by weakening the southwesterly wind and ascent. The SWJ–precipitation linkage also exists on interannual time scales, but the sensitivity of precipitation to interannual SWJ variability is systematically underestimated by the models compared with observation. The combined effects of the change in SWJ strength and the sensitivity of precipitation to SWJ explain about 40% of the intermodel spread of the projected precipitation changes. Observational constraint on the SWJ–precipitation relationship amplifies the projected drying trend and narrows the intermodel spread. It shows that the regional-averaged precipitation over subtropical East Asia decreases by 3.3% per degree of warming, and the amplitude of precipitation reduction over subtropical East Asia (southern China) is about 1.4 (3.4) times the raw projection.

Subfossil diatoms from Bandiala (southern branch of the Saloum estuary, Senegal): Evidence of a wet period in the upper part of the Néma Ba core.

Subfossil diatoms from Bandiala (southern branch of the Saloum estuary, Senegal): Evidence of a wet period in the upper part of the Néma Ba core.

Modeling the dispersal of the San Francisco Bay plume over the northern and central California shelf

High-resolution simulations by the Regional Ocean Modeling System (ROMS) were used to investigate the dispersal of the San Francisco Bay (SFB) plume over the northern-central California continental shelf during the period of 2011 to 2012. The modeled bulk dynamics of surface currents and state variables showed many similarities to corresponding observations. After entering the Pacific Ocean through the Golden Gate, the SFB plume is dispersed across the shelf via three pathways: (i) along the southern coast towards Monterey Bay, (ii) along the northern coast towards Point Arena, and (iii) an offshore pathway restricted within the shelf break. On the two-year mean timescale, the along-shore zone of impact of the northward-dispersed plume is about 1.5 times longer than that of the southern branch. Due to the opposite surface Ekman transports induced by the northerly or southerly winds, the southern plume branch occupies a broader cross-shore extent, roughly twice as wide as the northern branch which extends roughly two times deeper due to coastal downwelling. Besides these mean characteristics, the SFB plume dispersal also shows considerable temporal variability in response to various forcings, with wind and surface-current forcing most strongly related to the dispersing direction. Applying constituent-oriented age theory, we determine that it can be as long as 50 days since the SFB plume was last in contact with SFB before being flushed away from the Gulf of the Farallones. This study sheds light on the transport and fate of SFB plume and its impact zone with implications for California’s marine ecosystems.

Islamists in a Zionist coalition: the political and religious origins

ABSTRACT On June 13, 2021, the United Arab List, representing the Southern Branch of the Islamic Movement in Israel (SIM), became the first independent Arab party to join a Zionist governmental coalition. The article analyzes why the move hardly stirred opposition within the leadership and the popular base of a movement rooted in the Muslim Brothers. It demonstrates that the SIM’s coalition-oriented agenda responded to the firm and consistent demand for greater political impact voiced by a majority of the Arab public in Israel, and was commensurate with the religio-legal arguments introduced by the movement over two and a half decades of defending its decision to run for the Knesset. These arguments include stressing the importance of pragmatism in Islam and drawing analogies to religious narratives about cooperation with and service in infidel governments, such as the conduct of Muslims in Abyssinia and the conduct of Prophet Joseph in Egypt. Ironically, rather than limit its options, the Islamic premise upon which the United Arab List has operated turned out to allow it flexibility other Arab parties in Israel could not afford.

Subduction Initiation of the Southern Branch of the Paleo‐Asian Ocean in the Middle Ordovician in the Southern Beishan Orogen

AbstractThe subduction initiation and the early‐stage tectonics of the southern Paleo‐Asian Ocean have rarely been discussed. To address these problems, we report new geochemical and geochronological data of arc‐related volcanic rocks in the Huaniushan arc of the southern Beishan. Basaltic andesites and high‐Mg rocks yield zircon U‐Pb ages of 449–422 Ma and 460–437 Ma, respectively. The basaltic andesite is a continental arc‐related tholeiite with moderate amounts of TiO2; and is enriched in light rare earth elements (LREE), such as Rb, Ba, Th and Sr; it is also depleted in Nb, Ta and Eu; and has moderate εHf (t) (−0.3 to +5.5) and εNd (t) (−3.48 to +0.03) values; and high (87Sr/86Sr)i (0.7066–0.7079) values. The high‐Mg andesite and dacite are sanukitic‐type high‐Mg rocks, which have high MgO (Mg# = 49–62) contents, A/CNK (0.82–2.36) and (La/Sm)N values, low Sr/Y (3–15) and Ba/Th (11–182) ratios, moderate to low εHf (t) (−16.7 to +7.6) and εNd (t) (−3.74 to +0.05), and high (87Sr/86Sr)i values. All geochemical data indicate that they were sourced from mixing between mantle‐peridotite‐derived melts and silicic melts generated by the subducting oceanic slab and/or sediments in a hot subduction setting. After integrating the Sanukitic high‐Mg andesites (HMAs) with previously reported Nb‐enriched basalt, volumes of arc‐related tholeiitic to calc‐alkaline volcanic rocks, I‐ to S‐type granites, and HT eclogites, we conclude that the subduction initiation was one of the most likely geodynamic process for the metamorphism and magmatism in the Middle Ordovician to early Silurian.

Sedimentary evolution of the late Cretaceous - Eocene deep carbonates series of the foreland Magrebian chain. The Tellian domain of northern Tunisia

This paper aims to give an overview of the Upper Cretaceous – Eocene in the Tellian domain of the Magrebian chain in Tunisia. The sedimentological studies of the carbonates of this time interval, in the Fernana - Ain Draham area, offer a better knowledge of the Tellian foreland. Stratigraphic analysis of ten sections located in the structural units (Autochthonous, Para-autochthonous, and the allochthonous, Ediss Unit, Ain Draham - Adissa Unit and Kasseb unit) brings new results. The facies analysis of the nappes zone reinforces the definition of the allochthonous units that have undergone planar displacements during late Tertiary phases. The depositional setting evolutions during the Late Cretaceous - Eocene period testify to an area in the process of deformation. Since the late Cretaceous (Maastrichtian), the abundance of older dismantling rocks in the allochthonous units is interpreted as a synchronous shortening of the basin. The clastic deposits attributed to mélanges chaotic deposits forming events layers testify two tectonic stages of the early foreland basin formation with details: the upper Cretaceous (Gansseri Biozone) and the early Eocene (Lutetian). The studied deposits outcropping in the Tellian domain (part of the Maghrebian chain) invoke the earliest stage of synchronous compressive syn-sedimentary tectonics of the subduction of Europe over the African plate southern branch, as observed in the Mediterranean rim.

“You Are All Soldiers in the Battle against the Corona Virus and Your Commander Is the Prophet Muḥammad”: The Fatwās of Sheikh Rāʾid Badīr Regarding COVID-19

This article deals with the rulings of Sheikh Rāʾid Badīr, who served as a mediator between the Israeli government and the Muslim community over the course of the pandemic. As a senior leader and scholar of the southern branch of the Islamic Movement in Israel, Sheikh Rāʾid Badīr’s fatwās have historically addressed the unique circumstances and situational difficulties faced by Muslims living in Israel.

Environmental DNA metabarcoding reveals seasonal and spatial variation in the vertebrate fauna of Ilulissat Icefjord, Greenland

Ilulissat Icefjord in Greenland is experiencing the effects of climate change, with the Sermeq Kujalleq glacier being one of the fastest-moving and most productive ice streams in Greenland. This is likely affecting the distribution of species in the fjord, including those important to local fisheries. Due to heavy ice conditions, few studies on environmental and ecological conditions exist from the fjord. However, new techniques such as environmental DNA (eDNA) metabarcoding now allow deeper insight into the fjord system. Here, we combine local ecological knowledge with data on hydrographic conditions, stable isotopes (δ18O), and eDNA metabarcoding to investigate the spatial and seasonal distribution of marine fish and mammals inside Ilulissat Icefjord. Our eDNA results support local observations that Arctic char migrate to the southern fjord during summer, harp seals forage in large herds in the fjord system, polar cod is the dominant prey fish in the area, and Greenland shark likely does not reside in the fjord system. Lower predation pressure in the Icefjord, due to the absence of Greenland shark and polar bears as well as limited fishing/hunting, is presumably one of the reasons why ringed seals and Greenland halibut are larger in the Icefjord. Furthermore, our results indicate that in summer, the southern branch of the fjord system has a more diverse community of vertebrates and different water masses than the northern branch and main fjord, indicating a time lag between inflows to the different branches of the fjord system. Our approach highlights the value of combining local ecological knowledge with scientific research and represents a potential starting point for monitoring biological responses in Ilulissat Icefjord associated with climate-induced changes.

ფოთის პორტის ახალი მოლოს გავლენა სანაპირო ზოლის ლითოდინამიკურ პროცესებზე

In the city of Poti and its maritime region, for several decades there have been of environmental and geomorphological problems, which have been caused by anthropogenic interventions in this region. The impact of the breakwater of the new port of Poti on lithodynamic processes in the coastal zone is discussed in the paper. The sediment mass constancy equation is used in numerical experiments to determine the velocities of overbank and bank-driven sediment transport. To solve this equation, we use the finite element method and Crank–Nicolson schemes. According to calculations, 1,500,000 m3 of sediment migrates along the Nabada delta's banks, 850,000 m3 south of the delta to the harbor, and 65,000 m3 north of the delta to Khobiskal. The remaining 2,500,000 m3 is moved along the shore in a westerly direction before being dumped on the sea's underwater slope. After the new breakwater is built, all fine sediment movement in that direction will be stopped, and solid sediment will start to settle to the north of the new breakwater. Eventually, this will cause the southern branch of the Nabada Canal to become blocked. The total flow of water from the Nabada canal will be transferred to the northern branch, and the formation of a new delta will begin there.

Decision-Support System for Estimating Resource Consumption in Bridge Construction Based on Machine Learning

The paper presents and analyzes the state-of-the-art machine learning techniques that can be applied as a decision-support system in the estimation of resource consumption in the construction of reinforced concrete and prestressed concrete road bridges. The formed database on the consumption of concrete in the construction of bridges, along with their project characteristics, was the basis for the formation of the assessment model. The models were built using information from 181 reinforced concrete bridges in the eastern and southern branches of Corridor X in Serbia, with a value of more than 100 million euros. The application of artificial neural network models (ANNs), models based on regression trees (RTs), models based on support vector machines (SVM), and Gaussian processes regression (GPR) were analyzed. The accuracy of each model is determined by multi-criterion evaluation against four accuracy criteria root mean square error (RMSE), mean absolute error (MAE), Pearson’s linear correlation coefficient (R), and mean absolute percentage error (MAPE). According to all established criteria, the model based on GPR demonstrated the greatest accuracy in calculating the concrete consumption of bridges. According to the study, using automatic relevance determination (ARD) covariance functions results in the most accurate and optimal models and also makes it possible to see how important each input variable is to the model’s accuracy.

CORROSIVITY OF THE TROPICAL ATMOSPHERE OF SOUTH VIETNAM

Based on the results of annual corrosion tests at Kon Zo corrosion station, the southern branch of the Tropical Center in Ho Chi Minh City (Vietnam) determined the atmospheric corrosion rates of steel, copper, zinc, and aluminium. The corrosivity of atmosphere of Kon Zo corrosion station assessed in to relation to each metal according to the Methodology of international standard ISO 9223:2012 (Е). Using Dose-Response Functions (DRF) the corrosion rates of these metals for the first year (К1) were calculated with use of meteorological and aerochemical parameters of the atmosphere. A satisfactory correlation between the observed and calculated values for steel, copper and aluminium obtained. This indicates the possibility of using the DRF of international standard for determination the values К1 and corrosivity categories in areas of Vietnam.

Kết hợp liệu pháp oxy cao áp trong điều trị loét da, niêm mạc do biến chứng muộn sau xạ trị ở bệnh nhân ung thư vùng đầu, cổ

This article presents the results of the study "Study on the effects of combined hyperbaric oxygen therapy in the treatment of skin and mucosal ulcers caused by late complications after radiation therapy in patients with head and neck cancer" in order to determine the ratio ulcer improvement in this patient group. The study was conducted at High pressure oxygen Center (Southern Branch of Joint Vietnam - Russia Tropical Science and Technology Research Center) from June 2020 to May 2022, with 90 patients diagnosed with mucous and skin ulcers because of complications after radiotherapy of head and neck cancer, divided into 2 groups of 60 patients in the treatment group and 30 patients in the control group. Research results show that: the level of congestion, swelling, exudate at the ulcer improved significantly, the largest reduction is the day 20th of treatment onwards. The highest level of functional symptom improvement is pain relief reaching 100%, ranging from little pain relief to great pain relief; restricted mouth opening 97.1%; difficulty swallowing 97.4%; difficulty speaking 92.6%; difficulty turning 92.9 and dry mouth 91.7%. The overall ulcer improvement rate of patients after treatment increased gradually with the number of hours of HBOT treatment, on day 10, 20, 30, the rate was good and decreased by 18.3% and 58.3%, respectively; 71.7% and 20%; 6.5% and 6.7%; and especially 23.3% of patients recovered.

Simultaneous Rupture Propagation Through Fault Bifurcation of the 2021 Mw7.4 Maduo Earthquake

AbstractFault geometric complexity plays a critical role in earthquake rupture dimension. Fault bifurcations are commonly observed in earthquake geology, yet, robust kinematic rupture processes on bifurcated fault branches are largely missing, limiting our understanding of rupture dynamics and seismic hazard. Here, we holistically study the fault geometry and bilateral rupture of the 2021 Mw7.4 Maduo, China earthquake, that shows clear fault bifurcation near its eastern terminal. We integrate space geodesy imaging, back‐projection of high‐frequency teleseismic array waveforms, multiple point source and finite fault inversions, and constrain in detail the rupture process, in particular, through its fault bifurcation. Our models reveal a stable rupture speed of ∼2.5 km/s throughout the entire rupture and a simultaneous rupture through fault branches bifurcated at 20°. The rupture on bifurcated faults radiated more high‐frequency waves, especially from the stopping phases. The stopping phase on the southern branch likely stopped the rupture on the northern branch.

Late Cretaceous Transition From Calc-Alkaline to Alkaline Magmatism in the Eastern Anatolian Plateau: Implications for Microblock Collision Timing

Abstract In convergent belts, a collision between two blocks can reshape upper mantle geometry and processes responsible for a change in mechanisms of magma generation with distinct geochemical compositions. Therefore, identifying the turning point of a magma compositional shift can provide key constraints on collision timing, which is decisive in building a framework of regional tectonic evolution. The Eastern Anatolian Plateau is composed of a mosaic of rifted blocks assembled through successive collisional events, culminating with the terminal collision of Arabia with Eurasia and the closure of the southern branch of the Neotethys in the Cenozoic. The timing of the microblock collision of the Bitlis–Pütürge Massifs with the Eastern Taurides Block, the southern Eastern Anatolian Plateau, is a matter of debate due to limited constraints on the timing and petrogenesis of the (post-)collision-related magmatism during the Late Cretaceous. This study identifies three compositionally distinct intrusive suites aged from ~87 to ~69 Ma in the Eastern Taurides Block, the southern Eastern Anatolian Plateau. Group 1 intrusive rocks were emplaced in the southern Eastern Taurides Block at ~87–77 Ma and are characterized by high-K calc-alkaline compositions with predominantly depleted Hf and Nd isotope compositions [εHf(t) = 0.9 to +16.5 and εNd(t) = −2.3 to +6.9]. In contrast, the younger (~77–69 Ma) Group 2A comprises nepheline (Ne)-normative alkaline compositions, and Group 2B consists of shoshonitic compositions; both groups are mainly distributed in the central and northern Eastern Taurides Block. Groups 2A and 2B overlap in age between ~77 and 69 Ma and show relatively enriched Hf–Nd isotope compositions [Group 2A: εHf(t) = −1.0 to +4.7 and εNd(t) = −2.3 to +1.2; Group 2B: εHf(t) = −4.0 to +4.0 and εNd(t) = −6.5 to −1.3]. Group 1 intrusive rocks relate to the sub-arc asthenosphere-derived melts that differentiated toward the granite minimum by fractional crystallization. Parental melts of Group 2A intrusive rocks are interpreted to be derived from metasomatized subcontinental lithospheric mantle and differentiated toward the phonolite minimum. Crustal assimilation during magma ascent pushed the initially silica-undersaturated magma (Group 2A) into silica-(over)saturated compositions (Group 2B) through fractional crystallization that ultimately evolved toward the granite minimum. We propose that the Group 1 magmatism was related to northward subduction and closure of the Berit oceanic lithosphere, whereas the Group 2 magmatism results from collision-induced lithospheric delamination ± slab rollback. Together with the P–T–t evolution of the high-pressure metamorphic rocks from the Bitlis Massif and the spatiotemporal and geochemical variations of the Late Cretaceous magmatism in the Eastern Taurides Block, this study suggests that microblock collision of the Bitlis–Pütürge Massifs with the Eastern Taurides Block (Eurasia) most likely occurred at ~84–77 Ma. This study provides an example to constrain collision timing through a perspective of magmatic transition from calc-alkaline to alkaline series.

Late Paleocene – Middle Eocene magmatic flare-up in western Anatolia

A 3000-km long magmatic belt of predominantly Eocene age extends from Anatolia into Iran representing a major magmatic flare-up. We present new zircon U-Pb, Ar/Ar mica and apatite fission-track ages for this magmatism from northwestern Turkey, and review its geochemistry and geodynamic setting. The new age data show that magmatism started at the Late Paleocene (58 Ma) during the final stages of continental collision and continued into the early Middle Eocene (45 Ma) with most of the magmatism taking place in the Early-Middle Eocene (54 to 45 Ma). The Late Paleocene-Middle Eocene magmatism is separated from Late Cretaceous and Oligo-Miocene magmatic flare-ups by periods of magmatic quiescence. The Late Paleocene-Middle Eocene magmatism consists of plutonic and volcanic belts. The plutonic belt cuts across and post-dates the İzmir-Ankara suture. The plutonic rocks are mainly middle- to high-K calc-alkaline I-type granodiorite and granite, and the volcanic rocks are middle- to high-K calc-alkaline basalt, basaltic andesite and andesite. Geochemically, all the rocks are similar to those found in subduction-related environments. Crustal thicknesses calculated based on geochemistry suggest a thickened crust (60–70 km) at 58 to 54 Ma, and a relatively thin crust (ca. 40 km) at 54 to 45 Ma, which match with uplift and erosion during the Late Paleocene, and marine sedimentation during the Early-Middle Eocene in northwest Anatolia, respectively. The Late Paleocene-Middle Eocene magmatism is tentatively assigned to subduction of the southern branch of the Neo-Tethys.

Impact of early winter North Atlantic Oscillation on the dramatic alternation of seesaw haze intensity between late winter months in the North China Plain

The impact of early winter (December) North Atlantic Oscillation (NAO) on the subsequent dramatic seesaw haze intensity alternation (DSHA) phenomenon in the North China Plain (NCP) between late winter months of January and February is identified based on observational analyses and Community Earth System Model Large Ensemble Numerical Simulation (CESM-LENS) datasets in this study. Our research suggests that the late winter abrupt subseasonal haze intensity enhancement is preceded by the negative NAO-like pattern in December, and vice versa. Detailed analysis indicates that persistent North Atlantic tripole (NAT) sea surface temperature (SST) patterns play a crucial oceanic bridging role in relaying the delayed influence of NAO from December to the following January. In this circumstance, negative December NAO can induce a profound planetary-scale zonal Rossby wavetrain emanating from the central North Atlantic, in which the southern branch of this wavetrain propagates the negative NAO signal downstream to northeastern Asia, forming the Northeast Asian cyclonic anomaly in January and facilitating the repressed haze intensity via inducing the haze-unfavorable meteorology. However, in the subsequent February, the cyclonic anomaly centered southeast of the Yamal Peninsula plays a critical role in prolonging the influence of the December NAO, acting as an intermediate atmospheric bridge effect. The notable Northeast Asian anticyclonic anomaly can be induced in February accordingly, thus facilitating the haze intensity enhancement in the NCP via inducing the haze-favorable meteorology. As such, the dramatic subseasonal haze enhancement in the NCP between late winter months can be triggered by the preceding early winter NAO. It shows that the early winter NAO could be considered as a crucial precursory atmospheric signal predicting the late winter DSHA phenomenon in the NCP.

Delineation of estuarine ecological corridors using the MaxEnt model to protect marine fishery biodiversity

Ecological corridors (ECs) are important management tools to protect biodiversity by linking fragile habitats, especially for highly mobile organisms. ECs in terrestrial landscapes work as passages on land or in water. However, the significance of ECs to migratory species in estuaries has not been well elucidated. Based on annual fishery investigation in the Yangtze estuary and their dominance index rank, three of the top five species, including Larimochthys polyactis, Coilia mystus, and Gobiidae, exhibited absolute dominance in spring during the past 5 years. The temporal and spatial density variance of C. mystus supported its short-distance migration pattern. Redundancy analysis and the MaxEnt model predicted optimum habitats for C. mystus. C. mystus larvae survival was significantly related to salinity, total nitrogen, pH, reactive silicate, dissolved oxygen, surface water temperature, and chlorophyll-a in May and to salinity, surface water temperature, permanganate index, suspended particles, total nitrogen, and total phosphorus in August. The MaxEnt model predicted a broader longitudinal distribution range from offshore to the upstream freshwater area but narrower latitudinal distribution in the southern branch in May than in August. Finally, we delineated migratory corridors connecting optimum habitats for C. mystus using the least-cost route method. Optimum habitats close to the coastlines in the south branch might play a significant role in maintaining population or community connectivity in the Yangtze estuary. Our findings provide a perspective and method to quantify and facilitate the harmonious development of socioeconomy and fishery biodiversity conservation.

Detailed geophysical studies of the Ilych-Chikshinskaya fault system (Izyma-Pechora Monocline)

Research subject. The Ilych-Chikshinskaya fault system involved in the structure of the Izhma-Pechora monocline. The Ilych-Chikshinskii deep fault is the southern branch of the Pripechorskaya fault system, which separates the Timansky and Pechoromorsko-Bolshezemelsky geoblocks. Materials and methods. The data obtained during profile detailed magneto-metric and radon surveys, the materials of fund seismic surveys, and the maps of gravitational and magnetic fields of various scales were used. Measurements of the volume radon activity were carried out using portable radiometers РРА-01М-01 and Alfarad plus. Magnetometric observations were carried out with a MINIMAG magnetometer. Results. Radon surveys on two profiles were conducted in different years. According to the obtained results, the faults of the Ilych-Chikshin skaya system have no obvious manifestation in the radon field. The volume radon activity in different periods varied across a wide range from 50–200 to 200–600 Bq/m3, which indicates the absence of a constant deep source of radon. According to the data of detailed magnetometric surveys, the Ilych-Chikshinskii fault, against the background of a calm negative field, corresponds to a gradient zone of 4 km wide. Conclusion. The presence of low-intensity discontinuous radon anomalies along the line of profiles is associated with increased concentrations of parent uranium radionuclides in the soil and near-surface rocks. Since the rocks of the basement and sedimentary cover are nonmagnetic, the local magnetic anomaly indicates the presence of mafic and ultramafic intrusions in the zone of the Ilych-Chikshinskii fault.