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Possibilities for mitigating coastal erosion in the downdrift zone of port jetties using nearshore nourishment: A case study of Klaipėda Port, Lithuania /
No full textCoastal erosion hotspots frequently emerge in the downdrift zones of ports situated along open littoral drift seashores, often necessitating coastal protection measures. This study aims to evaluate the effectiveness of nearshore nourishment in mitigating coastal erosion using the downdrift zone of the Klaipėda Port (Baltic Sea) as a case study. In 2022, 79,390 m3 of sand was discharged at 2.0–3.5 depths at this site, forming an artificial sandbar parallel to the shoreline. The dynamics of the nourishment deposits were monitored for two years through beach and nearshore morphometric measurements and beach sand lithological composition sampling. Monitoring data indicated that the majority of the sand from the artificial sandbar migrated towards the subaerial coast, with minor depth variations also observed at depths of 4.0–5.6 m. Minor accretion in the nearshore was observed in regions beyond the designated nourishment area. The nearshore nourishment has successfully stabilised the subaerial coast at the discharge site for over two years, with 21.1% of the nourished sand accumulating on the subaerial coast and the shoreline position advancing seaward by an average of 10 metres. About 69.4% of the nourished sand remained at the nourishment site between the shoreline and the offshore boundary of the artificial sandbar, while approximately 9.5% was transported to the adjacent coast beyond the nourishment area
An overview of the neglected modes of existence in avian haemosporidian parasites /
No full textHaemosporidian parasites (Apicomplexa, Haemosporida) are diverse obligatory heteroxenous protists, which infect all major groups of terrestrial vertebrates and use dipterous blood-sucking insects as vectors. These pathogens are responsible for various diseases, including malaria, which remains an important human and animal illness. In the wild, haemosporidians are particularly diverse in reptiles and birds in tropical countries, where they are flourishing. Avian haemosporidians have been particularly extensively investigated, especially due to their high prevalence and global distribution, including the countries with cold climates. The general scheme of the life cycle of haemosporidians is known, but the details of development remain insufficiently investigated or even unknown in most of the described parasite species, suggesting the existence of knowledge gaps. This attracts attention to some recent observations, which remain fragmentary but suggest the existence of formerly neglected or underestimated modes of the haemosporidians’ survival in vertebrates. Such findings are worth discussion as they indicate the novel directions in wildlife haemosporidian research. This article overviews some recent findings, which call for broadening of the orthodox views on modes of existence of haemosporidian parasites in avian hosts. Among them are the role of blood merogony in the long-lasting persistence of malaria parasites in birds, the role of gametocytes in the long-lasting survival of Haemoproteus species in vertebrates, the possible reasons of undetectable avian Haemoproteus infections due to peculiarities of exo-erythrocytic development, and the plausible factors driving the narrow vertebrate host specificity of Haemoproteus species
Coastal inlet analysis by image color intensity variations: Implications for the barrier coast of Ukraine /
No full textInlets through coastal barriers in functionally non-tidal settings have been relatively understudied. Yet, they have morphosedimentary elements and morphodynamic behaviors that are similar to their tidal counterparts, especially microtidal (often wave-dominated) inlets. Increasingly, remote sensing technologies (aerial and satellite imagery, small unmanned aerial vehicles, etc.) are employed as sources of high-definition spatial databases. Such approaches are important in areas with limited access, especially in regions of military conflict, such as along parts of the northern Black Sea coast, Ukraine. For rapid spatial analysis of remotely sensed or archival datasets, image color intensity (ICI) patterns are obtained using grayscale (GS) spectra and a wide range of filter options. Areal and profile-style GS patterns based on relative ICI values are extracted from available imagery, so that in a full 256-value GS spectrum the deepest parts of a channel (inlet throat) will have the lowest (darkest) values (GS 100). Exposed siliciclastic/carbonate sand-dominated barriers and shoals will yield the lightest values (GS > 200), with dark vegetation requiring GS inversion. Hypsometric information, as well as key metrics (perimeter and area) can be easily computed using instant tracing tools, without the need for labor-intensive contour outlining. This study is the first example of assessing cross-shore and longitudinal channel morphology of microtidal (USA) and non-tidal (Ukraine) inlets. The approach is also extended to a temporal analysis of inlet closure and a recent re-activation by an intense storm
First report of Matryoshka RNA virus in an African-European migrant bird /
No full textViruses are diverse biological entities found virtually in all environments on Earth. Their association with parasitic protozoans was shown in the late 1980’s, followed by evidence that these viruses can influence the treatment of infections as well as influence parasite virulence. Recently, Matryoshka RNA viruses (MaRNAV) were discovered in Plasmodium vivax infected patients in Malaysia, as well as in species of the closely related avian haemosporidian genera Leucocytozoon and Haemoproteus in Oceania and North America. However, they have not been reported in other continents so far. The aim of this study was thus to screen haemosporidian infected European birds (African migrants and residents) for the presence of MaRNAV. Whole blood samples from wild birds were collected in Lithuania in May 2023. Haemosporidian parasite infections were first assessed by microscopic examination and later confirmed via PCR. RNA was isolated and tested by Reverse Transcriptase (RT) PCR for the presence of MaRNAV. Of the 12 samples that were RT-PCR-positive, only one from a common whitethroat (Curruca communis) had a sequence with 63% similarity to MARNAV-2 found in Leucocytozoon infected birds from Oceania. Total RNA from this sample was sequenced, bioinformatically analyzed, and a new virus, MaRNAV-7, was identified. At the amino acid level, it is phylogenetically closely related to MaRNAV-2, MaRNAV-3 and MaRNAV-6 RdRp sequences, all found in Leucocytozoon infected birds. This is the first report of MaRNAV in an African-European haemosporidian infected bird, and a first step in understanding MaRNAV prevalence, distribution, and specificity. However, the effects that MaRNAV can have on the parasites, modulation of the host immune response and transmission rates remain unknown
GABA and proline application induce drought resistance in oilseed rape /
No full textThis study investigates the effects of γ-aminobutyric acid (GABA) and proline, both individually and in combination, on the growth of oilseed rape under drought stress and following the resumption of irrigation. The goal was to determine whether the exogenous application of these compounds enhances the plants response to prolonged water deficit and, if so, to identify the biochemical processes involved in the plant tissue. The experiment was conducted under controlled laboratory conditions. After 21 days of plant cultivation, at the 3–4 leaf stage, seedlings were sprayed with aqueous solutions of GABA (0.1 mM) and proline (0.1 mM). The plants were then subjected to 8 days of severe drought stress, after which irrigation was resumed, and recovery was assessed over 4 days. The results showed that both amino acids alleviated the drought-induced stress as indicated by higher relative water content (RWC), increased levels of endogenous proline and photosynthetic pigments in leaves, and enhanced survival and growth recovery after drought. GABA-treated plants maintained membrane integrity and preserved plasma membrane (PM) ATPase activity during prolonged drought stress while reducing ethylene, H2O2, and MDA levels. Proline also influenced these biochemical responses, though to a lesser extent. The combination of GABA and proline facilitated better recovery of oilseed rape compared to the drought control group following rewatering. Notably, GABA treatment resulted in a significant increase in gene expression compared to the untreated control. Molecular analysis of drought-responsive genes revealed that the gene expression in plants treated with both proline and GABA was typically intermediate between those treated with proline alone and those treated with GABA alone. Based on these findings, we propose that GABA application could serve as an alternative to proline for improving oilseed rape’s drought tolerance, potentially increasing both crop yield and quality
Wildflower strips increase aculeate pollinator diversity but not abundance in agricultural landscapes with rapeseed in crop rotations /
No full textThe decline of pollinators in agricultural environments poses a significant threat to pollination ecosystem services. Wildflower strips are proposed as a strategy to support pollinator populations and enhance their species richness and diversity. We investigated the efficacy of flowering plant mixture in maintaining aculeate pollinator diversity (wild bees, predatory wasps, and their kleptoparasites) within intensively managed agricultural environments where rapeseed is a common rotational crop. Over four years, pollinators were counted five times per season using 250 m transect walks. Our results demonstrated that the diversity and the evenness of species abundance distribution of aculeate pollinators were higher in the sown wildflower strips, whereas mean abundance per transect was greater in the remnants of semi-natural grassland. The low diversity and evenness within the aculeate pollinator assemblage of the semi-natural habitat were attributed to the dominance of the sweat bee Lasioglossum pauxillum, which thrived on mass-flowering rapeseed and concentrated in the flowering grassland fragments after the rapeseed harvest. We conclude that wildflower strips enriched with sown flowering plant mixtures effectively enhance pollinator diversity. Furthermore, both wildflower strips and preserved patches of unmanaged or minimally managed semi-natural grassland habitats can essentially contribute to maintaining pollination ecosystem services within intensive agricultural environments
Environment, intraspecific lineages and geographic range jointly shape the high morphological variability of Dikerogammarus villosus (Sowinsky, 1894) (Crustacea, Amphipoda): a successful aquatic invader across Europe /
No full textPhenotypic variability is a key factor promoting the establishment and spread of invasive populations in new environments. The Ponto-Caspian region contains a diverse endemic fauna known for its exceptional environmental plasticity, with many species invading European waters. However, the extent to which the environment shapes the phenotypic variability of these successful invaders remains poorly understood. We test to what extent the environment, intraspecific lineage affinity and geographic range interact and shape the variability of ecologically relevant functional morphological traits of the amphipod, Dikerogammarus villosus. Our results show the highest differentiation among environments, with an enhancement of predation-related traits in brackish waters relative to freshwaters. Differentiation among lineages and ranges (native/invaded) was smaller, occurring in traits related to locomotion and food processing. Although we uncovered an overall increase in variability outside the native range, the dynamics of morphological change were lineage-specific: the Western Lineage (invading via the River Danube) underwent a shift towards increased appendage length, while the Eastern Lineage (invading via the River Dnieper) underwent a significant overall morphospace expansion. We conclude that D. villosus exhibits a remarkable morphological variability across Europe that is influenced by the interplay between the environment as well as its evolutionary and invasion history
Effect of phenological stage and leaf age on changes of chlorophyll and carotenoid contents in some weeds and invasive species /
No full textPotential sources of chlorophyll, widely used in the pharmaceutical and food industries, could be invasive species and weeds. The aim of the study was to estimate the effect of vegetation period and leaf age on changes of chlorophyll and carotenoid contents in leaves of six widespread plant species of four different families, as well as in the weed Urtica dioica as a “comparative” species. Plants were growing under the same environmental conditions, and chlorophylls and carotenoids were analyzed spectrophotometrically every two weeks from May to September. Average total chlorophyll (a + b) content only in leaves of Lamium album and Aegopodium podagraria was lower than in Urtica dioica and significantly differed from their content in Leonurus cardiaca and Agrimonia eupatoria. Total chlorophyll (a + b) content in leaves of common native Pastinaca sativa and very invasive Solidago canadensis was also higher or very similar to that of Urtica dioica. The highest amount of green pigments in all species was found at the budding and/or flowering period. Unlike other species, variation of total chlorophyll (a + b) in Leonurus cardiaca was little, and chlorophyll a/b ratio was lower than 2:1 during the vegetation period. In contrast to total chlorophyll (a + b), total carotenoid was higher in young leaves
Decryption of amphipod cryptic species: Ecological differentiation of syntopic lineages of a Gammarus species complex /
No full textCryptic species represent an ever-increasing proportion of discovered biological diversity. Thus, the number of observations of cryptic species co-occurring in syntopy also increases, raising the question of mechanisms facilitating this phenomenon. Gammarus fossarum is a widespread, ecologically important, and diversified cryptic species complex with dozens of deeply divergent lineages of Miocene origin, some of which have been observed in syntopy in its European range. We used a multifaceted approach to study the ecology of two syntopic, genetically differentiated G. fossarum lineages in the stable environment of a calcareous spring fen. We investigated the effects of spatial distribution of sampling sites and local environmental factors (water chemistry, substrate composition) on the fine-scale distribution of the two lineages, together with their trophic ecology (δ13C, δ15N and gut content analysis). Moreover, we assessed functional morphological differentiation of the lineages, and compared identification based on mitochondrial DNA with variation at three nuclear markers to confirm their reproductive isolation. Small-scale syntopy of both lineages prevailed across the studied locality, having been observed at 14 out of 15 sampling spots. Lineage ratios varied within the spring fen; they were significantly affected by spatial proximity between the sampling spots, but not by local environmental conditions. The two lineages significantly differed in body size as well as trophic niche. However, they were essentially morphologically indistinguishable, although significant shifts were observed in a few phenotypic traits mainly related to feeding. The lack of nuclear allele sharing confirmed the existence of a strong reproductive barrier between them. The two studied G. fossarum lineages are reproductively isolated species that significantly differ in trophic ecology and body size in syntopy. Their local coexistence may thus be facilitated by trophic niche differentiation due to alternative resource use. Our results add to the growing body of evidence that morphologically cryptic species may not be functionally fully equivalent, indicating that cryptic species complexes may be more ecologically differentiated than currently known
Morphological and molecular studies of tetracotyle-type Metacercariae of the genus Cotylurus Szidat, 1928 (Trematoda) from the gravel snail Lithoglyphus naticoides (Gastropoda) and host sex dependent differences in infection rate /
No full textThe Ponto-Caspian invader, the gravel snail Lithoglyphus naticoides (C. Pfeiffer, 1828), is infected with a diverse community of digenetic trematodes in its colonized range and most often serves as first intermediate host. We have performed the parasitological examination of L. naticoides snails sampled in Kaunas water reservoir (Lithuania) and found yet unknown strigeid metacercariae of the tetracotyle type using these snails as second intermediate host. In this study, we report data on morphology and molecular analysis based on two markers, the partial 28S rDNA gene and the ITS2 region of these metacercariae. Based on the comparative molecular and phylogenetic analysis, the metacercaria detected in L. naticoides was identified as Cotylurus cornutus (Rudolphi 1809) Szidat, 1928. Differences in metacercariae infection between snail sexes were assessed. The prevalence of infection in L. naticoides was significantly higher in males than in females. Additional molecular markers of tetracotyle of C. cornutus from Stagnicola palustris (O. F. Müller, 1774) and furcocercaria of Cotylurus strigeoides Dubois, 1958 from Physa fontinalis (Linnaeus, 1758), sampled in Curonian Lagoon, Lithuania, were obtained for the first time and used for comparative phylogenetic analysis