Phytoplankton and water quality of Lake Kuchane (Pskov region, Russia)

The phytoplankton communities of Lake Kuchane, located in the Mikhailovskoye Museum-Reserve, were studied during different 2016–2017 seasons for the first time. 213 specific and intraspecific taxa from 9 phylums were identified in the phytoplankton, namely: Bacillariophyta, Chlorophyta, Chrysophyta, Euglenophyta, Cyanobacteria, Dinophyta, Cryptophyta, Charophyta, and Xanthophyta. The ratio of the main phylums of microalgae during the studied seasons was similar. The floristic complex of the lake's algoflora consisted of diatoms (36.6%), green (27.2%) and golden (10.8%) algae. Most of the phytoplankton genera contained one species taxon only. The specific composition of the phytoplankton community in 2017 was similar from spring to autumn. The minimum specific similarity of the phytoplankton communities was noted in July, 2016, and August, 2017. According to the level of biomass of planktonic algae, the lake belongs to oligotrophic water bodies. The planktonic algoflora of Lake Kuchane is characterized by the predominance of cosmopolitan freshwater forms of microalgae. In relation to pH, the predominant representatives preferred slightly alkaline waters. The Milius trophic index varied in the range 18.0–39.6 with a maximum value in summer. The Pantle–Bukk saprobity index almost did not change during the entire study. The waters of Lake Kuchane corresponded to the betamesosaprobic self-purification zone, quality class III.

Baseline surface- and groundwater monitoring prior to an onshore shale gas operation in the Vale of Pickering, UK

A comprehensive programme of baseline groundwater hydrochemical monitoring has been carried out in connection with the proposed hydraulic fracturing of a 2 to 3 km deep Bowland Shale gas reservoir in borehole KM8 at Kirby Misperton, North Yorkshire, UK. The monitoring infrastructure encompassed: five on-site boreholes with hydraulically open intervals ranging from shallow weathered cover to a c. 200 m deep Corallian limestone aquifer, six off-site wells (hydraulically open in superficial materials and/or Kimmeridge Clay) and four surface water monitoring stations. Groundwater chemistry was high stratified with depth, ranging from slightly acidic, fresh, very hard Ca-HCO3-SO4 waters in shallow weathered cover, to brackish, calcium-depleted, highly alkaline waters in the Corallian aquifer. Dissolved methane was detected in most boreholes, with 10 µg/L being typical of shallow boreholes and around 50 mg/L in the Corallian. Low ethane concentrations and isotopic evidence suggest that the methane was predominantly microbial in origin (carboxylate fermentation at shallow depth, natural methanogenic CO2 reduction at greater depth). Elevated dissolved ethane (20-30 µg/L) was found in one well of intermediate depth, suggesting admixture of a possible thermogenic component, although this could be derived directly from the Kimmeridge Clay penetrated by the well.

Comparative Transcriptomic and Proteomic Analysis of Exopalaemon carinicauda in Response to Alkalinity Stress

Saline-alkaline waters are stressful environments where most aquatic animals can’t survive normally, and alkalinity is one of the key limited environmental factors. Due to strong adaptability to environment, the ridgetail white prawn Exopalaemon carinicauda is a potential good species suitable for large-scale culture in saline-alkaline waters. Exploring its alkaline adaptability mechanism will help to guide more marine crustaceans to saline-alkaline culture. In this study, an integrative analysis of the gill-specific transcriptome and proteome at 0, 12, and 36 h after alkalinity stress was performed to identify important regulators and pathways involved in alkalinity adaption of E. carinicauda. A total of 3,157 differentially expressed genes (DEGs) and 443 differentially expressed proteins (DEPs) were identified at 12 and 36 h compared with 0 h. Base on the transcriptome analysis, the Gene Ontology (GO) enriched terms were mainly related to ion transport, including “calcium-transporting ATPase activity,” “ATPase coupled ion transmembrane transporter activity,” “divalent inorganic cation transmembrane transporter activity,” etc., and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways mainly refer to the processes of endocrine system at both 12, and 36 h. Based on the proteomic analysis, KEGG pathways related to lipolysis and amino acids metabolism were significantly enriched at 12 h, and carbohydrate metabolism and immune response were significantly enriched at 36 h. There were significantly up-regulated expressions of ion transport related genes including aquaporin, carbonic anhydrase, ammonium transporter Rh type A-like, Na+/H+-exchanger, etc., as well as ion transport proteins including V-type proton ATPase 116 kDa subunit a-like isoform X1, sodium-potassium ATPase beta, vesicle associated membrane protein, etc. after alkalinity exposure, which indicating their important roles in response to alkalinity stress. The results of integrated analysis between proteome and transcriptome showed that up-regulated DEG/DEP (aldehyde dehydrogenase) was significantly enriched at 12 h and the up-regulated DEG/DEP (peptidylglycine alpha) was significantly enriched at 36 h, suggesting the two molecules may be critical in response to alkalinity change. This study reveals the first time-course, gill-specific, combined transcriptomic and proteomic profiling associated with alkalinity adaption of E. carinicauda and provides new insights into the mechanisms underlying the molecular response to alkalinity stress in shrimp.

Hydrochemical Evaluation of Groundwater in Al-Khasfa Area within Haditha, Western Iraq

The main aim of the research is to study the groundwater quality in Al-Khasfa area within Haditha district, western Iraq. To assess the groundwater, eighteen groundwater samples in the study area were collected and analyzed for major cations and anions. Results indicated that groundwater samples in the study area are between neutral and light alkaline, slightly brackish, and highly mineralized. The hydrochemical formula of the groundwater samples indicates the Ca-SO4 type dominance, except wells number 16 and 17 were of Ca-Cl water type. According to Piper diagram, the type of water is Earth-Alkaline waters. All groundwater samples are unsuitable for human drinking, industrial, and building uses, but it is suitable for livestock. For irrigation purposes, it is characterized by no Mg-harmful, good with SAR, Na%, RSC, and PI but unsuitable for salinity hazard due to very high salinity. The Water Quality Index for Euphrates aquifer in the study area in both periods are poor water for human drinking, except W-1 in dry period indicate very poor water and W-6, W-7, W-8, W-13, W-14, W-15, W-16 in wet period indicate good water.

Planothidium marganaiensis sp. nov. (Bacillariophyta), a new cavum-bearing species from a karst spring in south-western Sardinia (Italy)

Planothidium marganaiensis sp. nov. is described from periphytic samples collected at the karst spring San Giovanni at Domusnovas, Sardinia (Italy). Light and scanning electron microscope observations revealed that the taxon shares similarities with species within the Planothidium frequentissimum sensu lato, such as P. naradoense and P. victori. Planothidium marganaiensis seems to be morphologically closely related to P. frequentissimum but stands out for its smaller valves, lower striae density, subrostrate to slightly protracted apices, and areolation pattern of the striae in the rapheless valve (four to five areolae per stria). Planothidium marganaiensis was found in slightly alkaline waters presenting medium hardness and mineralization and phosphorus enrichment.

A review of research on the Lemanea genus in Serbia

The first data on the Lemanea genus in Serbia come from the late 20th century. Only one species, L. fluviatilis, was reported from 10 localities in Serbian riverine ecosystems between 1991 and 2017. Extensive research on this genus was performed in April–November 2017–2019, surveying 150 localities in 97 upland and mountain rivers. During this study period, the Lemanea genus was recorded at 14 localities in 12 rivers, while it disappeared from five previously reported localities. A total of four taxa were identified: Lemanea fucina, L. rigida, Lemanea sp. and L. fluviatilis. Lemanea fucina and L. rigida were recorded in Serbia for the first time. L. fluviatilis was the most common taxon. Our research confirmed that Lemanea species prefer similar specific environmental conditions. These species were found in temperate, soft or moderately hard, well-oxygenated and weakly alkaline waters, with low, moderate or high conductivity, and in waters with low content of inorganic nutrients. Due to their sensitivity to changes in environmental conditions, Lemanea species are exposed to negative anthropogenic impact leading to the degradation of their habitats. Intensive construction of small hydropower plants has threatened most habitats of the Rhodophyta species in the last few years.

On Bangia atropurpurea (Bangiales, Rhodophyta), the strictly protected red alga in Serbia

The first observation of the red alga Bangia atropurpurea (Bangiales, Rhodophyta) in Serbia was in 1991 in the Trgoviski Timok River (Eastern Serbia). From 1991 to 2017, the species was sporadically observed at four more locations in three hillmountain rivers in Southwestern (the Gvozdacka River and the Raska River) and Eastern (the Nisava River - two localities) Serbia. More intensive research on this alga was carried out from 2017 to 2020, and a total of 220 localities in 132 hillmountain watercourses were studied. Bangia atropurpurea was recorded at six locations in Southwestern and Eastern Serbia. Five of these locations represent new B. atropurpurea localities in Serbia (the Brusnicka River, the Golijska Moravica River, the Panjica River, the Resava River, and the second locality in the Trgoviski Timok River), while one of them is already known from previous studies (the Raska River). The species was found in running, moderately hard and very hard, well-oxygenated, slightly alkaline waters, mainly low in inorganic nutrients, and in highly variable values of temperature and conductivity. Despite the long period since its first observation in Serbian rivers, the species is still known in a small number of localities. The small number of localities, low relative abundance, and various anthropogenic influences affecting its habitats have led the species to be recognized as endangered and strictly protected in Serbia. The intensive development of small hydropower plants which have emerged in recent years may threaten B. atropurpurea habitats.

Diatomic flora of Lake Tikozero in the Holocene

Preliminary data of micropaleontological (diatom) study of sediments of Lake Tikozero located on the eastern coast of Lake Yokostrovskaya Imandra (Murmansk region) are presented. Based on the results of diatom analysis, the taxonomic composition and structure of diatom complexes were studied, the stages of the development of the ecosystem of the lake were established. The studied lake was characterized by the dominance of benthic forms and fouling in the composition of paleosocial communities. Upward in the column of sediments, there is a change in indicator groups with respect to pH: the proportion of acidophils decreases from 62% to 18%, and the proportion of alkaliphiles increases from 5% to 40%. A change in the dominant diatom complex was revealed: the acidophilic benthic species Brachysira zellensis (Grunow) Round & D.G. Mann is replaced by the littoral species Staurosira construens Ehrenberg, which prefers slightly alkaline waters.