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Microbial fuel cells (MFCs) are a kind of bioreactor for generating electricity, facilitated by exoelectrogens while treating wastewater. The present article focuses on the performance of an air cathode plexiglass MFC in terms of chemical oxygen demand (COD) removal efficiency and power output by performing two sets of experiments. The proton exchange membrane and electrode materials were Nafion 117 and carbon felts, whereas, for stable biofilm formation on the anode surface, a pure culture of Shewanella baltica 20 was used. Firstly, sterile Luria-Bertani (LB) media containing lactate, ranging from 20 to 100 mM, was continuously fed to an MFC, and a maximum power density of 55 mW/m2 was observed. Similarly, artificial wastewater with COD ranging from 3250 mg/L to 10,272 mg/L was supplied to the MFC in the second set of experiments. In this case, the maximum power density and COD removal efficiency were 12 mW/m2 and 57%, respectively. In both cases, the hydraulic retention time (HRT) was 1.5 h. It was found that electricity generation depends on the characteristics of the wastewater. These initial findings confirm that the design aspects of an MFC, i.e., surface area to volume ratio, and external resistance with respect to the quality of influent need to be optimised to improve the MFC’s performance.

Two new brachiopod–brachiopod symbiotic overgrowths have been discovered from the Kukruse Regional Stage (Sandbian, Ordovician) of Estonia. Both the Philhedra rivulosa–Porambonites sp. and the Petrocrania sp.–Porambonites sp. overgrowths were beneficial to the encrusting craniid and might have been slightly harmful to the host brachiopod. The craniids could have been facultative kleptoparasites. Our data show that craniids significantly preferred the smooth shells of Porambonites sp. over the coarsely ribbed shells of Platystrophia sp. and the moderately ribbed shells of Cyrtonotella sp. and Glossorthis sp. This suggests that, at least against craniids, having strong ribs could have been a successful antifouling strategy.

The correlation of the Silurian succession of Estonia with the global standard has long been considered reliable. However, new information, particularly on the distribution of microfossils, has changed our understanding of the Silurian stratigraphy in the region. Recent palaeontological and geochemical data suggest that: the lower part of the Juuru Regional Stage (RS) is of Hirnantian age; the age of the base of the Raikküla RS in terms of global chronostratigraphy remains problematic; the Aeronian–Telychian boundary correlates with a level in the middle of the Rumba Formation (Fm); the base of the Adavere RS is of latest Aeronian age; the former Riksu Fm is considered to be the proximal, older part of the Sõrve Fm; the traditional lower boundary of the Jaagarahu RS is diachronous, and the closest biostratigraphic horizon that could be used is the first appearance datum of Jeppssonia sagitta rhenana; the Wenlock–Ludlow boundary correlates with a level in the upper Rootsiküla RS; the base of the Paadla RS corresponds to a level in the upper Gorstian, in the lower(?) Phlebolepis ornata Vertebrate Biozone; the Sauvere and Himmiste beds of the Paadla Fm are of late Gorstian age, and the Uduvere Beds are of early Ludfordian age, corresponding to part of the Ancoradella ploeckensis Conodont Biozone; identifying the Ludlow–Přídolí boundary in the Estonian succession is problematic, lacking reliable criteria at present. With these amendments, we present an updated regional correlation scheme drawn on a regular time scale for the first time. A problem that needs to be addressed in the future is providing better biostratigraphic definitions for the bases of regional stages.

We investigated the paleogeography of Baltica via a paleomagnetic study of 471‐454 Ma limestones from the Siljan (Sweden) impact structure. Stepwise thermal demagnetization isolated a well‐defined magnetization component that unblocks up to the Curie temperature of magnetite and passes fold and reversal tests, indicative of a primary magnetization. Paleolatitude data show that Baltica experienced an initial stationary phase at approximately 55°S from 471 to 467 Ma, followed by a rapid northward drift (∼35 cm/yr) after 467 Ma. This motion slowed to ∼15 cm/yr at ∼463 Ma until 454 Ma when Baltica reached 33°S. A notable correlation was found between Baltica's latitude and the relative proportion of magnetite and hematite in the carbonates; they are relatively hematite rich at 55°S and magnetite rich by 33°S. Our results provide a high‐precision model how Baltica moved in the Ordovician with potential environmental implications regarding the oxidation state of the ocean at that time.

Vinn, O., Isakar, M., El Hedeny, M., Almansour, M.I. and Alfarraj, S. 2025. First record of agglutinated worm tubes from the uppermost Cambrian of Estonia. Acta Geologica Polonica, 75 (2), e41. A new species of agglutinated tube, Cryptosiphon oboloides sp. nov., is described from the Furongian of Estonia. The agglutinated tubes are composed of pieces of lingulate shells that are placed to form an overall pattern. The studied agglutinated tube strongly resembles cases of modern caddisfly larvae, though we do not suggest any phylogenetic affinity to caddisflies. The tubes originally contained an organic inner lining with a sticky external surface that enabled worms to glue on shell fragments and sand grains. The relatively well-arranged grains in the tube wall suggest that the animal actively assisted in gluing the shell fragments, orienting, and finding the right place for them. It is possible that worms capable of building agglutinated tubes from shell material originated in Baltica and later dispersed to the Armorican Terrane Assemblage and other regions in the Early to Middle Ordovician.

Viruses are fundamental to ecosystems ranging from oceans to humans, yet our ability to study them is bottlenecked by the lack of ecologically relevant isolates, resulting in “unknowns” dominating culture-independent surveys. Here we present genomes from 31 phages infecting multiple strains of the aquatic bacterium Cellulophaga baltica (Bacteroidetes) to provide data for an underrepresented and environmentally abundant bacterial lineage. Comparative genomics delineated 12 phage groups that (i) each represent a new genus, and (ii) represent one novel and four well-known viral families. This diversity contrasts the few well-studied marine phage systems, but parallels the diversity of phages infecting human-associated bacteria. Although all 12 Cellulophaga phages represent new genera, the podoviruses and icosahedral, nontailed ssDNA phages were exceptional, with genomes up to twice as large as those previously observed for each phage type. Structural novelty was also substantial, requiring experimental phage proteomics to identify 83% of the structural proteins. The presence of uncommon nucleotide metabolism genes in four genera likely underscores the importance of scavenging nutrient-rich molecules as previously seen for phages in marine environments. Metagenomic recruitment analyses suggest that these particular Cellulophaga phages are rare and may represent a first glimpse into the phage side of the rare biosphere. However, these analyses also revealed that these phage genera are widespread, occurring in 94% of 137 investigated metagenomes. Together, this diverse and novel collection of phages identifies a small but ubiquitous fraction of unknown marine viral diversity and provides numerous environmentally relevant phage–host systems for experimental hypothesis testing.

Marine bacteria display significant versatility in adaptation to variations in the environment and stress conditions, including temperature shifts. Shewanella baltica plays a major role in denitrification and bioremediation in the marine environment, but is also identified to be responsible for spoilage of ice-stored seafood. We aimed to characterize transcriptional response of S. baltica to cold stress in order to achieve a better insight into mechanisms governing its adaptation. We exposed bacterial cells to 8 °C for 90 and 180 min, and assessed changes in the bacterial transcriptome with RNA sequencing validated with the RT-qPCR method. We found that S. baltica general response to cold stress is associated with massive downregulation of gene expression, which covered about 70% of differentially expressed genes. Enrichment analysis revealed upregulation of only few pathways, including aminoacyl-tRNA biosynthesis, sulfur metabolism and the flagellar assembly process. Downregulation was observed for fatty acid degradation, amino acid metabolism and a bacterial secretion system. We found that the entire type II secretion system was transcriptionally shut down at low temperatures. We also observed transcriptional reprogramming through the induction of RpoE and repression of RpoD sigma factors to mediate the cold stress response. Our study revealed how diverse and complex the cold stress response in S. baltica is.

Here we present a detailed accounting of organic microfossils from late Ediacaran sediments of Finland, from the island of Hailuoto (northwest Finnish coast), and the Saarijärvi meteorite impact structure (~170 km northeast of Hailuoto, mainland Finland). Fossils were recovered from fine-grained thermally immature mudstones and siltstones and are preserved in exquisite detail. The majority of recovered forms are sourced from filamentous prokaryotic and protistan-grade organisms forming interwoven microbial mats. Flattened Nostoc-ball-like masses of bundled Siphonophycus filaments are abundant, alongside Rugosoopsis and Palaeolyngbya of probable cyanobacterial origin. Acritarchs include Chuaria, Leiosphaeridia, Symplassosphaeridium and Synsphaeridium. Significantly, rare spine-shaped sclerites of bilaterian origin were recovered, providing new evidence for a nascent bilaterian fauna in the terminal Ediacaran. These findings offer a direct body-fossil insight into Ediacaran mat-forming microbial communities, and demonstrate that alongside trace fossils, detection of a bilaterian fauna prior to the Cambrian might also be sought among the emerging record of small carbonaceous fossils (SCFs).

The Central Asian Orogenic Belt (c. 1000-250 Ma) formed by accretion of island arcs, ophiolites, oceanic islands, seamounts, accretionary wedges, oceanic plateaux and microcontinents in a manner comparable with that of circum-Pacific Mesozoic-Cenozoic accretionary orogens. Palaeomagnetic and palaeofloral data indicate that early accretion (Vendian-Ordovician) took place when Baltica and Siberia were separated by a wide ocean. Island arcs and Precambrian microcontinents accreted to the active margins of the two continents or amalgamated in an oceanic setting (as in Kazakhstan) by roll-back and collision, forming a huge accretionary collage. The Palaeo-Asian Ocean closed in the Permian with formation of the Solonker suture. We evaluate contrasting tectonic models for the evolution of the orogenic belt. Current information provides little support for the main tenets of the one- or three-arc Kipchak model; current data suggest that an archipelago-type (Indonesian) model is more viable. Some diagnostic features of ridge-trench interaction are present in the Central Asian orogen (e.g. granites, adakites, boninites, near-trench magmatism, Alaskan-type mafic-ultramafic complexes, high-temperature metamorphic belts that prograde rapidly from low-grade belts, rhyolitic ash-fall tuffs). They offer a promising perspective for future investigations.

The extensive use of neonicotinoid and butenolide insecticides in horticultural systems has raised concerns about their potential effects on nontarget soil organisms, including plant-parasitic nematodes and earthworms. This study evaluates the effects of two commonly used insecticides, a neonicotinoid (acetamiprid) and butenolide (flupyradifurone), on the survival of plant pathogenic nematodes , , and the earthworm in horticultural soils. A four-parameter Weibull model was used to analyze the survival dynamics following exposure of nematodes to one concentration of acetamiprid and to two concentrations. Both insecticides exhibited similar toxicity to earthworms, emphasizing the need for careful consideration of their use in sustainable pest management practices. These findings highlight the importance of evaluating the ecological risks of insecticides in horticulture, particularly regarding their unintended consequences on soil fauna. Further research is recommended to optimize the use of these insecticides while minimizing potential harm to beneficial soil organisms.