An amplicon-based metagenomic survey of archaea, fungi, and bacteria was performed on Livingston Island, Maritime Antarctica. In many of the samples, patterns of antagonism between these three superkingdoms were observed in the form of an inversely proportional dependence of the richnesses of the three types of microorganisms. The antagonism was quantified—based on the observed numbers of the total tags and the numbers of the operational taxonomic units (OTUs), and on four alpha diversity parameters—using the Shannon, the Simpson, the Chao1, and the ACE indices. We found that the most discriminative results in the antagonism measuring were obtained when the numbers of the OTUs and the ACE community richness estimator were compared. The antagonism between archaea and fungi was most potent, followed by that of archaea and bacteria. The fungi–bacteria antagonism was slightly detectable. Pearson and Spearman correlation analyses also showed a statistically significant negative correlation between the fungal and archaeal effective tags, while the correlation between archaeal and bacterial diversity was positive. Indications of the order of primary microbial succession in barren ecological niches were also observed, demonstrating that archaea and bacteria are the pioneers, followed by fungi, which would displace archaea over time.

The submerged petrified forest in Sozopol Bay, located along Bulgaria’s southeastern coast in the Black Sea, is an extraordinarily rare natural phenomenon that has remained unexplored in terms of microbial diversity until now. This study focuses on characterizing the microbial communities associated with this unique habitat. Ancient petrified tree remnants located at depths of 18–20 m were sampled in August–September 2024, targeting four tree trunks from different sites within the bay. The quantitative assessment of selected bacterial groups, essential for nutrient cycling, organic matter degradation, and marine ecosystem health, revealed distinct community profiles. 16S rDNA sequencing of cultivated isolates identified a diverse microbial community predominantly composed of γ-Proteobacteria, with key representatives such as Vibrio aestuarianus, Vibrio orientalis, Pseudoalteromonas, and Cobetia sp. The culture-independent approach confirmed the dominance of Proteobacteria, along with other prevalent phyla like Bacteroidetes, Planctomycetes, and Actinobacteria. The most abundant taxa included Woeseia oceani, Ilumatobacter coccineus, Halioglobus maricola, and Vibrio breoganii. Archaea made up about 3% of classified reads. Fungal sequences accounted for less than 2% of the total reads, indicating a low fungal prevalence. These results provide essential baseline data for future monitoring and the conservation of this unique habitat and its diverse microbial communities.

Within an amplicon-based metagenomic study of Archaea, Fungi, and Bacteria in Livingston Island, Maritime Antarctica, in many of the samples antagonisms between these three super kingdoms were observed under the form of an inversely proportional dependence of the richnesses of the three types of microorganisms. This was quantified - based on the observed numbers of the total tags and the numbers of the operational taxonomic units (OTUs), as well as based on four alpha diversity parameters – the Shannon, the Simpson, the Chao1, and the ACE indices. We found that the most discriminative results in the antagonism measuring were observed in the comparison of the numbers of the OTUs and the ACE community richness estimator. The antagonism between Archaea and Fungi was strongest, followed by that of Archaea and Bacteria. The Fungi-Bacteria antagonism was slightly detectable. Pearson and Spearman correlation analysis also showed a statistically significant negative correlation between the fungal and archaeal effective tags, while the correlation between archaeal and bacterial diversity was positive. Indications of the order of primary microbial succession in barren ecological niches were also observed, demonstrating that Archaea and Bacteria are the pioneers, followed by Fungi which in time would displace Archaea.

Here we report the first fossil leaf imprint part of a leaflet of Gleditsia cf. lyelliana (Fabaceae). The studied leaf fragment was obtained from the sedimentary successions at the bottom of the Sozopol Bay hosted the Underwater Petrified Forest natural phenomenon. This is the first fossil record of Gleditsia cf. lyelliana collected from the territorial waters of Bulgaria. The recent species Gleditsia aquatica, which is a nearest living relative of the fossil species, inhabits swamps, sloughs, bottomland forests in the Southeastern United States, suggesting close to subtropical climatic conditions at the time of deposition of the fossil material.

Scientific information on the abundance and biomass structure of shallow Antarctic coastal macrozoobenthos remains limited for many regions of the Antarctic Peninsula, particularly in shallow nearshore habitats where quantitative data are still scarce. The aim of this study was to characterise macrobenthic communities from shallow coastal habitats around South Bay (Livingston Island) and Marguerite Bay (Dismal and Horseshoe islands), with emphasis on the relative contribution of dominant higher taxa across different substrate types. In both study areas, macrozoobenthic communities were dominated in abundance by mobile crustacean taxa, mainly Amphipoda, while biomass was controlled by a small number of large-bodied taxa. At Livingston Island, biomass was strongly dominated by Bivalvia, while communities from Marguerite Bay exhibited a more even distribution of biomass among major taxa. Differences between the two areas were mainly expressed in the relative contribution of dominant taxa (Amphipoda, Bivalvia, Annelida, and Isopoda) rather than in overall taxonomic composition. In conclusion, the results clearly demonstrate a decoupling between abundance and biomass in shallow Antarctic coastal macrozoobenthic communities, and provide new quantitative data from poorly studied coastal regions of the Antarctic Peninsula.