Rositsa Yaneva

The Bulgarian Long-Term Ecological Research (LTER) site in Antarctica is located at the Bulgarian Antarctic Base St. Kliment Ohridski Base on Livingston Island, South Shetland Islands. In the context of rapid climate and environmental changes, Bulgarian scientists have conducted long-term research on the biodiversity and ecological conditions of Livingston Island. Following the establishment of the Bulgarian Antarctic Base on Livingston Island in 1993, investigations into polar ecosystems and their adaptation mechanisms in harsh environments began. Over the past 30 years, the research infrastructure has developed significantly, and the area of scientific research and sampling locations has expanded and become more accessible. Now facilitated with modern on-site laboratories, scientific equipment installed at the base and on board of the Bulgarian research vessel NIK 421 St. st. Cyril and Methodius, this LTER site provides unique opportunities to study the structure and function of the polar biota and understand how a shifting climate will alter the Antarctic ecosystems. Research on soils around the Bulgarian Antarctic Base have revealed a diverse community of free-living nematode species and described several species new to science, such as Mesodorylaimus chipevi . Diatoms communities on Livingston Island thrive in diverse marine, freshwater, and terrestrial habitats like moss-inhabiting communities and pools, including specialized endemic or rare taxa in low-salinity coastal rock pools near penguin rookeries, such as Halamphora moncheviana . Researches have also focus on the biodiversity and adaptation of micro-crustaceans, as significant ecosystem members of the South Shetland Islands. Lichens are growing abundantly around on Livingston Island, where they help form local polar soils (Cryosols) alongside mosses and Antarctic hair grass ( Deschampsia antarctica ), which is thriving due to regional warming trends. Bulgarian scientists and also international teams are continuously studying the terrestrial resilient ecosystems to monitor climate change impacts. Diverse cold-adapted microorganisms, including dominant bacterial groups (Oxyphotobacteria, Bacteroidia, Gammaproteobacteria) are present in soil and waters ecosystems around the Bulgarian Antarctic Base, alongside cold-tolerant fungal genera (Betamyces, Tetracladium). Research on composition of soils has detected trace amounts of potentially toxic elements and heavy metals, largely reflecting local geogenic backgrounds with minor points of human footprint. More recently studies were expanded to include also marine macroinvertebrates and fish (Nototheniidae, Channichthyidae) from South Bay (Livingston Is.). The specific location of LTER site Livingston Island makes it unique for continuous monitoring of the environmental components, as the area of Maritime Antarctica experiences the most significant and visible changes in biodiversity and ecosystem functioning. Systematic, long-term observations within the Bulgarian LTER site can therefore provide a holistic framework for understanding the ecosystem response to environmental change, trends and interactions between climate, biodiversity, ecosystem processes, and human pressures.

Soil erosion (SE) is a constant, complex land degradation process, a common natural disaster that occurs all over the world and severely impacts soil fertility, food security, and environmental balance. Soil erosion depends on many factors, including soil properties, slope, vegetation, rainfall amount and intensity, and anthropogenic activities. There are two main natural erosive forces by which soil is eroded and transported—water and wind. Water erosion refers to the detachment, transportation, and deposition of soil particles (solid runoff) into river networks. These particles, varying in size and composition, are the main products of soil erosion and most strongly affect river ecosystems. Solid runoff, or sediment-laden runoff, affects water quality, destroying habitats, carrying pollutants, reducing reservoir storage, and causing flooding. Erosion control activities also influence river ecosystems in different ways. Hydrotechnical facilities, a major erosion control practice, can alter the composition of aquatic biota by disrupting longitudinal connectivity and isolating populations. Reforestation and afforestation are other erosion control practices that have a strong impact on ecosystems. Stormwater retention systems in urban and forest areas are also important measures addressed in this review. This review examines complex environmental interactions and the roles of erosion and erosion control activities in river ecosystems. During the research, several key points were established: erosion and erosion control activities significantly affect river ecosystems. There is a lack of quantitative analysis of erosion intensity and its influence on ecosystems. This is probably due to the exceptional complexity and diversity of river ecosystems, but such a study would provide important information about complex relationships in nature.

Antarctica and its surrounding ocean host unique, endemic and cold adapted ecosystems. The Southern Ocean is furthermore, highly productive and provides globally important ecosystem services, from carbon sequestration to substantial genetic resources. The Antarctic region is a natural reserve for iconic marine mammals, penguins and flying seabirds, as well as krill and wider zooplankton communities that underpin pelagic food webs and biogeochemical cycling. Recent environmental changes such as rapid warming, ice loss, permafrost thawing, ocean acidification and arrival of pathogens and pollutants pose risks and uncertainties to Antarctic life as we know it. Furthermore, Antarctica and the Southern Ocean still host the least studied regions, and the largest gaps in biodiversity knowledge. This theme thus aims to strengthen the scientific basis for understanding and protecting Antarctic life across environmental boundaries, from terrestrial and intertidal habitats and ice shelves, surface waters down to the seafloor, and from microbes to top predators. It will integrate novel approaches for rapid biodiversity discovery and functional analyses of the networks of life in the Antarctic region. By integrating observations of terrestrial, sea-ice, pelagic and benthic biota and habitats, standardising protocols, and building cross-national collaborations, Antarctica InSync will enable a more holistic circum-Antarctic view of ecosystem dynamics and resilience in a rapidly changing environment. However, delivering representative circumpolar observations will depend on coordinated governance and operations across national programmes, including logistics, permitting pathways, standardised QA/QC procedures and harmonised data stewardship. This will contribute directly to the objectives of SCAR, SOOS, the Conservation of Antarctic Marine Living Resources (CCAMLR) and the IWC, as well as international initiatives such as the UN Ocean Decade, the 30 by 30 target, and the 5th International Polar Year, by improving the representation of biological ecosystems in circumpolar assessments and models and providing essential data to support future conservation and management frameworks.

Antarctica InSync is a global effort to synchronise research across Antarctica and the Southern Ocean, connecting ice, ocean, land, climate, and life to protect this vital region. This roadmap paper introduces the scientific and technological motivation and action plan to build an international programme for a coordinated field season in Antarctica and its surrounding seas. It lays out the international collaboration that is required to realise an ambitious action plan and the opportunities for the science community to address important scientific themes that identify current knowledge gaps. In the spirit of the Antarctic Treaty Consultative Meeting (ATCM), the planned scientific action mandates free data exchange, facilitates international collaboration, and derives expert scientific advice together with the Scientific Committee on Antarctic Research (SCAR). Aligned with challenges of the United Nation Ocean and Cryosphere Decades, we plan a shared global effort to better understand the role of Antarctica and its surrounding ocean for our global futures, building on decades of achievements in polar and ocean science. As a milestone leading up to the next International Polar Year in 2032/33 (IPY5), the ambition is to achieve a new level of cooperation, with opportunities for the next generation of polar scientists around the world by enhancing practices in sharing of ideas, infrastructure and information.

In 2023, a scientific project for studying the fungal biodiversity in organogenic soils in the area of the Bulgarian Antarctic Base ‘St. Kliment Ohridski’ on Livingston Island was funded by the National Center for the Polar Studies at Sofia University ‘St. Kliment Ohridski’, implemented under the National Program for Polar Research ‘From Pole to Pole’, adopted by the Ministry of Education and Science. In the period February-March 2023, a total of 126 soil samples were collected for analysis. Soil samples were carried out in the upper 0-5 cm soil layer. In places with deeper soil profiles, samples were collected from the deeper layer >5 cm. All samples were stored in sterile polyethylene bags in a freezer at minus 28°C on the Bulgarian ship ‘St. St. Cyril and Methodius’, which arrived in Bulgaria on 2nd May 2023. The present study aims to present the conceptual basis for the study of structure, composition, and bioecological features of fungal species occurring in Antarctic organogenic soils from Livingston Island, to investigate the representatives of separate taxonomic groups of invertebrate organisms interacting with the fungal species in the soil, and to establish the relationships with the soil characteristics in the studied sites. Studies of the biological and ecological features of representatives of the mycota in Antarctic organogenic soils, their physiological and biochemical behavior, and interaction with invertebrate organisms, are essential for a better understanding of the biological processes occurring in them, and the implementation of this project will have substantial contribution to these issues.

The assessment and mapping of ecosystems and their services is considered an important action that effectively contributes to proper understanding of how ecosystems support human well-being, and furthermore – to promote the sustainable use of natural resources. The diversity of cultural landscapes, especially in mountain areas, is a significant prerequisite for a variety of cultural ecosystem services that are valuable for the society. This evaluation is the basis for environmental management practices and policymaking. The study presents an approach for assessment and mapping of cultural ecosystem service (CES) “Cultural heritage” that is recognised as important and is provided by mountain protected areas (PAs) in “Pirin” National Park. The data from the Management Plan of “Pirin” NP were used for characterization and biophysical assessment of the condition of forest ecosystems and their potential to provide CESs. The analysis of the results revealed that the conservation regime allowed the territories to preserve a high degree of naturalness and a very good ecological condition as 94.80% of forest ecosystems are assessed with score 4 –“good” condition and 0.44% are with “very good” condition – score 5. The majority of forest ecosystems with “very good” ecological condition are Pinus peuce forests, located mainly on the territory of the reserves “Bayuvi Dupki- Dzhindzhiritsa” and “Yulen”, proving the importance of the protective regime of the territories. Forest ecosystems with average and high capacity to provide ES "Cultural heritage" prevailed, which is consistent with well-preserved and unique nature, the diversity of landscapes, and species richness. Considerable areas were assessed with score 5 – very high capacity, mostly on the territory of the reserves “Bayuvi Dupki- Dzhindzhiritsa” and “Yulen”, and at the foothill of the huts.

Polar soils under different vegetation cover from Livingston Island (Antarctica) were studied analyzing indicators of carbohydrates decomposition in soils: organic carbon, biomass carbon, total nitrogen, C:N ratio, cellulase, amylase, and invertase activity. The highest values of microbial biomass in soils were indicated for sites with vegetation cover while the lowest values in soils without vegetation, which correlate with the content of total organic carbon and the C:N ratio. The highest percentage of biomass carbon compared to the total organic biomass carbon is obtained for two sites with mosses, and the lowest in sites without vegetation, followed by the sites with lichens. Cellulase activity is highest in polar soils with moss cover. Amylase activity depends more strongly on the type of vegetation. The highest amylase activity is detected in soils under algae cover and the lowest in soils without vegetation. Invertase activity is limited by the extreme soil and climatic conditions of Antarctica. A very strong, positive correlation is found between total carbon and total nitrogen. The relationship between total carbon and the C:N ratio, as well as between biomass carbon and amylase activity, is moderate, and positive. The higher dependence of amylase activity from organic carbon with microbial origin correlates with higher values of the enzyme amylase compared to the enzyme cellulase. There is a strong (cellulase) and very strong (amylase) positive relationship between the activity of enzymes and the combination of factors: total carbon, total nitrogen, C: N ratio and biomass carbon.

The tundra and tundra barrens of the maritime Antarctica represent a unique type of terrestrial ecosystem, geographically confined to the region of the Antarctic Peninsula and a number of surrounding archipelagos. Antarctic soils are underestimated in the quantity of organic matter (OM) pools, organic remnant humification/mineralization rates, and biogenic-abiogenic interactions. The structure of reserves for humic substances within the permafrost zone, as well as the role of the molecular composition of organic substances, are still poorly understood. In this study, we investigate humic acids of selected sub-Antarctic soils in terms of elemental and structural composition to evaluate OM stabilization degree and to assess carbon distributions in the molecules by solid-state CP/MAS ¹³C NMR and ESR spectroscopy. The results obtained show that the studied humic acids consist mainly of aliphatic structural fragments. According to ESR spectroscopy, it was noted that the most stable molecules by the data of ESR spectroscopy are formed in postornithogenic soils. In contrast, the average portion of the aromatic compounds is about 30 in humic acids, extracted from soils with evident ornithogenic effect.

The paper focuses on the role of the Natural Heritage in Forest Areas (NHFA) as a resource that can generate economic, social and environmental benefits for society through the provision of a wide range of cultural ecosystem services. In the assessment of the role of NHFA, the approach for assessment and mapping of ES in a given territorial scope was applied in a pilot region of Velingrad Municipality, focusing on the capacity of the forest ecosystems to provide cultural ecosystem benefits and services to the people. The study confirms that the identification of NHFA could be a powerful driver for regional development by creating significant positive effects such as improving sustainable cultural tourism in forests, diversifying forestry and supporting sustainable development and management of forest areas. The integration of the cultural services of NHFA into forest-related legislation can encourage job creation in different sectors and for different levels of employment, education and cultural training. Evaluation and mapping of ecosystem services is an appropriate tool to support the development of a concept and methods for assessing and mapping the general knowledge framework for NHFA policy in Bulgaria by applying an interdisciplinary approach.

Under the global climatic changes and anthropogenic impacts on the environment, information about characteristics and specific features of soils in remote regions as Antarctica is valuable and could be used as references. This study focuses on the analyses of original data about the physico-chemical composition and micromorphological structure of Cryosols, collected in 2019 from the sampling area of the Bulgarian Antarctic Base “St. Kl. Ohridski” located on Livingston Island, Antarctica. The studied Cryosols are moderately acidic with slow and incomplete transformation of organic residues. The organic carbon content is low, except for soils formed under the influence of an ornithogenic factor. The mezo- and micromorphological observations show a predominance of the mineral phase, weakly affected by weathering processes. Many soil pores and voids are observed, which facilitates water-air and intra-soil exchange during the short Antarctic summer. The analyses showed an evidence for the connection of the processes of soil formation of Cryosols in the region with the pulsating degradation of the glaciers.