Olenin, Sergej

In recent decades, the melting of glaciers has led to a consistent increase in the number of periglacial coastal lagoons that form in the place of receding glaciers in Svalbard, European Arctic. There is limited data on the geomorphology and hydrology of these novel formations, primarily because conducting research in remote polar regions is logistically challenging and expensive. We present hydrological and bathymetric data collected in 2022-2024 in a newly formed lagoon located in the western part of Spitsbergen (Svalbard), between Eidembreen glacier and Eidembukta bay. The lagoon consists of several semi-isolated water bodies characterized by distinct bottom geomorphology and complex hydrological structure. The deepest part (42.8 m) was observed near the glacier front, while extensive shallow areas have depths of less than 1 m. Various hydrological parameters were measured during surveys (temperature, salinity, oxygen saturation, dissolved oxygen concentration, pH, photosynthetically active radiation, turbidity, conductivity, density, pressure and sound velocity), which indicate strong vertical stratification with pronounced halocline and thermocline in some parts of the lagoon. The data collected will be utilized to analyze the physical and geographical conditions of the lagoon, as well as the distinguishing characteristics of its various sections, which vary in age by several decades. The data is essential for understanding the distribution patterns of biodiversity and the functioning of the lagoon ecosystem, which is the subject of a separate study. Furthermore, this data can be utilized to monitor and conduct comparative analysis of periglacial lagoons that are forming in various regions of Svalbard due to the climate change. This dataset can also be used to develop models of hydrological processes in periglacial water bodies of this nature, which arise from the interaction between a melting glacier and the influence of the sea.

Over the last few decades, climate change in Svalbard (European Arctic) has led to the emergence and growth of periglacial coastal lagoons in the place of retreating glaciers. In these emerging water bodies, new ecosystems are formed, consisting of elements presumably entering the lagoon from the melting glacier, the surrounding tundra water bodies and the coastal ocean. The data presented here were collected from an emerging lagoon in the western region of Spitsbergen, Svalbard, situated between the retreating Eidembreen Glacier and Eidembukta Bay in 2022–2023. The current size of the lagoon area is approximately 6 square kilometers. The sampling was carried out at 26 sites across various sections of the lagoon, spanning from close proximity to the glacier to the furthest point away. The dataset contains the results of bacterioplankton (total cell concentration and carbon biomass), phytoplankton (taxonomic composition, cell size for selected taxa, abundance, biomass and carbon biomass), zooplankton (taxonomic composition, abundance), and environmental DNA (eDNA) metabarcoding. The dataset will be utilized to provide a comprehensive description of the structure of the lagoon ecosystem. It will also facilitate a comparison of its various parts, which vary in terms of their age of origin, i.e., release from the glacier. Additionally, the dataset will aid in the understanding of the intricate interactions between the freshwater and marine elements of the ecosystem. It can be used for comparative analysis of biodiversity assessment using eDNA and traditional microscopy methods in the identification of phyto- and zooplankton. Furthermore, these data can be utilized for environmental monitoring, tracing the temporal shifts and conducting comparative analysis of periglacial lagoons that are emerging in various regions of Svalbard as a result of climate change.

Climate change is warming the Arctic at a rate four times faster than the global average. Due to a unique pattern in ocean currents, the Kongsfjorden fjord in Svalbard (Norway) is experiencing even more rapid warming causing tidewater glaciers to retreat. Increasing freshwater and terrestrial inputs are expected to determine deep impacts at fjord head more than at fjord mouth, affecting both benthic communities and biogeochemistry, selecting highly tolerant pioneer taxa, such as polychaetes with a high bioturbation and nutrient recycling potential. In this work, 16 intact sediment cores were collected from the head and the mouth of Kongsfjorden and incubated in the dark at in situ temperature. Benthic fluxes of nutrients and gas, and denitrification rates were assessed during the incubations and macrofauna abundance and community composition were analyzed. Benthic metabolism and macrofauna bioturbation were then contrasted and interpreted with respect to the glacier disturbance. At the glacier front (fjord head), oxygen and nitrate respiration, methane efflux and nutrient regeneration were higher than at the fjord mouth. At the fjord head, the macrofauna community was more abundant and dominated by deep burrowing polychaetes, tolerant to glacier disturbance. Through bioturbation, they played a crucial role in stimulating coupled nitrification and denitrification, ammonium, and methane release. Our models indicate that polychaetes contribute significantly (32 %) to the total flux variability confirming their role in nutrient cycling. In this Arctic fjord, warming, glacial retreat and disturbance favor pioneer species of macrofauna that promote the recycle of nutrients and the evasion of methane.

Arctic coastal biodiversity faces increasing threats from anthropogenic activities and climate change. However, the effects on biodiversity are still poorly understood, hindering actions aimed at mitigating the impacts at a pan-Arctic scale. We present the results of a horizon scan that provides a road map to address knowledge gaps on the influence of anthropogenic activities, from increased shipping and harvesting to consequences of climate change including increasing temperatures, cryosphere loss, and freshwater runoff. Predictions on ecological change, species range expansions, and anthropogenic impacts on Arctic coasts are hampered by the lack of biodiversity data and scarcity of biological long-term monitoring programs. Filling these knowledge gaps will require coordinated international efforts and standardized experiments across the diverse ecosystems characterizing the Arctic.

Ballast Water Management (BWM) is a complex process in which decision-making must be based on proven scientific evidence. For example, data is needed to make decisions on the granting of exemptions from BWM, to support an early warning system to inform seafarers about where ballasting should not be conducted due to the presence of harmful organisms, to control and eradicate invasive species and to measure the effectiveness of the BWM Convention in reducing the rate of new species introductions. To support different BWM tools, the data should be diverse and multifaceted, ranging from taxonomy and biological traits of introduced species to the limits of their ecological tolerance, vectors of introduction, history of invasions and actual geographic distribution, their impact on human health, economy and environment. Here we present examples of how existing databases can be used to provide the information needed for the implementation of the BWM Convention in general. Particular attention is paid to AquaNIS, an information system on aquatic non-indigenous and cryptogenic species that stores a wealth of data and is equipped with several useful tools aiding decision-making processes.

Blue mussels Mytilus have returned to the high Arctic region of Svalbard in the beginning of twenty-first century after being absent for almost a 1000 years. Not only M. edulis had arrived in Svalbard, but also a complex of sympatric species including M. edulis, M. galloprovincialis, M. trossulus, and some of their hybrids, which may have a wide range of origins from both sides of the North Atlantic. Mussels were first found in the sublittoral at the entrance to Isfjorden, west coast of Spitsbergen island, and are spreading in other areas, and recently were also found in the intertidal zone. Here, we report viable larvae that were recovered from within the mantle cavity of mussels from the lower intertidal shore collected in late July 2019 and 2021 in Trygghamna, Isfjorden. The identity of larval and adult mussels was confirmed by sequencing of barcode region. Larvae ranged in size from 178 to 376 µm, from mussels 21 to 57 mm in shell length, and estimated to range over 3 to 12 years. It remains unclear whether the larval retention within the mantle cavity results from an intake of near shore concentrations and whether this may lead to larviphagy.

The introduction of harmful aquatic organisms and pathogens (HAOP) via the ballast water of ships can endanger human health, the environment, economic resource-related systems, as well as impair biological diversity. Early warning systems (EWS) are highly effective instruments for mitigating risks and enhancing readiness in the face of potential disasters, including those resulting from HAOP. The establishment of a regional EWS for the identification and notification of harmful organisms is a complex marine policy process involving communication with stakeholders, technical development, engagement of regional knowledge, and, ultimately, harmonization between key authorities and Participating States. The purpose of EWS is to promptly communicate the findings of HAOP to the appropriate stakeholders, such as government agencies and commercial companies. The paper elucidates in detail the criteria and procedure for developing a regionally standardized EWS, including its mechanism, the technical information platform that is required, and the obligations of EWS data providers. It also discusses the decision-making process for issuing alerts and identifies the intended recipients of the warning signals. The system has been operational in the Baltic Sea region for over two years, and the knowledge and insights gathered during its development may prove beneficial in other areas as well.