Estimation of glacial meltwater discharge into Svalbard coastal waters. Oceanologia 39

Abstract During the summer expeditions of r/v 'Oceania' in 1995'Oceania' in -1996, oceanographic investigations comprising CTD profiling and suspension measurements were conducted in Svalbard fjords and shelf waters. The freshwater volume was estimated independently from the salinity drop as compared with the assumed background salinity and from the distribution of mineral suspension density in surface waters. Preliminary calculations of the instantaneous freshwater volume based on the distribution of suspended matter (at depths of < 150 m) yielded a figure of 80 km 3 in Svalbard coastal waters in summer. Values for Hornsund and Kongsfjord ranged from 0.4 to 0.7 km 3 of freshwater at the height of summer. This corresponds well with glaciological estimations, which give an annual discharge of 14.6 to 27.5 km 3 of freshwater for Svalbard. The glacial discharge is estimated to make up some 42% of the freshwater budget of Svalbard shelf waters, the remainder being derived from Barents Sea Arctic waters of reduced salinity

Navigating the Future V: Marine Science for a Sustainable Future

Navigating the Future is a publication series produced by the European Marine Board providing future perspectives on marine science and technology in Europe. Navigating the Future V (NFV) highlights new knowledge obtained since Navigating the Future IV1 (2013). It is set within the framework of the 2015 Paris Agreement2 and builds on the scientific basis and recommendations of the IPCC reports3. NFV gives recommendations on the science required during the next decade to deliver the ocean we need to support a sustainable future. This will be important for the United Nations Decade of Ocean Science for Sustainable Development4 (2021 – 2030), the implementation of the UN Sustainable Development Goals5 and the European Commission’s next framework programme, Horizon Europe6 (2021 - 2027). There is a growing need to strengthen the links between marine science, society and policy since we cannot properly manage what we do not know. In recent years, the ocean and seas have received new prominence in international agendas. To secure a safe planet a priority is the management of the ocean as a “common good for humanity”, which requires smarter observations to assess of the state of the ocean and predictions about how it may change in the future. The ocean is a three-dimensional space that needs to be managed over time (thus four-dimensional), and there is a need for management and conservation practices that integrate the structure and function of marine ecosystems into these four dimensions (Chapter 2). This includes understanding the dynamic spatial and temporal interplay between ocean physics, chemistry and biology. Multiple stressors including climate change, pollution and over-fishing affect the ocean and we need to better understand and predict their interactions and identify tipping points to decide on management priorities (Chapter 3). This should integrate our understanding of land-ocean-atmosphere processes and approaches to reducing impacts. An improved science base is also needed to help predict and minimize the impact of extreme events such as storm surges, heat waves, dynamic sea-floor processes and tsunamis (Chapter 4). New technologies, data handling and modelling approaches will help us to observe, understand and manage our use of the fourdimensional ocean and the effect of multiple stressors (Chapter 5). Addressing these issues requires a strategic, collective and holistic approach and we need to build a community of sustainability scientists that are able to provide evidence-based support to policy makers within the context of major societal challenges (Chapter 6). We outline new frontiers, knowledge gaps and recommendations needed to manage the ocean as a common good and to develop solutions for a sustainable future (Chapter 7). The governance of sustainability should be at the core of the marine research agenda through co-production and collaboration with stakeholders to identify priorities. There is need for a fully integrated scientific assessment of resilience strategies, associated trade-offs and underlying ethical concepts for the ocean, which should be incorporated into decision support frameworks that involve stakeholders from the outset. To allow the collection, processing and access to all data, a key priority is the development of a business model that ensures the long-term economic sustainability of ocean observations

Age, growth rate, and otolith growth of polar cod (Boreogadus saida) in two fjords of Svalbard, Kongsfjorden and Rijpfjorden

This work presents biological information for polar cod (Boreogadus saida) collected with a Campelen 1800 shrimp bottom trawl in Kongsfjorden (two stations located in the inner part of the fjord adjacent to the glacier) and Rijpfjorden (one station at the entrance to the fjord) in September and October 2013. The otolith-based ages of polar cod collected in Kongsfjorden (6.1–24 cm total length TL; n = 813) ranged from 0 to 4 years. The growth rate was relatively constant at approximately 4.7 cm year−1 between years 1 and 4, which indicates that growth was fast in the glacier area. The ages of polar cod collected in Rijpfjorden (8.6–15.9 cm TL; n = 64) ranged from 2 to 3 years. The fish from Rijpfjorden were smaller at age than those from Kongsfjorden, and their growth rate between years 2 and 3 (no other age classes were available) was approximately 3.3 cm year−1. In both fjords, males and females were of the same size-at-age and the same weight-at-TL. The small sampling area means that the results on growth rate are not representative of the entire fjords. Instead, the results can be discussed as presenting the possible growth rates of some populations. A strong relationship was identified between otolith size (length and weight) and fish size (TL and TW), with no differences between males and females or the fjords. A significant, strong relationship was also noted between fish and otolith growth rates

Comparison of bacterial production in the water column between two Arctic fjords, Hornsund and Kongsfjorden (West Spitsbergen)

Bacterial production and the accompanying environmental factors were measured in the water columns of two Arctic fjords during the cruise in July and August 2013. Water samples were collected at six stations located in the central part of Hornsund and Kongsfjorden. In Hornsund, where average water temperatures were 1.25-fold lower than in Kongsfjorden, the bacterial production was twice as high (0.116 ± 0.102 vs 0.05 ± 0.03 mg C m−3 h−1). Statistical analysis indicated that chlorophyll a concentration itself was not a significant factor that affected bacterial production, in contrast to its decomposition product, pheophytin, originating from senescent algal cells or herbivorous activity of zooplankton. Single and multiple regression analysis revealed that water temperature, dissolved organic carbon (DOC), and pheophytin concentration were the main factors affecting bacterial production in both fjords

Colonies of Gyrosigma eximium: a new phenomenon in Arctic tidal flats

For the first time at Svalbard, a colonial form of the tube-dwelling diatom Gyrosigma eximium was found in summer 2010 in the tidal flats on Spitsbergen at 78°N. The colonies take the form of conical, green structures that are 1–2 cm high and are associated with other diatom taxa and cyanobacteria (Oscillatoriaceae). The diatom colonies were associated with rich meiofauna and apparently act as cohesive factors for the fine sediment. In the Arctic tidal flats, this represents the first observation of long-term sediment stabilization and biological enrichment. Since this first observation, this species has apparently colonized broader areas in Advenentelva's tidal flat

Primary producers and production in Hornsund and Kongsfjorden – comparison of two fjord systems

Hornsund and Kongsfjorden are two similar-sized Arctic fjords on the West coast of Spitsbergen. They are influenced by cold coastal Arctic water (Hornsund) and warmer Atlantic water (Kongsfjorden). Environmental conditions affect the timing, quantity, spatial distribution (horizontal and vertical) of spring and summer blooms of protists as well as the taxonomic composition of those assemblages. Here, we compile published data and unpublished own measurement from the past two decades to compare the environmental factors and primary production in two fjord systems. Kongsfjorden is characterized by a deeper euphotic zone, higher biomass and greater proportion of autotrophic species. Hornsund seems to obtain more nutrients due to the extensive seabird colonies and exhibits higher turbidity compared to Kongsfjorden. The annual primary production in the analysed fjords ranges from 48 g C m−2 y−1 in Kongsfjorden to 216 g C m−2 y−1 in Hornsund, with a dominant component of microplankton (90%) followed by macrophytes and microphytobenthos

Early detection of marine non-indigenous species on Svalbard by DNA metabarcoding of sediment

Non-indigenous species (NIS) in the Arctic have an increased likelihood of arrival from ship traffic in the region, while the survival potential of the species becomes more likely in a warming environment. Monitoring is essential to detect the rate and magnitude of the establishment of NIS. In this study, a list of 123 potential marine NIS for Svalbard was drafted and the presence of marine NIS in soft sediment of Kongsfjorden in Svalbard was assessed using molecular metabarcoding techniques. For 37 species, including eight potential Arctic NIS, we generated new 18S and/or COI barcode sequences to improve the available online reference databases. In total, 299 species were identified in the sediment samples, including seven potential NIS. Three of these potential NIS have not been reported before in Svalbard: the harpacticoid copepod Euterpina acutifrons, and the ascidians Botrylloides violaceus and Molgula manhattensis. Another novel observation for Svalbard was the polychaete Chone mollis. Additional studies are needed to assess whether the NIS have been established on Svalbard and what their potential impact on the local system may be. Metabarcoding proved to be an effective monitoring tool to detect the presence of new species in Svalbard marine waters. We advise its use to set up a baseline record for the presence of NIS at points of entry, especially harbours. This approach is also valuable for biodiversity monitoring, in particular the detection of small organisms and life stages that are hard to identify using current visual techniques.</p