24 February 2023 | 14:00 - 15:30 (GMT+1)
Open Session - HYBRID
Room: Hörsaal 7
Session Conveners: Shabnam Choudhary (National Centre for Polar and Ocean Research, India); Syed Mohammad Saalim (Patna University, India); Rahul Mohan (National Centre for Polar and Ocean Research, India); Neelu Singh (Independent Researcher, Norway)
Arctic amplification has drastically influenced the climatic variability in the northern high latitude region. Natural and anthropogenic stressors linked to climate change have increased the contaminants in the polar environment. Since the last century, melting glaciers has affected the distribution of contaminants accumulated beneath the glacier systems. As a consequence, fjord systems have been receiving heavy loads of contaminants, posing a potential threat to the ecosystem. Arctic terrestrial and coastal marine ecosystems have become susceptible to contamination in recent years since environmental impacts of climatic change have been amplified. Thus, it is essential to understand the key processes having an impact on contaminant fluxes to the marine ecosystem.
The proposed session focuses on the increased anthropogenic pollutants, climate change and its effect on biota in the Arctic region. This session would include the application of a range of proxies and natural archives to understand the effect of climate change on the ecosystem and the processes driving benthic biodiversity. Proxies will include geochemical information on oceanographic and sedimentary processes and the influence of benthic-pelagic coupling on distributions of nutrients and organic matter. Understanding the physical characteristics of habitats enables the prediction of potential shifts in benthic biodiversity due to changing environmental conditions, including sea-ice and ocean dynamics.
We invite contributions that integrate physical, biological and chemical components of the marine/freshwater environment, with a focus on examining environmental drivers of change, ecological impacts and identifying potential future impacts.
unfold_moreBioavailability of metals in modern fjord sediments, west Spitsbergen, and their influence on benthic foraminifera - Keynote Presentation
Shabnam Choudhary1; Syed Mohammad Saalim2; Rahul Mohan1
1National Centre for polar and Ocean Research; 2Patna University
Arctic fjords are ideal locations to investigate the impacts of climate change on the environment. As a consequence of global warming, metal concentrations in the Arctic region are increasing due to permafrost melting and changes in biological processes. Therefore, the fjord sediments were studied for the identification of provenance, mobility, bioavailability, and potential toxicity of metals in the fjord environment. Finer sediments and organic matter were found to be higher away from the glacier outlets, while coarser sediments were found to be higher near the glacier head. Illite, kaolinite, and chlorite constituted the clay mineral assemblage which slightly influenced the metal distributions. The variations in metal abundance were attributed largely to the glacial activity along with the influence of Atlantic water mass in western Spitsbergen. The Fjord system received sediment from the weathering of rocks indicating an input of terrigenous material. A comparison of metals in bulk sediment with Arctic sediment quality guidelines (ASQGs) showed that Zn and Cu were enriched in the sediment. However, to avoid the overestimation of the risk associated, fractionation of the metals was carried out which revealed higher Mn and Co in labile phases that pose a considerable risk to the biota. Further, population density and abnormality index of foraminifera in the sediments were calculated to understand the influence of bioavailable metal on benthic foraminifera. The presence of metals in bioavailable fractions impacted the abundance of the species, however, no morphological abnormalities were observed in the species.
unfold_moreArctic Kelp Communities in Kongsfjorden are Resilient to Global Change
Cale Miller1; Jean-Pierre Gattuso2; Frédéric Gazeau1; Steeve Comeau1; Samir Alliouane1; Anais Lebrun1; Pierre Urrutti1
1Sorbonne Université; 2Institute for Sustainable Development and International Relations
Fjord systems in the Svalbard archipelago are experiencing a climatic shift due to the Atlantification of the Arctic and the rapid retreat of sea-ice and sea terminating glaciers. These environmental changes have induced the expansion and incursion of boreal species to Arctic fjords, restructuring benthic communities and placing local species under potential physicochemical stress. The potential resilience of benthic communities in these fjord systems will depend on the response of mixed Arctic-boreal communities to periods of freshening from glacial melt, exposure to warmer waters, and increased turbidity resulting from meltwater runoff. All these factors have the potential to reshape biogenic habitats such as kelp communities, modifying ecosystem production and biogeochemical cycling. To assess the impact of future environmental changes on benthic productivity and resilience, we conducted a 2-month mesocosm experiment exposing mixed kelp communities to three future conditions comprising increased temperature (+3 and +5 °C), seawater freshening (-3 and -5 units), and decreased photosynthetically active radiation (PAR, -25 and -38%). Exposure to these treatments resulted in non-significant differences in short-term productivity, but modified the integrated sum of positive and negative rates over the experimental period suggesting a decrease in seasonal productivity at the most extreme conditions (+5°C, -5 salinity units, and -38% PAR). We place these results in the context of ecosystem productivity and biological resilience of kelp communities to future Arctic fjord systems.
unfold_moreThe microbial response of high Arctic freshwaters to nutrient enrichment
Nicolas Valiente1; Peter Dörsch2; Laurent Fontaine3; Jing Wei3; Sigrid Trier Kjær4; Dag O. Hessen3; Alexander Eiler3
1University of Vienna; 2Norwegian University of Life Sciences; 3University of Oslo; 4ETH Zurich
In the Arctic, climate change contributes to increased nutrients in freshwaters derived from sources such as permafrost thaw, atmospheric deposition and increasing geese populations. Freshwaters are highly sensitive to these changes, which may affect community composition and diversity at all levels, not the least microbial communities. To understand how high Arctic lakes respond to nutrient enrichment in terms of microbial diversity and greenhouse gas (GHG) concentrations, we studied 5 lakes in the vicinity of Ny-Ålesund (Svalbard) with and without impact of birds, notably geese. For each lake, we tested the response to nutrient addition, by adding an artificial nutrient solution with N and P, and the response to light or dark conditions. Samples were incubated at 4 ºC in 120 mL flasks containing 80 mL of unfiltered water and air. After 24h, samples for GHG (CO2, CH4 and N2O), nutrients (organic C, P and N) and eDNA (16S metabarcoding) were collected. We used Ar-corrected gas saturation of each GHG as a proxy of net metabolic changes. Compared to the initial conditions (i.e. lake sampling), our results showed a strong oversaturation in CH4, higher organic C and N2O production after 24h in bird-impacted lakes. Microbial community composition differed between bird-impacted and non-impacted lakes after 24h of incubation, including higher alpha diversity in non-impacted ones. With nutrient addition, we found significantly higher concentration of N but not P after 24h. All other parameters, including microbial community composition, were not affected by either nutrient addition or incubation under light or dark conditions. This work furthers our knowledge of biodiversity responses to nutrient enrichment in the Arctic freshwaters.
unfold_morePCBs & PAHs in the summer plankton from the West Spitsbergen fjords
Anna Pouch1; Agata Zaborska1; Anna Maria Dąbrowska1; Ksenia Pazdro1
1Institute of Oceanology, Polish Academy of Sciences
PCBs and PAHs were measured in plankton samples collected in 2015 and 2016 from Kongsfjorden, Hornsund, and Adventfjorden. Plankton nets with 20µm and 1000µm mesh sizes were used to collect planktonic protists and zooplankton. The contaminants were analyzed using gas chromatography techniques (GC-ECD and GC-FID). Σ7 PCB concentrations in protist samples and zooplankton taxa were up to 3.58 ng/g w.w. and 3.01 ng/g w.w. respectively. The concentration of 12 PAHs in protist samples ranged from below the quantification limit to 249 ng/g w.w. Σ12 PAHs concentration in zooplankton taxa was up to 888 ng/g w.w. The interrelationships between PCBs in an abiotic environment and the biota have been examined. The PCB composition in protist samples was in most cases similar to that reported earlier in suspended particulate matter (SPM), which confirms that PCBs are not easily degraded in the environment, also in the biota. In the case of PAHs, their composition in protist samples and SPM were quite different. The PAH group is more physicochemically diverse than the PCB group, which may explain the difference in the compositions in protist samples and SPM. The highest concentrations of PCBs & PAHs were detected in the predator Themisto abyssorum, while the lowest concentrations were measured in herbivorous Calanus spp., what indicate that feeding strategies have a prevailing influence on the accumulation of contaminants by organisms. PCBs in 95% and PAHs in 79% of studied cases bioaccumulate in organisms. Depending on the compounds analyzed, biomagnification occurs for even 95% of the predator-prey pairs of studied zooplankton.