22 February 2023 | 08:30 - 10:00 (GMT+1)
Open Session - HYBRID
Room: Hörsaal 3
Session Conveners: Artur Palacz (Institute of Oceanology of Polish Academy of Sciences, Poland); Sigrun Jonasdottir (Technical University of Denmark, Denmark); Claudia Schmidt (Helmholtz-Zentrum Hereon, Germany)
Session Description:
Open ocean ecosystem in the Arctic is changing fast, with increasing freshwater input from melting sea ice and rising sea surface temperature inducing changes to hydrography, water chemistry and seasonality, among other factors. These physical and chemical changes influence the species distribution patterns, productivity and timing of annually reoccurring events, with potential consequences for the functioning of the arctic marine ecosystem, the services that it provides and the dependent human communities. Nevertheless, our understanding of the links between the environmental change, biodiversity loss, ecosystem functions and ecosystem services in the Artic seas is still limited, despite the fact that a large part of the Arctic communities depend on fisheries for their livelihood.
We invite contributions that shed light on the complex relationships between multiple stressors, marine biodiversity and ecosystem services in the open ocean, as well as consequences of biodiversity change for human societies, and their adaptation and mitigation options. We particularly welcome contributions focusing on functional diversity, contributions synthetizing information from various sources (in situ and remote sensing observations, local ecological knowledge and models) or across multiple time scales (from paleo-oceanography to seasonal changes), as well as contributions that provide examples of adaptation strategies and mitigation options of human communities in response to changes in marine biodiversity. The session is organized by the Horizon2020 project ECOTIP, focusing on the causes and consequences of the biodiversity change in the Arctic seas.
Presentations:
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unfold_moreEffect of zooplankton community composition on the biological pump along onshore-offshore transects in West Greenland
Marja Koski1; Sigrun Jonasdottir1; Camilla Svensen2
1Technical University of Denmark; 2UiT The Arctic University of NorwayAbstract:
Different zooplankton species divert in their size, behavior, feeding preferences and ecophysiological rates, suggesting a high functional diversity among zooplankton and a direct effect of the community composition on ecosystem functions and services, including the biological carbon pump. Two groups of copepods that are likely to have different effects on the biological pump include large, herbivorous species (such as Calanus spp. and Metridia spp.) that perform vertical and / or seasonal migrations, and small species (such as Oithona spp., Oncaea spp. and Microsetella norvegica) that are known to feed on fecal pellets and marine snow particles. Changes in the proportional abundance of these two groups might have a large effect on the efficiency of the biological pump. We estimated the vertical distribution of zooplankton along onshore-offshore transects in West Greenland in July 2021, and combined the species composition with shipboard incubations on diet (gut chlorophyll) and pellet production rates of the dominant species. Our preliminary results indicate large differences both in proportional abundances of species and pellet production rates between the stations, suggesting that changing environment influences the effect of zooplankton on the biological pump, both through its effect on community composition and through its effect on ecophysiological rates.
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unfold_moreLife history reconstruction of the Arctic squid (Cephalopoda: Gonatus fabricii) by individual trajectories of δ13C and δ15N: biodiversity implications
Alexey Golikov1; Filipe Ceia2; Hendrik Hoving1; José Queirós2, 3; Rushan Sabirov; Martin Blicher4; Anna Larionova; Wojciech Walkusz5; Zakharov, Denis; Xavier, José2, 3
1GEOMAR Helmholtz Centre for Ocean Research; 2University of Coimbra; 3British Antarctic Survey; 4NIRAS A/S; 5Fisheries and Oceans CanadaAbstract:
The Arctic Ocean ecosystems are highly influenced by climate change. Biodiversity shifts with boreal species moving northward have been reported in the recent decades. Within individual lives, species can consecutively occupy several ecological roles, significantly increasing functional biodiversity within a single taxon. However, this concept is often not reflected in ecosystem models, decreasing their forecasting capability. Here, we reconstruct individual ecological trajectories of the most abundant Arctic cephalopod, squid Gonatus fabricii. This species is important in the Arctic as both prey (of at least 47 taxa) and predator (of at least 49 taxa), and reaches high biomass (up to 20 million t in the Nordic Basin). Individual (n = 14) and population (n = 105) isotopic trajectories of carbon (δ13C) and nitrogen (δ15N) of G. fabricii from West Greenland are performed, and plethora of analytical tools are applied to these data. Using this novel approach, four stages with clearly distinct ecology are revealed in the life cycle of G. fabricii in terms of ontogenetic diet and habitat changes, providing the necessary baseline for Arctic ecosystem modelling and forecasting. Additionally, it illustrates how much a single species with ontogenetic consecutive changes in ecology, can add to functional biodiversity.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement № 101065960.
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unfold_moreEffects of climate variables on diet and habitat use of coastal, anadromous, and offshore marine fish of the Canadian Beaufort Sea
Lauren Dares1; Ashley Ehrman1; Karen Dunmall1; Colin Gallagher1; Kimberly Howland1; Ellen Lea1; Zhenxia Long1, Lisa Loseto1, Andrew Majewski1, Darcy McNicholl1, William Perrie1; Minghong Zhang1, Andrea Niemi1
1Fisheries and Oceans CanadaAbstract:
Dynamics and biodiversity of local fish communities can be influenced by large-scale climate variables, yet information on the effects of these variables on diets and habitat use are lacking in the rapidly changing Arctic. Trophic and habitat biotracer data from 16 coastal, anadromous, and offshore marine fish species collected by four monitoring programs were analyzed for spatiotemporal differences and their isotopic niches constructed from measurements of δ13C and δ15N. The effects of large-scale climate variables on isotopic niches was investigated using generalized linear and generalized additive mixed effects models (GLMMs and GAMMs) to relate niches to ice and snow cover, upwelling, temperature, salinity and other variables obtained from a NEMO-LIM2 climate model downscaled in spatial and temporal resolution for the Canadian Beaufort Sea. Niches showed considerable interannual variability in standard ellipse area of the 95% niche, as well as Layman’s metrics, likely due to differences in magnitude of climate variables between years, as well as timing of seasonal events such as freshet and freeze-up. As climate change continues in the Arctic, shifts in fish diet and habitat use in response to changing environmental parameters are anticipated to increase competition for benthic and pelagic food resources, potentially compromising biodiversity of fish communities throughout the Canadian Beaufort Sea, including those important to Indigenous subsistence fisheries in the region.