21 February 2023 | 14:00 - 15:30 (GMT+1)
21 February 2023 | 16:00 - 18:00 (GMT+1)
Open Session - HYBRID
Room: Hörsaal 32
Session Conveners: Anna Nikolopoulos (Norwegian Polar Institute, Norway); Jacqueline M. Grebmeier (University of Maryland Center for Environmental Science, United States); Craig M. Lee (University of Washington, United States)
Session Description:
The Arctic climate system is in great distress, warming faster than the rest of the world and transforming more rapidly than previously anticipated. Sustained, focused and harmonized multidisciplinary information is needed for filling the knowledge gaps about the near-past and present processes in order to accurately predict the future changes and their consequences.
Since 2010, the Distributed Biological Observatory (DBO) has functioned as a “detection array” for ecosystem changes and trends in the Pacific sector of the Arctic Ocean. Similar marine observational networks were recently established in the Davis Strait region (DS-DBO) and in the Atlantic Arctic sector (A-DBO). These long-term, multi-disciplinary initiatives build on active involvement of scientists with the goal to strengthen the regional assessments of the coupled marine system.
Through increased collaboration with joint scientific objectives, findings from such key areas can be expanded to pan-Arctic perspectives and improve our understanding of the entire Arctic Ocean.
We invite contributions from these observatories, assessing the physical, biogeochemical or ecological state of the marine environment in the respective regions. Seasonal, inter-annual and long-term views are equally encouraged. The session will end with roundtable discussions on future priorities for integrating our regional knowledge base into a pan-Arctic system framework.
Presentations:
Session 1 (14:00 - 15:30 GMT+1):
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unfold_moreThe Distributed Biological Observatory: An Approach for Documenting Ecosystem Change in the Arctic - History, Lessons Learned and Broader Applications - Keynote Presentation
Lee W. Cooper1; Sue E. Moore2; Jacqueline M. Grebmeier1; Karen E. Frey3
1University of Maryland; 2University of Washington; 3Clark UniversityAbstract:
The Distributed Biological Observatory (DBO) has become a well-supported research approach for tracking ecosystem changes in the northern Bering and Chukchi seas. It includes multiple occupations of agreed-upon stations, many of which are associated with high biological productivity. As implemented, the DBO is providing insights on seasonal variability in biological production, the trajectories of biological communities and documenting environmental changes as seawater warms and seasonal sea ice declines. As an initial model, the Bering and Chukchi seas had specific advantages. Given highly variable bathymetry and ecosystem structure, oceanographic ship availability and differing national and international research priorities, newly developing DBOs elsewhere in the Arctic will have different approaches. Incorporating Indigenous knowledge and involving local communities in data collection and knowledge sharing is also necessary, meaning that even the original DBO will not continue to be viewed as successful without Indigenous community engagement. However, the need for ship-based sampling as an intrinsic requirement, and coordination with newer mooring and autonomous vehicle technologies means that there will be common approaches across the Arctic. A successful evolution of current and future DBOs will help lead to a more integrated and functional environmental observation system, which will contribute to understanding ecosystem level changes and key physical drivers.
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unfold_moreThe Nansen Legacy – Arctic marine collaboration across disciplines and institutions - Keynote Presentation
Marit Reigstad
UiT The Arctic University of NorwayAbstract:
The Nansen Legacy project (2018-2014) was initiated to close knowledge gaps following the receding sea ice in the northern Barents Sea and adjacent Arctic Basin. The motivation was both to prepare for future sustainable managements, but also to strengthen collaboration across Norwegian research institutions and marine disciplines. The partner institutions include universities, management institutions and private research institutes, and the complementary mandates strengthen the societal deliveries. The added value of such a research project is considerable. Involving >230 scientists (>80 early careers) from 10 partner institutions optimize the use of infrastructures and facilitates joint efforts on recruitment. The complementary expertise and need for common practices on data collection and data handling increase the competence across the entire research community and provides a true legacy. International collaboration further increases the focus on shared practices to provide comparable results and data across the Arctic regions to improve our understanding of climate change and environmental and ecosystem responses on a Pan Arctic scale.
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unfold_moreImpact of sea ice on late summer/early winter hydrography and nutrient concentrations in the Atlantic Water inflow north of Svalbard
Arild Sundfjord1; Angelika Renner2; Allison Bailey1; Marit Reigstad3
1Norwegian Polar Institute; 2Institute of Marine Research; 3UiT The Arctic University of NorwayAbstract:
Ongoing Atlantification of the European Arctic Ocean leading to more warm water, less sea ice and borealisation of Arctic marine ecosystems will affect biological and particularly primary productivity in the area. We investigate linkages between hydrographic conditions and nutrient concentrations with chlorophyll a and sea ice cover in the region north of Svalbard. There, one of the two branches of the Atlantic Water (AW) inflow into the Arctic dominate oceanographic conditions, bringing in heat, salt, nutrients and organisms. However, the interplay with sea ice and Polar Surface Water (PSW) determines the supply of nutrients to the euphotic layer especially northeast of Svalbard where AW subducts below PSW. To create a time series across the AW inflow, we conducted repeat ship-based sampling and data collection from moored sensors – primarily hydrography, nutrients and chl a – along a transect at 31 E, 81.5 N since 2012. We find large interannual variability in hydrography, nutrients and chl a, indicating varying consumption by primary producers over summer. Sea ice conditions varied considerably between the years, impacting surface stratification, light availability and potential wind-driven mixing. Such multidisciplinary observations provide insight into the interplay between physical, chemical and biological drivers in the marine environment and are key to understanding ongoing and future changes, especially at this entrance to the central Arctic Ocean.
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unfold_moreSummer variability in bio-optical properties and phytoplankton pigment signatures in two adjacent high Arctic fjords, Svalbard
Sarat Chandra Tripathy1; Shanmugam Palanisamy2; Anvita Kerkar1; Jane Bhaskar1; Siby Kurian3; Parli Bhaskar1; Manguesh Gauns3; Varunan Theenathayalan2
1National Centre for Polar and Ocean Research; 2Indian Institute of Technology; 3National Institute of OceanographyAbstract:
Arctic fjords are sensitive to the enhanced climate warming-induced glacial meltwater discharge that influences its hydrography and biology. This study explains the impacts of the underwater light environment and nutrient limitation on the phytoplankton biomass, composition, and light absorption in the sunlit zone of the Kongsfjorden (KG)-Krossfjorden (KR) twin fjord ecosystem during summer when the meltwater discharge is at maximum. Observations in two phases in each fjord revealed pronounced spatial hydrographic variations between the phases and among the fjords. The intrusion of warm Atlantic water into fjords and subsurface chlorophyll maxima was observed. Meltwater-induced higher concentrations of optically active constituents in KG resulted in a shallower euphotic zone than KR. Nitrate and silicate limitation was evident in both fjords. Higher phytoplankton light absorption coefficient (aph, m-1) and chlorophyll-a in KR implied its higher productivity potential. However, the light-absorption efficiency of surface microplankton was affected by pigment-package effect. Phytoplankton pigments analyses revealed an inter-fjord difference in surface phytoplankton composition predominated by microphytoplankton followed by nano and picoplankton. The average diversity index for the phytoplankton group (H') was higher in KR (0.71) than KG (0.55), which was possibly controlled by microzooplankton grazing. This study reveals that environmental settings in both fjords were quite different, which drives their productivity potential and species diversity. Thus, increased warming climate can have different impacts on fjord ecosystems despite their close geographical proximity.
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unfold_moreRapid ocean acidification in Arctic outflow waters in the last decade observed in the Fram Strait outflow observatory
Melissa Chierici1; Agneta Fransson2; Mats Granskog2; Paul Dodd2; Colin Stedmon3; Laura de Steur2
1Institute of Marine Research; 2Norwegian Polar Institute; 3Denmark Technical UniversityAbstract:
The Fram Strait is the main gateway and exit for Arctic waters in the western part to capture the surface and cold and fresh outflow waters from the Arctic Ocean. In this study, we explore the chemical change in the inorganic carbon, ocean acidification and nutrient concentrations and stochiometric ratios between 2011 and 2019 in the top 400 m at 79°N to follow the change in the East Greenland Current (EGC, 6°W-3°W), and on the NE Greenland (NEG) shelf between 11°-7°W. The EGC is the main outflow for waters originating in the Arctic Ocean and the Eurasian Arctic and the NEG is more influenced by local processes, and potentially the effect of glacial meltwater. Trends were estimated based on linear regression on annual mean values of carbonate system parameters such as pH, total alkalinity, and aragonite saturation (ΩAr), in four depths intervals: the polar mixed layer (<30m), the Arctic halocline (>40-150 m), and the >150-400m originating from the Atlantic water (AL). ΩAr and pH decreased in all depth layers and areas. Fastest change of -0.0077 yr-1 was observed in the PML in the EGC, which was nearly four times faster than the global ocean mean surface pH decrease. On the shelf, the fast CO2 (thus DIC) increase and pH decrease were explained by meltwater induced CO2 uptake in the fresh waters and potentially accelerated by glacial meltwater Drivers of trends such as anthropogenic CO2, meltwater and air-sea CO2 uptake, and reported changes on the Siberian shelves were explored and discussed in relation to reported changes in the Arctic Ocean such as freshening, warming and anthropogenic CO2 addition from Atlantic water.
Session 2 (16:00 - 18:00 GMT+1):
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unfold_moreSpatial and Temporal variability of Ocean Acidification in Davis Strait DBO - Keynote Presentation
Kumiko Azetsu-Scott1; Craig M. Lee2
1Fisheries and Oceans, Canada; 2University of WashingtonAbstract:
Davis Strait, together with Bering Strait and Fram Strait, represent major gateways connecting the Arctic Ocean with the subpolar oceans. Arctic outflows through numerous conduits in the Canadian Arctic Archipelago are integrated at Davis Strait, which makes Davis Strait an ideal location to investigate the propagation of changes from the Arctic west of Greenland. We can also observe the intrusion of warm, saline Atlantic water into Baffin Bay and the freshwater contribution of the melting Greenland Ice Sheet to the northern North Atlantic along Davis Strait. The Davis Strait region contains marine ecosystems with active and contrasting phytoplankton and zooplankton communities, commercially important fish populations, endemic hotspots of cold water corals, sea pens and sponges, and marine mammals which are important sources of food security and culture for Native Greenlanders and Canadian First Peoples. These marine ecosystems will be influenced by rapidly changing physical/chemical oceanographic conditions. Ocean Acidification is a global phenomenon, caused by the uptake of anthropogenic CO2 at the ocean surfaces. However, global scale ocean acidification is modulated by various processes at different spatial and temporal scales. Identifying the drivers of ocean acidification is necessary for the prediction, mitigation and adaptation, not only for the Eastern Canadian Arctic, but also for the downstream in the North Atlantic. Temporal and spatial variability of the carbonate system parameters and their drivers were investigated using a time series study across Davis Strait during 2004-2021, and extended spatial coverage into Baffin Bay and the Northern Labrador Sea.
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unfold_moreLight transmittance through the ocean water column across the Distributed Biological Observatory sites in the northern Bering and Chukchi Seas
Karen E. Frey1; Bonnie Light2
1Clark University; 2University of WashingtonAbstract:
Recent low sea ice extents across Distributed Biological Observatory (DBO) sites in the northern Bering and Chukchi Seas of the Pacific Arctic region have been due to both later fall/winter freeze-up and earlier spring breakup, which in turn have important cascading impacts on the physical, biological, and biogeochemical state of the overall marine environment throughout this region. Measurements of the transmittance of solar radiation through the ocean water column is one of the critical elements for understanding the potential implications of these recent shifts in sea ice, including impacts on primary production, damaging effects of UV radiation on phytoplankton, photodegradation of dissolved organic matter, and upper ocean heating. We present observations of downwelling irradiance and upwelling radiance profiles in the top ~30-50 meters of ocean waters, collected at discrete stations across DBO sites 1-5 in the northern Bering and Chukchi Seas. Profiles were collected during July 2018, 2019, 2021, and 2022 as part of the DBO program onboard the Canadian Coast Guard Ship (CCGS) Sir Wilfrid Laurier, and represent a first time series of optical measurements across these DBO sites. The potential heating owing to absorption by light-absorbing materials were compared to our optical observations through radiative transfer modeling, allowing for observation vs. model comparisons. Continued monitoring of the transmittance of solar radiation through the water column at these DBO sites will be crucial for understanding changes in the underwater light field as the duration of the ocean water season continues to lengthen with declining seasonal sea ice cover.
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unfold_moreKey Drivers of Marine Ecosystem Change under Climate Warming: Results from the Distributed Biological Observatory
Jacqueline M. Grebmeier1; Lee W. Cooper1; Sue E. Moore2; Karen E. Frey3
1University of Maryland; 2University of Washington; 3Clark UniversityAbstract:
In the Pacific Arctic, warming seawater and reduced sea ice have changed the state of the marine ecosystem in the northern Bering and Chukchi Seas in the Pacific Arctic. Changes in upper-ocean hydrography, primary productivity, pelagic-benthic coupling and carbon cycling, and lower and upper trophic levels are being evaluated through the Distributed Biological Observatory (DBO). This cooperative venture was initiated in 2010 and includes international coordination of research cruises. The DBO emphasizes standardized sampling on set transect lines to measure ecosystem status and environmental trends. Continuous data are obtained through moorings, satellite observations, and autonomous sampling. DBO sampling has revealed that seasonal and interannual hydrographic changes are driving shifts in species composition, distribution and abundance, with northward range expansions into Arctic waters for some temperate species and negative impacts for some cryophillic species. The seasonal timing of phytoplankton growth influences organic materials exported to epi- and infaunal benthic animals, which are important prey for benthic-feeding marine mammals and seabirds. Sediments are also indicators of changing organic carbon deposition providing seasonal and interannual records of water column biological events. This presentation will highlight findings from studies of biological change, the use of sediment chemistry to understand ecosystem status, and key physical drivers for these observed changes.
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unfold_moreCritical Thermal Maximum of an important Arctic prey item, Macoma calcarea
Christina Goethel1; Jacqueline M. Grebmeier1; Sophia Garms2
1University of Maryland; 2St. Mary's College of MarylandAbstract:
As bottom water temperatures rise in the Pacific Arctic, it is important to study and understand the temperature limits of dominant benthic prey items, such as bivalves. Shipboard and post-cruise laboratory experiments were run in 2022 to determine the critical thermal maximum (CTM) of the circum-Arctic bivalve species Macoma calcarea. Samples of M. calcarea were collected aboard the Canadian Coast Guard Cutter Sir Wilfrid Laurier during the Distributed Biological Observatory July cruise with van Veen grabs at stations north of Bering Strait. Water and air temperatures, as well as individual bivalve responses (response to touch or gaping) were monitored every 30-60 minutes during both shipboard and post cruise laboratory experiments at CBL. A select number of bivalve individuals (n=3 shipboard and n=4 laboratory) were measured with FireSting O2 meters and probes to examine O2 consumption as an additional indicator of stress. Shipboard maximum water temperatures reached 15.77°C with no death of individuals, but individuals were slow to respond when touched and were slightly gaped. During laboratory experiments maximum water temperature reached 22.6°C and all individuals (n=22) had died after approximately 1.5 hours at this temperature. These findings indicate a resilience of M. calcarea to near-term increases of bottom water temperatures with climate warming that have implications for the bivalve populations that are important prey for upper trophic benthivores.
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unfold_moreHow do we Integrate knowledge from regional marine observatories to pan-Arctic perspectives?
Panel Discussion