Vetenskapliga frågeställningar

The red thread: GEOEO addresses scientific questions focused on providing new knowledge on the marine cryosphere’s dynamic history and response to future climate change, including implications for marine and terrestrial ecosystems in North Greenland and the adjacent Arctic Ocean and the North Greenland Ice Sheet’s contribution to global sea-level rise.

Goal 1

Unravelling the Late Glacial to Holocene history and dynamics of the North Greenland Ice Sheet (NGIS)

  1. Can we document patterns, sudden dynamic changes, and/or specific locations/times of stability during the NGIS’s Late Glacial to Holocene retreat from the continental margin?
  2. How and when did the presence/absence of floating ice tongues/ice shelves, sea-ice conditions and influx of warmer ocean water of Atlantic origin influence the NGIS’s retreat pace and dynamics?
  3. Did seafloor geology (bedrock and/or the shape of the submerged landscape) influence the NGIS’s retreat dynamics?
  4. Can we identify areas where marine ice-cliff instability may have caused rapid ice break-up?

Contribution of new knowledge

As no field data exist, reconstructions of the NGIS in the Lincoln Sea area are hypothetical. New information on the retreat dynamics, the role of ice shelves/tongues and retreat-pace from palaeo-records (glacial landforms, sediment cores etc) will add to our knowledge on how fast marine based ice sheets can retreat, a critical question considering the present climate warming.

Goal 2

Providing new insights into the variability of the marine cryosphere of North Greenland and the adjacent Arctic Ocean

  1. When did the Arctic Ocean north of Greenland last experience sea-ice free summers?
  2. Have past occurrences with sea-ice free summers in the northern Greenland realm been linked to a complete loss of Arctic Ocean's summer sea-ice cover?
  3. Are sea-ice variations in northern Greenland during the Holocene linked to known climate forcings, e.g. solar insolation and atmospheric greenhouse gases?
  4. To what extent do variations of Atlantic water inflow to northern Greenland affect sea-ice conditions and the stability of ice tongues?
  5. How fast could the summer sea ice and collapsed ice tongues recover if the climate is cooled?
  6. Are there climatic thresholds beyond which the cryospheric retreat becomes irreversible?
  7. What are the water mass structures and distributions of dissolved constituents (gases, nutrients, carbonate system, transienttracers) in this key gateway area for export of Arctic-derived water of both Atlantic, Pacific and riverine origin to the North Atlantic?

Goal 3

Investigating the interaction between ecosystem community composition, anthropogenic dynamics and climate fluctuations

  1. How is genomic biodiversity distributed throughout the marine water column?
  2. To what extent are past changes in Holocene biodiversity correlated with inferred changes in temperature, sea-ice cover and ice shelf dynamics?
  3. Do we find invasive subpolar species? Does the presence-absence of DNA from organisms that depend on sea ice lend support to inferences of earlier periods of an ice-free Arctic Ocean?
  4. To what extent is the arrival and disappearance of human cultures on Greenland, as inferred from sedimentary ancient DNA, correlated with past climate change, coastal sea ice changes, and/or prey species population dynamics? In addition, dendrochronological data from north Greenland shrubs will be assembled to reconstruct past climate and investigate vegetation dynamics.

Contribution of new knowledge

The plankton/benthos surveys will document the current state of Arctic marine biology in unexplored regions North of Greenland. Genomic analyses will contribute completely novel insights into temporal dynamics in marine biodiversity and how these are related to past changes in climate and sea-ice cover. On the terrestrial side, the analyses will enhance our knowledge of the extent to which pioneering human populations were affected by changes in terrestrial and marine biotic communities, especially prey population demography, in the context of Holocene climate fluctuations.

Goal 4

Quantifying ecosystem production and nutrient state in changing marine ecosystems north of Greenland

  1. What is the coupling between meltwater plumes, Arctic Ocean circulation, warm water pools and biological productivity, export, and demineralization?
  2. Who are the primary producers in these ecosystems?
  3. What sustains the biological productivity in fjords and near shore areas–nutrient inflow of Arctic Ocean water or subglacial runoff from land?
  4. What were the biogeochemical changes over the past decades and what can they tell us about future ecosystem changes?

Contribution of new knowledge

Through on-board continuous CO2and stable isotope water monitoring systems, CTD Rosette profiling for nutrients, microscopic and primary productivity measurements, and chemical and biological profiling of sediments and porewaters we can provide new data for both local and regional synoptic insights of the present and future Arctic marine carbon and nutrient cycles.

Goal 5

Mapping of the remote ocean frontiers

There has been growing recognition that our limited knowledge of the seafloor shape and depth has a severe impact on our ability to model ocean circulation and global heat transport, understand sediment dynamics and glacial history, assess sea-level rise, predict tsunamis and storm surges, and manage critical benthic habitats. The Decade of Ocean Science in Support of Sustainable Development has identified the complete mapping of the seafloor as a priority research area, necessary for meeting several of the U.N. Sustainable Development Goals (SDGs). The seafloor around NorthernGreenland is virtually unmapped.

Contribution of new knowledge

We will provide all mapping data fromtheNorthof Greenland2024 Expeditiondirectly to the International Bathymetric Chart of the Arctic Ocean (IBCAO)/Seabed 2030 project, which assembles these data to freely available data compilations provided to the community through the General Bathymetric Chart of the Oceans (GEBCO).

Goal 6

Mapping the presence of gas hydrates in marine sediments and gas in water column and atmosphere

  1. Are there gas hydrates in the sediments?
  2. Do we see signs of hydrate dissociation and seafloor methane release?
  3. How sensitive are the hydrate deposits (if present) to climate warming?

Contribution of new knowledge

In regional and global assessments of future warming-induced seafloor methane release, it is assumed that hydrates are ever-present along the continental shelf slope off northern Greenland, but this is purely based on assumption. If we reach this area to acquire new data, it will provide the first insights from a region that to-date has no geological base information on gas hydrates in previous assessments.

Goal 7

Numerical modelling of the ice-ocean-atmosphere-geodynamic system

  1. What is the potential contribution to global sea-level rise from the NGIS under IPCCs RCPs/SSPs?
  2. How sensitive is Glacial Isostatic Adjustment (GIA) to geophysical inferred variations in deeper crustal and upper mantle rheologies and how do this geodynamics affect ice dynamics and contribution to sea-level rise?
  3. Which are the most critical feedback processes and environmental parameters (influx of warmer water, etc.) controlling the NGIS’s future behaviour under the different climate scenarios RCP?

Contribution of new knowledge

As there are no observation data from the Lincoln Sea north of 82°30’ N or from the fjords north of Sherard Osborn Fjord where Ryder Glacier drains, there are no assessments based on numerical modelling using observational data as boundary and/or initial conditions. Hence the contribution to new knowledge will be profound.