Biomarker characterization of the North Water Polynya, Baffin Bay: Implications for local sea ice and temperature proxies

The North Water Polynya (NOW, Greenlandic Inuit: Pikialasorsuaq), Baffin Bay, is the largest polynya and one of the most productive regions in the Arctic. This area of thin to absent sea ice is a critical moisture source for local ice sheet sustenance and coupled with the inflow of nutrient-rich Arctic Surface Water, supports a diverse community of Arctic fauna and indigenous people. Although paleoceanographic records can provide critical insight into the NOW’s past behavior, it is critical that we fully understand the modern functionality of the paleoceanographic proxies beforehand. In this study, we analyzed lipid biomarkers, including algal highly-branched isoprenoids and sterols for sea ice extent and pelagic productivity, and algal alkenones and archaeal GDGTs for ocean temperature, in a suite of modern surface sediment samples from within and around the NOW. Our data show that all highly-branched isoprenoids exhibit strong correlations with each other and show highest concentrations within the NOW, which suggests a spring/autumn sea ice diatom source rather than a combination of sea ice and open water diatoms as seen elsewhere in the Arctic. Sterols are also highly concentrated in the NOW and exhibit an order of magnitude higher concentration here compared to sites south of the NOW, consistent with the order of magnitude higher primary productivity observed within the NOW relative to surrounding waters in spring/summer months. Finally, our temperature calibrations for alkenones, GDGTs and OH-GDGTs reduce the uncertainty present in global temperature calibrations, but also identify some additional variables that may be important in controlling their local distribution, such as salinity, nutrients, and dissolved oxygen. Collectively, our datasets provide new insight into the utility of these lipid biomarker proxies in high-latitude settings and will help provide a refined perspective on the Holocene development of the NOW with their application in downcore reconstructions.

An Examination of the Non-Formation of the North Water Polynya Ice Arch

The North Water (NOW), situated between Ellesmere Island and Greenland in northern Baffin Bay, is the largest recurring polynya in the Canadian Arctic. Historically, the northern border of the NOW is defined by an ice arch that forms annually in Kane Basin, which is part of the Nares Strait system. In 2007 the NOW ice arch failed to consolidate for the first time since observations began in the 1950s. The non-formation of the NOW ice arch occurred again in 2009, 2010, 2017 and 2019. Satellite Advanced Very High Resolution Radiometry data shows that large floes broke off from the normally stable landfast ice in Kane Basin for each of these years, impeding ice arch formation. A closer analysis of a 2019 event, in which 2500 km2 of ice sheared away from Kane Basin, indicates that significant tidal forces played a role. The evidence suggests that thinning ice from a warming climate combined with large amplitude tides is a key factor in the changing ice dynamics of the NOW region. The non-formation of the NOW ice arch results in an increased loss of multiyear ice through Nares Strait.

A Study of the North Water Polynya Ice Arch using Four Decades of Satellite Data

Polynyas are sections of the polar ocean that remain relatively ice-free during winter, imparting significant physical and biological impact on the region. The North Water polynya (NOW) situated between Ellesmere Island and Greenland is the largest recurring Arctic polynya. Historically, the NOW forms every season when Arctic Ocean floes moving southward through Nares Strait become congested and form an ice arch that defines the northern border of the polynya. This blockage usually forms during winter and breaks down in spring. It is conjectured that the polynya is maintained by latent heat of fusion from the continuous formation of new ice as floes are swept southward from the ice arch by wind and ocean currents. Analysis of four decades of satellite imagery indicates a growing instability in the location of the ice arch, challenging previous models of polynya maintenance. A linear trend of the data indicates the number of days of Nares Strait blockage has decreased 2.1 days/year between 1979 and 2019 with wide interannual variations. Prior to 2007, ice arches blocked Nares Strait an average of 177 days/year compared to 128 days/year since that time. The overall trend of reduced ice arch duration is a contributing factor to the dramatic loss of multiyear ice in the Arctic basin.

POTENTIALS FOR THE PROTECTION OF PIKIALASORSUAQ IN THE SHADOW OF CONTEMPORARY MARITIME INDUSTRIES

The Pikialasorsuaq or North Water Polynya is a polynya that lies between Greenland and Canada in northern Baffin Bay. For centuries small scale family-based markets had been developed between the Inuit of two sides based on cross-border transportation. However, the emerged modern maritime industries have posed serious challenges for the polynya where the free cross-border transportation is nowadays banned, and the environmental threat has become a reality deteriorated further by climate change. Indigenous participation and Free Prior and Informed Consent are crucial for the conservation of the polynya. Accordingly, this article was designed as a descriptive study of the current situation in Pikialasorsuaq, providing the legal framework for the protection of the region and highlighting the existing system’s shortcomings.

Baffin Bay sea ice inflow and outflow: 1978–1979 to 2016–2017

Baffin Bay serves as a huge reservoir of sea ice which would provide the solid freshwater sources to the seas downstream. By employing satellite-derived sea ice motion and concentration fields, we obtain a nearly 40-year-long record (1978–1979 to 2016–2017) of the sea ice area flux through key fluxgates of Baffin Bay. Based on the estimates, the Baffin Bay sea ice area budget in terms of inflow and outflow are quantified and possible causes for its interannual variations and trends are analyzed. On average, the annual (September–August) inflows through the northern gate and Lancaster Sound are on the order of 205.8(±74.7)×103 km2 and 55.2(±17.8)×103 km2. In particular, a comparison with published results seems to suggest that about 75 %–85 % of the inflow through the northern gates is newly formed ice produced in the recurring North Water Polynya (NOW), in addition to the inflow via Nares Strait and Jones Sound. Meanwhile, the mean outflow via the southern gate approaches 394.3(±110.2)×103 km2. The distinct interannual variability for ice area flux through the northern gate and southern gate is partly explained by wind forcing associated with cross-gate sea level pressure difference, with correlations of 0.62 and 0.68, respectively. Also, significant increasing trends are found for the annual sea ice area flux through the three gates, amounting to 38.9×103, 82.2×103, and 7.5×103 km2 decade−1 for the northern gate, southern gate, and Lancaster Sound. These trends are chiefly related to the increasing ice motion, which is associated with thinner ice owing to the warmer climate (i.e., higher surface air temperature and shortened freezing period) and increased air and water drag coefficients over the past decades.

Toxic splash: Russian rocket stages dropped in Arctic waters raise health, environmental and legal concerns

ABSTRACTRussia has dropped rocket stages fuelled with unsymmetrical dimethylhydrazine (UDMH) into the Barents Sea and the North Water Polynya—areas of considerable ecological importance—on ten occasions since 2002. The stages come from SS-19 intercontinental missiles that have been re-purposed for launching satellites. UDMH is a highly toxic chemical that has caused widespread health and environmental damage in Kazakhstan and Russia as a result of its extensive use there as a rocket fuel. Not all of the fuel on-board is consumed during a launch and the residual fuel tends to escape the incoming stages and form aerosol clouds that drift over large areas. This dropping of the rocket stages is of considerable concern to the Inuit of Canada and Greenland, who only learned about the practice in 2016. It is also a violation of several treaties as well as customary international law. At least two more launches of UDMH-fuelled rockets on the same trajectory are currently planned—even though alternative non-toxic rocket systems exist.