Highlights of Papers Published on Issue 35 (2) of Advances in Polar Science

The peer-reviewed journal Advances in Polar Science (APS) published Issue 35(2) in June 2024. This issue covers 11 articles, the titles and highlights of which are presented below. All papers published on APS could be accessible and downloaded free of charge. See more details via APS website: aps.chinare.org.cn.

Picture: Cover of Issue 35(2)

(1) Pan-African metamorphism and magmatism in the Prydz Belt, East Antarctica: a geochronological perspective

The Prydz Belt in East Antarctica underwent extensive metamorphism during the late Neoprotertozoic–early Paleozoic. The metamorphism features high-ultrahigh temperature metamorphism with clockwise P–T trajectories. The study compiles and analyzes the age and composition data of zircon and monazite from metamorphic rocks and links the typical features in the age and composition of dating minerals to the metamorphic evolution of the Prydz Belt. The results show that the frequency of metamorphic zircon U-Pb ages significantly increases from ~555 Ma and peaks between 530 Ma and 520 Ma, followed by a sharp decrease after 520 Ma. Meanwhile, the frequency of monazite ages progressively increases from ~540 Ma, reaches its peak at ~515 Ma, and then rapidly decreases after 490 Ma. The main crystallization stage of monazite postdates that of zircon by ~5–15 Ma, indicating a relatively slow average cooling rate. The rapid growth of zircon and the systemic increase in Th/U values after 545 Ma may suggest the transition to the cooling process in the Prydz Belt. Granitic intrusions accompanied the Pan-African metamorphism, with the ages of the intrusions distributed at different stages of metamorphism. The compiled data indicate that the Pan-African period event may peak at ~555–545 Ma and cool to near solidus conditions at ~520–510 Ma, suggesting a relatively low average cooling rate from peak to solidus.

Citation:  Bao H, Wang W, Liu X S, et al. Pan-African metamorphism and magmatism in the Prydz Belt, East Antarctica: a geochronological perspective. Adv Polar Sci, 2024, 35(2): 143-156, doi: 10.12429/j.advps.2023.0023

(2) Migration and role of zinc in biogeochemical cycles in the Antarctic Ice Sheet and the Southern Ocean

We compared trace metal Zn concentrations in different regions of the Antarctic ice cap and the Southern Ocean and analyzed the reasons for the differences in Zn concentrations, revealing that the change of Zn concentration in the mid-twentieth century is closely related to human activities. The study of Zn biogeochemical cycles in Antarctica is of great significance to the study of Antarctic climate.

Citation: Liu J W, Li C J, Du Z H, et al. Migration and role of zinc in biogeochemical cycles in the Antarctic Ice Sheet and the Southern Ocean. Adv Polar Sci, 2024, 35(2): 157-177, doi: 10.12429/j.advps.2023.0032

(3) A progress review of black carbon deposition on Arctic snow and ice and its impact on climate change

Numerous observations have been conducted and provided a snapshot of black carbon (BC)  concentrations in snow in the Arctic (the maximum in the western Arctic of Russia, and the minimum in Greenland). BC records in the Arctic ice core already peaked in 1920s and 1970s, and shows a regional difference between Greenland and Arctic Canada. The different temporal variations of Arctic BC ice core records in different regions are closely related to the large variability of BC emissions and transportation processes across the Arctic region. Model simulations usually underestimate the concentration of BC in snow and ice by 2–3 times, and cannot accurately reflect the seasonal and regional changes in BC deposition. Arctic BC deposition significantly influence regional climate change in the Arctic, increasing fire activities in the Arctic have made BB sources of Arctic BC more crucial. Reliable source information and long-term and high-resolution observations on Arctic BC deposition will be crucial for a more comprehensive understanding and a better mitigation strategy of Arctic BC.

Citation:  Zhang Z L, Zhou L B, Zhang M G. A progress review of black carbon deposition on Arctic snow and ice and its impact on climate change. Adv Polar Sci, 2024, 35(2): 178-191, doi: 10.12429/j.advps.2023.0024

(4) Polymetamorphism of the ultrahigh-temperature granulites in the Rauer Group, East Antarctica: new evidence from zircon SHRIMP U-Pb ages

Metamorphic zircon mantles in two UHT granulites in the Rauer Group record two SHRIMP U-Pb ages of 918 Ma and 901 Ma, respectively. Metamorphic zircon rims in the two UHT granulites record two SHRIMP U-Pb ages of 523 Ma and 532 Ma, respectively. New zircon SHRIMP U-Pb age data support that the UHT granulites in the Rauer Group experienced polymetamorphism in Grenvillian and Pan-African. The two high-grade metamorphic events may be associated with the assembly of supercontinents Rodinia and Gondwana.

Citation: Tong L X, Liu Z, Li C, et al. Polymetamorphism of the ultrahigh-temperature granulites in the Rauer Group, East Antarctica: new evidence from zircon SHRIMP U-Pb ages. Adv Polar Sci, 2024, 35(2): 192-205, doi: 10.12429/j.advps.2024.0001

(5) Microscopic analysis on eukaryotic algae and cyanobacteria in nine seasonal lakes and ponds in Vestfjella, Dronning Maud Land, Antarctica

Antarctic continental lakes and ponds are some of the most impoverished aquatic environments on Earth, yet many of them support flourishing populations of cyanobacteria, eukaryotic algae, and even some multicellular animals. Through microscopic analysis of cyanobacteria and eukaryotic algae from nine diverse types of Antarctic continental water bodies during the austral summer of December 2014/January 2015, this study supplements and expands upon previous research on the limnological characteristics of epiglacial and supraglacial lakes and ponds in Dronning Maud Land. The results indicate that all investigated water bodies contained organisms capable of surviving harsh winter conditions and thriving in summer. The most frequently identified taxon among the samples was the eukaryotic Mesotaenium cf. berggrenii, followed by the prokaryotes Gloeocapsopsis and Leptolyngbya, Chlamydomonas and Cyanothece. The number of taxa observed varied from 7 to 21, with the highest diversity found in a supraglacial lake and the lowest in an epiglacial lake. Interestingly, the results did not show a clear correlation between the abundance of any taxa and water chemistry, but water bodies containing inorganic sediments exhibited higher cell densities and biomasses compared to those without sediment. This highlights the potential importance of sediment in supporting biological diversity in these ultraoligotrophic lakes and ponds.

Citation:  Arvola L, Leppäranta M, Li Z J. Microscopic analysis on eukaryotic algae and cyanobacteria in nine seasonal lakes and ponds in Vestfjella, Dronning Maud Land, Antarctica. Adv Polar Sci, 2024, 35(2): 206-218, doi: 10.12429/j.advps.2023.0029

(6) Antarctic red algae in dye-sensitized photoelectrochemical cells for water splitting

Phycoerythrin extracted from Antarctic red seaweeds shows promising characteristics to be applied as an anode sensitizer in water-splitting photoelectrochemical cells. Under light irradiation and using an LED lamp, the red-colored protein shows an interesting ability to profit the incident light, as confirmed by the presence of oxygen bubbles next to the electrode surface without applying any external potential. Our results showed that the addition of iodide is helpful to allow the regeneration of the dye; nevertheless, oxygen evolution is not favored. Thermodynamics analysis of the involved semi-reactions is also helpful to understand the observed results. The exploration of Antarctic resources offers then an alternative for the development of green energies, with a particular focus on their use as sensitizers to profit from the sunlight in water-splitting as well as in photovoltaic devices.

Citation: Arispe F, Cerdá M F. Antarctic red algae in dye-sensitized photoelectrochemical cells for water splitting. Adv Polar Sci, 2024, 35(2): 219-227, doi: 10.12429/j.advps.2024.0005

(7) Research and exploration of direct current power supply and distribution systems for Antarctic research stations

The power supply and distribution systems for Antarctic research stations have special characteristics. In light of a worldwide trend toward a gradual increase in the application of renewable energy, an analysis was performed to assess the feasibility of achieving a direct current power supply and distribution at Antarctic research stations by comparing the characteristics of direct current and alternating current electricity. Research was also performed on the status quo and future trends in direct current power supply and distribution systems in Antarctic research stations in combination with case studies.

Citation: Wang L. Research and exploration of direct current power supply and distribution systems for Antarctic research stations. Adv Polar Sci, 2024, 35(2): 228-237, doi: 10.12429/j.advps.2023.0011

(8) Comparison of the precision of glacier flow rates derived from offset-tracking using Sentinel-2 and Landsat-8/9 imagery

This research evaluates the offset-tracking precision of the most popular and free access optical satellites imagery, Sentinel-2 (10 m) and Landsat-8/9 (15 m), for glacier flow rates study. Three typical study sites at Greenland, High-Mountains Asia and Antarctic are selected and 128 acquisitions in summer of 2022 are analyzed. Unlike other studies that mostly evaluate the offset-tracking precision by employing the displacement values at off-glacier regions, this study applied a least square method to evaluate the offset-tracking error on glaciers directly based on the error propagation theory. The result reveals that the RMSE of Sentinel-2 and Landsat-8/9 offset-tracking at off-glacier region ranges from 0.4–1.2 m and 0.8–1.2 m, respectively. Similarly, Sentinel-2 also find slightly higher offset-tracking precision on ice, the RMSEs are 0.4–1.7 m for Sentinel-2 and 1.7–2.9 m for Landsat-8/9. In terms of daily velocity precision, although the repeat cycle of Landsat-8/9 is longer than Sentinel-2, the daily velocity RMSEs are 0.06–0.21 m·d^–1 for Sentinel-2 and 0.16–0.29 m·d^–1 for Landsat-8/9, the former is still 26% better than the latter. The results conclude that benefit by the higher resolution, Sentinel-2 offers higher precision in estimating glacier flow rate time series than Landsat-8/9.

Citation: Yang Z B, Chen Z Q, Li G, et al. Comparison of the precision of glacier flow rates derived from offset-tracking using Sentinel-2 and Landsat-8/9 imagery. Adv Polar Sci, 2024, 35(2): 238-251, doi: 10.12429/j.advps.2023.0019

(9) Methods for ice velocity mapping in West Antarctica using historical optical satellite images

The Antarctic Ice Sheet contains over 90% of the Earth’s ice mass, and has suffered significant losses due to dynamic thinning, especially in the West Antarctica. We utilized declassified and Landsat satellite imagery before 1990, employing normalized-cross-correlation for image matching and an adaptive combination of techniques for hierarchical, constrained measurements to map historical ice velocities in West Antarctica. A comprehensive velocity map covering the coastal regions of the majority of West Antarctica’s large-scale glaciers and ice shelves has been successfully created. Adjustments revealed overestimations in ice velocity measurements over an extended period, leading to the development of a spatially deterministic, temporally averaged ice velocity map. Among the velocity measurements, the Thwaites Glacier showed significant spatial variations in the fastest ice flowlines and velocity distribution. The distribution of overestimations on the Thwaites Glacier corresponded closely with the locations of subsequent calving events at the glacier’s front, providing insights into the instabilities of the ice shelves. Considering the denser set of ice velocity measurements, the ongoing discussion about estimating the ice mass balance prior to 1990 can be informed by the findings of this study, which aids in refining the estimates of ice discharge.

Citation: Zhang Y J, An L, Tang L Y, et al. Methods for ice velocity mapping in West Antarctica using historical optical satellite images. Adv Polar Sci, 2024, 35(2): 252-263, doi: 10.12429/j.advps.2024.0002

(10) Promoting China-U.S. Arctic education cooperation: challenges, opportunities and recommendations

This article discusses the definition and type of Arctic education, and examines international cooperation in higher education from the perspective of international relations theory. It proposes the establishment of new platforms for collaboration, such as the Sino-American Arctic Social Science Forum hosted by Tongji University. It also suggests initiating inter-agency cooperation projects and developing multilateral forms of collaboration. Furthermore, it emphasizes a recommendation for China and the United States to enhance cooperation in Arctic education through a science-based treaty. The document underscores the potential for collaboration in areas of mutual interest, including combating climate change, environmental protection, and related fields, as well as promoting cooperation in establishing a network of young scholars. Additionally, it advocates for an understanding between China and the United States to address the complex situation in the Arctic region. 

Citation: He L, Shan Y Y, Liu F C. Promoting China-U.S. Arctic education cooperation: challenges, opportunities and recommendations. Adv Polar Sci, 2024, 35(2): 264-274, doi: 10.12429/j.advps.2023.0017

(11) Some recent advances in remote sensing-based monitoring of changes in the Greenland Ice Sheet.

This paper reviews recent research in the field of the Greenland Ice Sheet change based on satellite monitoring, introducing the significant contributions in using satellite data for ice sheet mass balance research. By processing historical satellite data from the 1960s to the 1980s, gaps in existing ice velocity maps were filled, providing valuable data for estimating historical mass balance in Greenland. By combining GRACE and GRACE-FO data, the monthly mass balance of the Greenland Ice Sheet from 2002 to 2020 was estimated, revealing a loss of approximately 4443 ±75 Gt during this period. Based on data collected from 2006 to 2020, a more detailed and updated boundary of Greenland’s glaciers was provided, offering critical data support for studying global sea level changes.

Citation: Feng T T, Jia J Y, Wang W, et al. Some recent advances in remote sensing-based monitoring of changes in the Greenland Ice Sheet. Adv Polar Sci, 2024, 35(2): 275-278, doi: 10.12429/j.advps.2023.0033