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To explore the possibility of using ground ice archives for studies of the cosmogenic radionuclide 10Be, we analyzed the beryllium isotopes in ice wedges exposed in the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel and the Barrow Permafrost Tunnel in Alaska. We determined the concentrations of 10Be and 9Be in samples pretreated following two procedures: acidification before (procedure A) and after (procedure B) removal of particles. The 10Be and 9Be concentrations spanned wide ranges. Concentrations in procedure A samples were higher than those in procedure B samples. The 10Be/9Be ratios fell within a narrow range, and values from CRREL (about 8.5 × 10−9) and Barrow (about 7 × 10−9) were of the same order of magnitude. Further studies are needed to validate our findings and assess the feasibility of using the 10Be/9Be ratio of syngenetic ice wedges for reconstruction of 10Be variations due to cosmogenic and environmental changes, and radiometric dating of ice-wedge sequences that contain very old (beyond 1 Ma) ice.

For atmospheric gases and aerosols, snow and ice provide a useful archive of paleoenvironmental history. In the northern hemisphere, this archive has been largely limited to Greenland ice, but promising pioneering work has been done recently using chronology of an ice wedge in Barrow, northern Alaska. Here, we investigate past aerosols at the same ice-wedge sampling site, reconstructing the sea-ice fluctuations in the adjacent Beaufort Sea during the Bolling/Allerod (BA) and Younger Dryas (YD) periods. We confirm the integrity of methanesulfonate ion (MS−) concentrations in the BIWS as marine proxies, and then find that the ice wedge has a high MS− concentration through the beginning (coldest) YD periods. The high MS− concentration indicates that even during the coldest YD periods (12,900–12,700 yrBP), the near-shore region in the Alaskan Beaufort Sea near Barrow may not have been completely filled by permanent sea ice.

Objectives Bacteria harbouring antimicrobial resistance genes (ARGs) have been isolated from various locations, including ancient microbiomes, indicating that these genes pre-date the discovery of antibiotics. To gain further information regarding ARGs in the pre-antibiotic era, ice samples derived from Dome Fuji Station, Eastern Antarctica, were examined. Methods DNA was extracted from firn or ice core samples (n = 3; 1200–1400 ybp, 1700–2100 ybp and 2200–2800 ybp, respectively) under sterile conditions. Whole-genome amplification and PCR analyses were utilised to detect ARGs. Results A 2764-bp gene cluster containing the type II dihydropteroate synthase gene sul2 and the aminoglycoside phosphotransferase genes strA and strB was detected in the 1200–1400-year-old Antarctic ice core (DF-63.5). The sul2–strA–strB gene cluster is frequently associated with plasmid RSF1010 and transposon Tn5393; however, these elements were not detected in sample DF-63.5. The gene cluster exhibited a high level of sequence identity to sequences harboured in present-day bacteria, although there were sequence polymorphisms in the strA gene. Furthermore, expression of this gene cluster in Escherichia coli resulted in reduced susceptibility to dihydrostreptomycin and sulfamethoxazole. Conclusion The results of this study provide further evidence that certain ARGs existed in the pre-antibiotic era. Because the sul2 gene confers resistance to the synthetic compound sulfamethoxazole, these findings suggest that ARGs against synthetic antimicrobials emerged in bacteria during the pre-antibiotic era.

We provide continuous records of biomass burning molecular tracers (levoglucosan and dehydroabietic acid) in a Greenland ice core collected from the Southeastern Dome (the SE-Dome ice core) over the past several decades to assess the paleoclimatic utility of these tracers in Greenland ice cores. An air mass backward-trajectory analysis indicates that eastern Canada is likely the primary source region of the biomass burning tracers. Comparisons of levoglucosan and dehydroabietic acid data in the SE-Dome ice core and area burned (vegetation fire) events in Canada suggests that the biomass burning tracers in the ice core document most of the pronounced biomass burning events in eastern Canada over the past several decades, confirming that analyses of biomass burning molecular tracers in Greenland ice cores are useful to reconstruct the frequency of significant biomass burning events in a local region. However, our study also highlights that the wind pattern when the biomass burning occurs is decisive for the registration of a biomass burning event in an ice core even though long-term changes in the wind regime associated with decadal-scale climate oscillations do not significantly influence the transport and deposition of biomass burning tracers on the Greenland ice sheet.

129I in natural archives, such as ice cores, can be used as a proxy for human nuclear activities, age marker, and environmental tracer. Currently, there is only one published record of 129I in ice core (i.e., from Fiescherhorn Glacier, Swiss Alps) and its limited time resolution (1–2 years) prevents the full use of 129I for the mentioned applications. Here we show 129I concentrations in an ice core from SE-Dome, Greenland, covering years 1956–1976 at a time resolution of ∼6 months, the most detailed record to date. Results revealed 129I bomb peaks in years 1959, 1962, and 1963, associated to tests performed by the former Soviet Union, one year prior, in its Novaya Zemlya test site. All 129I bomb peaks were observed in winter (1958.9, 1962.1, and 1963.0), while tritium bomb peaks, another prominent radionuclide associated with nuclear bomb testing, were observed in spring or summer (1959.3, and 1963.6; Iizuka et al., 2017). These results indicate that 129I bomb peaks can be used as annual and seasonal age markers for these years. Furthermore, we found that 129I recorded nuclear fuel reprocessing signals and that these can be potentially used to correct timing of estimated 129I releases during years 1964–1976. Comparisons with other published records of 129I in natural archives showed that 129I can be used as common age marker and tracer for different types of records. Most notably, the 1963 129I bomb peak can be used as common age marker for ice and coral cores, providing the means to reconcile age models and associated trends from the polar and tropical regions, respectively.

Environments along the coast of Greenland are rapidly changing under the influence of a warming climate in the Arctic. To better understand the changes in the coastal environments, we performed researches in the Qaanaaq region in northwestern Greenland as a part of the ArCS (Arctic Challenge for Sustainability) Project. Mass loss of ice caps and marine-terminating outlet glaciers were quantified by field and satellite observations. Measurements and sampling in fjords revealed the important role of glacial meltwater discharge in marine ecosystems. Flooding of a glacial stream in Qaanaaq and landslides in a nearby settlement were investigated to identify the drivers of the incidents. Our study observed rapid changes in the coastal environments, and their critical impact on the society in Qaanaaq. We organized workshops with the residents to absorb local and indigenous knowledge, as well as to share the results and data obtained in the project. Continuous effort towards obtaining long-term observations requiring involvement of local communities is crucial to contribute to a sustainable future in Greenland.

Major ions, stable oxygen isotopes (δ 18 O), and accumulation rates are analyzed using high temporal resolution data from shallow ice cores and snow pits from East and West Antarctica. Seasonal cycles of major ions and δ 18 O are well preserved at sites with an accumulation rate threshold of >100 kg m −2 a −1 and calm wind conditions. The seasonal cycle is unclear at sites with high wind speeds, even if the accumulation rate is greater than the threshold. To eliminate the influences of different source regions on major ion and δ 18 O signals in ice cores, we calculate correlation coefficients between annually averaged major ion concentrations and δ 18 O, and then compare these with accumulation rates and other geographical variables such as latitude, elevation, and distance from the coast. We find that accumulation rates are highly correlated with elevation and the 10-m snow temperature, and that major ions and δ 18 O are negatively correlated at low accumulation sites in inland Antarctica. Negative correlations could reflect inconsistent accumulation due to a large inter-annual variability in the accumulation rate. The results show that the relationships between major ions and δ 18 O may not reflect climatic signatures, and could be a result of the unique characteristics of this arid environment.

We analyze snow-pit samples collected in May 2015 at the South East Dome (SE Dome) on the Greenland ice sheet. The analysis includes high-resolution records of δD and δ18O, as well as the major ions, CH3SO3−, Cl−, NO3−, SO42−, Na+, NH4+, K+, Ma2+, and Ca2+. We find that the 3.55-m snow pit recorded temperature and aerosol proxies back to summer or autumn of 2014. This indicates a higher accumulation rate than those at other major drilling sites in Greenland. Due to this high accumulation rate, ion concentrations except Na+ are lower than those typical of the central Greenland ice sheet. Concerning seasonal variability, the Na+, Cl−, Ca2+, Mg2+, and NO3− vary similarly to other sites in Greenland, with the Na+ and Cl− peaking in winter to early spring, Ca2+ peaking in spring, Mg2+ peaking in winter to spring, and NO3− towards a peak in summer while showing smaller peaks in winter to spring. The NH4+ increased in spring, and SO42− increased in autumn to winter at SE Dome. On the other hand, the seasonal trend in the Cl−/Na+ ratio differs from those in the inland region. As we did not fully recover one seasonal cycle, some seasonal peaks may have been missed.

Water-soluble trace constituents affect the physicochemical properties of polar ice. Their structural distribution provides important insights into the formation history of ice and inclusions. We report the first finding of KAl(SO 4 ) 2 ·12H 2 O (potassium alum) and Al 2 (SO 4 ) 3 · n H 2 O (aluminum sulfate) micro-inclusions in the Dome Fuji ice core, East Antartica, using a micro-Raman technique. Eutectic temperatures of these water-soluble species determined using thermal analysis were −0.4 °C for potassium alum and −8.0 °C for aluminum sulfate. Although the formation process of the aluminum-bearing sulfates remains unclear, the occurrence of these salts largely depends on ice depth.

A new interpretation of the data from Sweeping-TXRF (total reflection X-ray fluorescence) was proposed for the analysis of semiconductor contamination. Formerly, we focused on the accumulated spectrum that represents average concentration. In the proposed method, the individual spectra are also utilized to obtain rough mapping information for the entire wafer surface. Although the individual integration time of measurement is very short (4–8 s/spot), a limit of detection at the level of 10 10 atoms cm −2 is maintained for each spot. This method was used to analyze actual wafers that had particulate contaminants on them, and the capability of particle detection was demonstrated. In addition, this method simultaneously gives the average concentration by using the accumulated spectrum, as reported before. Dedicated software for Sweeping-TXRF is under development and has already achieved a throughput of ca. 30 min for 200-mm wafers and ca. 50 min for 300-mm wafers.

Characteristics of myeloma protein can be best detected through serum electrophoresis, and are also detected as abnormal results of flocculation tests or hyperglobulinemia by routine laboratory work. The authors identified 38 cases of multiple myeloma in 5 years, actively making use of the available informations in the laboratory. The number screened was 7 times as many as the incidence previously observed, and most of them were screened in subclinical conditions. A formula to discriminate multiple myeloma from other diseases was obtained referring to the thymol turbidity test (TTT) and zinc sulfate turbidity test (ZTT) results through analytical processing the data from the first examination of the 38 patients. The most efficient and practical screening method for multiple myeloma was then developed by combining the formula by which suspicious serum specimens in routine tests are screened, with electrophoresis which confirms the disease.