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The long-term refrigerated storage of melted snow and/or ice samples for analyses of insoluble microparticles (hereafter, microparticles) may be limited by increases in the biological particle concentration caused by microbial growth after ~1–2 weeks. In this study, we examined an ultraviolet (UV) disinfection method for the storage of melted snow and/or ice samples and determined the effects of this method on microparticles. Surface snow obtained from Glacier No. 31 in the Suntar-Khayata Range, eastern Siberia, Russia was divided into two portions for UV treatment and untreated controls. Microparticle concentrations and size distributions (in the range of 0.52–12.0 μm) in the samples were measured using a Coulter counter. Whereas the microparticle concentration in untreated samples increased, no obvious increase was observed over 53 d in the samples subjected to UV treatment. Microbial growth was detected in only untreated samples using a viable particle counter. In addition, the original microparticle concentrations and size distributions were unaffected by UV treatment. Our results demonstrated that the microparticle size distribution in untreated melted water samples reflects the growth, decomposition and succession of microorganisms over time and further indicate that UV irradiation is effective for long-term storage for microparticle analysis.
Fumio Nakazawa; Kumiko Goto-Azuma. Ultraviolet germicidal irradiation of melted snow and ice samples: inactivation of microorganisms and effects on insoluble microparticles. Journal of Glaciology 2021, 1 -8.
AMA StyleFumio Nakazawa, Kumiko Goto-Azuma. Ultraviolet germicidal irradiation of melted snow and ice samples: inactivation of microorganisms and effects on insoluble microparticles. Journal of Glaciology. 2021; ():1-8.
Chicago/Turabian StyleFumio Nakazawa; Kumiko Goto-Azuma. 2021. "Ultraviolet germicidal irradiation of melted snow and ice samples: inactivation of microorganisms and effects on insoluble microparticles." Journal of Glaciology , no. : 1-8.
We collected snow samples from two pits with depths of 4.02 and 3.18 m at the East Greenland Ice Core Project camp (75°37′N, 35°59′W), Greenland in the summer of 2016 to estimate recent annual snow deposition and examine seasonal variation in major ion species, stable isotopes of water and microparticles (dust). Dating based on clear seasonal variation in chemical components indicated that the 4.02- and 3.18-m-deep pits included snow deposition corresponding to ten years from 2006 to 2016 and seven years from 2009 to 2016, respectively. The mean values for annual snow deposition for the 4.02-m-deep pit were 138 and 145 mm yr−1 in water equivalent (mm w.e. Yr−1) in 2006–2016 and 2009–2016, respectively. The average deposition for the 3.18-m-deep pit was 149 mm w.e. Yr−1 between 2009 and 2016. Seasonal variation in concentrations of major ion species and dust were similar to those previously reported for Greenland. The maximum Cl−/Na+ concentration ratios in the summer were much higher than the ratios at other sites in Greenland.
Fumio Nakazawa; Naoko Nagatsuka; Motohiro Hirabayashi; Kumiko Goto-Azuma; Jørgen Peder Steffensen; Dorthe Dahl-Jensen. Variation in recent annual snow deposition and seasonality of snow chemistry at the east Greenland ice core project (EGRIP) camp, Greenland. Polar Science 2020, 27, 100597 .
AMA StyleFumio Nakazawa, Naoko Nagatsuka, Motohiro Hirabayashi, Kumiko Goto-Azuma, Jørgen Peder Steffensen, Dorthe Dahl-Jensen. Variation in recent annual snow deposition and seasonality of snow chemistry at the east Greenland ice core project (EGRIP) camp, Greenland. Polar Science. 2020; 27 ():100597.
Chicago/Turabian StyleFumio Nakazawa; Naoko Nagatsuka; Motohiro Hirabayashi; Kumiko Goto-Azuma; Jørgen Peder Steffensen; Dorthe Dahl-Jensen. 2020. "Variation in recent annual snow deposition and seasonality of snow chemistry at the east Greenland ice core project (EGRIP) camp, Greenland." Polar Science 27, no. : 100597.
Temporal variability in surface mass balance (SMB) on the Greenland ice sheet is important for understanding the mass balance of the ice sheet. Additionally, knowledge of the spatial variability in SMB at ice core drilling sites helps to interpret the spatial representativeness of SMB data obtained from a single ice core. In this study, to investigate the spatiotemporal variability in recent SMB in the East Greenland Ice Core Project (EGRIP) area in the northeastern Greenland ice sheet, pit observations were made at six sites in the summers of 2016–2018. In all pits, depth profiles of water isotope ratios showed clear seasonal variations. The annual SMB differed from site to site, which is probably due to post-depositional redistribution of snow caused by wind erosion and snowdrift. However, the multiple-site averages of annual SMBs, which ranged from 134 to 157 mm w. e. yr−1 (average 146 mm w. e. yr−1) during 2009–2017, were very similar. This indicates that annual SMBs in the EGRIP area were nearly constant in this period. The seasonal SMBs in the EGRIP area tended to be larger in the summer–winter period than in the winter–summer period.
Yuki Komuro; Fumio Nakazawa; Motohiro Hirabayashi; Kumiko Goto-Azuma; Naoko Nagatsuka; Wataru Shigeyama; Sumito Matoba; Tomoyuki Homma; Jørgen Peder Steffensen; Dorthe Dahl-Jensen. Temporal and spatial variabilities in surface mass balance at the EGRIP site, Greenland from 2009 to 2017. Polar Science 2020, 27, 100568 .
AMA StyleYuki Komuro, Fumio Nakazawa, Motohiro Hirabayashi, Kumiko Goto-Azuma, Naoko Nagatsuka, Wataru Shigeyama, Sumito Matoba, Tomoyuki Homma, Jørgen Peder Steffensen, Dorthe Dahl-Jensen. Temporal and spatial variabilities in surface mass balance at the EGRIP site, Greenland from 2009 to 2017. Polar Science. 2020; 27 ():100568.
Chicago/Turabian StyleYuki Komuro; Fumio Nakazawa; Motohiro Hirabayashi; Kumiko Goto-Azuma; Naoko Nagatsuka; Wataru Shigeyama; Sumito Matoba; Tomoyuki Homma; Jørgen Peder Steffensen; Dorthe Dahl-Jensen. 2020. "Temporal and spatial variabilities in surface mass balance at the EGRIP site, Greenland from 2009 to 2017." Polar Science 27, no. : 100568.
We review major scientific results from Subtheme (1) Variability of the Greenland Ice Sheet and climate under Research Theme 2 Variations in the ice sheet, glaciers, and the environment in the Greenland region of the Arctic Challenge for Sustainability (ArCS) project. We participated in the international East Greenland Ice Core Project (EGRIP) led by Denmark, conducted snow pit observations near the coring site and reconstructed the surface mass balance over the past 10 years. Analyses of an ice core from Northwest Greenland revealed temporal variability in black carbon concentration over the past 350 years and in mineral dust over the past 100 years. To understand the mechanisms of ice-sheet flow, which is necessary for accurate predictions of sea level rise, we conducted laboratory experiments using artificial ice and derived an improved flow law for ice containing impurities. Ice sheet modeling was improved by including effects of impurities and ice stream dynamics. As part of the Ice Sheet Model Intercomparison Project for the Coupled Model Intercomparison Project Phase 6 (ISMIP6), we simulated ice sheet mass loss and contribution to sea level rise over the 21st century and beyond. Furthermore, we developed a Glacial Isostatic Adjustment model to better constrain ice sheet models.
Kumiko Goto-Azuma; Tomoyuki Homma; Tomotaka Saruya; Fumio Nakazawa; Yuki Komuro; Naoko Nagatsuka; Motohiro Hirabayashi; Yutaka Kondo; Makoto Koike; Teruo Aoki; Ralf Greve; Jun'ichi Okuno. Studies on the variability of the Greenland Ice Sheet and climate. Polar Science 2020, 27, 100557 .
AMA StyleKumiko Goto-Azuma, Tomoyuki Homma, Tomotaka Saruya, Fumio Nakazawa, Yuki Komuro, Naoko Nagatsuka, Motohiro Hirabayashi, Yutaka Kondo, Makoto Koike, Teruo Aoki, Ralf Greve, Jun'ichi Okuno. Studies on the variability of the Greenland Ice Sheet and climate. Polar Science. 2020; 27 ():100557.
Chicago/Turabian StyleKumiko Goto-Azuma; Tomoyuki Homma; Tomotaka Saruya; Fumio Nakazawa; Yuki Komuro; Naoko Nagatsuka; Motohiro Hirabayashi; Yutaka Kondo; Makoto Koike; Teruo Aoki; Ralf Greve; Jun'ichi Okuno. 2020. "Studies on the variability of the Greenland Ice Sheet and climate." Polar Science 27, no. : 100557.
Pollen taxa in sediment samples can be identified based on morphology. However, closely related species do not differ substantially in pollen morphology, and accurate identification is generally limited to genera or families. Because many pollen grains in glaciers contain protoplasm, genetic information obtained from pollen grains should enable the identification of plant taxa at the species level. In the present study, species identification of Pinus pollen grains was attempted using whole-genome amplification (WGA). We used pollen grains extracted from surface snow (depth, 1.8–1.9 m) from the Belukha glacier in the summer of 2003. WGA was performed using a single pollen grain. Some regions of the chloroplast genome were amplified by PCR, and the DNA products were sequenced to identify the pollen grain. Pinus includes approximately 111 recognized species in two subgenera, four sections, and 11 subsections. The tree species Pinus sibirica and P. sylvestris are currently found at the periphery of the glacier. We identified the pollen grains from the Belukha glacier to the level of section or subsection to which P. sibirica and P. sylvestris belong. Moreover, we specifically identified two pollen grains as P. sibirica or P. cembra. Fifteen species, including P. sibirica, were candidates for the remaining pollen grain.
Fumio Nakazawa; Yoshihisa Suyama; Satoshi Imura; Hideaki Motoyama. Species Identification of Pinus Pollen Found in Belukha Glacier, Russian Altai Mountains, Using a Whole-Genome Amplification Method. Forests 2018, 9, 444 .
AMA StyleFumio Nakazawa, Yoshihisa Suyama, Satoshi Imura, Hideaki Motoyama. Species Identification of Pinus Pollen Found in Belukha Glacier, Russian Altai Mountains, Using a Whole-Genome Amplification Method. Forests. 2018; 9 (8):444.
Chicago/Turabian StyleFumio Nakazawa; Yoshihisa Suyama; Satoshi Imura; Hideaki Motoyama. 2018. "Species Identification of Pinus Pollen Found in Belukha Glacier, Russian Altai Mountains, Using a Whole-Genome Amplification Method." Forests 9, no. 8: 444.
This paper outlines meteorological and glaciological observations of Glacier No. 31 in the Suntar-Khayata Range, east Siberia, obtained from 2012 to 2014. We set up meteorological instruments and seven stakes on the glacier for the purpose of measuring surface mass balance and flow velocity. The mean air temperature between July 8, 2012 and August 7, 2013 was -13.9°C at site 31-2 (2446m a.s.l.) and the minimum temperature was -46.0°C. The air temperature on the glacier from November to April was approximately 10°C higher than that at Oymyakon village, suggesting a temperature inversion phenomenon, which typically occurs during winter in this region. The snow depth records show that snow increased at the beginning and end of winter, and that there was almost no change from the beginning of October until the end of April. The maximum snow depth from the previous summer was 158cm at site 31-2 on May 28, 2013. The average annual surface mass balance for the 6sites was -1256mm water equivalent (w.e.) during the period from August 24, 2012 to August 16, 2013, indicating that ablation proceeded rapidly in all areas of the glacier. Surface flow velocity in 2013/2014 was 1.57ma−1 at the approximate midpoint of the glacier, and was much slower than that measured during the IGY (International Geophysical Year) period (4.5ma−1) in 1957/1958. The length and areal extent of the glacier were 3.85km and 3.2km2 in 1958/1959 and 3.38km and 2.27km2 in 2012/2013, respectively, showing a decrease over the last 54years.
Tatsuo Shirakawa; Tsutomu Kadota; Alexander Fedorov; Pavel Konstantinov; Takafumi Suzuki; Hironori Yabuki; Fumio Nakazawa; Sota Tanaka; Masaya Miyairi; Yuta Fujisawa; Nozomu Takeuchi; Ryo Kusaka; Shuhei Takahashi; Hiroyuki Enomoto; Tetsuo Ohata. Meteorological and glaciological observations at Suntar-Khayata Glacier No. 31, east Siberia, from 2012-2014. Bulletin of Glaciological Research 2016, 34, 33 -40.
AMA StyleTatsuo Shirakawa, Tsutomu Kadota, Alexander Fedorov, Pavel Konstantinov, Takafumi Suzuki, Hironori Yabuki, Fumio Nakazawa, Sota Tanaka, Masaya Miyairi, Yuta Fujisawa, Nozomu Takeuchi, Ryo Kusaka, Shuhei Takahashi, Hiroyuki Enomoto, Tetsuo Ohata. Meteorological and glaciological observations at Suntar-Khayata Glacier No. 31, east Siberia, from 2012-2014. Bulletin of Glaciological Research. 2016; 34 ():33-40.
Chicago/Turabian StyleTatsuo Shirakawa; Tsutomu Kadota; Alexander Fedorov; Pavel Konstantinov; Takafumi Suzuki; Hironori Yabuki; Fumio Nakazawa; Sota Tanaka; Masaya Miyairi; Yuta Fujisawa; Nozomu Takeuchi; Ryo Kusaka; Shuhei Takahashi; Hiroyuki Enomoto; Tetsuo Ohata. 2016. "Meteorological and glaciological observations at Suntar-Khayata Glacier No. 31, east Siberia, from 2012-2014." Bulletin of Glaciological Research 34, no. : 33-40.
This study analyzed pollen in snow pits dug in late summer (2008–2011) on the upstream side of Potanin Glacier, a summer accumulation-type glacier in the Mongolian Altai, to reconstruct the recent snow depositional environment, particularly melting conditions. Annual snow pit observations were performed at sites 0 and 4 (3752 and 3890 m a.s.l., respectively). Seasonal layers in the pits were identified according to the presence of pollen from three taxa (Betulaceae, Pinus, and Artemisia), which have different pollen seasons typically between May and early September. The pollen-dating method was successful in snow pits where conventional methods such as ice layer dating and use of δ 18O records were unreliable due to significant melting. Depths of pollen concentration peaks for the three taxa differed annually at both sites. In some years, concentration peaks of the three pollen taxa were found at different depths, but in other years, peaks associated with each taxon were found at the same depth. This difference was explained by summer temperature. Snow melting during the relatively warm summers of 2007 and 2008 caused pollen grains to concentrate on the glacier surface, producing peaks at the same depth. In contrast, snow melting during the relatively cool summer of 2009 did not substantially alter pollen grain location, and each peak thus retained its original depth. The median temperatures in 2010 and 2011 corresponded to pollen concentrating on the glacier surface at site 0 but retaining their original position at site 4.
Fumio Nakazawa; Keiko Konya; Tsutomu Kadota; Tetsuo Ohata. Depositional and summer snow melting features in 2007–2011 on the upstream side of Potanin Glacier, Mongolian Altai, reconstructed by pollen and oxygen isotope analysis. Environmental Earth Sciences 2015, 74, 1851 -1859.
AMA StyleFumio Nakazawa, Keiko Konya, Tsutomu Kadota, Tetsuo Ohata. Depositional and summer snow melting features in 2007–2011 on the upstream side of Potanin Glacier, Mongolian Altai, reconstructed by pollen and oxygen isotope analysis. Environmental Earth Sciences. 2015; 74 (3):1851-1859.
Chicago/Turabian StyleFumio Nakazawa; Keiko Konya; Tsutomu Kadota; Tetsuo Ohata. 2015. "Depositional and summer snow melting features in 2007–2011 on the upstream side of Potanin Glacier, Mongolian Altai, reconstructed by pollen and oxygen isotope analysis." Environmental Earth Sciences 74, no. 3: 1851-1859.
The aim of this study was to estimate the age of glacier ice in the No. 31 Glacier in the Suntar-Khayata Range of eastern Siberia by performing dating of insects thought to be long-legged fly species (Dolichopodidae) as well as plants (species unknown) fragments preserved in the ice. Ice samples containing organisms were collected at depths of 0.4–1.1 m at five points from the middle to lowest parts of the glacier in 2013. The age of an insect collected at the lowest point on the glacier was estimated as 2038 ± 32 yr B.P. Insects collected at higher points had a modern or near-modern radiocarbon age. The age of plant fragments collected at the uppermost and middle points was 1531 ± 44 and 1288 ± 26 yr B.P., respectively, and that of a mixture of plant and insect fragments collected at the lowest point was 9772 ± 42 yr B.P. When comparing specimens collected at the same point, the plant fragments were found to be older than the insects. In 2012–2014 observations, some living insects were found on the glacier, and thus the age of the insects appears to correspond to the age of the ice. On the other hand, the plant fragments might have already aged since detachment from the source plants. This study found an approximately 2000-year gap in the age of the ice between the lowest and higher points. Annual mass balance observations from 2012 to 2014 showed that in recent years, the glacier sometimes had no accumulation area. Therefore, the wide gap in the age of ice may be due to a difference in past melting processes between the lowest and higher points on the glacier.
F. Nakazawa; M. Uchida; M. Kondo; T. Kadota; T. Shirakawa; H. Enomoto; Alexander Fedorov; Y. Fujisawa; P.Y. Konstantinov; R. Kusaka; M. Miyairi; T. Ohata; H. Yabuki. Radiocarbon ages of insects and plants frozen in the No. 31 Glacier, Suntar-Khayata Range, eastern Siberia. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2015, 361, 574 -579.
AMA StyleF. Nakazawa, M. Uchida, M. Kondo, T. Kadota, T. Shirakawa, H. Enomoto, Alexander Fedorov, Y. Fujisawa, P.Y. Konstantinov, R. Kusaka, M. Miyairi, T. Ohata, H. Yabuki. Radiocarbon ages of insects and plants frozen in the No. 31 Glacier, Suntar-Khayata Range, eastern Siberia. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 2015; 361 ():574-579.
Chicago/Turabian StyleF. Nakazawa; M. Uchida; M. Kondo; T. Kadota; T. Shirakawa; H. Enomoto; Alexander Fedorov; Y. Fujisawa; P.Y. Konstantinov; R. Kusaka; M. Miyairi; T. Ohata; H. Yabuki. 2015. "Radiocarbon ages of insects and plants frozen in the No. 31 Glacier, Suntar-Khayata Range, eastern Siberia." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 361, no. : 574-579.
Pollen taxon in sediment samples can be identified by analyzing pollen morphology. Identification of related species based on pollen morphology is difficult and is limited primarily to genus or family. Because pollen grains of various ages are preserved at below 0 °C in glaciers and thus are more likely to remain intact or to suffer little DNA fragmentation, genetic information from such pollen grains should enable identification of plant taxa below the genus level. However, no published studies have attempted detailed identification using DNA sequences obtained from pollen found in glaciers. As a preliminary step, this study attempted to analyze the DNA of Pinus pollen grains extracted from surface snow collected from the Belukha glacier in the Altai Mountains of Russia in the summer of 2003. A 150-bp rpoB fragment from the chloroplast genome in each Pinus pollen grain was amplified by polymerase chain reaction, and DNA products were sequenced to identify them at the section level. A total of 105 pollen grains were used for the test, and sequences were obtained from eight grains. From the sequences obtained, the pollen grains were identified as belonging to the section Quinquefoliae. Trees of the extant species Pinus sibirica in the section Quinquefoliae are currently found surrounding the glacier. The consistency of results for this section suggests that the pollen in the glacier originated from the same Pinus trees as those found in the immediate surroundings.
Fumio Nakazawa; Jun Uetake; Yoshihisa Suyama; Ryo Kaneko; Nozomu Takeuchi; Koji Fujita; Hideaki Motoyama; Satoshi Imura; Hiroshi Kanda. DNA analysis for section identification of individual Pinus pollen grains from Belukha glacier, Altai Mountains, Russia. Environmental Research Letters 2013, 8, 014032 .
AMA StyleFumio Nakazawa, Jun Uetake, Yoshihisa Suyama, Ryo Kaneko, Nozomu Takeuchi, Koji Fujita, Hideaki Motoyama, Satoshi Imura, Hiroshi Kanda. DNA analysis for section identification of individual Pinus pollen grains from Belukha glacier, Altai Mountains, Russia. Environmental Research Letters. 2013; 8 (1):014032.
Chicago/Turabian StyleFumio Nakazawa; Jun Uetake; Yoshihisa Suyama; Ryo Kaneko; Nozomu Takeuchi; Koji Fujita; Hideaki Motoyama; Satoshi Imura; Hiroshi Kanda. 2013. "DNA analysis for section identification of individual Pinus pollen grains from Belukha glacier, Altai Mountains, Russia." Environmental Research Letters 8, no. 1: 014032.
Keiko Konya; Tsutomu Kadota; Fumio Nakazawa; Gombo Davaa; Kalsan Purevdagva; Hironori Yabuki; Tetsuo Ohata. Surface mass balance of the Potanin Glacier in the Mongolian Altai Mountains and comparison with Russian Altai glaciers in 2005, 2008, and 2009. Bulletin of Glaciological Research 2013, 31, 9 -18.
AMA StyleKeiko Konya, Tsutomu Kadota, Fumio Nakazawa, Gombo Davaa, Kalsan Purevdagva, Hironori Yabuki, Tetsuo Ohata. Surface mass balance of the Potanin Glacier in the Mongolian Altai Mountains and comparison with Russian Altai glaciers in 2005, 2008, and 2009. Bulletin of Glaciological Research. 2013; 31 ():9-18.
Chicago/Turabian StyleKeiko Konya; Tsutomu Kadota; Fumio Nakazawa; Gombo Davaa; Kalsan Purevdagva; Hironori Yabuki; Tetsuo Ohata. 2013. "Surface mass balance of the Potanin Glacier in the Mongolian Altai Mountains and comparison with Russian Altai glaciers in 2005, 2008, and 2009." Bulletin of Glaciological Research 31, no. : 9-18.
Fumio Nakazawa; Keiko Konya; Tsutomu Kadota; Tetsuo Ohata. Reconstruction of the depositional environment upstream of Potanin Glacier, Mongolian Altai, from pollen analysis. Environmental Research Letters 2012, 7, 035402 .
AMA StyleFumio Nakazawa, Keiko Konya, Tsutomu Kadota, Tetsuo Ohata. Reconstruction of the depositional environment upstream of Potanin Glacier, Mongolian Altai, from pollen analysis. Environmental Research Letters. 2012; 7 (3):035402.
Chicago/Turabian StyleFumio Nakazawa; Keiko Konya; Tsutomu Kadota; Tetsuo Ohata. 2012. "Reconstruction of the depositional environment upstream of Potanin Glacier, Mongolian Altai, from pollen analysis." Environmental Research Letters 7, no. 3: 035402.
Yeong-Cheol Han; Young-Sook Huh; Sung-Min Hong; Soon-Do Hur; Hideaki Motoyama; Shuji Fujita; Fumio Nakazawa; Kotaro Fukui. Quantification of Total Mercury in Antarctic Surface Snow using ICP-SF-MS: Spatial Variation from the Coast to Dome Fuji. Bulletin of the Korean Chemical Society 2011, 32, 4258 -4264.
AMA StyleYeong-Cheol Han, Young-Sook Huh, Sung-Min Hong, Soon-Do Hur, Hideaki Motoyama, Shuji Fujita, Fumio Nakazawa, Kotaro Fukui. Quantification of Total Mercury in Antarctic Surface Snow using ICP-SF-MS: Spatial Variation from the Coast to Dome Fuji. Bulletin of the Korean Chemical Society. 2011; 32 (12):4258-4264.
Chicago/Turabian StyleYeong-Cheol Han; Young-Sook Huh; Sung-Min Hong; Soon-Do Hur; Hideaki Motoyama; Shuji Fujita; Fumio Nakazawa; Kotaro Fukui. 2011. "Quantification of Total Mercury in Antarctic Surface Snow using ICP-SF-MS: Spatial Variation from the Coast to Dome Fuji." Bulletin of the Korean Chemical Society 32, no. 12: 4258-4264.