Extreme levels of fallout radionuclides and other contaminants in glacial sediment (cryoconite) and implications for downstream aquatic ecosystems

Owens, Philip N.; Blake, William H.; Millward, Geoffrey

doi:10.1038/s41598-019-48873-z

Cited by 39 publications

(32 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reported activity levels in this study are extremely high and comparable to soil samples from nuclear incident and explosion sites (Steinhauser et al, 2014;Abella et al, 2019). Subsequent studies, carried out in different regions of the global cryosphere (Alps, Caucasus, Svalbard and Canada), corroborated the ability of cryoconite to accumulate radionuclides (Baccolo et al, 2017;Łokas et al, 2016Owens et al, 2019), with radioecological consequences concerning the presence of FRNs that extend to the proglacial areas (Łokas et al, 2017;Owens et al, 2019). In addition to FRNs, cryoconite has also been shown to accumulate other anthropogenic contaminants including heavy metals (Nagatsuka et al, 2010;Łokas et al, 2016;Baccolo et al, 2017;Singh et al, 2017;Huang et al, 2019), artificial organic compounds (Ferrario et al, 2017;Weiland-Bräuer et al, 2017) and microplastics (Ambrosini et al, 2019).…”

Section: Introductionsupporting

confidence: 74%

“…The formation of cryoconite holes is attributable to the dark color, and thus low albedo, of cryoconite, which enhances the absorption of solar radiation and locally increases ice melting to foster the development of holes in the ice surface. Due to its contribution to ice melting, its diverse composition and the role in biodiversity, cryoconite has been studied by a range of disciplines, including glaciology, microbiology, biogeochemistry and ecology (Takeuchi et al, 2001;Langford et al, 2010;Cook et al, 2015;Ferrario et al, 2017;Pittino et al, 2018a). More recently cryoconite has been the subject of renewed interest due to its ability to accumulate specific substances, including anthropogenic contaminants (Pittino et al, 2018b).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cryoconite: an efficient accumulator of radioactive fallout in glacial environments

et al. 2020

View full text Add to dashboard Cite

Abstract. Cryoconite is rich in natural and artificial radioactivity, but a discussion about its ability to accumulate radionuclides is lacking. A characterization of cryoconite from two Alpine glaciers is presented here. Results confirm that cryoconite is significantly more radioactive than the matrices usually adopted for the environmental monitoring of radioactivity, such as lichens and mosses, with activity concentrations exceeding 10 000 Bq kg−1 for single radionuclides. This makes cryoconite an ideal matrix to investigate the deposition and occurrence of radioactive species in glacial environments. In addition, cryoconite can be used to track environmental radioactivity sources. We have exploited atomic and activity ratios of artificial radionuclides to identify the sources of the anthropogenic radioactivity accumulated in our samples. The signature of cryoconite from different Alpine glaciers is compatible with the stratospheric global fallout and Chernobyl accident products. Differences are found when considering other geographic contexts. A comparison with data from literature shows that Alpine cryoconite is strongly influenced by the Chernobyl fallout, while cryoconite from other regions is more impacted by events such as nuclear test explosions and satellite reentries. To explain the accumulation of radionuclides in cryoconite, the glacial environment as a whole must be considered, and particularly the interaction between ice, meltwater, cryoconite and atmospheric deposition. We hypothesize that the impurities originally preserved into ice and mobilized with meltwater during summer, including radionuclides, are accumulated in cryoconite because of their affinity for organic matter, which is abundant in cryoconite. In relation to these processes, we have explored the possibility of exploiting radioactivity to date cryoconite.

show abstract

Section: Introductionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Cryoconite: an efficient accumulator of radioactive fallout in glacial environments

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Besides living organisms, cryoconite is known to concentrate pollutants such as contaminants and radionuclides 11,12 . This may represent a problem in the future, with a possible secondary release of these substances to the environment 13,14 .Cryoconite accumulated in cryoconite holes has a limited impact on glacier and ice sheet surface mass balance. Instead, the presence of distributed organic material on the margin of ice sheets recently motivated the formalization of the concept of "bioalbedo feedback" 15-17 .…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Glacier algae foster ice-albedo feedback in the European Alps

Mauro

Garzonio

Baccolo

et al. 2020

Sci Rep

View full text Add to dashboard Cite

the melting of glaciers and ice sheets is nowadays considered a symbol of climate change. Many complex mechanisms are involved in the melting of ice, and, among these processes, surface darkening due to organic material on bare ice has recently received attention from the scientific community. The presence of microbes on glaciers has been shown to decrease the albedo of ice and promote melting.Despite several studies from the Himalaya, Greenland, Andes, and Alaska, no quantitative studies have yet been conducted in the european Alps. in this paper, we made use of DnA sequencing, microscopy and field spectroscopy to describe the nature of glacier algae found at a glacier (Vadret da Morteratsch) of the European Alps and to evaluate their effect on the ice-albedo feedback. Among different algal species identified in the samples, we found a remarkable abundance of Ancylonema nordenskioeldii, a species that has never previously been quantitatively documented in the Alps and that dominates algal blooms on the Greenland ice Sheet. our results show that, at the end of the ablation season, the concentration of Ancylonema nordenskioeldii on the glacier surface is higher than that of other algal species (i.e. Mesotaenium berggrenii). Using field spectroscopy data, we identified a significant correlation between a reflectance ratio (750 nm/650 nm) and the algae concentration. This reflectance ratio could be useful for future mapping of glacier algae from remote sensing data exploiting band 6 (740 nm) and band 4 (665 nm) of the MultiSpectral Instrument (MSI) on board Sentinel-2 satellite. Here we show that the biological darkening of glaciers (i.e. the bioalbedo feedback) is also occurring in the european Alps, and thus it is a global process that must be taken into account when considering the positive feedback mechanisms related to glacier melting.Glaciers and ice sheets are not lifeless 1 . It has been demonstrated that several species of microorganisms, algae and small arthropods find their optimal environment on melting ice and snow. These organisms are also able to shape their environment, through a feedback cycle that involves the albedo. In fact, since these organisms are darker than snow and ice, their presence increases the light absorption and promotes the melting of underlying snow or ice 2-4 . On the surface of glaciers, such extremophiles often aggregate with inorganic material (i.e. mineral dust) to form cryoconite 5,6 . Cryoconite is a dark sediment 5,7 that increases the absorption of visible radiation 4,8 , and promotes the formation of characteristic cryoconite holes 9 which are globally recognized as an hot spot of biodiversity on ice 10 . Besides living organisms, cryoconite is known to concentrate pollutants such as contaminants and radionuclides 11,12 . This may represent a problem in the future, with a possible secondary release of these substances to the environment 13,14 .Cryoconite accumulated in cryoconite holes has a limited impact on glacier and ice sheet surface mass balance. Instead, the presen...

show abstract

“…After being accumulated at the surface of glaciers, cryoconite and its radioactive content are released by glaciers in association with meltwater. Preliminary results have shown that a fraction of cryoconite radioactivity is accumulated in proglacial areas, and pose a risk of potential ecological impacts (Łokas et al, 2014,2017Owens et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics

Baccolo¹,

Nastasi²,

Massabò³

et al. 2019

Preprint

View full text Add to dashboard Cite

Cryoconite, a sediment found on the surface of glaciers, is known for its ability to accumulate radionuclides. New data on cryoconite from the Morteratsch glacier (Switzerland) are presented with the aim to shed light on the mechanisms that control the distribution of radioactivity in cryoconite. Among the many radionuclides detected in our samples, we have identified 108mAg, an artificial species which has never been observed in terrestrial environments before. This finding supports that cryoconite has an extraordinary ability to accumulate radioactivity. Our results also show that the radioactivity of cryoconite is far from uniform. Both the absolute amount of radioactivity and the relative contribution of single radionuclides is highly variable in samples from the Morteratsch glacier. To investigate the processes responsible for such variability, we have explored the correlation between radionuclides, organic and inorganic carbon fractions and the morphological features of cryoconite deposits. We have found that the degree to cryoconite is connected with supraglacial hydrology is particularly important, since it strongly influences the accumulation of radionuclides in cryoconite. Cryoconite holes connected with supraglacial channels is rich in cosmogenic 7Be; in contrast, poorly connected deposits are rich in artificial fallout radionuclides and elemental carbon. The very different half-lives of 7Be and artificial radionuclides allowed us to discuss our findings in relation to the age and maturity of cryoconite deposits, highlighting the potential use of radionuclides to investigate hydrological supraglacial processes and material cycling at the surface of glaciers.

show abstract

Extreme levels of fallout radionuclides and other contaminants in glacial sediment (cryoconite) and implications for downstream aquatic ecosystems

Cited by 39 publications

References 26 publications

Cryoconite: an efficient accumulator of radioactive fallout in glacial environments

Cryoconite: an efficient accumulator of radioactive fallout in glacial environments

Glacier algae foster ice-albedo feedback in the European Alps

Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics

Contact Info

Product

Resources

About