Investigation of perfluoroalkyl substances in proglacial rivers and permafrost seep in a high Arctic watershed

2022 ◽  
Author(s):  
John MacInnis ◽  
Amila O. De Silva ◽  
Igor Lehnherr ◽  
Derek C. G. Muir ◽  
Kyra A. St. Pierre ◽  
...  
Keyword(s):  
High Arctic ◽  
Perfluoroalkyl Substances ◽  
Ice Melting ◽  
Snow And Ice

We measured perfluoroalkyl substances (PFAS) in proglacial rivers and along a non-glacial freshwater continuum to investigate the role of snow and ice melting in their transport and fate within the Lake Hazen watershed (82° N).

scholarly journals The littoral zone of polar lakes: inshore–offshore contrasts in an ice-covered High Arctic lake

2020 ◽  
pp. 1-24
Author(s):  
Paschale N. Bégin ◽  
Milla Rautio ◽  
Yukiko Tanabe ◽  
Masaki Uchida ◽  
Alexander I. Culley ◽  
...  
Keyword(s):  
Light Availability ◽  
Sharp Decrease ◽  
Open Water ◽  
High Arctic ◽  
Early Summer ◽  
Fatty Acid Profiles ◽  
Canadian High Arctic ◽  
Abrupt Increase ◽  
Horizontal Gradients

In ice-covered polar lakes, a narrow ice-free moat opens up in spring or early summer, and then persists at the edge of the lake until complete ice loss or refreezing. In this study, we analyzed the horizontal gradients in Ward Hunt Lake, located in the Canadian High Arctic, and addressed the hypothesis that the transition from its nearshore open-water moat to offshore ice-covered waters is marked by discontinuous shifts in limnological properties. Consistent with this hypothesis, we observed an abrupt increase in below-ice concentrations of chlorophyll a beyond the ice margin, along with a sharp decrease in temperature and light availability and pronounced changes in benthic algal pigments and fatty acids. There were higher concentrations of rotifers and lower concentrations of viruses at the ice-free sampling sites, and contrasts in zooplankton fatty acid profiles that implied a greater importance of benthic phototrophs in their inshore diet. The observed patterns underscore the structuring role of ice cover in polar lakes. These ecosystems do not conform to the traditional definitions of littoral versus pelagic zones but instead may have distinct moat, ice-margin, and ice-covered zones. This zonation is likely to weaken with ongoing climate change.

scholarly journals The role of moisture transport for precipitation in the inter-annual and inter-daily fluctuations of the Arctic sea ice extension

2019 ◽  
Vol 10 (1) ◽  
pp. 121-133 ◽  
Author(s):  
Luis Gimeno-Sotelo ◽  
Raquel Nieto ◽  
Marta Vázquez ◽  
Luis Gimeno
Keyword(s):  
Sea Ice ◽  
Moisture Transport ◽  
Arctic Region ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Melting ◽  
Sea Ice Extent ◽  
Moisture Sources ◽  
Arctic Sea

Abstract. By considering the moisture transport for precipitation (MTP) for a target region to be the moisture that arrives in this region from its major moisture sources and which then results in precipitation in that region, we explore (i) whether the MTP from the main moisture sources for the Arctic region is linked with inter-annual fluctuations in the extent of Arctic sea ice superimposed on its decline and (ii) the role of extreme MTP events in the inter-daily change in the Arctic sea ice extent (SIE) when extreme MTP simultaneously arrives from the four main moisture regions that supply it. The results suggest (1) that ice melting at the scale of inter-annual fluctuations against the trend is favoured by an increase in moisture transport in summer, autumn, and winter and a decrease in spring and, (2) on a daily basis, extreme humidity transport increases the formation of ice in winter and decreases it in spring, summer, and autumn; in these three seasons extreme humidity transport therefore contributes to Arctic sea ice melting. These patterns differ sharply from that linked to the decline on a long-range scale, especially in summer when the opposite trend applies, as ice melt is favoured by a decrease in moisture transport for this season at this scale.

scholarly journals On the Disintegration of Ice Shelves: the Role of Thinning

1982 ◽  
Vol 3 ◽  
pp. 146-151 ◽  
Author(s):  
T. J. Hughes
Keyword(s):  
Weak Links ◽  
Ice Melting ◽  
Ice Shelf ◽  
Ice Streams ◽  
Ice Shelves ◽  
Ross Ice Shelf ◽  
Tidal Pumping ◽  
Grounding Line ◽  
Converging Flow

It is proposed that an ice shelf disintegrates when its calving front retreats faster than its grounding line. This paper examines the role of ice thinning in grounding-line retreat. Thinning occurs as a result of creep spreading and ice melting. Thinning by creep is examined for the general regime of bending converging flow in an ice shelf lying in a confined embayment, and at the grounding lines of ice streams that supply the ice shelf and ice rises where the ice shelf is grounded on bedrock. Thinning by melting is examined at these grounding lines for tidal pumping and for descent of surface melt water into strandline crevasses, where concentrated melting is focused at the supposed weak links that connect the ice shelf to its embayment, its ice streams, and its ice rises. Applications are made to the Ross Ice Shelf.

Emerging investigator series: a 14-year depositional ice record of perfluoroalkyl substances in the High Arctic

2017 ◽  
Vol 19 (1) ◽  
pp. 22-30 ◽  
Author(s):  
John J. MacInnis ◽  
Katherine French ◽  
Derek C. G. Muir ◽  
Christine Spencer ◽  
Alison Criscitiello ◽  
...  
Keyword(s):  
High Arctic ◽  
Perfluoroalkyl Substances ◽  
Ice Cap

Detection of perfluoroalkyl substances from a remote ice cap indicate the importance of indirect and novel direct atmospheric sources.

scholarly journals Seasonality of halogen deposition in polar snow and ice

2014 ◽  
Vol 14 (6) ◽  
pp. 8185-8207 ◽  
Author(s):  
A. Spolaor ◽  
P. Vallelonga ◽  
J. Gabrieli ◽  
T. Martma ◽  
M. P. Björkman ◽  
...  
Keyword(s):  
Sea Ice ◽  
Atmospheric Chemistry ◽  
Salt Content ◽  
The Arctic ◽  
First Year ◽  
Polar Regions ◽  
Biological Communities ◽  
Polar Snow ◽  
Snow And Ice

Abstract. The atmospheric chemistry of iodine and bromine in polar regions is of interest due to the key role of halogens in many atmospheric processes, particularly tropospheric ozone destruction. Bromine is emitted from the open ocean but is enriched above first-year sea ice during springtime bromine explosion events, whereas iodine is emitted from biological communities hosted by sea ice. It has been previously demonstrated that bromine and iodine are present in Antarctic ice over glacial-interglacial cycles. Here we investigate seasonal variability of bromine and iodine in polar snow and ice, to evaluate their emission, transport and deposition in Antarctica and the Arctic and better understand potential links to sea ice. We find that bromine enrichment (relative to sea salt content) and iodine concentrations in polar ice do vary seasonally in Arctic snow and Antarctic ice and we relate such variability to satellite-based observations of tropospheric halogen concentrations. Peaks of bromine enrichment in Arctic snow and Antarctic ice occur in spring and summer, when sunlight is present. Iodine concentrations are largest in winter Antarctic ice strata, contrary to contemporary observations of summer maxima in iodine emissions.

scholarly journals Short–Lived Damming of a High–Arctic Ice–Marginal Stream, Ellesmere Island, N.W.T., Canada

1980 ◽  
Vol 25 (93) ◽  
pp. 487-491 ◽  
Author(s):  
C.K. Ballantyne ◽  
S.B McGann
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
Discharge Pattern ◽  
Diurnal Pattern ◽  
Flood Events ◽  
High Discharge ◽  
Discharge Fluctuations ◽  
Arctic Ice ◽  
Snow And Ice

Abstract The discharge pattern of the “Schei River”, which drains a 91.2 km2 partly glacierized catchment on Ellesmere Island, is dominated by diurnal oscillations reflecting variations in the melt rate of snow and ice in the basin. Superimposed on this diurnal pattern are numerous short–lived discharge fluctuations of irregular periodicity and magnitude. The characteristics of such irregular fluctuations are described and attributed to periodic collapse of the glacier margin and concomitant damming of the main tributary of the “Schei River”. Collapse is initiated by the river undercutting the ice margin, and tends to be most frequent in the latter part of the flow season during periods of high discharge. Release of ponded water following the collapse of such ice dams may engender significant flood events.

Pregnancy exposure to perfluoroalkyl substances, prolactin concentrations and breastfeeding in the Odense Child Cohort

2021 ◽  
Author(s):  
Clara Amalie Gade Timmermann ◽  
Marianne Skovsager Andersen ◽  
Esben Budtz-Jørgensen ◽  
Henriette Boye ◽  
Flemming Nielsen ◽  
...  
Keyword(s):  
Cell Phone ◽  
Potential Role ◽  
Text Messages ◽  
Perfluoroalkyl Substances ◽  
Serum Prolactin ◽  
Public Health Importance ◽  
Increased Risk ◽  
Duration Of Breastfeeding

Abstract Context Human exposure to perfluoroalkyl substances (PFAS) has been associated with reduced duration of breastfeeding, though not consistently so, and mechanisms by which PFAS might affect breastfeeding are unknown. Objective To examine the association between early pregnancy serum-PFAS concentrations and breastfeeding termination and elucidate the potential role of serum-prolactin concentrations in pregnancy. Materials and methods Pregnant women from the Odense Child Cohort provided blood samples for analysis of five major PFAS (n=1300) and prolactin concentrations (n=924). They subsequently provided information about the duration of breastfeeding in questionnaires at three and eighteen months postpartum, and a subgroup also provided breastfeeding information via weekly cell phone text messages. Associations between serum-PFAS concentrations and breastfeeding termination were analyzed using Cox regressions, while linear regression was used to assess associations between serum-PFAS and prolactin concentrations. Results Increased serum concentrations of PFOS, PFOA, PFNA and ∑PFAS were associated with a 16% (95% CI: 4-30%), 14% (95% CI: 2-26%), 14% (95% CI: 3-27%), and 20% (95% CI: 6-36%), respectively, increased risk of terminating breastfeeding at any given time after childbirth. Serum-PFAS concentrations were not associated with serum-prolactin concentrations. Conclusions These findings are of public health importance due to the global exposures to PFAS. Because breastfeeding is crucial to promote both child health and maternal health, adverse PFAS effects on the ability to breastfeed may have long-term health consequences.

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