Mercury and other elements in landlocked char from East and West Lake, Cape Bounty (Melville Island)

The Cape Bounty Arctic Watershed Observatory (CBAWO) utilizes two adjacent, geologically similar watersheds, West and East, which are currently undergoing climate-driven changes. Climate over the period 2007-12 was unusually warm during summer months and resulted in changing hydrology and permafrost degradation across the area. In addition, the West catchment experienced numerous large active layer detachments during 2007-2008 while the East catchment experienced relatively minor disturbances. These alterations to runoff patterns, erosion and permafrost degradation are also driving changes in biogeochemical cycling. We are investigating whether these changes are also seen in bioaccumulation of mercury (Hg) and other elements, as well as persistent organic pollutants, in arctic char and the food webs of West and East Lakes. We hypothesize that increased erosional inputs into West Lake will result in increasing Hg concentrations in landlocked arctic char (Salvelinus alpinus) and other bioaccumulative elements such as cesium (Cs) and rubidium (Rb). To investigate this arctic char have been collected annually at the end of July, from 2008 to 2019, and analysed for a suite of 34 elements using ICP-MS, and Hg. Carbon (C) and nitrogen (N) stable isotope analysis showed that char have significantly more depleted d13C in East vs West Lake (mean ± SD; -27.26±0.82 % (N=96) vs -24.72±1.10 ‰ (N=101)) indicative of greater terrestrial carbon inputs to West Lake. Also d15N is significantly lower in West Lake char (10.1±0.99 % vs 11.2±0.51%) suggesting differences in food sources. Mean THg concentrations in arctic char from West Lake continue to be significantly greater than those in East Lake except in 2009 when char were feeding on more pelagic carbon. THg in char muscle is mainly (>90%) in the form of MeHg. Mercury has increased in char from West Lake (7.3 %/yr) while declining in East Lake (-5.9%/yr). Cesium increased significantly in char from West Lake (4.8 %/yr) and declined significantly in East Lake (-7.5 %/yr). Rubidium and thallium did not increase in West Lake (1.2 and -1.5 %/yr) but declined significantly in East Lake (-5.1 and -8.4 %/yr) while selenium showed no time trend but has been consistently higher in East Lake char unlike most other elements. Arsenic, potassium, and zinc were present at similar concentrations in char in both lakes throughout the study period with no clear trends.

Identifier
Source https://www.polardata.ca/pdcsearch/PDCSearchDOI.jsp?doi_id=11595
Metadata Access http://www.polardata.ca/oai/provider?verb=GetRecord&metadataPrefix=fgdc&identifier=11595_fgdc
Provenance
Creator Muir, Derek; Barst, Ben; Burke, Samantha; Cabrerizo, Ana; Kirk, Jane; Lamoureux, Scott
Publisher Canadian Cryospheric Information Network
Contributor Polar Data Catalogue
Publication Year 2020
Rights Research programs, CCIN, or ArcticNet take no liability for the use or transmission of this data
OpenAccess true
Contact derek.muir(at)ec.gc.ca; pdc(at)uwaterloo.ca
Representation
Language English
Format Computer file
Discipline Biogeochemistry;Chemistry
Spatial Coverage (-109.600W, 74.800S, -109.500E, 74.800N)
Temporal Coverage Begin 2008-07-25T00:00:00Z
Temporal Coverage End 9999-12-31T00:00:00Z