Eutrophication and climatic changes lead to unprecedented cyanobacterial blooms in a Canadian sub-Arctic landscape

Sivarajah, Branaavan; Simmatis, Brigitte; Favot, Elizabeth J.; Palmer, Michael; Smol, John P.

doi:10.1016/j.hal.2021.102036

Cited by 31 publications

(23 citation statements)

References 73 publications

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“…The most striking mining pollution-induced diatom shifts occurred at heavily polluted Pocket Lake, where planktic D. stelligera decreased to negligible abundances while benthic metal(loid)tolerant Navicula taxa (Austin et al 1985) increased (Thienpont et al 2016). Similarly, declines in planktic D. stelligera were also observed at BC-17 and Jackfish as a response to mining pollution (Figure 2; Sivarajah et al 2021). However, the magnitude of diatom changes observed at BC-17 were much smaller relative to Pocket Lake, even though BC-17 is located only 2 km away from Pocket Lake (Figure 3).…”

Section: Diverse Diatom Responses To Multiple Environmental Stressors...mentioning

confidence: 91%

“…Furthermore, the mean summer and annual air temperatures have generally been higher relative to the long-term mean (Stewart et al 2018). Notable increases in air temperature have also been associated with declining ice-cover in this region (Sivarajah et al 2021).…”

Section: Study Areamentioning

confidence: 91%

“…The turn of the 21 st century coincides with the warmest decades on the meteorological record of Yellowknife (Stewart et al 2018). Therefore, it is likely that the recent diatom assemblage changes observed around this period were a response to warming-mediated changes to lake thermal properties and the legacies of past land-use changes (Stewart et al 2018;Perrett et al 2021;Sivarajah et al 2021).…”

Section: Differences In the Timing Of Diatom Assemblage Changes Among...mentioning

confidence: 99%

“…In Yellowknife, the increases in benthic fragilarioid taxa generally occurred at lakes that were impacted by both contaminants from roaster stack emissions and local disturbances. For example, Kam Lake received accidental spills of salt-rich tailings that originated from Con Mine (Perrett et al 2021), while Jackfish Lake was impacted by run-off from nearby waste disposal site (Sivarajah et al 2021).…”

Section: Diverse Diatom Responses To Multiple Environmental Stressors...mentioning

confidence: 99%

“…~1800s to present) and contain enough samples from the pre-disturbance period to establish reasonable baseline assemblages. In this study, we compiled diatom records from ten lakes, including four new records (BC-02, BC-17, BC-43, Vee) and six published in previous case studies (Alexie, Grace, Jackfish, Kam, Niven, Pocket; Thienpont et al 2016;Stewart et al 2018;Sivarajah et al 2020Sivarajah et al , 2021Perrett et al 2021), that are representative of the diverse limnological characteristics observed around Yellowknife (Palmer et al 2015;Houben et al 2016). Specifically, the study sites were chosen to encompass large gradients in contaminant concentrations related to mining, influence from land-use changes, and water column depth, as these factors can strongly influence biological responses to multiple environmental stressors in this region.…”

Section: Introductionmentioning

confidence: 99%

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Algal responses to metal(loid) pollution, urbanization, and climatic changes in subarctic lakes around Yellowknife, Canada

et al. 2022

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The lakes around Yellowknife (Northwest Territories, Canada) have been impacted by multiple environmental stressors throughout the 20th and early 21st centuries. Here, we have synthesized diatom assemblage data from ten lake sediment cores from the Yellowknife area and used a landscape-scale paleolimnological approach to investigate the cumulative impacts of past gold mining activities, urbanization, and climate warming on aquatic biota. Our investigations indicated that diatom species turnover (measured using detrended canonical correspondence analysis) was highest at lakes closer to the city and mines, as these sites were more severely impacted by land-use changes (e.g. sewage disposal, run-off from waste disposal sites) and roaster stack emission from the gold mines. Diatom assemblage shifts indicative of climate-induced changes to lake thermal properties were also observed across the gradient of human activities. The inclusion of remote sites was useful to disentangle the effects of climate-mediated changes from impacts related to mining and urbanization. This investigation suggests that the diatom assemblages of the lakes around Yellowknife have changed markedly over the last ~80 years and there are no signs of biological recovery since the cessation of mining activities around the turn of the 21st century. The biota of the sub-Arctic lakes around Yellowknife are now strongly influenced by climate-mediated changes to lake thermal properties and the urban lakes are also influenced by the legacies of past land-use changes.

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Section: Diverse Diatom Responses To Multiple Environmental Stressors...mentioning

confidence: 91%

Section: Study Areamentioning

confidence: 91%

Section: Differences In the Timing Of Diatom Assemblage Changes Among...mentioning

confidence: 99%

Section: Diverse Diatom Responses To Multiple Environmental Stressors...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Algal responses to metal(loid) pollution, urbanization, and climatic changes in subarctic lakes around Yellowknife, Canada

et al. 2022

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Long-term effects of a 1940s fertilization experiment on diatoms from Cache Lake (Algonquin Provincial Park, Ontario, Canada)

Wilkins,

Rühland,

Paterson

et al. 2023

J Paleolimnol

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Cache Lake, an ultra-oligotrophic Precambrian Shield lake located in Algonquin Provincial Park (Ontario, Canada), was manipulated in the summers of 1946 and 1947 when approximately 9.4 tons (cumulatively) of 12-24-12 (nitrogen-phosphorus-potassium) fertilizer was added to promote plankton growth and the possible enhancement of sh populations. Little is known about the long-term impacts of this lake manipulation, nor the effects of previous disturbances such as logging in the late-1800s, increased tourism following the extension of the Grand Trunk Railway to Cache Lake in 1896, limited cottage development starting ca. 1905, and subsequent construction of Highway 60 in the 1930s. We used a diatom-based paleolimnological approach to track limnological changes during the past ~ 200 years. Prior to the 1940s, assemblage changes were minimal, although small increases in, for example, Aulacoseira ambigua, likely tracked modest nutrient inputs from historical watershed disturbances. The most striking change was an increase in planktonic Fragilaria tenera in tandem with the near extirpation of the previously abundant Discostella stelligera from the sediment record that was concurrent with the 1946-1947 lake fertilization experiment. Although other lake sediment archives in the region record increases in D. stelligera with limnological changes linked to recent climate warming, this taxon never recovered to pre-disturbance abundances in Cache Lake following nutrient enrichment, but continued to be replaced by other planktonic taxa, also linked to recent warming (e.g. F. tenera, Asterionella formosa). The 1940s experimental fertilization has left a long-term legacy on Cache Lake diatoms, despite its return to ultra-oligotrophic conditions.

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Tracking the long-term limnological impacts of silver mining near Keno City (Yukon, subarctic Canada)

Jones,

Michelutti,

Would

et al. 2024

J Paleolimnol

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Mining in Northern Canada has been known to cause major environmental repercussions; however, monitoring data are scarce or non-existent. Here, we use a multi-proxy (metals, bioindicators, pigments) paleolimnological approach to track the impacts of mining activity near Keno City, on the traditional land of the First Nation of Na-Cho Nyäk Dun, in central Yukon (Canada). Silver was discovered in the early-1900s, primarily on or between two hills (Galena Hill and Keno Hill) and intensive mining has taken place ever since, with brief hiatuses dependent to ore prices and ownership of the claims. Christal Lake, a shallow site located in the valley between both hills, lies nearby many historical and current mines, and was once the site of a processing mill. Geochemical data show elevated background concentrations of many metals and faithfully track known mining activity. Interestingly, background (pre-mining) sediment concentrations of arsenic, cadmium, and zinc were all elevated above the Canadian Sediment Quality Guidelines for the Protection of Aquatic Life, re ecting the high concentrations of these elements in the local catchment. These, and other metal(loid)s, increased and peaked in sedimentary concentration after ca. 1920s, when intensive mining began. Sedimentary chlorophyll-a concentrations plummeted with the rise of metal concentrations, although increased again slightly in more recent sediments, perhaps re ecting the decline in recent metal inputs and reclamation of historic mine sites. Meanwhile, subfossil diatom assemblages were dominated by small benthic Fragilaria sensu lato taxa, whose assemblage composition only changed subtly with mining (similar to other shallow, non-acidi ed sites in Norilsk, Siberia). There was no biological evidence of acidi cation, likely due to the neutralizing effect of the carbonate-rich catchment. Cladoceran subfossils were only present in very low numbers throughout the core, re ecting both the shallow nature and high background metal concentrations in the lake. Collectively, these data show the long-term impacts of silver mining in this subarctic environment.

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Eutrophication and climatic changes lead to unprecedented cyanobacterial blooms in a Canadian sub-Arctic landscape

Cited by 31 publications

References 73 publications

Algal responses to metal(loid) pollution, urbanization, and climatic changes in subarctic lakes around Yellowknife, Canada

Algal responses to metal(loid) pollution, urbanization, and climatic changes in subarctic lakes around Yellowknife, Canada

Long-term effects of a 1940s fertilization experiment on diatoms from Cache Lake (Algonquin Provincial Park, Ontario, Canada)

Tracking the long-term limnological impacts of silver mining near Keno City (Yukon, subarctic Canada)

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