The Taconite Inlet Lakes Project: a systems approach to paleoclimatic reconstruction

Bradley, Raymond S.; Retelle, Michael J.; Ludlam, Stuart D.; Hardy, Douglas R.; Zolitschka, Bernd; Lamoureux, Scott F.; Douglas, Marianne S. V.

doi:10.1007/bf00176930

Cited by 52 publications

(32 citation statements)

References 35 publications

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“…In addition to evidence of long-term lake ice covers from the existence of thermal maxima, these lakes were observed to have a refrozen candled ice cover prior to the onset of melt, which suggests that the ice cover was perennial (Hattersley-Smith et al 1970;Belzile et al 2001). Between 1969 and 1998, these lakes were never reported to have lost their ice cover during the summer beyond melting around the lake shore that created a ''moat'' of variable but limited extent (Bradley et al 1996;Ludlam 1996).…”

Section: Methodsmentioning

confidence: 95%

“…data). The C lakes form a continuum from highly stratified Lake C1, with a small (3.3 km 2 ) unglacierized catchment; to Lake C2, with a 23.5 km 2 glacierized catchment area; to freshwater Lake C3, which can receive variable amount of flow from the Taconite River (glacierized catchment, 11 to 260 km 2 ; Bradley et al 1996;Van Hove et al 2006). Lakes A and B have unglacierized catchment areas of 37 km 2 (Van Hove et al 2006) and approximately 5 km 2 , respectively.…”

Section: Methodsmentioning

confidence: 99%

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High Arctic lakes as sentinel ecosystems: Cascading regime shifts in climate, ice cover, and mixing

Mueller

Hove

Antoniades

et al. 2009

Limnology & Oceanography

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Climate and cryospheric observations have shown that the high Arctic has experienced several decades of rapid environmental change, with warming rates well above the global average. In this study, we address the hypothesis that this climatic warming affects deep, ice-covered lakes in the region by causing abrupt, threshold-dependent shifts rather than slow, continuous responses. Synthetic aperture radar (SAR) data show that lakes (one freshwater and four permanently stratified) on Ellesmere Island at the far northern coastline of Canada have experienced significant reductions in summer ice cover over the last decade. The stratified lakes were characterized by strong biogeochemical gradients, yet temperature and salinity profiles of their upper water columns (5-20 m) indicated recent mixing, consistent with loss of their perennial ice and exposure to wind. Although subject to six decades of warming at a rate of 0.5uC decade 21 , these lakes were largely unaffected until a regime shift in air temperature in the 1980s and 1990s, when warming crossed a critical threshold forcing the loss of ice cover. This transition from perennial to annual ice cover caused another regime shift whereby previously stable upper water columns were subjected to mixing. Far northern lakes are responding discontinuously to climate-driven change via a cascade of regime shifts and have an indicator value beyond the regional scale.There is a broad consensus that the world is entering a period of accelerated climate change (Solomon et al. 2007). Anthropogenic emissions of greenhouse gases and the resultant increase in net radiative forcing are widely accepted as the cause of this rapidly changing climate (Hansen et al. 2006). We are now faced with the challenge of evaluating the extent and pace of this change and its effect on the biosphere.Computer models and direct observations (Serreze and Francis 2006) indicate that the highest amplitude and most rapid climate changes are occurring in the Arctic. Although there is considerable variability among regions, the annual average air temperature in the North American continental Arctic increased by 1.06uC decade 21 during the last two decades (Comiso 2003), well above the global average of 0.2uC decade 21 during the same period (Hansen et al. 2006). The thinning and decrease in extent of Arctic sea ice cover (Maslanik et al. 2007) will lead to even more pronounced changes through an albedo-driven positive feedback that would cause Arctic Ocean warming, a further decrease in sea ice extent, and more amplification of high latitude warming.Many reports have shown significant climate change and associated ecosystem effects in the Arctic since the beginning of the short observational period in this region (Serreze et al. 2000). Long-term trends, however, have been difficult to resolve in the Arctic, in part because of the lack of site-specific data and substantial interannual variability in climate, which is exacerbated by the Northern Annular Mode. These factors act to obscure underlying tre...

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Section: Methodsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

High Arctic lakes as sentinel ecosystems: Cascading regime shifts in climate, ice cover, and mixing

Mueller

Hove

Antoniades

et al. 2009

Limnology & Oceanography

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“…Annually laminated (varved) lake sediments can provide unique, high-resolution records of past environmental change for many different parts of the world (e.g., Leonard, 1985;ltkonen and Salonen, 1994;Bradley et al, 1996;Zolitschka, 1998). To ascertain the paleoclimatic signal represented by interannual thickness variations in a clastic sedimentary record, the modem climate signal represented by land-to-lake sediment transfer must first be understood.…”

Section: Introductionmentioning

confidence: 99%

Streamflow and Suspended Sediment Transfer to Lake Sophia, Cornwallis Island, Nunavut, Canada

Braun

Hardy

Bradley

et al. 2000

Arctic, Antarctic, and Alpine Research

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To ascertain the climatic controls on sediment transport to Lake Sophia, Comwallis Island, Nunavut, Canada, we made detailed hydrological and meteorological measurements in the Sophia River watershed through the 1994 melt season. Streamflow and suspended sediment transport are limited, on an annual time scale, by the supply of snow and sediment in the watershed. Suspended sediment yield from the watershed was only 0.46 t k:m-2 , which is lower than any previously published yield for a stream in the High Arctic. Snowmelt rgnoff accounted for 88% of the annual suspended sediment load, whereas 6 and 9% were transported in response to a slushflow event and summer rainfall, respectively. These measurements provide no direct evidence that modem-day sediment delivery to Lake Sophia is related to fluctuations in air temperature, which has implications for the paleoenvironmental signal preserved in Lake Sophia's laminated sediments. We suggest that on-site sediment transport studies are necessary to establish the relationships among geology, geography, climate, and hydrology unique to each watershed-lake system and need to be an integral part of any calibration attempt. Additional years of data are needed however to define the interannual variability of streamflow and sediment transport in response to climate.

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“…1, Van Hove et al 2006). These lakes are , 5 m asl, and hence were isolated from the marine system during the late Holocene (Bradley et al 1996). These lakes represent divergent pathways of evolution from the explanation above, which Van Hove et al (2006) attribute to catchment water balance.…”

Section: Discussionmentioning

confidence: 92%

The chemical development of a hypersaline coastal basin in the High Arctic

Dugan

Lamoureux

2011

Limnology & Oceanography

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We investigated a hypersaline, seasonally isolated marine basin (SIMB) in the Canadian High Arctic to elucidate the role of brine rejection, tidal forcing, and groundwater input over the formation of hypersalinity. Analyses of physical parameters and seasonal sampling of ionic and isotopic composition were carried out on a coastal basin near Shellabear Point, Melville Island, Northwest Territories (75uN, 113uW). Observations reveal daily and seasonal variability in the water column due to a seasonal tidal connection during the ice-free season, which lasts substantially longer than the period of freshwater inflow from the catchment. An ice formation model of the volume of brine rejected from surface ice formed from marine water indicates that rapid saline enrichment of the basin due to ice formation is possible from tidally replenished marine water, and that the current hypersalinity may have formed in less than a decade. Modeled isotopic composition of brines are consistent with observations and provide an alternative to freshwater isotopic dilution suggested by other workers. A tidal connection is a critical consideration in lake evolution, and many hypersaline polar lakes could have developed their current chemical composition before full marine isolation. By contrast, in some coastal lakes, marine stratification caused by ice shelves before isolation provides a setting for minimal brine formation and subsequent meromictic conditions to develop. Hence, the marine setting at the time of isolation represents a key factor in explaining divergent lake chemical evolution in the High Arctic.

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The Taconite Inlet Lakes Project: a systems approach to paleoclimatic reconstruction

Cited by 52 publications

References 35 publications

High Arctic lakes as sentinel ecosystems: Cascading regime shifts in climate, ice cover, and mixing

High Arctic lakes as sentinel ecosystems: Cascading regime shifts in climate, ice cover, and mixing

Streamflow and Suspended Sediment Transfer to Lake Sophia, Cornwallis Island, Nunavut, Canada

The chemical development of a hypersaline coastal basin in the High Arctic

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