Paleo-environmental gateways in the eastern Canadian arctic – Recent isotope hydrology and diatom oxygen isotopes from Nettilling Lake, Baffin Island, Canada

Abstract

a b s t r a c tNettilling Lake is located on Baffin Island, Nunavut, Canada between the areas of past warming (Canadian High Arctic to the North) and climatic stability (Northern Quebec and Labrador region to the South). Despite being the largest lake in the Nunavut region with a postglacial marine to lacustrine transition history only a few paleo-environmental investigations were completed in this area. O silica-water of 1000 ln a (silica-water) ¼ 40.2‰ for sub-recent diatoms of Nettilling Lake was calculated matching the known water-silica fractionation for fossil sediments well and thereby showing the general applicability of this proxy for paleo-reconstructions in this region.Extremely large d 18O diatom variations in the core of more than 13‰ are mainly induced by changes in the isotopic composition of the lake water due to a shift from glaciomarine (d 18O diatom ¼ þ34.6‰) through brackish (þ23.4 to þ27.2‰) towards lacustrine (þ21.5‰) conditions (transition zones glaciomarine to brackish at 69 cm/7300 yr cal. BP and brackish to lacustrine at 35 cm/6000 yr cal. BP) associated with a shift in the degree of salinity. Our study provides the first evidence that paleo-salinity can be reconstructed by d 18 O diatom . Additionally, for the lacustrine section it could be demonstrated that d 18 O diatom may serve as a proxy for past air temperature within the same core recording a late Holocene cooling of about 4 C being consistent with other published values for the greater Baffin region.

Holocene atmospheric circulation in the central North Pacific: A new terrestrial diatom and δ18O dataset from the Aleutian Islands

“…d 18 O diatom is controlled by several environmental parameters which depend on local hydrology, climate, and the seasonality of diatom growth Rioual et al 2001;Jones et al 2004;Rosqvist et al 2004;Leng and Barker, 2006;Schiff et al 2009;Mackay et al 2011;Meyer et al 2015;Chapligin et al 2016). Previous work by Bailey et al (2015) showed that the surface core d 18 O diatom record from Heart Lake correlates significantly with the winter NPI during the instrumental period (1900e2009 AD) (r ¼ 0.43, p < 0.02, n ¼ 28).…”

Arctic hydroclimate variability during the last 2000 years – current understanding and research challenges

“…Canada (Chapligin et al, 2016). High-resolution isotope analysis combined with the study of the specific composition of diatom assemblages were an important addition to palaeoenvironmental.…”

Holocene hydrological variability of Lake Ladoga, northwest Russia, as inferred from diatom oxygen isotopes

“…Diatom oxygen isotopes in combination with data of taxonomy analysis have become one of the most reliable sources of information about past ecological, hydrological, environmental and climate changes especially for northern regions where ice archives are unavailable and/ or biogenic carbonates limited Jones et al 2004;Swann et al 2010;Chapligin et al 2012bChapligin et al , 2016Narancic et al 2016). Existing d 18 O diatom records have been interpreted to evaluate past changes in air temperature (Chapligin et al 2012b), precipitation amounts and/or air-mass sources (Barker et al 2001;Shemesh et al 2001;Jones et al 2004;Rosqvist et al 2004;Kostrova et al 2013;Meyer et al 2015;Bailey et al 2018), the precipitation/evaporation balance (Rioual et al 2001;Kostrova et al 2014) and palaeohydrological variability (Mackay et al 2008(Mackay et al , 2011(Mackay et al , 2013Chapligin et al 2016;Narancic et al 2016). Existing d 18 O diatom records have been interpreted to evaluate past changes in air temperature (Chapligin et al 2012b), precipitation amounts and/or air-mass sources (Barker et al 2001;Shemesh et al 2001;Jones et al 2004;Rosqvist et al 2004;Kostrova et al 2013;Meyer et al 2015;Bailey et al 2018), the precipitation/evaporation balance (Rioual et al 2001;Kostrova et al 2014) and palaeohydrological variability (Mackay et al 2008(Mackay et al , 2011(Mackay et al , 2013Chapligin et al 2016;Narancic et al 2016).…”

“…Diatoms, photosynthetic microalgae with an external frustule composed of biogenic silica (opal, SiO 2 ÁnH 2 O), are abundant in most aquatic systems and typically well preserved in lacustrine sediments (Round et al 1990). Diatom oxygen isotopes in combination with data of taxonomy analysis have become one of the most reliable sources of information about past ecological, hydrological, environmental and climate changes especially for northern regions where ice archives are unavailable and/ or biogenic carbonates limited Jones et al 2004;Swann et al 2010;Chapligin et al 2012bChapligin et al , 2016Narancic et al 2016). Lacustrine d 18 O diatom reflects the oxygen isotope composition of the lake water (d 18 O lake ) and lake temperature (T lake ) (Leng & Barker 2006).…”

“…Lacustrine d 18 O diatom reflects the oxygen isotope composition of the lake water (d 18 O lake ) and lake temperature (T lake ) (Leng & Barker 2006). Existing d 18 O diatom records have been interpreted to evaluate past changes in air temperature (Chapligin et al 2012b), precipitation amounts and/or air-mass sources (Barker et al 2001;Shemesh et al 2001;Jones et al 2004;Rosqvist et al 2004;Kostrova et al 2013;Meyer et al 2015;Bailey et al 2018), the precipitation/evaporation balance (Rioual et al 2001;Kostrova et al 2014) and palaeohydrological variability (Mackay et al 2008(Mackay et al , 2011(Mackay et al , 2013Chapligin et al 2016;Narancic et al 2016).…”