Oxygen isotope composition of diatoms as Late Holocene climate proxy at Two-Yurts Lake, Central Kamchatka, Russia

Abstract

Especially in combination with other proxies, the oxygen isotope composition of diatom silica (δ 18 O diatom ) from lake sediments is useful for interpreting past climate conditions. This paper presents the first oxygen isotope data of fossil diatoms from Kamchatka, Russia, derived from sediment cores from Two-Yurts Lake (TYL). For reconstructing Late Holocene climate change, palaeolimnological investigations also included diatom, pollen and chironomid analysis. The most recent diatom sample (δ 18 O diatom = +23.3‰) corresponds well with the present day isotopic composition of the TYL water (mean δ 18 O = −14.8‰) displaying a reasonable isotope fractionation in the system silicawater. Nonetheless, the TYL δ 18 O diatom record is mainly controlled by changes in the isotopic composition of the lake water. TYL is considered as a dynamic system triggered by differential environmental changes closely linked with lake-internal hydrological factors. The diatom silica isotope record displays large variations in δ 18O diatom from +27.3‰ to +23.3‰ from about 4.5 kyr BP until today. A continuous depletion in δ 18O diatom of 4.0‰ is observed in the past 4.5 kyr, which is in good accordance with other hemispheric environmental changes (i.e. a summer insolation-driven Mid-to Late Holocene cooling). The overall cooling trend is superimposed by regional hydrological and atmospheric-oceanic changes. These are related to the interplay between Siberian High and Aleutian Low as well as to the ice dynamics in the Sea of Okhotsk. Additionally, combined δ 18O diatom and chironomid interpretations provide new information on changes related to meltwater input to lakes. Hence, this diatom isotope study provides further insight into hydrology and climate dynamics of this remote, rarely investigated area.

Holocene environment of Central Kamchatka, Russia: Implications from a multi-proxy record of Two-Yurts Lake

“…8), which probably reached its local maximum during the time presented by the hiatus within the sediment record. Cooling in concert with high amounts of precipitation achieved glaciation or the build-up of large and long-lasting snow packs in the hinterland of TYL (Meyer et al, 2015-in this volume). The postulated glacial advances around TYL coincided with the onset of mid-to late Holocene glacier advances in the Sredniaya Avacha catchment mountains after 4300 cal yrs BP, which border the southern part of the Central Kamchatka Valley (Savoskul, 1999;Dirksen et al, 2015-in this volume) (Fig.…”

Oxygen isotope composition of diatoms from sediments of Lake Kotokel (Buryatia)

“…Although being yet few, oxygen isotope archives available from Russia (Chapligin et al, 2012à;Jones et al, 2004;Meyer et al, 2015;Swann et al, 2010) extend the knowledge of global change, lake hydrology, and atmospheric circulation that controls moisture inputs. Specifically, δ 18 O diatom data from Lake Baikal revealed general trends in the system responses to global change (Kalmychkov et al, 2007;Mackay et al, 2008Mackay et al, , 2011Mackay et al, , 2013Morley et al, 2005).…”

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

“…Oliver (1964) measured the water temperature in the respective summer months at 5 locations with all sites yielding a variation of less than 3 C with no gradient down the water column (in the range of DT ¼ 3 C ¼ À0.6‰). As the lake is well-mixed with no thermocline and a measured Secchi disc depth of mostly greater than 10 m (Oliver, 1964) Consequently, as in many other lakes (Chapligin et al, 2012b;Kostrova et al, 2013;Meyer et al, 2015) the major impact factor must be the isotopic change of the lake water. This change can originate from either an isotopic variation in precipitation (mainly forced by different air temperatures) or by a changing hydrological environment.…”