Northern Russian chironomid-based modern summer temperature data set and inference models

Abstract

West and East Siberian data sets and 55 new sites were merged based on the high taxonomic similarity, and the strong relationship between mean July air temperature and the distribution of chironomid taxa in both data sets compared with other environmental parameters. Multivariate statistical analysis of chironomid and environmental data from the combined data set consisting of 268 lakes, located in northern Russia, suggests that mean July air temperature explains the greatest amount of variance in chironomid distribution compared with other measured variables (latitude, longitude, altitude, water depth, lake surface area, pH, conductivity, mean January air temperature, mean July air temperature, and continentality). We established two robust inference models to reconstruct mean summer air temperatures from subfossil chironomids based on ecological and geographical approaches. The North Russian 2-component WA-PLS model (RMSEP Jack = 1.35°C, r Jack 2 = 0.87) can be recommended for application in palaeoclimatic studies in northern Russia. Based on distinctive chironomid fauna and climatic regimes of Kamchatka the Far East 2-component WAPLS model (RMSEP Jack = 1.3°C, r Jack 2 = 0.81) has potentially better applicability in Kamchatka.

Holocene climate and environmental change in north-eastern Kamchatka (Russian Far East), inferred from a multi-proxy study of lake sediments

“…S. coracina-type is typically a cold stenotherm (Brodin, 1986). The weighted average (WA) temperature optimum of this taxon in the eastern Russian data set is 8.8°C, which is one of the lower temperature optima (Nazarova et al, 2014).…”

“…Mean July air temperatures were inferred using a chironomid-based temperature inference model (WA-PLS, 2 component, R 2 boot = 0.81, RMSEP boot = 1.43 °C) (Nazarova et al, 2014) based on a modern calibration data set of 88 lakes from eastern Russia (53°-75°N, 141°-163°E) covering a mean July air temperature range of 1.8-13.3°C. The reliability of the chironomid-inferred temperature reconstructions was assessed by the following methods.…”

“…The chironomid stratigraphy is divided into three assemblage zones (CAZ-1 to CAZ-3) described as follows ( Fig. 4 (Nazarova et al, 2014) occurs briefly at ca. 3000 cal yrs BP and between ca.…”

“…9000 cal yrs BP and are replaced by increasing abundances of taxa with higher temperature optima such as Polypedilum nubeculosum-type and Paratanytarsus penicillatus-type. Lauterborniella, which has one of the warmest optima in the modern east Russian data set(Nazarova et al, 2014), reaches its peak abundance (3-4%) between 8200 and 7300 cal yrs BP before declining throughout the remainder of the zone. Sergentia coracina-type increases in abundance from ca.…”

Modern and Fossil Diatom Assemblages from Bol'shoy Lyakhovsky Island (New Siberian Archipelago, Arctic Siberia)

“…Statistical analysis was performed using the Canoco 4.5 program and mainly according to the procedures described by Nazarova et al (Nazarova et al, 2013;Nazarova et al, 2015). The analysis included diatom taxa found in at least one lake with a relative abundance of at least 5%.…”