We are studying Holocene chironomid and diatom assemblages in Russia to identify the drivers of global climate change.
Kamchatka, in the far northeast of Russia, is an important region for understanding climate linkages between the North Atlantic and North Pacific regions – the key drivers of global climate change.
To better understand Holocene climate in Kamchatka, chironomids from three sites will be analysed at intervals of 40-80 years throughout the Holocene. This information and our ‘midge thermometer’ will allow us to quantify Holocene summer air temperatures.
Changes in seasonality are estimated by the chironomids found:
We are analysing diatoms to quantify changes in the length of the summer and variations in pH and nutrients. We will compare our results with records of vegetation change and volcanic activity developed by colleagues at Queens University Belfast and AWI Potsdam.
An innovative aspect of this project is the analysis of stable oxygen isotopes in chironomid heads, made from chitin.
Detail of a chironomid head made of chitin.
Oxygen in the chitin molecule is derived from the lake water in which it lives. The ratio of stable oxygen isotopes incorporated into the chironomid heads reflects that of the water source.
In non-evaporative lakes this reveals which air masses were driving the prevailing climate at that time, Eurasia or the North Pacific.
By comparing our records with Holocene climate records available from other sites we will be able to establish the extent of global climate links at times of different climatic regimes, for example the magnitude and timing of the Holocene Thermal Maximum and the Little Ice Age. (Lead: Alex Lombino).
Novel chironomid-based quantitative summer air temperature inference models have been developed.
One based on a modern calibration set of 80 lakes from northwest and central Russia, the first of its kind for this region, and another by combining elements of a modern Norwegian calibration set with the Russian calibration set.
These inference models have been applied to four lake sediment sequences from northern Russia as part of a multiproxy study of Holocene environmental change. (Lead: Angela Self).
Research entomologist focusing on freshwater insect diversity and abundance as an indicator of annual, decadal and millenial environmental change.
The Holocene is a geological epoch that began 11,000 years ago to the present. It corresponds with growth of the human species, importantly the advent of agriculture and industrialisation.
Isotopes are variations of an element with the same number of protons but differing numbers of neutrons. Some isotopes are radioactive whereas stable isotopes do not decay over time.