Pollen grains are also a valuable proxy for studying past climate. Despite the extreme cold of Greenland and Norway there are a variety of plant species that live there: shrubs, herbs and grasses, with club mosses and ferns (no trees), and so pollen is sufficiently abundant for analysis. Depending on the characteristics of the environment, pollen can be used as an indicator of both local and regional past climate. Analysis of the pollen collected from the sediment of a small lake tells researchers about the local vegetation that grew around the lake, and hence the local climatic conditions, whereas from a large lake, which collects pollen from a broader range of plants, could be used to infer regional climatic conditions. Different plants also have different tolerances to warmth, cold and water availability.
Pollen grains are collected in the same way as the midges, by extraction from sediment cores. Studying local and regional pollen samples allows researchers to see what was happening at different times in the past within various landscapes. Once the samples are collected they are taken to a laboratory in Durham for analysis where they are identified and counted using a high power microscope because the individual grains cannot be seen with the naked eye.
(Pollen and spore grains approx. .03mm across).
Photos credit: H. Ranner