Biosphere

Snail shells provide detailed records of environmental change

By Dr Jonathan Lewis and Prof Melanie Leng The shells of molluscs from all over the world – on land, in lakes, and in the ocean – contain very detailed imprints of past climate change. Using isotope analysis, we can extract these signals and start to piece together long-term climate variations. You will never look at a garden snail in the same way again! What are molluscs? Molluscs are soft-bodied (invertebrate) organisms that are widespread in terrestrial, freshwater, and marine habitats. We can split them into two basic groups: Gastropods: Molluscs with up to one shell or ‘valve’ (such as snails or slugs) Bivalves: Molluscs...

Microbes on ice: Climate amplifiers?

Lifeless ice? At first glance, the cryosphere – including all frozen water on Earth – appears to comprise vast, cold expanses devoid of biology. However, even the most remote, hostile and unlikely icy locations in both hemispheres have been found to harbour diverse and active microbial life. It is hard to imagine ice offering many viable places for microbes to exploit; but liquid water and energy sources exist beneath, within, and especially on the surfaces of glaciers and ice sheets. Research has shown us that not only are ice-dwelling microbial communities crucial stores of biodiversity, they might be important amplifiers of global climate change. The area...