The oceans are a big contributor to the global carbon cycle, with phytoplankton taking up carbon through photosynthesis and incorporating it into their shells. When these organisms die their shells sink and make a calcareous contribution to seafloor sediments. Of course, with the formation of limestone, this carbon is locked out of the atmosphere for long periods of geological time. Until recently ...[Read More]
Geosciences Column: Tracing Toba
Large volcanic eruptions have a significant impact on the Earth’s climate as aerosols (including sulphur dioxide and water vapour), together with ash are released into the atmosphere and increase the amount of sunlight reflected back into space (the albedo). This increase in reflectance (or decrease in energy absorption) can cause widespread climatic cooling, known as a ‘volcanic winter’. However, ...[Read More]
Geosciences Column: Rainfall and Climate – a Dynamic Problem
“Rain is grace; rain is the sky descending to the earth; without rain, there would be no life.” – John Updike Rain quenches the thirst of soils and vegetation, fuelling ecosystems and much of the world’s agriculture. Whether it ruins a day on the beach or destroys a season’s harvest, it makes humans deeply aware of their vulnerability to the vagaries of the atmosphere. It’s important to understand ...[Read More]
Geosciences Column: Larvae, Climate and Calcification
The absorption of atmospheric CO2 by the oceans results in a decline in ocean pH, hence ‘ocean acidification’, and reduces the availability of carbonate. This presents a problem to calcifying organisms (those that deposit calcium as either calcite or aragonite as hard parts) because they cannot produce their shells, valves (in the case of bivalves), or tests (in the case of diatoms) as readily. To ...[Read More]