An international team of scientists, led by physicists from the University of York, has shed important new light on coral skeleton formation.
Their investigations, carried out at the nanoscale, provide valuable new information for scientists and environmentalists working to protect and conserve coral from the threats of acidification and rising water temperatures.
As corals grow, they produce limestone calcium carbonate - skeletons which build up over time into vast reefs. The skeleton's role is to help the living biofilm to move towards the light and nutrients.
Understanding the calcification mechanism by which these skeletons are formed is becoming increasingly important due to the potential impact of climate change on this process.
The scientists looked at the smallest building blocks that can be identified a microstructure called sphemlites by making a thin cross-section less than 100 nanometres in thickness of a skeleton crystal. They then used Transmission Electron Microscopy (TEM) to analyse the crystals in minute detail.
The TEM micrographs revealed three distinct regions: randomly orientated granular, porous nanocrystals; partly oriented nanocrystals which were more granular and porous; and densely packed aligned needle-like crystals.
These different regions could be directly correlated to times of the day - at sunset, granular and porous crystals are formed, but as night falls, the calcification process slows down and there is a switch to long aligned needles.
Corresponding author Rene van de Locht, a final-year PhD student with the Department of Physics at the University of York, says, "Coral plays a vital role in a variety of eco-systems and supports around 25 per cent of all marine species. In addition, it protects coastlines from wave erosion and plays a key role in the fisheries and tourism industries. However, the fundamental principles of coral's skeleton formation are still not fully understood.
|Contact: Caron Lett|
University of York