In the acidiCO₂ceans project we will investigate how acidified conditions in the sea can affect calcified tissues (e.g. shells) of organisms in the sea. We want to study how the morphology and the structure of these tissues changes. To do this, we will image the organisms with a micro-CT scanner.
Micro-CT is an abbreviation of micro-computed tomography, also called x-ray microtomography. It is a three-dimensional imaging technique similar to computer tomography used in hospitals, just on a much smaller scale. The scanner in the Hellenic Centre for Marine Research can scan samples of a few millimetres up to a size of a mouse, and structures in the range of a few microns can be seen in the images.
The SkyScan 1172 micro-CT scanner in the Hellenic Centre for Marine Research
Micro-CT scanning is based on X-ray imaging. During the scanning process, the sample is placed between an X-ray source and a camera. The sample then rotates and the camera takes images from every angle (usually less that one degree).
Micro-CT scanning process
In the SkyScan 1172 the setup is as follows:
The scanning process then creates a large number of so-called "projection images" - these are black and white images of the specimen from all angles, in which the dark values represent dense areas and the bright values less dense areas.
These images then are processed by a computer software to create cross- sections through the sample, from top to bottom, and which in turn can then be used to display three-dimensional images of the scanned specimen:
Of course the data can not only be used for visualizing the specimens but also to analyse different parts, such as how dense certain parts are. By comparing the density of calcified tissues in animals living under normal conditions to those of animals living in acidified conditions we can assess how Ocean Acidification might impact animals, their bodies and their behaviour.