Corals as archives
The global effects of climate change are now a major concern for us and future generations. To predict the future climate and the associated environmental consequences, it is important for scientists to have a good record and understanding of past climate variations. Much of this information is in our oceans, and paleo-oceanographers need robust records of water mass history to truly understand past climate variations. In the last few decades, oceanographic research has focused on looking at the relationship between deep and shallow water masses, and many scientists are now using cold-water corals to help them understand the past.
Cold-water corals can be used as archives because their skeletons contain information on the chemistry of the oceans at the time the skeleton was made. We can work out the age of the coral, how fast they grew, and what their environment was like, all by examining their aragonite skeleton. The coral Lophelia pertusa is particularly useful as an archive as is found at many depths, and grows relatively fast. In fact, it grows from 4 to 26 mm per year, which may not seem like much, but does mean that we can get a lot of detailed information about the past climate.