Finally, attempts are made to directly calibrate stained segments of sclerosponges to real temperature and water chemistry data taken over a three year period from the caves in which the sclerosponges were growing. Direct calibration involves very fine sampling resolution from the top millimetre of the skeleton, which is achieved via LA-ICP and micro-milling techniques. Through three independent means of calibrating sclerosponges to their modern environment, questions of their use as high-resolution proxies over longer time scales can be addressed.