Chitinozoa were exclusively marine microorganisms and were distributed globally. They have a broad geographic distribution and occurrence in a wide range of depositional environments. It was discovered, through the study of Silurian Chitinozoa in Gotland, that the abundance of chitinozoa is almost directly proportionate with the contents of calcium carbonate in the rocks. A decrease in the percent of calcium carbonate is coupled with and increased abundance of chitinozoa.