Sterols in the marine food web

Sterols occur in practically all animals, plants, and microorganisms. The naturally occuring sterols found up to the present time are generally steroid alcohols containing 27 to 30 carbon atoms. In higher animals, cholesterol is the main sterol. In marine invertebrates, however, there is a great diversity in the occurance and distribution of sterols. There have been many studjes done on the sterols of different marine animals. It was indicated that many sterols in these animals are either of dietary origin or formed by minor modifications of the dietary sterols. Unfortunately, these studies were so limited to individual specimens that no conclusions can be drawn on the relationships among these different marine sterols. In order to obtain a more complete picture of sterols in the marine food web, we studied specimens from one single habitat.