<I>Trichodesmium</I> Shapes (IMAGE) Woods Hole Oceanographic Institution Caption Trichodesmium forms colonies of a wide variety of shapes are clearly visible to the naked eye (the diameter of the test tube is about the same as a US$ quarter). These remarkable organisms drive a previously unknown redox cycle of phosphorus in the upper ocean. Credit Carly Buchwald, Woods Hole Oceanographic Institution Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.