Light micrograph of a colony of Phaeocystis globosa. Phaeocystis forms large colonies measuring up to 5mm with several tens of thousands of individual cells with golden brown chloroplasts. When these colonies are caused to burst in heavy seas, the typical foam is formed that regularly washes up on the beach in the North Sea during rough weather. In this image, pennate diatoms have settled on the colony surface. Microscopic contrast method : differential interference contrast. Magnification 800x at a print width of 10 cm.