Spirulina  is a rich source of  potassium , and also contains  calcium ,  chromium ,  copper ,  iron ,  magnesium ,  manganese ,  phosphorus ,  selenium ,  sodium , and  zinc . [7] [8] Photosynthetic pigments Spirulina  contains many pigments, including  chlorophyll-a ,  xanthophyll ,  beta-carotene ,  echinenone ,  myxoxanthophyll ,