A study on a marine green alga, Caulerpa cactoides, found three main chlorophyll-protein complexes. These complexes include chlorophyll a-proteins related to photosystem 1 and 2, as well as chlorophyll a/b-proteins of the light-harvesting complex. The alga has a low chlorophyll a/chorophyll b ratio of 1.62, with more chlorophyll b in the light-harvesting complex. The light-harvesting complex contains 61% of total chlorophyll, while 23% and 6% are in the reaction center complexes of photosystems 1 and 2, respectively. This shows variations in pigment contents in chlorophyll b-containing plants, affecting the amounts of chlorophyll a and b in the light-harvesting complexes.