Fig. 1

Sankey map of the number of the literature related to the three pigments in algae. The number of the literature is based on the ISI Web of Science search engine search using the following topics, The Phycobiliprotein bar chart contains the search results of Phycobiliprotein, Phycoerythrin, and Phycocyanin. Lines of the same color represent keywords from the same type. The last row of columns with different colors represents different years, and the different thickness of the columns represents the number of the literature related to the keywords