Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide Wernand, Marcel R. ; van der Woerd, Hendrik J. ; Gieskes, Winfried W. C. Abstract Publication: PLoS ONE Pub Date: June 2013 DOI: 10.1371/journal.pone.0063766 Bibcode: 2013PLoSO...863766W