This data set contains the standard deviation of SeaWIFS chlorophyll generated from the climatology monthly means; the monthly climatologies represent the mean values for each month across the whole dataset time series. Chlorophyll a is a plant pigment which provides a measurement of the biomass (or quantity) of plants. In the water column, it is a measure of the suspended (or planktonic) biomass of single-celled microscopic plants. Chlorophyll is a commonly used measure of water quality. High levels of chlorophyll represent algal blooms. The data are received as monthly composites, with a 4 km resolution, and are constrained to the region between 90E and 180E, and 10N to 60S. The data was sourced from http://oceancolor.gsfc.nasa.gov/SeaWiFS/. This dataset is a contribution to the CERF Marine Biodiversity Hub.