Marine humic and fulvic acids: their effects on remote sensing of ocean chlorophyll

Marine humic and fulvic acids were concentrated from about 1400 liters of seawater from the Gulf of Mexico, and specific absorption coefficients were measured for each from 240 to 675 nm. Marine fulvic and humic acids appear to account for most if not all water color or Gelbstoff in the offshore regions of the Gulf of Mexico. Based on a remote-sensing reflectance model, it appears that the increase in the Gelbstoff: chlorophyll ratio for waters adjacent to and downstream from regions of high primary productivity accounts for much of the deviation found for such waters from the global chlorophyll algorithm of the Coastal Zone Color Scanner. -Authors