gelbstoff /ˈɡɛlpʃtɔf/ noun1 •The optically measurable component of dissolved organic matter in water, which primarily occurs naturally from tannin released from decaying detritus. As the amount of organic matter increases, it causes the water to appear green, yellow-green, and then brown.Like soil humus and humic materials indigenous to freshwaters, seawater gelbstoff absorbs light strongly into the ultraviolet region of the spectrum: Sieburth and Jensen (1968) noted a peak at 263 nm. — 1979
