High-Nutrient, low-chlorophyll

HNLC (english high nutrient low chlorophyll ) is in the marine geosciences an acronym for marine areas that stand out by a lack of chlorophyllhaltigem phytoplankton ( engl. low chlorophyll ), although the sea water is rich in major nutrients nitrate and phosphate in them ( engl. high nutrient ). This phenomenon is attributed to the absence of micro-nutrients such as iron. Vast regions in which these conditions occur are upwelling areas, such as the Southern Ocean, the North Pacific or the equatorial areas of the Pacific.