Enhanced permafrost warming and increased arctic river discharges have heightened concern about the input of terrigenous matter into Arctic coastal waters. The IPY project 'OCoc- from Ocean Colour to Organic Carbon' (2008-2010) uses Ocean Colour data for synoptic monitoring of the input of organic matter - from both fluvial and coastal sources - into the Arctic coastal waters. Initial results from the German-Russian Expedition Lena08 along the southeastern Laptev Sea Coast (Arctic Siberia, Russia) in August 2008 are presented. Preliminary investigations using the MERIS Case2Regional Processor (C2R) show that the inherent optical properties (IOP) parameter C2R-'total absorption' and the optical parameter C2R-'Z90' (equivalent to the first attenuation depth layer wherefrom 90 % of the water leaving signal originates) are of immediate value for synoptic and dynamic investigations of northeastern Siberian coastal waters that are influenced by organic-rich terrigenous input.