Submicron organic matter in a peri-alpine, ultra-oligotrophic lake

摘要: Combining organic carbon (OC) measurements with the classic MBTH (3-methyl-2-benzothiazolinone hydrochloride) method for carbohydrate determination and a new voltammetric of refractory matter (ROM) made it possible, first time, to quantify types, sources fate submicron present in an ultra-oligotrophic lake (Lake Brienz, Switzerland). The is extremely rich suspended glacial flour summer (glacier melting season). Measurements were taken from June 2004 October 2005 1.2 {mu}m filtered samples. OC concentration remained low throughout year (below 1 mg C L{sup -1}). was very (0.06-0.43 -1}) two tributary rivers (0.06-0.25 Lake only correlated phytoplanktonic biomass at onset productivity period. results suggest that differences may sometimes reflect nature carbohydrates rather than concentration. Extensive fibril formation evidenced by transmission electron microscopy (TEM) observations. ROM also (0.1-0.2 Significant variation riverine input due either annual occurrences (snow melting) ormore » irregular episodes (floods). Melting snow responsible about 30% lake's input. One box mass balance calculations showed 25% lost within lake. Evidence gleaned TEM STXM (scanning X-ray microscopy) observations clearly indicates this mainly caused sedimentation after association inorganic colloids.« less