COMBINED FATTY-ACIDS AND AMINO-ACIDS IN THE DISSOLVED PLUS COLLOIDAL AND PARTICULATE FRACTIONS OF THE WATERS FROM A DYSTROPHIC LAKE

The combined amino acids and fatty acids in the dissolved + colloidal and particulate phases of the waters from a dystrophic lake have been studied. The former encompass 0.9-1.5% of the dissolved organic carbon (DOC) and about 10% of the particulate organic carbon (POC). The latt er are minor compounds representing 0.023-0.067% and about 0.3% of DOC and POC, respectively. The high phase distribution coefficients of al l individual components are indicative of the fatty acid and amino aci d association with organic materials that are predominant in the suspe nded particles. Furthermore, their similar coefficients point to a rat her uniform phase distribution pattern which is characteristic of part itioning between the particulate and the colloidal fraction. Despite t his general uniformity, two major distinct features have been observed when comparing the composition of the two phases. These concern the d ominance of glycine in the dissolved + colloidal fraction and the high proportion of unsaturated fatty acids in the particulate matter. The differences correspond with the predominance of algal and terrestrial inputs in the particulate fraction and with the selective enrichment o f microbial components in the dissolved + colloidal phase. The higher proportion of microbial fatty acids in this fraction appears to be a c haracteristic feature of this dystrophic lake when compared with the p hase-dependent fatty acid distributions of riverine and marine waters previously studied.