Seasonal variations and distributions of dissolved free and total carbohydrates at the ?zmir Bay, Aegean Sea

摘要

Seasonal variations and distributions of dissolved carbohydrate concentrations at the ?zmir Bay were investigatedwith salinity, chlorophyll a (Chl a), and dissolved organic carbon (DOC) levels to understand their relationships.Samples were collected from surface, subsurface and bottom depths at seven stations. DOC concentrationsranged from 32.2 to 244.2 μmol/L, and in general, DOC levels increased from winter to summer, then slightlydecreased in autumn. Monosaccharide (MCHO), polysaccharide (PCHO) and total dissolved carbohydrate(TDCHO) levels were found between 0.7–8.3, 0.7–19.5, and 2.6–24.6 μmol/L. DOC, MCHO, PCHO and TDCHOlevels were found higher in middle-inner bays, under the influence of anthropogenic inputs, compared to outerbay. Seasonal changes of MCHO/DOC, PCHO/DOC and TDCHO/DOC ratios were statistically significant (p<0.05)and the ratios showed decrease trends from winter to summer-autumn seasons. Distributions of TDCHO/DOCratios at wide ranges (2.5％–42.3％) indicated the presence of newly forming and degrading fractions of DOM.According to results of factor analysis, Chl a, MCHO and TDCHO were explained in the same factor groups. Inconclusion, the results showed that dissolved carbohydrate levels in the ?zmir Bay might be influenced bybiological processes and terrestrial/anthropogenic inputs.