ISSN:
1573-515X
Keywords:
benthic diatoms
;
colloidal carbohydrates
;
mud flats
;
extracellular polymeric substances
;
GC-MS
;
EPS
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract The extracellular secretions of epipelic diatoms (Bacillariophyceae) axe an important source of carbohydrates on intertidal sediments. For analytical purposes, sediment carbohydrates have been operationally separated into colloidal and bulk fractions that are often assumed to be similar in their chemical properties. However, there has been little investigation into the nature of the two fractions. In this study, carbohydrate fractions were sampledin situ, isolated, purified and biochemically characterised using gas chromatography-mass spectrometry (GC-MS). Both carbohydrate fractions were found to contain similar sugars although in different proportions. Glucose represented more than 80% of the monosaccharides identified in the colloidal carbohydrate fraction while only 37% of monosaccharides present in the bulk carbohydrate fraction. Colloidal carbohydrate concentrations showed short-term variability and were correlated with diatom biomass (as chlorophylla) suggesting the colloidal fraction is labile and may be of recent origin, perhaps representing diatom activity. Concentrations of the bulk carbohydrate fraction did not show significant short-term variation and was therefore more refractory. This combination of biochemical and field data suggested that the bulk and colloidal carbohydrate fractions were chemically and physically different. These findings have relevance to studies of estuarine carbon cycling.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00993005
