Seasonal variation in the chemical composition and carbohydrate signature compounds of biofilm

Abstract

Biofilm developed on stainless steel was characterised using biological, chemical and biochemical parameters, as well as aldose molecular biomarkers. Biofilm biomass and carbohydrate concentration increased on stainless steel, whereas C:N and organic carbon:chlorophyll a ratios decreased over the period of immersion. Despite the abundance of microalgal biomass, carbohydrate concentration was lower than that observed for proteins. Carbohydrate composition varied during the period of immersion. Glucose, arabinose and xylose were relatively more abundant during the initial period (5 d) of immersion, whereas rhamnose, fucose, ribose and galactose were more abundant during the latter period (> 5 d) of immersion. The sugar distribution trends suggest that biofilm carbohydrates were mostly derived from degraded biogenic and/or terrestrial sources, especially during the initial period (< 5 d) of immersion. As the period of immersion increased, the contribution of biogenic sources to the biofilm carbohydrates increased. This conclusion was also supported by principal component analysis based on wt % aldose composition. Multi-parameter approaches such as the one used in the present study provide a better picture of the sources and nature of biofilm organic matter.

Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

“…The lowest level of GAL and MAN at this station (Table 4) might have been associated with the selective degradation of these two monosaccharides. Selective degradation of hexoses was also observed for POM in a Mediterranean river (da Cunha et al, 2002) and for vascular plant tissues (Opsahl and Benner, 1999). It has also been demonstrated that molecular structure can significantly affect the degradation rates of carbohydrates (Arnosti, 2000;Arnosti and Repeta, 1994).…”

“…Relatively high RHA (10.3-24.0%) was observed in the Pearl River Estuary and SCS shelf sediments as compared to Mandovi Estuary sediments (5.6-11.2%) and Dabob Bay sediments (9.3-10.3%) (Cowie and Hedges, 1984a;Khodse et al, 2008). RHA is abundant in bacteria and/or fungi (Cowie and Hedges, 1984a;D'Souza et al, 2005;Hicks et al, 1994), but it is a relatively minor constituent of phytoplanktonic carbohydrate (Biersmith and Benner, 1998;Cowie and Hedges, 1984a). An unusually high value of RHA was found at station E8-1 (20.9%) and at station S5 (24.0%).…”

“…Therefore, a high abundance of hexoses might suggest more "fresh" organic matter. In contrast, fucoidan is resistant to hydrolysis in bottom water as well as in the surface sediment (Arnosti, 2000), and the deoxysugars FUC and RHA are suggested as good indicators of degraded organic matter (da Cunha et al, 2002;Hedges et al, 1994;Ittekkot and Arain, 1986). Therefore, the ratio of hexoses/deoxysugar may be used as an indicator to discriminate between fresh and refractory organic matter.…”

“…Carbohydrates preserved in sediments are predominantly structural polysaccharides (Hernes et al, 1996), the compositions of which are different depending upon the original sources (Cowie and Hedges, 1984a;Degens and Mopper, 1976;Hernes et al, 1996). Such a composition at the molecular level is, therefore, potentially powerful in order to distinguish between organic matter with a terrestrial or a marine source (Biersmith and Benner, 1998;Cowie and Hedges, 1984b;da Cunha et al, 2002). Moreover, the molecular composition of carbohydrates may also provide insights into the diagnosis of different organic matter biogeochemical processes (Benner and Opsahl, 2001;Keil et al, 1998).…”

Biofilm development on acrylic coupons during the initial 24 hour period of submersion in a tropical coastal environment

“…Several studies have shown that bacteria and phytoplankton populations produce lower concentrations of carbohydrate and higher amounts of protein during the early logarithmic growth phase (Rice et al 2000, D'Souza et al 2005. According to Snopok and Kotykevich (2006), the rate of protein adsorption is proportional to the concentration of protein in a solution.…”