Effect of CNP on composition and structure of lotic biofilms as detected with lectin-specific glycoconjugates

Abstract

Biofilms were cultivated in rotating annular reactors supplied with river water supplemented with carbon, nitrogen, phosphorus or a combined nutrient addition. Confocal laser scanning microscopy and digital image analysis were used in combination with a panel of fluor-conjugated lectin probes to assess the changes in biofilm glycoconjugates with depth, time and in response to the nutrient additions. In addition, nucleic acid staining and autofluorescence were utilised to monitor bacterial and photosynthetic populations respectively. These analyses indicated that in lotic biofilms both quantitative and proportional differences in glycoconjugate composition developed under each nutrient regime. The differences in the biofilms were detected with time and with depth. Comparison of C, N, P, and CNP treatments with the control showed differences in the total amount of photosynthetic organisms, bacteria and extracellular polymeric substance (EPS)-specific glycoconjugates. For example, C, N, and CNP nutrient additions resulted in a minimal increase of 50% lectin-specific EPS glycoconjugates. Accumulation of different glycoconjugates over time in the different biofilms showed a similar pattern in the single nutrient treatments, with a maximum accumulation at 3 wk, followed by sloughing in Week 5 and regrowth in Week 7. In contrast, both the control and the combined CNP treatment showed a continuous increase and a plateau phase for the glycoconjugates as a whole. Both visualisation and quantification indicated that under each treatment the distribution of 4 specific glycoconjugates (Arachis hypogaea, Canavalia ensiformis, Glycine max, Ulex europaeus) varied with depth and, in addition, changed over time. Further, the glycoconjugate make-up of the single nutrient additions were similar to each other, as was the make-up of the control and combined nutrient treatment. Application of fluorescence in situ hybridisation analysis indicated that significant changes occurred in the beta-proteobacteria community composition as a consequence of nutrient addition. The results demonstrate the effect of nutrient regime on the cellular composition and glycoconjugate chemistry of lotic biofilms.

Influence of phosphorus availability on the community structure and physiology of cultured biofilms

“…Wetzel et al (1997 regarded the production of EPS as a mechanism for nutrient retention. Furthermore, it has been shown that nutrient depletion in biofilms could induce an increase of EPS production (Mohamed et al, 1998;Wang et al, 2005;Zhang et al, 2014), and there appeared to be more EPS matrix in treatments containing insufficient phosphorus concentration and imbalanced N:P ratios (Artigas et al, 2012;Neu et al, 2005). In the present study, we also found that biofilms cultured under low P levels were easier to aggregate together, and to be removed as a layer of thin film.…”

Metatranscriptomic Analysis of the Response of River Biofilms to Pharmaceutical Products, Using Anonymous DNA Microarrays

“…In such systems, dilution is low, and effects on aquatic organisms may be more severe than in those systems where sewage effluents are highly diluted, as in the South Saskatchewan River (SSR). The SSR receives tertiary-treated sewage that is highly diluted (in the 200:1 range during winter flows and in the 33:1 range during low summer flows), and the river is nutrient (nitrogen and phosphorus) and carbon limited and therefore oligotrophic (19,24 Rotating annular reactors for biofilm growth. The rotating annular reactor design for biofilm development was previously described (19,20).…”

Aerobic Biofilms Grown from Athabasca Watershed Sediments Are Inhibited by Increasing Concentrations of Bituminous Compounds

“…The overlying water plus sediment was then continuously recirculated through 3 replicate reactors for each treatment (each replicate reactor was supplied independently via a peristaltic pump but from the same reservoir and was randomly placed on the reactor bench) for about 50 days at a rate of 500 ml per day at 22 Ϯ 2°C, giving 36 bioreactors. The reactors were run with continuous illumination (2.1 E s Ϫ1 m Ϫ2 ) as described in Neu et al (33). Each replicate reactor contained 12 identical coupons, made in-house out of polycarbonate as previously described (32).…”