Autotrophic biomass

S.R. Juliastuti, J. Baeyens, C. Creemers, D. Bixio, E. Lodewyckx, The inhibitory effects of heavy metals and organic compounds on the net maximum specific growth rate of the autotrophic biomass in activated sludge, J. Hazard. Mater. B100 (2003) 271-283. 

As one component of the decade-long VERTEX program, an oceanic time-series station (33°N, 139°W) was occupied for an 18-month period from October 1986 to May 1988. During this observation period, the site was visited on 7 occasions ( 90-day interval) for approximately 1 week per expedition to retrieve and redeploy a free-drifting sediment trap array, to collect water samples and to conduct experiments relevant to C- and N-cycle processes (Harrison et al., 1992 Knauer et al., 1990). The uptake and assimilation of NOa and NH4 substrates were measured during incubation experiments that were designed to assess, and correct for, isotope dilution of the added tracers. Photoautotrophic N assimilation was measured using the into protein method, described later in this section. Measurements were also made of the concentrations of NOs , NH4, DON, PON, total microbial biomass, autotrophic biomass, heterotrophic biomass, primary productivity and the export of particulate matter (Harrison et al, 1992). In many ways this was, at that time, the most comprehensive study of the marine N-cycle ever conducted in the North Pacific trades biome. 

R. eutropha is actually an autotrophic hydrogen-oxidizing bacterium which can also produce poly(3HB) from C02, H2, and 02 [34]. The critical factor in such autotrophic cultivation processes is to avoid possible gas explosions. Therefore, a recycled gas, closed circuit culture system equipped with several safety features was developed and the oxygen concentration in the substrate gas phase was kept below the lower limit for gas explosions. A bacterial biomass of 91.3 g 1 1 has been achieved and the poly(3HB) content reached up to 67% per cell dry weight under these oxygen-limited conditions [35]. 

Biofilms are a complex mixture of bacteria, algae and other organisms (Fig. 11). In well-illuminated environments, micro-algae (phytobenthos) make up the largest fraction of the biofilm biomass, which plays a vital role as a primary producer. However, in non-lit environments, heterotrophs (bacteria, protozoa) account for the greatest proportion within the biofilm. The composition and abundance of phytobenthos (periphyton or autotrophic biofilm) have a recognised role by the WFD. 

Xs = slowly biodegradable substrate XAUT = autotrophic, nitrifying biomass XpHA = stored polyhydroxyalkanoate XPA0 = phosphorus-accumulating organisms... 

McCollom TM (1999) Methanogenesis as a potential source of chemical energy for primary biomass production by autotrophic organisms in hydrothermal systems on Europa. J Geophys Res 104 30,729-30,742... 

Assimilation of DON involves the uptake and incorporation of organic forms of N, such as amino acids, into biomass by both heterotrophic and autotrophic organisms. 

In the course of community development, the biomass and the production of autotrophic and heterotrophic organisms decrease [7]. Meanwhile, the correlation between the biodiversity and productivity of the communities is not yet clear and is still being discussed. The objective of this chapter is to consider the main results of the studies on species diversity in the Black Sea from the point of view of their interrelation to the production processes and to the ecological and physiological characteristics of the phytoplankton community. 

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