Bacterial growth and DOC consumption in a tropical coastal lagoon

Abstract

The aims of this research were to determine the main limiting nutrient to bacterial growth in Imboassica lagoon, southeastern Brazil, to estimate the percentage of dissolved organic carbon (DOC) available for bacterial growth, and to determine the bacterial growth efficiency (BGE) of natural assemblages. Bacterial growth and DOC consumption were determined in batch culture experiments, in which water samples were supplemented with nitrogen and phosphorus together or separately, or incubated without nutrient additions. When added together, N and P stimulated higher bacterial growth rates and production, as well as higher DOC consumption. The BGEs and DOC consumption rates were strongly dependent on the method used to determine bacterial production. The BGE ranged from 11 to 72%. However, only a minor fraction of bulk DOC was consumed by the planktonic bacteria (from 0.7 to 3.4%). The results suggest that low availability of phosphorus and nitrogen coupled with excess organic carbon was the main factor responsible for the relatively low bacterial utilization of DOC in Imboassica lagoon.

Influence of nitrogen sources on the enzymatic activity and grown by Lentinula edodes in biomass Eucalyptus benthamii

“…There are differences in the secretion and release of specific nitrogenase in the growth phase, the processing and use in source of nitrogen metabolism (Lee et al, 2004). Nitrogen may also be a limiting factor for microbial growth, include bacteria (Farjalla, et al, 2006). For the cultivation of L. edodes a source of nitrogen in this type of substrate, such as rice bran or wheat is required, as observed by Philippoussis et al (2002).…”

Different natural organic matter isolates cause similar stress response patterns in the freshwater amphipod, Gammarus pulex

“…The black soil layer is the source of the extremely high DOC content in the lagoons. Bulk DOC studies with respect to photodegradability and nutrition of microorganisms have been conducted by Suhett et al (2007) and Farjalla et al (2002Farjalla et al ( , 2006, and a geochemical characterization of the organic carbon in the sediment of three Restingas lagoons is provided by Zink et al (2004). For exposure purposes in our experiment, an aqueous extract was produced and characterized by HPSEC as the other two sources.…”

Community Biomass and Bottom up Multivariate Nutrient Complementarity Mediate the Effects of Bioturbator Diversity on Pelagic Production

“…We evaluated the effects of bioturbator diversity and biomass on these nutrients because they have been demonstrated to be important for subsidizing secondary microbial production in aquatic ecosystems worldwide [64], [65]. The NH 4 -N determination was performed manually with the phenol-hypochlorite technique according to Solorzano [66].…”