Impact of DOM composition on bacterial lipids and community structure in estuaries

Abstract

This study explored the relationship between lipid composition and bacterial community structure during growth of natural bacterial communities in the Chesapeake and Delaware bays. Experiments examined the effect of the addition of protein, glucose and site-specific >1 kDa ultrafiltered DOM (dissolved organic matter) on bacterial fatty acids and bacterial community structure determined by fluorescence in situ hybridization (FISH). We examined 3 environments over an estuarine gradient comprising a freshwater marsh, the anoxic waters of the central Chesapeake Bay channel, and the Lower Delaware Bay, to encompass a range of bacterial communities and to determine how each community might respond to varying DOM sources in terms of both community structure and lipid signatures. The results demonstrated that fatty acids produced by bacteria depend on carbon source, with consistent trends regardless of physical environment and initial community structure. In contrast to the fatty acid signatures, the FISH results suggested that no single group of bacteria responded consistently to the addition of DOM, either as individual substrates or as complex natural material. The results suggest that while fatty acid synthesis appears strongly associated with dissolved substrates, assignments of specific bacterial groups to fatty acid signatures are not possible at broad phylogenetic levels.

Effects of differences in organic supply on bacterial diversity subject to viral lysis

“…S2). In accordance with our study, low‐molecular‐weight carbon compounds like glucose have been reported to stimulate growth of bacteria belonging to the Gammaproteobacteria group, especially when applied in high concentrations (Øvreås et al ., ; Pinhassi & Berman, ; Harvey et al ., ). In addition, the dominance of the families Colwelliaceae and Vibrionaceae as seen in our study in the glucose treatment has also been reported in other studies (Eilers et al ., ,b), where these two families responded rapidly to culturing conditions.…”

“…Heterotrophic bacteria are known to have distinct carbon uptake patterns, depending on the molecular weight (Cottrell & Kirchman, ; Elifantz et al ., ) and the availability of organic carbon compounds (Alonso & Pernthaler, ). Glucose, as a low‐molecular‐weight carbon, is preferred by bacteria belonging to the Alphaproteobacteria (Elifantz et al ., ; Alonso‐Saez & Gasol, ), but also bacteria belonging to the Gammaproteobacteria are known to be easily stimulated by high concentrations of glucose (Øvreås et al ., ; Pinhassi & Berman, ; Harvey et al ., ). Extracellular DOC released by different phytoplankton communities differs in quantity (Wolter, ; Lancelot, ) and quality (Myklestad, ).…”

Resource Quantity Affects Benthic Microbial Community Structure and Growth Efficiency in a Temperate Intertidal Mudflat

“…Similarly, there were no appreciable changes in the proportional uptake of 13 C into different PLFAs in a deep-sea sediment community when exposed to two different quantities of 13 C-enriched diatoms [46]. Differences in the relative distribution of 13 C-labelling between the treatments in our experiment may therefore reflect a resource-dependent change in the balance between catabolism and anabolism of individual PLFAs within the active component of the bacterial community; the relative abundance of certain PLFAs are known to be affected by external stressors [56], [57] and can change in response to the substrates used for biosynthesis [58]. However, the most dominant factors discriminating between the low-, medium- and high-treatments, 10Me-18:0, 17:1(n-8) and 17:0cy respectively, are typical of sulfate-reducing bacteria [56], [59].…”

Deciphering associations between dissolved organic molecules and bacterial communities in a pelagic marine system

“…There is growing evidence that the BC composition in the marine realm is driven to a large extent by deterministic selection through environmental factors (Stegen et al, 2012;Valentin-Vargas et al, 2012), among which substrate availability and composition of DOM rank prominently (Harvey et al, 2006;Gomez-Consarnau et al, 2012), but also physical factors have a role (Liu et al, 2013). Closely related and functionally similar taxa are found across similar habitats more often than expected by chance (Kraft et al, 2007;Teeling et al, 2012) and substratespecific allocation to the vast niche space offered by complex DOM may contribute to maintaining the highly diverse microbial communities in the oceans (Hutchinson, 1961;Zinger et al, 2011;Gifford et al, 2013).…”