Master recyclers: features and functions of bacteria associated with phytoplankton blooms

Abstract

Marine phytoplankton blooms are annual spring events that sustain active and diverse bloom-associated bacterial populations. Blooms vary considerably in terms of eukaryotic species composition and environmental conditions, but a limited number of heterotrophic bacterial lineages - primarily members of the Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria - dominate these communities. In this Review, we discuss the central role that these bacteria have in transforming phytoplankton-derived organic matter and thus in biogeochemical nutrient cycling. On the basis of selected field and laboratory-based studies of flavobacteria and roseobacters, distinct metabolic strategies are emerging for these archetypal phytoplankton-associated taxa, which provide insights into the underlying mechanisms that dictate their behaviours during blooms.

Marine bacterial community structure resilience to changes in protist predation under phytoplankton bloom conditions

“…The resulting prevalence of Rhodobacteraceae in a community subjected to strong grazing pressure could be related to a smaller effect of HNF on this group compared with the others. However, as grazing losses did not seem to be phylotypespecific in this experiment, the resulting dominance of Rhodobacteraceae was most likely because of their reported genotypic and metabolic diversity (Brinkhoff et al, 2008) and their ability to take advantage of the environmental conditions associated with algal blooms (Eilers et al, 2001;Pinhassi et al, 2004;Allers et al, 2007;Baltar et al, 2007;Buchan et al, 2014) and the phytoplanktonderived DOC produced (Zubkov et al, 2001;Vila et al, 2004;Alonso and Pernthaler, 2006;Sarmento and Gasol, 2012), more than due to a superior grazing-avoidance capability. Thus, whether avoidance or lessening of grazing losses is a crucial ecological trait for bacteria, and thus a critical factor for the observed dominance of marine bacterial clusters such as Rhodobacteraceae, remains to be shown for marine systems.…”

Interactive network configuration maintains bacterioplankton community structure under elevated CO<sub>2</sub> in a eutrophic coastal mesocosm experiment

“…Lin et al: Interactive network configuration maintains bacterioplankton community structure ing the highly efficient, extracellular, multi-protein complex TonB-dependent transporter (TBDT) system, based on previous in situ proteomics and metatranscriptomics data (Teeling et al, 2012). Higher abundance of Flavobacteria under elevated CO 2 means more HMW DOM could be degraded and so enter into the carbon cycle (Buchan et al, 2014). Based on the results reported here, it can be speculated that increased amounts of Flavobacteria under the elevated CO 2 treatment in eutrophic seawater could promote the TBDT system to break down HMW DOM and lead to improved efficiency of the microbial carbon pump (MCP), and possibly further influence carbon storage in the ocean (Jiao et al, 2010).…”

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

“…Bacteria of the orders Flavobacteriales and Rhodobacterales were the most abundant taxa. Both phylogenetic groups are well known to be important during phytoplankton blooms (Teeling et al, 2012;Buchan et al, 2014). As shown by CCorA, the composition of the total BC at 'species' level (see reasons for restriction to this phylogenetic level in following paragraph) significantly correlated with chlorophyll a fluorescence (but not chlorophyll a concentration), DOC and TDN concentrations, whereas the active BC composition exhibited a significant correlation with TDN concentration only (Supplementary Table S5).…”