RT journal article
T1 Different types of diatom-derived extracellular polymeric substances drive changes in heterotrophic bacterial communities from intertidal sediments
A1 Bohórquez Ferrando, Julio
A1 McGenity, Terry John
A1 Papaspyrou, Sokratis
A1 García Robledo, Emilio Guillermo
A1 Corzo Rodríguez, Alfonso
A1 Underwood, Graham J. C.
A2 Biología
K1 EPS
K1 microphytobenthos
K1 intertidal sediment
K1 nutrient regeneration
K1 G-model
K1 degradation rate
K1 microbial community
K1 pyrosequencing
AB Intertidal areas support extensive diatom-rich biofilms. Such microphytobenthic (MPB) diatoms exude large quantities of extracellular polymeric substances (EPS) comprising polysaccharides, glycoproteins and other biopolymers, which represent a substantial carbon pool. However, degradation rates of different EPS components, and how they shape heterotrophic communities in sediments, are not well understood. An aerobic mudflat-sediment slurry experiment was performed in the dark with two different EPS carbon sources from a diatom-dominated biofilm: colloidal EPS (cEPS) and the more complex hot-bicarbonate-extracted EPS. Degradation rate constants determined over 9 days for three sediment fractions [dissolved organic carbon (DOC), total carbohydrates (TCHO), and (cEPS)] were generally higher in the colloidal-EPS slurries (0.105-0.123 d-1) compared with the hot-bicarbonate-extracted-EPS slurries (0.060-0.096 d-1). Addition of hot-bicarbonate-EPS resulted in large increases in dissolved nitrogen and phosphorous by the end of the experiment, indicating that the more complex EPS is an important source of regenerated inorganic nutrients. Microbial biomass increased ~4-6-fold over 9 days, and pyrosequencing of bacterial 16S rRNA genes revealed that the addition of both types of EPS greatly altered the bacterial community composition (from 0 to 9 days) compared to a control with no added EPS. Bacteroidetes (especially Tenacibaculum) and Verrucomicrobia increased significantly in relative abundance in both the hot-bicarbonate-EPS and colloidal-EPS treatments. These differential effects of EPS fractions on carbon-loss rates, nutrient regeneration and microbial community assembly improve our understanding of coastal-sediment carbon cycling and demonstrate the importance of diverse microbiota in processing this abundant pool of organic carbon.
PB Frontiers Research Foundation
SN 1664-302X
YR 2017
FD 2017
LK http://hdl.handle.net/10498/35489
UL http://hdl.handle.net/10498/35489
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 05-nov-2026