More than 50% of terrestrially-derived organic carbon (terrOC) flux from the continents to the ocean is remineralised in the coastal zone despite its perceived high refractivity. The efficient degradation of terrOC in the marine environment could be fuelled by labile marine-derived material, a phenomenon known as "priming effect", but experimental data to confirm this mechanism are lacking. We tested this hypothesis by treating coastal sediments with C-13-lignocellulose, as a proxy for terrOC, with and without addition of unlabelled diatom detritus that served as the priming inducer. The occurrence of priming was assessed by the difference in lignocellulose mineralisation between diatom-amended treatments and controls in aerobic sediment slurries. Priming of lignocellulose degradation was observed only at the initial stages of the experiment (day 7) and coincided with overall high microbial activity as exemplified by total CO2 production. Lignocellulose mineralisation did not differ consistently between diatom treatments and control for the remaining experimental time (days 14-28). Based on this pattern, we hypothesize that the faster initiation of lignocellulose mineralisation in diatom-amended treatments is attributed to the decomposition of accessible polysaccharide components within the lignocellulose complex by activated diatom degraders. The fact that diatom-degraders contributed to lignocellulose degradation was also supported by the different patterns in C-13-enrichment of phospholipid fatty acids between treatments. Although we did not observe differences between treatments in the total quantity of respired lignocellulose at the end of the experiment, differences in timing could be important in natural ecosystems where the amount of time that a certain compound is subject to aerobic degradation before burial to deeper anoxic sediments may be limited.
Bibliographical noteFunding: E.G. was funded by the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland, grant reference HR09011). B.T. received funding from the Scottish Government's Rural and Environment Science and Analytical
Services (RESAS) Division. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Data Availability: All dataset files are available from the figshare database. DOI: http://dx.doi.org/10.6084/m9.figshare.1554752.
21 Apr 2016: The PLOS ONE Staff (2016) Correction: Occurrence of Priming in the Degradation of Lignocellulose in Marine Sediments. PLoS ONE 11(4): e0154365. doi: 10.1371/journal.pone.0154365
View correction at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154365
- dissolved organic matter
- ratio mass-spectrometry
- coastal ocean
- microbial communities
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Gontikaki, E. (Creator), Thornton, B. (Creator), Cornulier, T. (Creator) & Witte, U. (Creator), Figshare, 3 Dec 2015