Microbial uptake kinetics of dissolved organic carbon (DOC) compound groups from river water and sediments

Dr Helen Glanville1, Miss Francesca  Brailsford2, Professor Peter Golyshin2, Professor Penny  Johnes3, Dr Chris Yates3, Professor Davey Jones1

1Keele University, Crewe, United Kingdom, 2Bangor University , Bangor, United Kingdom, 3Bristol University, Bristol, United Kingdom, 4University of Western Australia, Perth, Australia

Since completing my PhD (2013), I have worked as a biogeochemist on 2 large NERC-funded consortium projects (2013-2017), both at Bangor university. My research explored critical thresholds controlling microbial pathways in terrestrial and aquatic environments (North Wales and SW England) to understand their role in larger scale, global nutrient (C, N and P) cycling processes (for further project information follow the links http://www.turf2surf.org/ and http://www.nerc-domaine.uk/).

Dissolved organic matter (DOM) represents a key component of carbon cycling in freshwater ecosystems. While the behaviour of bulk DOC in aquatic ecosystems is well studied, comparatively little is known about the turnover of specific dissolved organic carbon (DOC) compounds. The aim of this study was to investigate the persistence of 14C-labelled low molecular weight (LMW) DOC at a wide range of concentrations (0.1 µM to 10 mM), in sediments and waters from oligotrophic and mesotrophic rivers within the same catchment. Overall, rates of DOC loss varied between compound groups (amino acids > sugars = organic acids > phenolics). Sediment-based microbial communities contributed to higher DOC loss from river waters, which was attributed, in part, to its greater microbial biomass. At higher DOC compound concentrations, DOC loss was greater in mesotrophic rivers in comparison to oligotrophic headwaters. A lag-phase in substrate use within sediments provided evidence of microbial growth and adaptation, ascribed here to the lack of inorganic nutrient limitation on microbial C processing in mesotrophic communities. We conclude that the higher microbial biomass and available inorganic nutrients in sediments enables the rapid processing of LMW DOC, particularly during high C enrichment events and in N and P-rich mesotrophic environments.


Biography: After graduating with an MSci. in Geology from Birmingham University, I worked in the oil and gas industry as a formation damage geologist for 6 months. I then had a complete career change and moved to South Korea to work as an English teacher. After 2 years as a senior teacher, I returned to the UK (2008) to pursue a career in academia by studying for a Ph.D in soil biogeochemistry at Bangor University, looking at drivers controlling soil respiration in temperate grasslands and high Arctic tundra in Svalbard. I was awarded the Drapers’ Company Bronze medal (2013) in recognition of outstanding academic achievements and for providing pastoral support to my peers.

Since completing my PhD (2013), I have worked as a biogeochemist on 2 large NERC-funded consortium projects (2013-2017), both at Bangor university. My research explored critical thresholds controlling microbial pathways in terrestrial and aquatic environments (North Wales and SW England) to understand their role in larger scale, global nutrient (C, N and P) cycling processes (for further project information follow the links http://www.turf2surf.org/ and http://www.nerc-domaine.uk/).

I then joined the Geography, Geology and the Environment group at Keele university as a Lecturer in Physical Geography in 2017 where I am keen to develop new and exciting research ideas and continue to widen my research collaborations

SOIL ORGANIC MATTER

7th International Symposium
Soil Organic Matter

6 – 11 October 2019

Hilton Adelaide

Adelaide, South Australia

Australia

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