 |
| Titel |
Microbial origin of fluorescent dissolved organic matter: bacterial species fluorescence signatures |
| VerfasserIn |
Bethany Fox, Robin Thorn, Dann Turner, Alexandre Anesio, Darren Reynolds |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250137905
|
| Publikation (Nr.) |
 EGU/EGU2017-776.pdf |
|
|
|
|
|
| Zusammenfassung |
| Dissolved organic matter (DOM) is ubiquitous in aquatic systems, undertaking an essential
role in global biogeochemical cycling (Hudson et al. 2007). Recent research has seen the
increasing use of fluorescence spectroscopy for monitoring naturally occurring fluorescent
DOM (FDOM), with advances in the technology and in the analysis of data leading to an
improved understanding of the interactions between the ecosystem and FDOM (Hudson et al.
2008, Carstea 2010). This work has defined the origins of FDOM as autochthonous, produced
in situ, often termed ‘microbially derived’, and allochthonous, transported into
the system from external source, often termed ‘terrestrially sourced’ (Coble et al.
2014).
Previously at EGU we have presented research that has explored microbial processing and
production of Peak T, an autochthonous FDOM peak. Within this work we have identified the
autochthonous production of a range of FDOM peaks, including Peak T as well as larger
molecular weight compounds solely associated with allochthonous derivation. From this
we have begun to understand more about the important role that the underpinning
microbial community plays in the transformation, utilisation and production of
FDOM.
To further this research and enhance the knowledge surrounding microbially derived
FDOM our recent research has focussed on the analysis of the FDOM signature of different
bacterial species; Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. To do this,
we have developed a non-fluorescent media to culture individual bacteria species. By
undertaking bacterial growth curves, alongside fluorescence spectroscopy, we have been able
to determine FDOM development with population growth, highlighting which FDOM peaks
are associated with cell multiplication and which as a metabolic by-product from other
processes. We have also analysed the intracellular and extracellular fluorescence signature of
each species to understand how the microbial community structure may impact the
FDOM signal in aquatic systems. We have also explored the notion that cell lysis is
responsible for the presence of microbial larger FDOM compounds (Elliot et al.
2006).
From this work we have been able to identify the different fluorescence signatures of the
species analysed, as well as highlight the range of FDOM that can be of microbial origin.
This has further informed our understanding of microbial FDOM and the wider impact this
can have on aquatic DOM, ecosystem sustainability and biogeochemical cycling. |
|
|
|
|
|
|