Temporal drivers of tryptophan-like fluorescent dissolved organic matter along a river continuum

Harris, N.A.; Sorensen, J.P.R.; Marchant, B.; Old, G.H. ORCID:; Naden, P.S.; Bowes, M.J. ORCID:; Scarlett, P.M.; Nicholls, D.J.E.; Armstrong, L.K.; Wickham, H.D.; Read, D.S. ORCID:; Lapworth, D. ORCID:; Bond, T.; Pond, K.. 2024 Temporal drivers of tryptophan-like fluorescent dissolved organic matter along a river continuum. Science of The Total Environment, 928, 172285. 13, pp.

Full text not available from this repository. (Request a copy)


Tryptophan-like fluorescence (TLF) is used to indicate anthropogenic inputs of dissolved organic matter (DOM), typically from wastewater, in rivers. We hypothesised that other sources of DOM, such as groundwater and planktonic microbial biomass can also be important drivers of riverine TLF dynamics. We sampled 19 contrasting sites of the River Thames, UK, and its tributaries. Multivariate mixed linear models were developed for each site using 15 months of weekly water quality observations and with predictor variables selected according to the statistical significance of their linear relationship with TLF following a stepwise procedure. The variables considered for inclusion in the models were potassium (wastewater indicator), nitrate (groundwater indicator), chlorophyll-a (phytoplankton biomass), and Total bacterial Cells Counts (TCC) by flow cytometry. The wastewater indicator was included in the model of TLF at 89 % of sites. Groundwater was included in 53 % of models, particularly those with higher baseflow indices (0.50–0.86). At these sites, groundwater acted as a negative control on TLF, diluting other potential sources. Additionally, TCC was included positively in the models of six (32 %) sites. The models on the Thames itself using TCC were more rural sites with lower sewage inputs. Phytoplankton biomass (Chlorophyll-a) was only used in two (11 %) site models, despite the seasonal phytoplankton blooms. It is also notable that, the wastewater indicator did not always have the strongest evidence for inclusion in the models. For example, there was stronger evidence for the inclusion of groundwater and TCC than wastewater in 32 % and 5 % of catchments, respectively. Our study underscores the complex interplay of wastewater, groundwater, and planktonic microbes, driving riverine TLF dynamics, with their influence determined by site characteristics.

Item Type: Publication - Article
Digital Object Identifier (DOI):
UKCEH and CEH Sections/Science Areas: Hydro-climate Risks (Science Area 2017-)
Soils and Land Use (Science Area 2017-)
Water Resources (Science Area 2017-)
ISSN: 0048-9697
Additional Keywords: fluorescent organic matter, tryptophan-like, microbial processing, in situ microbial production, catchment characteristics
NORA Subject Terms: Ecology and Environment
Date made live: 12 Apr 2024 14:37 +0 (UTC)

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...