Introduction Method• 44 sites across upland Wales (Fig. 3)

sampled• Water-PAM (Walz, Germany) used to take

approx. 60 readings at each site• Readings calibrated using a light curve that

was obtained from each site• Water samples collected for DNA and nitrate

analysis.• Habitat survey conducted• Analysis of water chemistry

(pH,temperature, conductivity and % O2) using a portable multiparameter meter (HANNA instruments, USA) for further analysis of nitrates concentration in stream water.

Results, conclusion and Future Directions• Establish nitrate concentrations in rivers and streams across upland Wales.

• Practical implications include evaluating the effect of pesticide run off from farm land• Future work would involve continued assessment on a biannual basis. Developing biofilm as a important early bio-indicator of water

quality. Providing vital information to reduce and predict pesticide run off.• Thus reducing the harmful effect of pesticide on a river biofilm(4).• Reducing this negative effect suggest that that biodiversity and the economically valuable ecosystem services provided by rivers and

streams , which are dependent on biofilm and correct nitrate levels can be sustainably maintained.

Biofilms are made up from a cluster of bacteria, algae, cyanobacteria and protozoa, which are held in a polysaccharide matrix(1). Biofilms , as well as having medical implications are a essential component to the river ecosystem. The levels of biofilm have been shown to be affected by water temperature, , nutrient levels and pesticides(2). Through analysis of biofilm levels we are able to predict the corresponding levels of algae biomass, functional chlorophyll A and nitrates. Such factors are key to British river biodiversity and to the maintenance of ecosystem services, a industry which is currently valued at £200 billion (3).

References1) Diaz Villanueva, V., Font, J., Schwartz, T., Romani, A.M. (2011). Biofilm formation at warming temperature: acceleration of microbial colonization and microbial interactive effects. Biofouling 27:59-71 •2)Proia, L., Osorio, V., Soley, S., Köck-Schulmeyer, M., Pérez, S., Barceló, D., Romaní, A.M., Sabater, S.(2013). Effects of pesticides and pharmaceuticals on biofilms in a highly impacted river. Environmental Pollution 178:220-8• 3) http://nerc-duress.org/?page_id=40 [Accessed, August 2013.]•4) Hayashi, S., Jang, J.E., Itoh, K., Suyama, K., Yamamoto, H. 2011. Construction of river model biofilm for assessing pesticide effects. Arch Environ Contam Toxicol. 60:44-56.

Fig. 1) The water –PAM used that took one of 5,500 readings taken during this study.

Assessing the role of biofilm in nitrate regulation in streams and rivers in upland Wales using fluorescence analysis

Rhys Luckwell*, Hugh Feeley, Anne-Laure Sauvadet, Rupert Perkins, Andrew Weightman & Isabelle Durance

Fig. 3) Map of Wales with the 44 sites (black points) sampled.

Fig 4) Looking downstream form our site on the Honddu river, Powys

Fig. 2) Rhys Luckwell carrying out water chemistry analysis on the Conway river, near Snowden in upland Wales.