8Vineyard areas are important causes of water contamination, especially by pesticides 9 and residues. These compounds can markedly disturb aquatic communities particularly 10 photosynthetic organisms that are targeted by herbicides. Biofilms and diatoms were used as 11 bioindicators for quality assessment in the Morcille watershed, an area impacted by 12Beaujolais vineyards (SE France), during the pesticide spreading period (April-May 2008). 13Biofilms were allowed to settle on glass slides for 4 or 8 weeks at three sites along a 7-km 14 long gradient of trophic (mainly orthophosphate) and pesticide pollution. After a 4-week 15 colonisation, samples from the two contaminated downstream sites were transferred upstream 16 to the clean site for four weeks while others were left in the same place. 17In vivo fluorescence measurements indicated that the periphytic communities were 18 dominated by diatoms. Going downstream, biofilm biomass and diatom species richness 19 decreased; normalized diatom indices (including the French standard BDI) expressed the 20 increase in trophic status quite well. The species composition of the assemblages was used to 21 discriminate between the effects of nutrients and toxicants, which increased simultaneously as 22 the river continued downstream. 23The way in which the biofilm samples transferred upstream recovered was quite 24 different depending on the location of the original site in the contamination gradient. Most of 25 the quantitative descriptors reached a level comparable to that of the reference communities, 26 Manuscript Click here to view linked ReferencesRecovery potential of periphytic communities in a river impacted by a vineyard watershed. Morin, S. etal. 2010. Ecological Indicators, vol. 10, n° 2. p. 419-426. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W87-4X30C60-1&_user=5403746&_rdoc=1&_fmt=&_orig=search&_sort=d&_docan but the diatom assemblages (cell density per surface unit, taxonomic composition) varied 27 between dates and along the gradient. These communities did not entirely recover a reference 28 structure but the increase in diversity, associated with the settlement of sensitive species, 29 suggested an elevated recovery potential. 30 31 Keywords 32 River biofilms; diatoms; pesticides; Biological Diatom Index; community analysis; diuron; 33 recovery 34 35Recovery potential of periphytic communities in a river impacted by a vineyard watershed. Morin, S. etal.

SUMMARY1. A major challenge in environmental risk assessment of pollutants is establishing a causal relationship between field exposure and community effects that integrates both structural and functional complexity within ecosystems. 2. Pollution-induced community tolerance (PICT) is a concept that evaluates whether pollutants have exerted a selection pressure on natural communities. PICT detects whether a pollutant has eliminated sensitive species from a community and thereby increased its tolerance. PICT has the potential to link assessments of the ecological and chemical status of ecosystems by providing causal analysis for effect-based monitoring of impacted field sites. 3. Using PICT measurements and microbial community endpoints in environmental assessment schemes could give more ecological relevance to the tools that are now used in environmental risk assessment. Here, we propose practical guidance and a list of research issues that should be further considered to apply the PICT concept in the field.

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15Films of biogenic compounds exposed to the atmosphere are ubiquitously found on surfaces of cloud droplets, aerosol particles, buildings, plants, soils, and the ocean. These air/water interfaces host countless amphiphilic compounds concentrated there with respect to bulk water, leading to a unique chemical environment. Here, photochemical processes at the air/water interface of biofilmcontaining solutions were studied, demonstrating abiotic VOC production from authentic biogenic 20 surfactants under ambient conditions. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants, and VOC production. In particular, irradiation of samples containing solely 25 biofilm cells without matrix components exhibited the strongest VOC production upon irradiation. In agreement with previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy-radical chemistry. Up to now such VOC emissions were directly accounted to high biological activity in surface waters. However, the obtained results suggest that abiotic photochemistry can 30 lead to similar emissions into the atmosphere, especially in less biologically-active regions.Furthermore, chamber experiments suggested that oxidation (O 3 /OH-radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting 2 atmospheric chemistry and climate-related processes, such as cloud formation or the Earth's radiation budget. 3 IntroductionAir/water interfaces are omnipresent in the ambient atmosphere, reaching from the nm-scale for single aerosol particles to the surface of the ocean, which covers more than 70% of the Earth's surface. In the past, it was shown that unique photochemical reactions with significant implications for atmospheric processes can occur at such interfaces, leading to the formation of volatile organic 5 compounds (VOCs) 1-5 and secondary organic aerosols, 6 or acting as sinks for reactive species, such as NO 2 or ozone. [7][8][9][10] This interfacial photochemistry is exclusively due to the presence of surfactants which tend to concentrate in surface layers with respect to the underlying bulk water. Additionally, such surfactants also increase the propensity of less surface-active compounds to enrich there as well, creating a unique chemical environment, affecting not only chemistry but also trace-gas 10 exchange. 5,[10][11][12][13][14][15][16] A major source of biogenic surfactants in the ambient environment are so-called biofilms, loosely defined as a population of microorganisms (i.e., fungi, algae, archaea) that accumulate at an interface. In addition, such microorganisms can also form cel...