. Kuehn, This study was funded through a project of the French National Program EC2CO (2009-2010) to A. Lecerf and the InBioProcess project of the ANR Biodiversity Program (ANR-2006-BDIV-007) to E, Chauvet. LITERATURE CITED

S. B. Baines and M. L. Pace, The production of dissolved organic matter by phytoplankton and its importance to bacteria: Patterns across marine and freshwater systems, Limnology and Oceanography, vol.36, issue.6, pp.1078-1090, 1991.
DOI : 10.4319/lo.1991.36.6.1078

F. Ba¨rlocherba¨rlocher, Leaf mass loss estimated by litter bag technique. Pages 171?176 in Methods to study litter decomposition: a practical guide, 2005.

G. Bengtsson, Interactions between fungi, bacteria and beech leaves in a stream microcosm, Oecologia, vol.36, issue.4, pp.542-549, 1992.
DOI : 10.1007/BF00317161

T. S. Bianchi, The role of terrestrially derived organic carbon in the coastal ocean: A changing paradigm and the priming effect, Proceedings of the National Academy of Sciences, vol.108, issue.49, pp.19473-19481, 2011.
DOI : 10.1073/pnas.1017982108

G. Bratbak and T. F. Thingstad, Phytoplankton-bacteria interactions: an apparant paradox? Analysis of a model system with both competition and commensalism, Marine Ecology Progress Series, vol.25, pp.23-30, 1985.
DOI : 10.3354/meps025023

J. J. Cole, Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget, Ecosystems, vol.95, issue.1, pp.171-184, 2007.
DOI : 10.1007/s10021-006-9013-8

W. F. Cross, J. P. Benstead, P. C. Frost, and S. A. Thomas, Ecological stoichiometry in freshwater benthic systems: recent progress and perspectives, Freshwater Biology, vol.43, issue.2, pp.1895-1912, 2005.
DOI : 10.1046/j.1365-2427.2003.01094.x

W. F. Cross, J. P. Benstead, A. D. Rosemond, and J. B. Wallace, Consumer-resource stoichiometry in detritus-based streams, Ecology Letters, vol.69, issue.8, pp.721-732, 2003.
DOI : 10.1016/S0022-1910(02)00060-4

D. J. Currie and J. Kalff, A comparison of the abilities of freshwater algae and bacteria to acquire and retain phosphorus1, Limnology and Oceanography, vol.29, issue.2, pp.298-310, 1984.
DOI : 10.4319/lo.1984.29.2.0298

M. Danger, J. Cornut, A. Elger, and E. Chauvet, Effects of burial on leaf litter quality, microbial conditioning and palatability to three shredder taxa, Freshwater Biology, vol.4, issue.5, pp.1017-1030, 2012.
DOI : 10.1111/j.1365-2427.2012.02762.x
URL : https://hal.archives-ouvertes.fr/hal-00955458

M. Danger, J. Leflaive, C. Oumarou, L. Ten-hage, and G. Lacroix, Control of phytoplankton-bacteria interactions by stoichiometric constraints, Oikos, vol.116, pp.1079-1086, 2007.
URL : https://hal.archives-ouvertes.fr/bioemco-00177050

M. Danger, C. Oumarou, D. Benest, and G. Lacroix, Bacteria can control stoichiometry and nutrient limitation of phytoplankton, Functional Ecology, vol.31, issue.2, pp.202-210, 2007.
DOI : 10.1046/j.1365-2426.2003.01158.x
URL : https://hal.archives-ouvertes.fr/bioemco-00178018

T. Daufresne and M. Loreau, Ecological stoichiometry, primary producer-decomposer interactions, and ecosystem persistence, Ecology, vol.82, pp.3069-3082, 2001.
DOI : 10.2307/2679835
URL : http://dx.doi.org/10.6084/M9.FIGSHARE.C.3297488

J. Drews, Drug Discovery: A Historical Perspective, Science, vol.287, issue.5460, pp.1960-1964, 2000.
DOI : 10.1126/science.287.5460.1960

S. Findlay, K. Howe, and D. Fontvielle, Bacterial-Algal Relationships in Streams of the Hubbard Brook Experimental Forest, Ecology, vol.74, issue.8, pp.2326-2336, 1993.
DOI : 10.2307/1939585

S. G. Fisher and G. E. Likens, Energy Flow in Bear Brook, New Hampshire: An Integrative Approach to Stream Ecosystem Metabolism, Ecological Monographs, vol.43, issue.4, pp.421-439, 1973.
DOI : 10.2307/1942301

S. Fontaine and S. Barot, Size and functional diversity of microbe populations control plant persistence and long-term soil carbon accumulation, Ecology Letters, vol.25, issue.10, pp.1075-1087, 2005.
DOI : 10.1111/j.1461-0248.2005.00813.x

R. J. Franken, B. Waluto, E. T. Peeters, J. J. Gardeniers, J. A. Beijer et al., Growth of shredders on leaf litter biofilms: the effect of light intensity, Freshwater Biology, vol.37, issue.3, pp.459-466, 2005.
DOI : 10.1046/j.1365-2427.2001.00720.x

P. C. Frost and J. J. Elser, Growth responses of littoral mayflies to the phosphorus content of their food, Ecology Letters, vol.60, issue.2, pp.232-240, 2002.
DOI : 10.1146/annurev.ecolsys.25.1.1

M. O. Gessner and E. Chauvet, Ergosterol-to-biomass conversion factors for aquatic hyphomycetes, Applied and Environmental Microbiology, vol.59, pp.502-507, 1993.
URL : https://hal.archives-ouvertes.fr/hal-01494940

M. O. Gessner and E. Chauvet, Importance of Stream Microfungi in Controlling Breakdown Rates of Leaf Litter, Ecology, vol.75, issue.6, pp.1807-1817, 1994.
DOI : 10.2307/1939639

M. O. Gessner and E. Chauvet, Growth and production of aquatic hyphomycetes in decomposing leaf litter, Limnology and Oceanography, vol.42, issue.3, pp.496-505, 1997.
DOI : 10.4319/lo.1997.42.3.0496
URL : https://hal.archives-ouvertes.fr/hal-00870750

L. C. Gilpin, K. Davidson, and E. Roberts, The influence of changes in nitrogen: silicon ratios on diatom growth dynamics, Journal of Sea Research, vol.51, issue.1, pp.21-35, 2004.
DOI : 10.1016/j.seares.2003.05.005

B. Guenet, M. Danger, L. Abbadie, and G. Lacroix, Priming effect: bridging the gap between terrestrial and aquatic ecology, Ecology, vol.54, issue.10, pp.2850-2861, 2010.
DOI : 10.1007/s10533-004-8130-8

T. B. Gurung, J. Urabe, and M. Nakanishi, Regulation of the relationship between phytoplankton Scenedesmus acutus and heterotrophic bacteria by the balance of light and nutrients, Aquatic Microbial Ecology, vol.17, pp.27-35, 1999.
DOI : 10.3354/ame017027

S. Gu¨sewellgu¨sewell and M. O. Gessner, N??:??P ratios influence litter decomposition and colonization by fungi and bacteria in microcosms, Functional Ecology, vol.437, issue.1, pp.211-219, 2009.
DOI : 10.1111/j.1365-2435.2008.01478.x

J. Harte and A. P. Kinzig, Mutualism and Competition between Plants and Decomposers: Implications for Nutrient Allocation in Ecosystems, The American Naturalist, vol.141, issue.6, pp.829-846, 1993.
DOI : 10.1086/285511

C. L. Hax and S. W. Golladay, Macroinvertebrate colonization and biofilm development on leaves and wood in a boreal river, Freshwater Biology, vol.90, issue.1, pp.79-87, 1993.
DOI : 10.1146/annurev.ecolsys.17.1.567

D. O. Hessen, G. I. Agren, T. R. Andersen, J. J. Elser, and P. C. De-ruiter, CARBON SEQUESTRATION IN ECOSYSTEMS: THE ROLE OF STOICHIOMETRY, Ecology, vol.85, issue.5, pp.1179-1192, 2004.
DOI : 10.1046/j.1365-2435.2003.00724.x

D. O. Hessen and T. R. Anderson, Excess carbon in aquatic organisms and ecosystems: Physiological, ecological, and evolutionary implications, Limnology and Oceanography, vol.53, issue.4, pp.1685-1696, 2008.
DOI : 10.4319/lo.2008.53.4.1685

M. Hieber and M. O. Gessner, CONTRIBUTION OF STREAM DETRIVORES, FUNGI, AND BACTERIA TO LEAF BREAKDOWN BASED ON BIOMASS ESTIMATES, Ecology, vol.83, issue.4, pp.1026-1038, 2002.
DOI : 10.2307/1467795

W. R. Hill, M. G. Ryon, and E. M. Schilling, Light Limitation in a Stream Ecosystem: Responses by Primary Producers and Consumers, Ecology, vol.76, issue.4, pp.1297-1309, 1995.
DOI : 10.2307/1940936

H. Hillebrand and M. Kahlert, Effect of grazing and nutrient supply on periphyton biomass and nutrient stoichiometry in habitats of different productivity, Limnology and Oceanography, vol.46, issue.8, pp.1881-1898, 2001.
DOI : 10.4319/lo.2001.46.8.1881

S. S. Kilham, D. A. Kreeger, S. G. Lynn, C. E. Goulden, and L. Herrera, COMBO: a defined freshwater culture medium for algae and zooplankton, Hydrobiologia, vol.337, pp.147-159, 1998.

Y. Kuzyakov, J. K. Friedel, and K. Stahr, Review of mechanisms and quantification of priming effects, Soil Biology and Biochemistry, vol.32, issue.11-12, pp.1485-1498, 2000.
DOI : 10.1016/S0038-0717(00)00084-5

C. Lagrue, J. S. Kominoski, M. Danger, J. Baudoin, S. Lamothe et al., Experimental shading alters leaf litter breakdown in streams of contrasting riparian canopy cover, Freshwater Biology, vol.67, issue.10, pp.2059-2069, 2011.
DOI : 10.1111/j.1365-2427.2011.02637.x

J. Leflaive, M. Danger, G. Lacroix, E. Lyautey, C. Oumarou et al., Nutrient effects on the genetic and functional diversity of aquatic bacterial communities, FEMS Microbiology Ecology, vol.66, issue.2, pp.379-390, 2008.
DOI : 10.1111/j.1574-6941.2008.00593.x
URL : https://hal.archives-ouvertes.fr/bioemco-00321407

R. L. Lindeman, The trophic-dynamic aspect of ecology, Ecology, vol.4, pp.399-417, 1942.

D. R. Lyon and S. E. Ziegler, Carbon cycling within epilithic biofilm communities across a nutrient gradient of headwater streams, Limnology and Oceanography, vol.54, issue.2, pp.439-449, 2009.
DOI : 10.4319/lo.2009.54.2.0439

A. E. Magurran, Measuring biological diversity, 2004.

C. Mille-lindblom, H. Fischer, and L. J. Tranvik, Antagonism between bacteria and fungi: substrate competition and a possible tradeoff between fungal growth and tolerance towards bacteria, Oikos, vol.42, issue.2, pp.233-242, 2006.
DOI : 10.1111/j.2006.0030-1299.14337.x

C. Mille-lindblom, E. V. Wachenfeldt, and L. J. Tranvik, Ergosterol as a measure of living fungal biomass: persistence in environmental samples after fungal death, Journal of Microbiological Methods, vol.59, issue.2, pp.253-262, 2004.
DOI : 10.1016/j.mimet.2004.07.010

B. Mindl, B. Sonntag, J. Pernthaler, J. Vrba, R. Psenner et al., Effects of phosphorus loading on interactions of algae and bacteria: reinvestigation of the ??phytoplankton-bacteria paradox?? in a continuous cultivation system, Aquatic Microbial Ecology, vol.38, pp.203-213, 2005.
DOI : 10.3354/ame038203

J. C. Moore, Detritus, trophic dynamics and biodiversity, Ecology Letters, vol.69, issue.7, pp.584-600, 2004.
DOI : 10.1111/j.1461-0248.2004.00606.x
URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.334.1133

H. T. Odum, Primary Production in Flowing Waters1, Limnology and Oceanography, vol.1, issue.2, pp.102-117, 1956.
DOI : 10.4319/lo.1956.1.2.0102

K. G. Porter and Y. S. Feig, The use of DAPI for identifying and counting aquatic microflora1, Limnology and Oceanography, vol.25, issue.5, pp.943-948, 1980.
DOI : 10.4319/lo.1980.25.5.0943

R. Development and C. Team, R: A language and environment for statistical computing. R Foundation for Statistical Computing, 2010.

S. T. Rier, K. A. Kuehn, and S. N. Francoeur, Algal regulation of extracellular enzyme activity in stream microbial communities associated with inert substrata and detritus, Journal of the North American Benthological Society, vol.26, issue.3, pp.439-449, 2007.
DOI : 10.1899/06-080.1

B. J. Roberts, P. J. Mulholland, and W. R. Hill, Multiple Scales of Temporal Variability in Ecosystem Metabolism Rates: Results from 2??Years of Continuous Monitoring in a Forested Headwater Stream, Ecosystems, vol.9, issue.4, pp.588-606, 2007.
DOI : 10.1007/s10021-007-9059-2

A. M. Romani, H. Fischer, C. Mille-lindblom, and L. J. Tranvik, INTERACTIONS OF BACTERIA AND FUNGI ON DECOMPOSING LITTER: DIFFERENTIAL EXTRACELLULAR ENZYME ACTIVITIES, Ecology, vol.87, issue.10, pp.2559-2569, 2006.
DOI : 10.1007/BF02927592

J. Rosenfeld and J. C. Roff, Primary production and potential availability of autochthonous carbon in southern Ontario streams, Hydrobiologia, vol.45, issue.2, pp.99-109, 1991.
DOI : 10.1007/BF00006866

J. T. Scott, J. A. Back, J. M. Taylor, and R. S. King, Does nutrient enrichment decouple algal???bacterial production in periphyton?, Journal of the North American Benthological Society, vol.27, issue.2, pp.332-344, 2008.
DOI : 10.1899/07-108.1

R. L. Sinsabaugh, B. H. Hill, and J. J. Shah, Ecoenzymatic stoichiometry of microbial organic nutrient acquisition in soil and sediment, Nature, vol.81, issue.7274, pp.795-798, 2009.
DOI : 10.1038/nature08632

A. D. Steinman, G. A. Lamberti, and P. R. Leavitt, Biomass and pigments of benthic algae, Methods in stream ecology, 2006.

J. L. Tank, E. J. Rosi-marshall, N. A. Griffiths, S. A. Entrekin, and M. L. Stephen, A review of allochthonous organic matter dynamics and metabolism in streams, Journal of the North American Benthological Society, vol.29, issue.1, pp.118-146, 2010.
DOI : 10.1899/08-170.1

M. Torres-ruiz and J. D. Wehr, Changes in the nutritional quality of decaying leaf litter in a stream based on fatty acid content, Hydrobiologia, vol.15, issue.1, pp.265-278, 2010.
DOI : 10.1007/s10750-010-0305-9

W. N. Venables and B. D. Ripley, Modern applied statistics with S. Fourth edition, 2002.

S. E. Ziegler and D. R. Lyon, Factors regulating epilithic biofilm carbon cycling and release with nutrient enrichment in headwater streams, Hydrobiologia, vol.55, issue.2, pp.71-88, 2010.
DOI : 10.1007/s10750-010-0296-6