CDOM; DOC; mesocosms; viruses; cyanobacteria; heterotrophic; bacteria; CO2
Résumé :
[en] Chromophoric dissolved organic matter (CDOM) represents the optically active fraction of the bulk dissolved organic matter (DOM) pool. Recent evidence pointed towards a microbial source of CDOM in the aquatic environment and led to the proposal that phytoplankton is not a direct source of CDOM, but that heterotrophic bacteria, through reprocessing of DOM of algal origin, are an important source of CDOM. In a recent experiment designed at looking at the effects of elevated pCO(2) on blooms of the coccolithophorid alga Emiliania huxleyi, we found that despite the 3 different pCO(2) levels tested (190, 414 and 714 ppm), no differences were observed in accumulation of CDOM over the 20 d of incubation. Unlike previous mesocosm experiments where. relationships between CDOM accumulation and bacterial abundance have been observed, none was observed here. These results provide some new insights into the apparent lack of effect of pCO(2) on CDOM accumulation in surface waters, and question the previously proposed mechanisms and rates of CDOM production in natural phytoplankton blooms.
Disciplines :
Sciences aquatiques & océanologie Sciences de l’environnement & écologie Sciences de la terre & géographie physique
Auteur, co-auteur :
Rochelle-Newall, Emma; CNRS-Université de Paris 6 > Laboratoire d’Océanographie
Delille, Bruno ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Océanographie chimique
Frankignoulle, Michel; Université de Liège - ULiège > Océanographie Chimique
Gattuso, Jean-Pierre; CNRS-Université de Paris 6 > Laboratoire d’Océanographie
Jacquet, Stéphan; UMR CARRTEL > Station INRA d’Hydrobiologie Lacustre
Riebesell, Ulf; Alfred Wegener Institute for Polar and Marine Research
Terbruggen, Anja; Alfred Wegener Institute for Polar and Marine Research
Zondervan, Ingrid; Alfred Wegener Institute for Polar and Marine Research
Langue du document :
Anglais
Titre :
Chromophoric dissolved organic matter in experimental mesocosms maintained under different pCO(2) levels
DG RDT - Commission Européenne. Direction Générale de la Recherche et de l'Innovation CNRS - Centre National de la Recherche Scientifique F.R.S.-FNRS - Fonds de la Recherche Scientifique
Arrigo RA, Brown CW (1996) Impact of chromophoric dissolved organic matter on UV inhibition of primary productivity in the sea. Mar Ecol Prog Ser 140:207-216
Balch WM, Vaughn J, Novotny J, Drapeau DT and 5 others (2002) Fundamental changes in light scattering associated with infection of marine bacteria by bacteriophage. Limnol Oceanogr 47:1554-1561
Blough NV, Del Vecchio R (2002) Chromophoric dissolved organic matter in the coastal environment. In: Hansell D, Carlson CA (eds) Biogeochemistry of marine dissolved organic matter. Academic Press, New York
Carlson CA, Ducklow HW, Michaels AF (1994) Annual flux of dissolved organic carbon from the euphotic zone in the northwestern Sargasso Sea. Nature 371:405-408
Egge JK, Heimdal BR (1994) Blooms of phytoplankton including Emiliania huxleyi (Haptophyta). Effects of nutrient supply in different N:P ratios. Sarsia 79:333-348
Engel A, Delille B, Jacquet J, Riebesell U, Rochelle-Newall E, Terbrüggen A, Zondervan I (2004) TEP and DOC production during a bloom experiment with Emiliana huxleyi exposed to different CO2 concentration. Aquat Microb Ecol 34:93-104
Gattuso JP, Allemand D, Frankignoulle M (1999) Photosynthesis and calcification at cellular, organismal and community levels in coral reefs: a review on interactions and control by carbonate chemistry. Am Zool 39:160-183
Hein M, Sand-Jensen K (1997) CO2 increases oceanic primary production. Nature 388:526-527
IPCC (Intergovernmental Panel on Climate Change) (2001) Climate change 2001: the scientific basis. Contribution of Working Group I to the third assessment report of the IPCC. Cambridge University Press, Cambridge
Jacquet S, Heldal M, Iglesias-Rodriguez D, Larsen A, Wilson W, Bratbak G (2002) Flow cytometric analysis of an Emiliana huxleyi bloom terminated by viral infection. Aquat Microb Ecol 27:111-124
Larsen A, Castberg T, Sandaa RA, Brussaard CPD and 6 others (2001) Population dynamics and diversity of phytoplankton, bacteria and viruses in a seawater enclosure. Mar Ecol Prog Ser 221:47-57
Larsen A, Flaten GAF, Sandaa RA, Castberg T, Thyrhaug R, Erga SR, Jacquet S, Bratbak G (2004) Spring phytoplankton bloom in Norwegian coastal waters: microbial community succession and diversity. Limnol Oceanogr 49:180-190
Milliman JD, Droxler AW (1996) Neritic and pelagic carbonate sedimentation in the marine environment: ignorance is not bliss. Geol Rund 85:496-504
Nelson NB, Seigel DA, Michaels AF (1998) Seasonal dynamics of colored dissolved organic matter in the Sargasso Sea. Deep-Sea Res I 45:931-957
Passow U (2002) Transparent exopolymer particles (TEP) in aquatic environments. Prog Oceanogr 55:287-333
Porter KG, Feig TS (1980) The use of DAPI for identifying and counting aquatic microflora. Limnol Oceanogr 25:943-948
Riebesell U, Zondervan I, Rost B, Tortell PD, Morel FMM (2000) Reduced calcification of marine plankton in response to increased atmospheric CO 2. Nature 407: 364-367
Robertson JE, Robinson C, Turner DR, Holligan P, Watson AJ, Boyd P, Fernandez E, Finch M (1994) The impact of a coccolithophore bloom on oceanic carbon uptake in the northeast Atlantic during summer 1991. Deep-Sea Res I 41:297-314
Rochelle-Newall EJ, Fisher TR (2002a) An investigation into phytoplankton as a source of chromophoric dissolved organic matter. Mar Chem 77:7-21
Rochelle-Newall EJ, Fisher TR (2002b) Chromophoric dissolved organic matter and dissolved organic carbon in Chesapeake Bay. Mar Chem 77:23-41
Rochelle-Newall EJ, Fisher TR, Fan CL, Glibert PM (1999) Dynamics of chromophoric dissolved organic matter and dissolved organic carbon in experimental mesocosms. Int J Remote Sens 20:627-641
Stedmon CA, Markager S, Kaas H (2000) Optical properties and signatures of Chromophoric Dissolved Organic Matter (CDOM) in Danish coastal waters. Estuar Coast Shelf Sci 51:267-278
Vaulot D (1989) CytoPC: processing software for flow cytometric data. Signal Noise 2:8
Williamson CE, Stemberger RS, Morris DP, Frost TM, Paulsen SG (1996) Ultraviolet radiation in North American lakes: attenuation estimates from DOM measurements and implications for plankton communities. Limnol Oceanogr 41:1024-1034
