Sulfur is an essential element for life that is very abundant in the ocean in the form of the sea salt component sulfate. Most marine microbes transform sulfate into usable sulfur for the synthesis of proteins, cell structures and functional compounds, from which it is cycled and recycled through the food web and by the action of sunlight.
A major portion of the biogeochemical cycling of organic sulfur in the pelagic ocean occurs through dimethylated forms: dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO).
The burst of interest in these compounds began with the hypothesized involvement of the volatile species, DMS, in aerosol and cloud formation, hence in climate regulation, over the oceans.
Over the last three decades, it has become clear that the global climate-related role of dimethylated sulfur emerges from processes occurring at the microscale. Indeed, extensive research has revealed that dimethylated sulfur compounds are involved in mechanisms against ecophysiological stress, chemical signaling among marine organisms (from plankton microbes to mammals), and sulfur transference among trophic levels of planktonic food webs. Genetic and genomic tools, single cell methods, microscale behavior observation techniques, lagrangian oceanographic cruises across day-night or calm-storm cycles, time series studies, and models are being used to understand the fundamental roles that dimethylated sulfur plays in marine ecosystems, and how it escapes to the atmosphere to eventually influence climate.
Keywords (click to see featured articles from the lab):
Simó R. (2001). Production of atmospheric sulfur by oceanic plankton: biogeochemical, ecological and evolutionary links. Trends in Ecology and Evolution 16: 287-294.
Simó R. (2004). From cells to globe: approaching the dynamics of DMS(P) in the ocean at multiple scales. Canadian Journal of Fisheries and Aquatic Sciences 61(5): 673-684.
Galí M., R. Simó (2015). A meta-analysis of oceanic DMS and DMSP cycling processes: disentangling the summer paradox. Global Biogeochemical Cycles. 29.
Vallina S.M., R. Simó, M. Manizza (2007). Weak response of oceanic dimethylsulfide to upper mixing shoaling induced by global warming. Proceedings of the National Academy of Sciences USA 104: 16004-16009
Galí M., V. Saló, R. Almeda, A. Calbet, R. Simó (2011). Stimulation of gross dimethylsulfide (DMS) production by solar radiation. Geophysical Research Letters 38, L15612.
Berdalet E., G. Llaveria, R. Simó (2011). Modulation of dimethylsulfoniopropionate (DMSP) concentration in an Alexandrium minutum (Dinophyceae) culture by small-scale turbulence: a link to toxin production? Harmful Algae 11: 88-95.
Ruiz-González C., R. Simó, M. Vila-Costa, R. Sommaruga, J.M. Gasol (2012). Sunlight modulates the relative importance of heterotrophic bacteria and picophytoplankton in DMSP-sulphur uptake. ISME Journal 6: 650-659.
Galí M., C. Ruiz-González, T. Lefort, J.M. Gasol, C. Cardelús, C. Romera-Castillo, R. Simó (2013). Spectral irradiance dependence of sunlight effects on plankton dimethylsulfide production. Limnology and Oceanography 58: 489-504.
Galí M., R. Simó, G.L. Pérez, C. Ruiz-González, H. Sarmento, S.-J. Royer, A. Fuentes-Lema, J.M. Gasol (2013). Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to static vs. dynamic light exposure in upper mixed-layer summer sea waters. Biogeosciences 10: 7983–7998.
Frade P.R., V. Schwaninger, B. Glasl, E. Sintes, R.W. Hill, R. Simó, G.J. Herndl (2016). Coral dimethylsulfoniopropionate: responses to light and stress, and interrelations with bacterial assemblages in surface mucus. Environmental Chemistry 13: 252–265.
Steiner P.A., E. Sintes, R. Simó, D. De Corte, D.M. Pfannkuchen, I. Ivančic, M. Najdek, G.J. Herndl (2019). Seasonal dynamics of marine snow-associated and free-living demethylating bacterial communities in the coastal northern Adriatic Sea. Environmental Microbiology Reports 11: 699–707.
Simó R., C. Pedrós-Alió (1999). Role of vertical mixing in controlling the oceanic production of dimethyl sulphide. Nature 402: 396-399.
Galí M., R. Simó, M. Vila-Costa, C. Ruiz-González, J.M. Gasol, P. Matrai (2013). Diel patterns of oceanic dimethylsufide (DMS) cycling: microbial and physical drivers. Global Biogeochemical Cycles 27: 1–17.
Simó R., J. Dachs (2002). Global ocean emission of dimethylsulfide predicted from biogeophysical data. Global Biogeochemical Cycles 16: 1078.
Vallina S.M., R. Simó, M. Manizza (2007). Weak response of oceanic dimethylsulfide to upper mixing shoaling induced by global warming. Proceedings of the National Academy of Sciences USA 104: 16004-16009.
Vallina S.M., R. Simó, T.R. Anderson, A. Gabric, R. Cropp, J.M. Pacheco (2008). A dynamic model of oceanic sulfur (DMOS) applied to the Sargasso Sea: Simulating the dimethylsulfide summer-paradox. J. Geophysical Research – Biogeosciences 113, G01009.
Vila M., R. Simó, R. Kiene, J. Pinhassi, J.M. González, M. A. Moran, C. Pedrós (2004). Dimethylsulfoniopropionate incorporation by marine bacterioplankton taxa studied by microautoradiography and fluorescent in situ hybridization. Applied Environmental Microbiology 70 : 4648-4657.
Vila-Costa M., J. Pinhassi, C. Alonso, J. Pernthaler, R. Simó (2007). An annual cycle of DMSP-sulfur assimilating bacterioplankton in the coastal NW Mediterranean. Environmental Microbiology 9: 2451–2463.
Simó R., S. Archer, C. Pedrós-Alió, L. Gilpin, C. Stelfox-Widdicombe (2002). Coupled dynamics of DMSP and DMS cycling and the microbial food-web in surface waters of the North Atlantic. Limnology and Oceanography 47: 53-61.
Saló V., R. Simó, M. Vila-Costa, A. Calbet (2009). Sulfur assimilation by Oxyrrhis marina feeding on a 35S-DMSP labelled prey. Environmental Microbiology 11: 3063-3072.
Simó R., V. Saló, R. Almeda, J. Movilla, I. Trepat, E. Saiz, A. Calbet (2018). The quantitative role of microzooplankton grazing in dimethylsulfide (DMS) production in the NW Mediterranean. Biogeochemistry 141: 125-142.
Vallina S.M., R.Simó (2007). Strong relationship between DMS and the solar radiation dose over the global surface ocean. Science 315: 506-509.
Vila-Costa M., R.P. Kiene, R. Simó (2008). Seasonal variability of the dynamics of dimethylated sulfur compounds in a coastal northwest Mediterranean site. Limnology Oceanography 53: 198-211.
Simó R., M. Vila-Costa, L. Alonso-Sáez, C. Cardelús, Ò. Guadayol, E. Vázquez-Domínguez, J.M. Gasol (2009). Annual series of DMSP contribution to S and C fluxes through phytoplankton and bacterioplankton in a NW Mediterranean coastal site. Aquatic Microbial Ecology 57: 43-55.
I am interested in ocean biosphere-atmosphere interactions in the Earth System. For nearly 30 years, I have investigated the biological and environmental actors that govern the production and emission of volatile sulfur from the ocean, which I have recently extended to other volatile compounds and gel-like substances. I like to look at both sides of the ocean-atmosphere interface and follow the path of oceanic emissions into aerosols and clouds.
I am also interested in chemical communication between marine organisms, and how this communication shapes trophic interactions and symbioses.
For my research I count on a network of collaborators and use a broad array of methodologies, from “single-cell biogeochemistry” and omics, and trace gas and aerosol measurements, through experimental plankton physiology and ecology, all the way up to satellite analyses and modeling of the global ocean and atmosphere. I have conducted fieldwork in the Arctic, Antarctica, across the Atlantic, tropical Pacific and Mediterranean Sea.