Biogenic gels and volatiles

As waste products of their activities, plankton microorganisms in the ocean  produce and release organic compounds, some of which are susceptible to assembling into polymeric matter and forming gel-like particles and aggregates. Two measurable types of gel-like particles are the so-called transparent exopolymeric particles (TEP), composed of polysaccharides, and the Coomassie-blue stainable particles (CSP), composed of proteinaceous material. Once formed in seawater, these particles can be colonized and consumed by bacteria, sink and export carbon and nitrogen to the deep ocean, or rise with bubbles to the very sea surface and be lifted by the wind into aerosols. We investigate how TEP and CSP are distributed in the world’s oceans, and what organisms and environmental factors are responsible for their production and recycling.

Volatile organic compounds (VOC) are also side and waste products of marine microbes. They could be regarded as mere waste products, since they will be largely lost to the atmosphere, but a number of key physiological and ecosystem functions have been identified or suggested for VOC in the pelagic ocean, including alleviation of oxidative stress, chemical communication between organisms, and climate regulation. We aim at deciphering the chemical, ecophysiological and environmental factors driving their production and cycling, and their scales of variability. The ultimate goal is to advance in getting information for diagnosing and simulating their distribution in the surface ocean.

Among the myriad of VOC found in the ocean, we focus on a few that generally occur supersaturated in surface waters and, therefore, undergo a net efflux to the atmosphere:

Dimethylsulfide (DMS) is, by far, the most abundant volatile sulfur compound in the surface ocean. Its production is related to phytoplankton, seaweed and coral taxonomy, oxidative stress, grazing on phytoplankton and algal-bacterial interactions. It is consumed by bacteria and sunlight, and, upon emission to the atmosphere, participates in aerosol formation and growth, with implications for climate.

Carbonyl sulfide (COS) and carbon disulfide (CS2) are less abundant and less known volatile sulfur compounds that form mainly when light hits marine organic matter. They further contribute sulfur to the atmosphere and, in the case of the longer-lived COS, it is the main oceanic source of sulfur to the stratosphere.

Methylamines (mono-, di- and trimethyl) result from the microbial degradation of phytoplankton-derived quaternary ammonium compounds. They are consumed by bacteria and contribute to aerosol formation and growth. Their measurement is very challenging and, hence, there is little information of their cycling processes.

Isoprene (2-methyl-1,3-butadiene) is produced in the ocean mainly by phytoplankton as a side product of photosynthesis. Very little is known of its microbial turnover. Once in the atmosphere, it contributes to aerosol growth.

Iodo- and bromomethanes, which are produced by phytoplankton and seaweeds, catalyze O3 destruction in the lower troposphere. Volatile iodine can also form new aerosols. Their production is related to oxidative stress, organic matter, sunlight and temperature, and little is known as to whether, how and how fast they are biologically consumed.

To study marine VOC, we combine multiple experimental approaches: (i) a time-series study in the coastal Mediterranean; (ii) transect studies across contrasting waters of the world’s oceans; (iii) diel cycle studies on lagrangian oceanographic cruises in Mediterranean, tropical and Antarctic waters; (iv) lab and field experiments with Mediterranean marine sponges; (v) a coral reef ecosystem study in the tropical South Pacific; and (vi) meta-analyses, satellite algorithms and numerical simulations at regional and global scales.

Sampling and analyzing VOC in a coral reef.

Keywords (click to see featured articles from the lab):


Ortega-Retuerta, E., M.M. Sala, E. Borrull, M. Mestre, F.L. Aparicio, R. Gallisai, C. Antequera, C. Marrasé, F. Peters, R. Simó, J.M. Gasol (2017). Horizontal and vertical distributions of Transparent exopolymer particles (TEP) in the NW Mediterranean Sea are linked to chlorophyll a and O2 variability. Frontiers in Microbiology 7.

Dall’Osto, M., J. Ovadnevaite, M. Paglione, D.C.S. Beddows, D. Ceburnis, C. Cree, P. Cortés, M. Zamanillo, S.O. Nunes, G.L. Pérez, E. Ortega-Retuerta, M. Emelianov, D. Vaqué, C. Marrasé, M. Estrada, M.M. Sala, M. Vidal, M.F. Fitzsimons, R. Beale, R. Airs, M. Rinaldi, S. Decesari, M.C. Facchini, R.M. Harrison, C.D. O’Dowd, R. Simó (2017).  Antarctic sea ice region as a source of biogenic organic nitrogen in aerosols. Scientific Reports 7: 6047. 

Ortega-Retuerta, E., C. Marrasé, A. Muñoz-Fernández, M.M. Sala, R. Simó, J.M. Gasol (2018). Seasonal dynamics of transparent exopolymer particles (TEP) and their drivers in the coastal NW Mediterranean Sea. Science of the Total Environment 631-632:180-190.

Zamanillo, M., E. Ortega–Retuerta, S. Nunes, P. Rodríguez–Ros, M. Dall’Osto, M. Estrada, M.M. Sala, R. Simó (2019). Main drivers of transparent exopolymer particle distribution across the surface Atlantic Ocean. Biogeosciences 16: 733–749.

Zamanillo, M., E. Ortega-Retuerta, S. Nunes, M. Estrada, M.M. Sala, S.-J. Royer, D.C. López-Sandoval, M. Emelianov, D. Vaqué, C. Marrasé, R. Simó (2019). Distribution of transparent exopolymer particles (TEP) in distinct regions of the Southern Ocean. Science of the Total Environment 691: 736-748.


Simó, R. (2011). The role of marine microbiota in short-term climate regulation. In The Role of Marine Biota in the Functioning of the Biosphere (C. Duarte, ed.). Fundación BBVA, Rubes Ed., Bilbao, pp. 107-130. ISBN 978-84-92937-04-2.


Simó, R., J. Dachs (2002). Global ocean emission of dimethylsulfide predicted from biogeophysical data. Global Biogeochemical Cycles 16: 1078.

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.

Lana, A., T.G. Bell, R. Simó, S.M. Vallina, J. Ballabrera-Poy, A.J. Kettle, J. Dachs, L. Bopp, E.S. Saltzman, J. Stefels, J.E. Johnson, P.S. Liss (2011). An updated climatology of surface dimethlysulfide concentrations and emission fluxes in the global ocean. Global Biogeochemical Cycles 25, GB1004.

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.

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.

Royer, S.-J., A.S. Mahajan, M. Galí, E.S. Saltzman, R. Simó (2015). Small-scale variability patterns of DMS and phytoplankton in surface waters of the tropical and subtropical Atlantic, Indian and Pacific oceans. Geophysical Research Letters 42: 475–483.

Royer, S-J., M. Galí, A.S. Mahajan, O.N. Ross, G.L. Pérez, E.S. Saltzman, R. Simó (2016). A high-resolution time-depth view of dimethylsulfide cycling in the surface sea. Scientific Reports 6: 32325.

Galí, M., D.J. Kieber, C. Romera-Castillo, J.D. Kinsey, E. Devred, G.L. Pérez, G.R. Westby, C. Marrasé, M. Babin, M. Levasseur, C. Duarte, S. Agustí, R. Simó (2016). CDOM sources and photobleaching control quantum yields for oceanic DMS photolysis. Environmental Science and Technology 50: 13361–13370. 

Galí, M., M. Levasseur, E. Devred, R. Simó, M. Babin (2018). Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales. Biogeosciences 15: 3497–3519.

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.


Lennartz, S.T., C.A. Marandino, M. von Hobe, P. Cortés, B. Quack, R. Simó, D. Booge, A. Pozzer, T. Steinhoff, D.L. Arévalo-Martínez, C. Kloss, A. Bracher, R. Röttgers, E. Atlas, K. Krüger (2017). Direct oceanic emissions unlikely to account for the missing source of atmospheric carbonyl sulfide. Atmospheric Chemistry and Physics 17: 385–402.

Lennartz, S.T., C.A. Marandino, M. von Hobe, M.O. Andreae, K. Aranami, E. Atlas, M. Berkelhammer, H. Bingemer, D. Booge, G. Cutter, P. Cortes, S. Kremser, C. Law, A. Marriner, R. Simó, B. Quack, G. Uher, H. Xie, X. Xu (2020). Marine carbonyl sulfide (OCS) and carbon disulfide (CS2): a compilation of measurements in seawater and the marine boundary layer. Earth System Science Data 12: 591–609.


Dall’Osto, M., J. Ovadnevaite, M. Paglione, D.C.S. Beddows, D. Ceburnis, C. Cree, P. Cortés, M. Zamanillo, S.O. Nunes, G.L. Pérez, E. Ortega-Retuerta, M. Emelianov, D. Vaqué, C. Marrasé, M. Estrada, M.M. Sala, M. Vidal, M.F. Fitzsimons, R. Beale, R. Airs, M. Rinaldi, S. Decesari, M.C. Facchini, R.M. Harrison, C.D. O’Dowd, R. Simó (2017).  Antarctic sea ice region as a source of biogenic organic nitrogen in aerosols. Scientific Reports 7: 6047.

Dall’Osto, M., R. Airs, R. Beale, C. Cree, M. Fitzsimons, D. Beddows, R. Harrison, D. Ceburnis, C. O’Dowd, M. Rinaldi, M. Paglione, A. Nenes, S. Decesari, R. Simó (2019). Simultaneous detection of alkylamines in the surface ocean and atmosphere of the Antarctic sympagic environment. ACS Earth and Space Chemistry 3 : 854-862.

Decesari, S., M. Paglione, M. Rinaldi, M. Dall’Osto, R. Simó, N. Zanca, F. Volpi, M.C. Facchini, T. Hoffmann, S. Götz, C.J. Kampf, C. O’Dowd, J. Ovadnevaite, D. Ceburnis, E. Tagliavini (2020). Shipborne measurements of Antarctic submicron organic aerosols: an NMR perspective linking multiple sources and bioregions. Atmospheric Chemistry and Physics 20: 4193–4207.


Rodríguez-Ros, P., P. Cortés, C.M. Robinson, S. Nunes, C. Hassler, S.-J. Royer, M. Estrada, M.M. Sala, R. Simó (2020). Distribution and drivers of marine isoprene concentration across the Southern Ocean. Atmosphere 11: 556.

Rodríguez-Ros, P., M. Galí, P. Cortés, C.M. Robinson, D. Antoine, C. Wohl, M.X. Yang, R. Simó. (2020). Remote sensing retrieval of isoprene concentrations in the Southern Ocean. Geophysical Research Letters 47: e2020GL087888.


Prados-Roman, C., C.A. Cuevas, T. Hay, R.P. Fernandez, A.S. Mahajan, S-J. Royer, M. Galí, R. Simó, J. Dachs, K. Großmann, D.E. Kinnison, J-F. Lamarque, A. Saiz-Lopez (2015). Iodine oxide in the global marine boundary layer. Atmospheric Chemistry and Physics 15: 583–593.


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 warmingProceedings of the National Academy of Sciences USA 104: 16004-16009

Rafel Simó

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.

Institute of Marine Sciences, Barcelona
Telf. +34 932309590