Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Dimethyl sulfide mediates microbial predator–prey interactions between zooplankton and algae in the ocean

Abstract

Phytoplankton are key components of the oceanic carbon and sulfur cycles1. During bloom events, some species can emit large amounts of the organosulfur volatile dimethyl sulfide (DMS) into the ocean and consequently the atmosphere, where it can modulate aerosol formation and affect climate2,3. In aquatic environments, DMS plays an important role as a chemical signal mediating diverse trophic interactions. Yet, its role in microbial predator–prey interactions remains elusive with contradicting evidence for its role in either algal chemical defence or in the chemo-attraction of grazers to prey cells4,5. Here we investigated the signalling role of DMS during zooplankton–algae interactions by genetic and biochemical manipulation of the algal DMS-generating enzyme dimethylsulfoniopropionate lyase (DL) in the bloom-forming alga Emiliania huxleyi6. We inhibited DL activity in E. huxleyi cells in vivo using the selective DL-inhibitor 2-bromo-3-(dimethylsulfonio)-propionate7 and overexpressed the DL-encoding gene in the model diatom Thalassiosira pseudonana. We showed that algal DL activity did not serve as an anti-grazing chemical defence but paradoxically enhanced predation by the grazer Oxyrrhis marina and other microzooplankton and mesozooplankton, including ciliates and copepods. Consumption of algal prey with induced DL activity also promoted O. marina growth. Overall, our results demonstrate that DMS-mediated grazing may be ecologically important and prevalent during prey–predator dynamics in aquatic ecosystems. The role of algal DMS revealed here, acting as an eat-me signal for grazers, raises fundamental questions regarding the retention of its biosynthetic enzyme through the evolution of dominant bloom-forming phytoplankton in the ocean.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Reduced DL activity of E. huxleyi impaired grazing by O. marina.
Fig. 2: Overexpression of DL in algal prey cells enhanced grazing efficiency and growth by O. marina.
Fig. 3: Induced DMS production in algal prey enhanced grazing by diverse zooplankton.
Fig. 4: The ecological impact of algal DMS on planktonic prey–predator interactions.

Similar content being viewed by others

Data availability

The data supporting Figs. 13 and all Extended Data figures in this study are deposited in Dryad and are available at https://doi.org/10.5061/dryad.cjsxksn66. The amplicon sequencing data were deposited on NCBI; accession numbers are MZ645612MZ645697 for the 16S analysis and MZ662955MZ663668 for the 18S analysis. Source data are provided with this paper.

Code availability

No new code was used in this study.

References

  1. Simó, R. Production of atmospheric sulfur by oceanic plankton: biogeochemical, ecological and evolutionary links. Trends Ecol. Evol. 16, 287–294 (2001).

    Article  PubMed  Google Scholar 

  2. Charlson, R. J., Lovelock, J. E., Andreae, M. O. & Warren, S. G. Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate. Nature 326, 655–661 (1987).

    Article  CAS  Google Scholar 

  3. Wang, S., Maltrud, M. E., Burrows, S. M., Elliott, S. M. & Cameron-Smith, P. Impacts of shifts in phytoplankton community on clouds and climate via the sulfur cycle. Glob. Biogeochem. Cycles 32, 1005–1026 (2018).

    Article  CAS  Google Scholar 

  4. Wolfe, G. V., Steinke, M. & Kirst, G. O. Grazing-activated chemical defence in a unicellular marine alga. Nature 387, 894–897 (1997).

    Article  CAS  Google Scholar 

  5. Seymour, J., Simó, R., Ahmed, T. & Stocker, R. Chemoattraction to dimethylsulfoniopropionate throughout the marine microbial food web. Science 329, 342–345 (2010).

    Article  CAS  PubMed  Google Scholar 

  6. Alcolombri, U. et al. Identification of the algal dimethyl sulfide-releasing enzyme: a missing link in the marine sulfur cycle. Science 348, 1466–1469 (2015).

    Article  CAS  PubMed  Google Scholar 

  7. Alcolombri, U., Lei, L., Meltzer, D., Vardi, A. & Tawfik, D. S. Assigning the algal source of dimethylsulfide using a selective lyase inhibitor. ACS Chem. Biol. 12, 41–46 (2017).

    Article  CAS  PubMed  Google Scholar 

  8. Kettle, A. J. & Andreae, M. O. Flux of dimethylsulfide from the oceans: a comparison of updated data sets and flux models. J. Geophys. Res. Atmos. 105, 26793–26808 (2000).

    Article  CAS  Google Scholar 

  9. Carpenter, L. J., Archer, S. D. & Beale, R. Ocean–atmosphere trace gas exchange. Chem. Soc. Rev. 41, 6473–6506 (2012).

    Article  CAS  PubMed  Google Scholar 

  10. Franklin, D. J., Steinke, M., Young, J., Probert, I. & Malin, G. Dimethylsulphoniopropionate (DMSP), DMSP-lyase activity (DLA) and dimethylsulphide (DMS) in 10 species of coccolithophore. Mar. Ecol. Prog. Ser. 410, 13–23 (2010).

    Article  CAS  Google Scholar 

  11. Keller, M. D. Dimethyl sulfide production and marine phytoplankton: the importance of species composition and cell size. Biol. Oceanogr. 6, 375–382 (1989).

    Google Scholar 

  12. Curson, A. R. J. et al. DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton. Nat. Microbiol. 3, 430–439 (2018).

    Article  CAS  PubMed  Google Scholar 

  13. Sunda, W., Kieber, D. J., Kiene, R. P. & Huntsman, S. An antioxidant function for DMSP and DMS in marine algae. Nature 418, 317–320 (2002).

    Article  CAS  PubMed  Google Scholar 

  14. Kirst, G. O. in Biological and Environmental Chemistry of DMSP and Related Sulfonium Compounds (eds Kiene, R. P. et al.) 121−129 (Springer, 1996).

  15. Darroch, L. et al. Effect of short-term light- and UV-stress on DMSP, DMS, and DMSP lyase activity in Emiliania huxleyi. Aquat. Microb. Ecol. 74, 173–185 (2015).

  16. Barak-Gavish, N. et al. Bacterial virulence against an oceanic bloom-forming phytoplankter is mediated by algal DMSP. Sci. Adv. 4, eaau5716 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Amin, S. A. et al. Interaction and signalling between a cosmopolitan phytoplankton and associated bacteria. Nature 522, 98–101 (2015).

    Article  CAS  PubMed  Google Scholar 

  18. Garcés, E., Alacid, E., Reñé, A., Petrou, K. & Simó, R. Host-released dimethylsulphide activates the dinoflagellate parasitoid Parvilucifera sinerae. ISME J. 7, 1065–1068 (2013).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  19. Steinke, M., Stefels, J. & Stamhuis, E. Dimethyl sulfide triggers search behavior in copepods. Limnol. Oceanogr. 51, 1925–1930 (2006).

    Article  CAS  Google Scholar 

  20. Breckels, M., Bode, N., Codling, E. & Steinke, M. Effect of grazing-mediated dimethyl sulfide (DMS) production on the swimming behavior of the copepod Calanus helgolandicus. Mar. Drugs 11, 2486 (2013).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  21. Procter, J., Hopkins, F. E., Fileman, E. S. & Lindeque, P. K. Smells good enough to eat: dimethyl sulfide (DMS) enhances copepod ingestion of microplastics. Mar. Pollut. Bull. 138, 1–6 (2019).

    Article  CAS  PubMed  Google Scholar 

  22. Foretich, M. A., Paris, C. B., Grosell, M., Stieglitz, J. D. & Benetti, D. D. Dimethyl sulfide is a chemical attractant for reef fish larvae. Sci. Rep. 7, 2498 (2017).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  23. Savoca, M. S. & Nevitt, G. A. Evidence that dimethyl sulfide facilitates a tritrophic mutualism between marine primary producers and top predators. Proc. Natl Acad. Sci. USA 111, 4157–4161 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Wright, K. L. B., Pichegru, L. & Ryan, P. G. Penguins are attracted to dimethyl sulphide at sea. J. Exp. Biol. 214, 2509–2511 (2011).

    Article  PubMed  Google Scholar 

  25. Owen, K. et al. Natural dimethyl sulfide gradients would lead marine predators to higher prey biomass. Commun. Biol. 4, 149 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Wolfe, G. V. & Steinke, M. Grazing-activated production of dimethyl sulfide (DMS) by two clones of Emiliania huxleyi. Limnol. Oceanogr. 41, 1151–1160 (1996).

    Article  CAS  Google Scholar 

  27. Simó, R. et al. The quantitative role of microzooplankton grazing in dimethylsulfide (DMS) production in the NW Mediterranean. Biogeochemistry 141, 125–142 (2018).

    Article  Google Scholar 

  28. Evans, C., Kadner, S. V. & Darroch, L. J. The relative significance of viral lysis and microzooplankton grazing as pathways of dimethylsulfoniopropionate (DMSP) cleavage: an Emiliania huxleyi culture study. Limnol. Oceanogr. 52, 1036–1045 (2007).

    Article  Google Scholar 

  29. Kiene, R. P. Dimethyl sulfide production from dimethylsulfoniopropionate in coastal seawater samples and bacterial cultures. Appl. Environ. Microbiol. 56, 3292–3297 (1990).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Bullock, H. A., Luo, H. & Whitman, W. B. Evolution of dimethylsulfoniopropionate metabolism in marine phytoplankton and bacteria. Front. Microbiol. https://doi.org/10.3389/fmicb.2017.00637 (2017).

  31. Strom, S. et al. Chemical defense in the microplankton I: feeding and growth rates of heterotrophic protists on the DMS-producing phytoplankter Emiliania huxleyi. Limnol. Oceanogr. 48, 217–229 (2003).

    Article  CAS  Google Scholar 

  32. Calbet, A. & Landry, M. R. Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems. Limnol. Oceanogr. 49, 51–57 (2004).

    Article  CAS  Google Scholar 

  33. Schmoker, C., Hernández-León, S. & Calbet, A. Microzooplankton grazing in the oceans: impacts, data variability, knowledge gaps and future directions. J. Plankton Res. 35, 691–706 (2013).

    Article  Google Scholar 

  34. Steinke, M., Wolfe, G. V. & Kirst, G. O. Partial characterisation of dimethylsulfoniopropionate (DMSP) lyase isozymes in 6 strains of Emiliania huxleyi. Mar. Ecol. 175, 215–225 (1998).

    Article  CAS  Google Scholar 

  35. Breckels, M. N., Roberts, E. C., Archer, S. D., Malin, G. & Steinke, M. The role of dissolved infochemicals in mediating predator–prey interactions in the heterotrophic dinoflagellate Oxyrrhis marina. J. Plankton Res. 33, 629–639 (2011).

    Article  Google Scholar 

  36. Saló, V., Simó, R., Vila-Costa, M. & Calbet, A. Sulfur assimilation by Oxyrrhis marina feeding on a 35S-DMSP-labelled prey. Environ. Microbiol. 11, 3063–3072 (2009).

    Article  PubMed  CAS  Google Scholar 

  37. Raina, J. B. et al. Subcellular tracking reveals the location of dimethylsulfoniopropionate in microalgae and visualises its uptake by marine bacteria. eLife 6, e23008 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  38. Franklin, D. J. et al. Identification of senescence and death in Emiliania huxleyi and Thalassiosira pseudonana: cell staining, chlorophyll alterations, and dimethylsulfoniopropionate (DMSP) metabolism. Limnol. Oceanogr. 57, 305–317 (2012).

    Article  CAS  Google Scholar 

  39. Kettles, N. L., Kopriva, S. & Malin, G. Insights into the regulation of DMSP synthesis in the diatom Thalassiosira pseudonana through APR activity, proteomics and gene expression analyses on cells acclimating to changes in salinity, light and nitrogen. PLoS ONE 9, e94795 (2014).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  40. Poulsen, N., Chesley, P. M. & Kröger, N. Molecular genetic manipulation of the diatom Thalassiosira pseudonana (bacillariophyceae). J. Phycol. 42, 1059–1065 (2006).

    Article  Google Scholar 

  41. Armbrust, E. V. et al. The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism. Science 306, 79–86 (2004).

    Article  CAS  PubMed  Google Scholar 

  42. Malviya, S. et al. Insights into global diatom distribution and diversity in the world’s ocean. Proc. Natl Acad. Sci. USA 113, E1516–E1525 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Apt, K. E. et al. In vivo characterization of diatom multipartite plastid targeting signals. J. Cell Sci. 115, 4061–4069 (2002).

    Article  CAS  PubMed  Google Scholar 

  44. McParland, E. L., Wright, A., Art, K., He, M. & Levine, N. M. Evidence for contrasting roles of dimethylsulfoniopropionate production in Emiliania huxleyi and Thalassiosira oceanica. New Phytol. 226, 396–409 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Keeling, P. J. et al. The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): illuminating the functional diversity of eukaryotic life in the oceans through transcriptome sequencing. PLoS Biol. 12, e1001889 (2014).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  46. Olson, M. B. & Strom, S. L. Phytoplankton growth, microzooplankton herbivory and community structure in the southeast Bering Sea: insight into the formation and temporal persistence of an Emiliania huxleyi bloom. Deep-Sea Res. II 49, 5969–5990 (2002).

    Article  CAS  Google Scholar 

  47. Challenger, F. & Simpson, M. I. Studies on biological methylation; a precursor of the dimethyl sulphide evolved by Polysiphonia fastigiata; dimethyl-2-carboxyethylsulphonium hydroxide and its salts. J. Chem. Soc. 3, 1591–1597 (1948).

    Article  CAS  PubMed  Google Scholar 

  48. Haas, P. The liberation of methyl sulphide by seaweed. Biochem. J. 29, 1297–1299 (1935).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Stefels, J. & Dijkhuizen, L. Characteristics of DMSP-lyase in Phaeocystis sp. (Prymnesiophyceae). Mar. Ecol. 131, 307–313 (1996).

    Article  CAS  Google Scholar 

  50. Wolfe, G. V., Sherr, E. B. & Sherr, B. F. Release and consumption of DMSP from Emiliania huxleyi during grazing by Oxyrrhis marina. Mar. Ecol. 111, 111–119 (1994).

    Article  CAS  Google Scholar 

  51. Reisch, C. R., Moran, M. A. & Whitman, W. B. Bacterial catabolism of dimethylsulfoniopropionate (DMSP). Front. Microbiol. 2, 172 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. von Dassow, P. et al. Transcriptome analysis of functional differentiation between haploid and diploid cells of Emiliania huxleyi, a globally significant photosynthetic calcifying cell. Genome Biol. 10, R114 (2009).

    Article  CAS  Google Scholar 

  53. Strom, S., Wolfe, G., Slajer, A., Lambert, S. & Clough, J. Chemical defense in the microplankton II: inhibition of protist feeding by β-dimethylsulfoniopropionate (DMSP). Limnol. Oceanogr. 48, 230–237 (2003).

    Article  CAS  Google Scholar 

  54. Li, W. Eat-me signals: keys to molecular phagocyte biology and “appetite” control. J. Cell. Physiol. 227, 1291–1297 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  55. Tyssebotn, I. M. B. et al. Concentrations, biological uptake, and respiration of dissolved acrylate and dimethylsulfoxide in the northern Gulf of Mexico. Limnol. Oceanogr. 62, 1198–1218 (2017).

    Article  Google Scholar 

  56. Curson, A. R. J., Todd, J. D., Sullivan, M. J. & Johnston, A. W. B. Catabolism of dimethylsulphoniopropionate: microorganisms, enzymes and genes. Nat. Rev. Microbiol. 9, 849–859 (2011).

    Article  CAS  PubMed  Google Scholar 

  57. Spiese, C. E., Le, T., Zimmer, R. L. & Kieber, D. J. Dimethylsulfide membrane permeability, cellular concentrations and implications for physiological functions in marine algae. J. Plankton Res. 38, 41–54 (2015).

    Article  CAS  Google Scholar 

  58. Hatton, A. D., Shenoy, D. M., Hart, M. C., Mogg, A. & Green, D. H. Metabolism of DMSP, DMS and DMSO by the cultivable bacterial community associated with the DMSP-producing dinoflagellate Scrippsiella trochoidea. Biogeochemistry 110, 131–146 (2012).

    Article  CAS  Google Scholar 

  59. Laber, C. P. et al. Coccolithovirus facilitation of carbon export in the North Atlantic. Nat. Microbiol. 3, 537–547 (2018).

    Article  CAS  PubMed  Google Scholar 

  60. Endres, C. S. & Lohmann, K. J. Perception of dimethyl sulfide (DMS) by loggerhead sea turtles: a possible mechanism for locating high-productivity oceanic regions for foraging. J. Exp. Biol. 215, 3535–3538 (2012).

    Article  PubMed  Google Scholar 

  61. Savoca, M. S. Chemoattraction to dimethyl sulfide links the sulfur, iron, and carbon cycles in high-latitude oceans. Biogeochemistry 138, 1–21 (2018).

    Article  CAS  Google Scholar 

  62. Steinke, M., Malin, G. & Liss, P. Trophic interactions in the sea: an ecological role for climate relevant volatiles? J. Phycol. 38, 630–638 (2002).

    Article  CAS  Google Scholar 

  63. Pohnert, G., Steinke, M. & Tollrian, R. Chemical cues, defence metabolites and the shaping of pelagic interspecific interactions. Trends Ecol. Evol. 22, 198–204 (2007).

    Article  PubMed  Google Scholar 

  64. Lewis, N. et al. Grazing-induced production of DMS can stabilize food-web dynamics and promote the formation of phytoplankton blooms in a multitrophic plankton model. Biogeochemistry 110, 303–313 (2012).

    Article  CAS  Google Scholar 

  65. Lewis, N. D., Breckels, M. N., Steinke, M. & Codling, E. A. Role of infochemical mediated zooplankton grazing in a phytoplankton competition model. Ecol. Complex. 16, 41–50 (2013).

    Article  Google Scholar 

  66. Hansen, F. C., Reckermann, M., Breteler, W. C. M. K. & Riegman, R. Phaeocystis blooming enhanced by copepod predation on protozoa: evidence from incubation experiments. Mar. Ecol. Prog. Ser. 102, 51–57 (1993).

    Article  Google Scholar 

  67. Levasseur, M. et al. Production of DMSP and DMS during a mesocosm study of an Emiliania huxleyi bloom: influence of bacteria and Calanus finmarchicus grazing. Mar. Biol. 126, 609–618 (1996).

    Article  CAS  Google Scholar 

  68. Guillard, R. R. & Ryther, J. H. Studies of marine planktonic diatoms. I. Cyclotella nana Hustedt, and Detonula confervacea (cleve) Gran. Can. J. Microbiol. 8, 229–239 (1962).

    Article  CAS  PubMed  Google Scholar 

  69. Parada, A. E., Needham, D. M. & Fuhrman, J. A. Every base matters: assessing small subunit rRNA primers for marine microbiomes with mock communities, time series and global field samples. Environ. Microbiol. 18, 1403–1414 (2016).

    Article  CAS  PubMed  Google Scholar 

  70. Apprill, A., McNally, S., Parsons, R. & Weber, L. Minor revision to V4 region SSU rRNA 806R gene primer greatly increases detection of SAR11 bacterioplankton. Aquat. Microb. Ecol. https://doi.org/10.3354/ame01753 (2015).

  71. Callahan, B. J. et al. DADA2: high-resolution sample inference from Illumina amplicon data. Nat. Methods 13, 581–583 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  72. Quast, C. et al. The SILVA ribosomal RNA gene database project: improved data processing and web-based tools. Nucleic Acids Res. 41, D590–D596 (2013).

    Article  CAS  PubMed  Google Scholar 

  73. McMurdie, P. J. & Holmes, S. phyloseq: an R package for reproducible interactive analysis and graphics of microbiome census data. PLoS ONE 8, e61217 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  74. Frost, B. W. Effects of size and concentration of food particles on the feeding and behavior of the marine planktonic copepod Calanus pacificus. Limnol. Oceanogr. 17, 805–815 (1972).

    Article  Google Scholar 

  75. Johnson, M. D., Michelle, R. & Stoecker, D. K. Microzooplankton grazing on Prorocentrum minimum and Karlodinium micrum in Chesapeake Bay. Limnol. Oceanogr. 48, 238–248 (2003).

    Article  Google Scholar 

  76. Stoeck, T. et al. Multiple marker parallel tag environmental DNA sequencing reveals a highly complex eukaryotic community in marine anoxic water. Mol. Ecol. 19, 21–31 (2010).

    Article  CAS  PubMed  Google Scholar 

  77. Piredda, R. et al. Diversity and temporal patterns of planktonic protist assemblages at a Mediterranean Long Term Ecological Research site. FEMS Microbiol. Ecol. https://doi.org/10.1093/femsec/fiw200 (2017).

  78. Guillou, L. et al. The Protist Ribosomal Reference database (PR2): a catalog of unicellular eukaryote small sub-unit rRNA sequences with curated taxonomy. Nucleic Acids Res. 41, D597–D604 (2013).

    Article  CAS  PubMed  Google Scholar 

  79. Slamovits, C. H., Saldarriaga, J. F., Larocque, A. & Keeling, P. J. The highly reduced and fragmented mitochondrial genome of the early-branching dinoflagellate Oxyrrhis marina shares characteristics with both apicomplexan and dinoflagellate mitochondrial genomes. J. Mol. Biol. 372, 356–368 (2007).

    Article  CAS  PubMed  Google Scholar 

  80. Untergasser, A. et al. Primer3Plus, an enhanced web interface to Primer3. Nucleic Acids Res. 35, W71–W74 (2007).

    Article  PubMed  PubMed Central  Google Scholar 

  81. Dagg, M. J., Jackson, G. A. & Checkley, D. M. The distribution and vertical flux of fecal pellets from large zooplankton in Monterey Bay and coastal California. Deep-Sea Res. I 94, 72–86 (2014).

    Article  Google Scholar 

Download references

Acknowledgements

We thank I. Nussbaum and A. Spierer for assisting in laboratory experiments, Y. Finkel for helping in genetic transformation of T. pseudonana, D. Meltzer (Weizmann Institute of Science, Israel) for synthesizing Br-DMSP used in grazing experiments, E. M. Avrahami for conducting scanning electron microscopy analysis for T. pseudonana cells, Y. Avrahami for helping with field sampling and flow cytometry and C. Kuhlisch for her constructive feedback on the manuscript. We thank the Inter-University Institute for Marine Sciences in Eilat for access to its infrastructure and services. We gratefully acknowledge financial support from the Israeli Science Foundation (grant no. 1515/15 and 1972/20) and the support by a research grant from the Estate of Bernard Berkowitz both awarded to A.V. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. During the final preparation of this paper, Prof. D. S. Tawfik died tragically; he was a brilliant, world-renowned scientist with a great passion to explore protein evolution. We would like to dedicate this paper to his memory.

Author information

Authors and Affiliations

Authors

Contributions

A.S. and A.V. conceptualized the research questions and hypothesis, designed the experiments and wrote the manuscript. A.S. performed all the experiments and analysed the data. U.A., M.J.F. and D.S.T helped in establishing the experimental system, developing the experimental tools and contributed to scientific discussions. D.S. conducted genetic transformation of T. pseudonana. A.S. and V.F. designed and conducted mesozooplankton grazing experiments. S.B.-D. performed bioinformatics analysis. R.R. performed statistical analysis. F.V. conducted 18S and 16S analyses and commented on the manuscript.

Corresponding author

Correspondence to Assaf Vardi.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Microbiology thanks Virginia Edgcomb, Jonathan Todd and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 DMS accumulation in the media of E. huxleyi 373 in response to grazing by O. marina.

DMS emission during grazing was compared to starved predator and prey-only controls. Prey: predator ratio was ~10 (initial prey concentration was 3 × 104 E. huxleyi cells ml-1). DMS was measured directly in the sealed grazing vials. Values represent a single biological replicate (the DMS measurement itself takes ~30 min). At T20, values represent the mean ± s.d.; n = 3. Error bars are smaller than symbols.

Source data

Extended Data Fig. 2 Br-DMSP toxicity for O. marina cells.

a, O. marina cells were treated with 0.1–2 µM Br-DMSP and stained with Sytox Green as an indicator of cell death. The percentage of Sytox positive cells after 2 and 3.5 h was determined by flow cytometry. At least 250 cells were analysed per sample. Horizontal lines represent the mean ± s.d.; n = 6. The percentage of Sytox positive Br-DMSP treated cells was not statistically different from the untreated control, except of 2 µM Br-DMSP at 2 h (**P = 0.0011) and 3.5 h (***P < 0.001, 1-way ANOVA, followed by Dunnett’s post-hoc). b, O. marina culture (starved or fed with Ehux 373) was treated with 0.1–2 µM Br-DMSP and measured for cell abundance. The inhibitor and prey were added at t = 0. After 3 h, O. marina cells were fixed with Lugol and quantified manually. Each data point represents a biological replicate (flask); n= 2. A total of 622-859 cells were counted per sample. No significant changes compared to untreated control were detected, P = 0.318 (2-way ANOVA).

Source data

Extended Data Fig. 3 Gating strategy of prey and predator cells in O. marina-E. huxleyi and O. marina-T. pseudonana model systems.

Ingestion rate (IR) analysis was conducted by using flow cytometry and gating of specific prey and predator population based on chlorophyll red fluorescence and light side scattering (SS). In this representative flow cytometry plot from feeding experiments, three distinct cell populations and corresponding merged fluorescent micrographs are shown: (1) free algae, (2) grazers with ingested algae, and (3) starved grazers.

Extended Data Fig. 4 Exogenous application of DL activity products had inconsistent effect on the uptake of E. huxleyi CCMP2090 or wild-type T. pseudonana by O. marina.

Ingestion rate (IR) was calculated in the presence of DMS and/or acrylate which were added to the co-culture media of E. huxleyi-O. marina (a-c) or T. pseudonana-O. marina (d-f). E. huxleyi strain CCMP2090 contains similar amount of DMSP as CCMP373, but has no detectable DMS emission, and thus considered as a low DL strain. Wild-type T. pseudonana contains ~10 fold lower cellular DMSP than E. huxleyi and has no DL enzyme, thus does not produce DMS or acrylate. Approximately 3,000-5,000 cells were analysed per sample. Horizontal lines represent the mean ± s.d.; For E. huxleyi, three independent experiments were conducted for each treatment (DMS, acrylate and DMS + acrylate), including n = 4, testing different concentrations as follows: Exp. 1 and 2 tested 5 and 10 nM; Exp. 3 tested 50 nM. Statistical significance was calculated with 2-way ANOVA followed by Dunnett’s post-hoc. For T. pseudonana, two independent experiments were conducted for each treatment, testing different concentrations as follows: For DMS, Exp. 1 tested 5-20 nM, n = 3; Exp. 2 tested 100 and 500 nM, n = 4. For acrylate, Exp. 1 tested 10 and 20 nM, n = 4; Exp. 2 tested 100 and 1000 nM, n = 4. For DMS + acrylate, Exp. 1 tested 5-20 nM, n = 3; Exp. 2 tested 20 and 50 nM, n = 4. The difference in the grazing response of O. marina on T. pseudonana in the presence of DMS and/or acrylate as compared to the respective no-addition control was not statistically significant (2-way ANOVA followed by Dunnett’s post-hoc).

Source data

Extended Data Fig. 5 Morphology, growth and DL Alma1 protein expression in T. pseudonana transformants.

a, Scanning electron microscopy (SEM) analysis showing the delicate silica frustule of exponentially growing wild-type T. pseudonana cells (upper panel) and Tp DL-GFP transformants (lower panel). No differences in silica frustule were observed following genetic transformation, such as thickness, pores and girdle bands. The micrographs represent ~20 cells observed from each type. b, T. pseudonana cell abundance during normal growth, as measured by flow cytometry. Values are mean ± s.d.; n = 3. Error bars are smaller than symbols. c, Merged bright field and fluorescence micrographs of T. pseudonana wild-type and transgenic Tp DL-GFP cells. The micrographs represent ~50 cells observed from each type. d, Western blot analysis using α-Alma1 polyclonal antibody raised by immunization with recombinant Alma16. The antibody may have some cross reactivity. One major band is observed in Tp DL-GFP cell lysate (~65 kDa), corresponding to the size of Alma1 monomer (~40 kDa) plus the GFP tag. Purified Alma1 protein (recombinant Alma1 with an additional His-Tag and linker, 2 ng) was used as positive control, showing the predicted monomer and dimer forms of the enzyme. Tp wild type (WT) and Tp GFP were used as negative controls. E. huxleyi CCMP373 (Ehux 373), which highly expresses Alma1, was used as reference, with characteristic 4–5 major bands6, including the monomer and dimer forms of the enzyme. Three independent experiments were repeated with similar results. The uncropped blot is provided in Supplementary Fig. 5.

Source data

Extended Data Fig. 6 A detailed examination of the short-term grazing response on Tp DL-GFP prey by O. marina.

a, Ingestion rate (IR) on Tp DL-GFP or wild-type cells plotted as a function of prey availability. Values are mean ± s.d.; n = 4. The trends of the two series (presented as dotted lines) are significantly different, P = 4.8 × 10-9 (ANCOVA using initial prey concentration (continuous) and genotype (categorical)). b, IR was calculated for 1 h and 2 h time intervals. This is the continuation of the measurement presented in Fig. 2g in the main text. Horizontal lines represent the mean ± s.d.; n = 6. ***P ≤ 1 × 10-4. No significant difference was found between wild type and Tp GFP, P ≥ 0.68 (two-sided mixed effects model with random intercept for batch, followed by Tukey post-hoc). The results presented in (b) were repeated in three independent experiments.

Source data

Extended Data Fig. 7 Different Tp DL clones exhibited similar grazing phenotypes by O. marina.

a, DL activity in cell lysates of T. pseudonana transgenic clones. DL activity levels were measured by DMS generation following the addition of 10 mM DMSP. Values are mean ± s.d.; n = 2. b, T. pseudonana growth curve. Values are mean ± s.d.; n = 3. Error bars are smaller than symbols. Growth of Tp wild type was similar to transgenic lines expressing the Alma protein. c, Ingestion rate (IR) values were calculated for O. marina feeding on Tp DL clones as prey during 1-4 h. Horizontal lines represent the mean ± s.d.; n = 4. IR of the two Tp DL clones was not statistically different, P ≥ 0.057, but significantly higher than on wild type, P ≤ 1.3 × 10-3 (two-sided, generalized linear mixed model followed by Tukey post-hoc). Three independent experiments were conducted with similar results as presented in (a-c).

Source data

Extended Data Fig. 8 18 S amplicon sequencing of the natural grazer community from the Red Sea during grazing experiments with transgenic diatom prey.

During two field experiments conducted in 2020 (presented in Fig. 3b.), seawater were collected by a concentrating plankton net (5 µm pore size) and then passed through a 200 µm mesh (as described in Supplementary Fig. 2). The 5–200 µm fraction contained various grazers that were fed with the transgenic diatoms. With the aim of characterizing the grazer population in the experiment, a sample of grazer-containing seawater was filtered prior to the addition of the diatom prey, and used for DNA extraction and 18 S sequencing. a, The relative abundance of taxonomic groups with grazer species. Two water samples are presented (technical replicates). Non-grazer taxa such as parasites, fungi, autotrophic phytoplankton and land plants were omitted from the graph. A detailed taxonomic analysis is shown for the main phyla represented in the analysis, namely arthropoda (b), ciliophora (c) and the superclass dinoflagellata (d).

Source data

Extended Data Fig. 9 Uptake of T. pseudonana transgenic cells by wild tintinnid ciliates.

Natural microzooplankton were collected from the Red Sea and incubated with Tp DL-GFP or Tp GFP cells as prey for 24 h. a, A variety of tintinnids observed during grazing experiments. Samples were fixed with Lugol. b, A tintinnid feeding on Tp GFP cells. Some ingested diatoms are observed inside the lorica. The ciliate itself is at the oral end of the lorica, collecting prey using its cilia. The diatoms’ GFP cannot be clearly observed in this case, since this tintinnid has natural green fluorescence. c, A tintinnid fed with Tp DL-GFP cells. The ciliate cell itself is contracted inside the lorica. d, A magnified view of the inset in (c), showing the fluorescence of ingested Tp DL-GFP cells. The micrographs represent ~20 ciliate cells which were observed with ingested prey during different experiments as summarized in Fig. 3b in the main text.

Extended Data Fig. 10 Faecal pellet production by mesozooplankton following tritrophic interaction with O. marina and DMS-producing phytoplankton.

A summary of three independent experiments testing the consumption of pretreated O. marina cells by crustaceans. O. marina was pre-fed with different diets as indicated in the ‘Prey’ column. The crustaceans gut content was measured after 48 h by qPCR in order to estimate their direct feeding response on O. marina (Om). For technical reasons, gut content analysis based on prey-DNA content yielded very low values and could not be quantified accurately. Thus, only approximate evaluation of O. marina ingestion by the crustaceans is presented in the ‘Om ingested’ column. The crustaceans faecal pellet (FP) production was estimated after 48 h as a proxy for their ingestion. The pellets were counted manually under a light microscope and quantified for pellet count, volume and carbon content, assuming a carbon: volume ratio of 55 [µg C mm-3]81. Statistical significance (p-value) is related to FP biovolume and carbon, as was calculated by 1-way ANOVA with Dunnett’s post-hoc test, for compering each diet to the no-prey treatment. ani = animal; d = day.

Source data

Supplementary information

Supplementary Information

Supplementary Figs. 1–5 and Tables 1–3.

Reporting Summary

Supplementary Data 1

Statistical source data.

Supplementary Data 2

Statistical source data.

Supplementary Data 3

Statistical source data.

Peer Review File

Source data

Source Data Fig. 1

Statistical source data.

Source Data Fig. 2

Statistical source data.

Source Data Fig. 3

Statistical source data.

Source Data Extended Data Fig. 1

Statistical source data.

Source Data Extended Data Fig. 2

Statistical source data.

Source Data Extended Data Fig. 4

Statistical source data.

Source Data Extended Data Fig. 5

Statistical source data.

Source Data Extended Data Fig. 6

Statistical source data.

Source Data Extended Data Fig. 7

Statistical source data.

Source Data Extended Data Fig. 8

Statistical source data.

Source Data Extended Data Fig. 10

Statistical source data.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Shemi, A., Alcolombri, U., Schatz, D. et al. Dimethyl sulfide mediates microbial predator–prey interactions between zooplankton and algae in the ocean. Nat Microbiol 6, 1357–1366 (2021). https://doi.org/10.1038/s41564-021-00971-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41564-021-00971-3

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing