Research ArticleMICROBIOLOGY

Aquatic and terrestrial cyanobacteria produce methane

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Science Advances  15 Jan 2020:
Vol. 6, no. 3, eaax5343
DOI: 10.1126/sciadv.aax5343
  • Fig. 1 δ13C-CH4 values measured during incubation experiments of 13 different filamentous and unicellular freshwater, soil, and marine cyanobacterial cultures with and without NaH13CO3 supplementation.

    All cyanobacterial cultures produced CH4. Using NaH13CO3 as carbon source (CL) resulted in increasing stable δ13C-CH4 values as compared to the starting condition. This establishes the direct link between carbon fixation and CH4 production. The 13C enrichment is not quantitative and thus not comparable between cultures. Error bars represent SD (n = 4).

  • Fig. 2 Continuous measurements of CH4 and oxygen under light/dark periods using a MIMS.

    Examples are shown for two cultures. Data for other cultures can be found in fig. S2. A decrease in CH4 concentration is a result of either reduced or no production coupled with degassing from the supersaturated, continuously mixing, semiopen incubation chamber toward equilibrium with atmospheric CH4 (2.5 and 2.1 nM for fresh water and seawater, respectively). Calculated CH4 production rates account for the continuous emission of CH4 from the incubation chamber for as long as the CH4 concentrations are supersaturated. The light regime for the experiments was as follows: Dark (black bars) from 19:30 to 09:00, and then light intensity (yellow bars) was programmed to increase to 60, 120, 180, 400 μmol quanta m−2 s−1 with a hold time of 1.5 hours at each light intensity. After the maximum light period, the light intensity was programmed to decrease in reversed order with the same hold times until complete darkness again at 19:30.

  • Fig. 3 Average CH4 production rates obtained from multiple long-term measurements (2 to 5 days) using a MIMS.

    The rates are designated by color according to the environment from which the cyanobacteria were originally isolated. Dark blue, marine environment; light blue, freshwater environment; green, soil environment. Gray and red lines represent median and mean values, respectively. Rates for the larger cyanobacteria in (A) are given in μmol g dry weight−1 hour−1 and rates for the picocyanobacteria (B) are given in pmol per 106 cells per hour−1.

  • Table 1 Cyanobacterial cultures used in this study and their growth conditions.

    Cultures marked with an asterisk are fully axenic, while others are monoalgal. IBVF: Culture collection of the Institute for Plant Biochemistry and Photosynthesis, Sevilla Spain; CCALA: Culture collection of autotrophic organisms; HUJI: Laboratory of A. Kaplan, Hebrew University of Jerusalem, Jerusalem Israel; IOW: Laboratory of F. Pollehne, Leibniz Institute for Baltic Sea research, Warnemünde, Germany; MPI-MM: Max Planck Institute for Marine Microbiology, Bremen, Germany; IGB: Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany; University of Freiburg, Laboratory of Claudia Steglich, Freiburg University, Freiburg, Germany; Haifa University, Laboratory of D. Sher. Media source: BG11: (50); f/2: (51); YBCII: (65); AMP1: (52); filtered sea water (FSW)/artificial sea water Pro99: (52).

    Strain nameSourceMorphologyGrowth mediumIncubation
    temperature (°C)
    Anabaena sp. PCC 7120*IBVFFilamentousBG1130
    Anabaena cylindrica
    ATCC29414
    IBVFFilamentousBG1130
    Anabaena borealisCCALAFilamentousBG1130
    Scytonema hofmanni PCC 7110IBVFFilamentousBG1130
    Leptolyngbya sp. (desert crust)HUJIFilamentousBG1130
    Phormidium persicinumIBVFFilamentousf/226
    Trichodesmium erythraeumMPI-MMFilamentousYBCII26
    Nodularia spumigenaIOWFilamentousf/2 [8 PSU (practical salinity unit)]20
    Chroococcidiopsis sp. PCC 9317IBVFUnicellularBG1130
    Microcystis aeruginosa PCC 7806IGBUnicellularBG1130
    Prochlorococcus sp. MIT9313University of FreiburgUnicellularAMP122
    Prochlorococcus sp. MIT9312*Haifa UniversityUnicellularASW-Pro9922
    Prochlorococcus sp. MIT0604*Haifa UniversityUnicellularFSW-Pro9922
    Prochlorococcus sp. NATL2A*Haifa UniversityUnicellularASW-Pro9922
    Prochlorococcus sp. MED4*Haifa UniversityUnicellularASW-Pro9922
    Synechococcus sp. WH7803*Haifa UniversityUnicellularASW-Pro9922
    Synechococcus sp. WH8102*Haifa UniversityUnicellularASW-Pro9922

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/6/3/eaax5343/DC1

    Fig. S1. Temporal profiles of CH4, O2, and cyanobacterial derived chlorophyll a between July 2014 and 2016.

    Fig. S2. Continuous measurements of CH4 and oxygen under light/dark cycles using a MIMS in 17 different cyanobacterial cultures.

    Fig. S3. Community composition of the cyanobacterial cultures as obtained when sequenced using archaea-specific primers resulting in 71,981 reads for PCC 7110, 5442 reads for PCC 7806, 14,489 reads for PCC 9317, 91,105 reads for A. borealis, 13,173 reads for ATCC29414, 133,336 reads for Leptolyngbia sp., 172,112 reads for MIT9313, 35,257 for T. erythraeum, and 82,190 reads for P. persicinum of 200,000 commissioned reads.

    Fig. S4. Effects of photosynthesis inhibitors on cyanobacterial CH4 production.

    Fig. S5. Average CH4 production rates (μmol g dry weight−1 hour−1) obtained from multiple long-term measurements (2 to 5 days) with a MIMS.

    Fig. S6. Methane ionization pattern.

    Fig. S7. Raw signal obtained from mass 15 (CH4) and mass 40 (Argon) plotted against the calculated solubility at different salinities at 30°C.

    Table S1. Estimated global CH4 production rates divided into various cyanobacterial habitats showing the potential contribution of cyanobacteria in global CH4 cycling.

    References (6671)

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Temporal profiles of CH4, O2, and cyanobacterial derived chlorophyll a between July 2014 and 2016.
    • Fig. S2. Continuous measurements of CH4 and oxygen under light/dark cycles using a MIMS in 17 different cyanobacterial cultures.
    • Fig. S3. Community composition of the cyanobacterial cultures as obtained when sequenced using archaea-specific primers resulting in 71,981 reads for PCC 7110, 5442 reads for PCC 7806, 14,489 reads for PCC 9317, 91,105 reads for A. borealis, 13,173 reads for ATCC29414, 133,336 reads for Leptolyngbia sp., 172,112 reads for MIT9313, 35,257 for T. erythraeum, and 82,190 reads for P. persicinum of 200,000 commissioned reads.
    • Fig. S4. Effects of photosynthesis inhibitors on cyanobacterial CH4 production.
    • Fig. S5. Average CH4 production rates (μmol g dry weight−1 hour−1) obtained from multiple long-term measurements (2 to 5 days) with a MIMS.
    • Fig. S6. Methane ionization pattern.
    • Fig. S7. Raw signal obtained from mass 15 (CH4) and mass 40 (Argon) plotted against the calculated solubility at different salinities at 30°C.
    • Table S1. Estimated global CH4 production rates divided into various cyanobacterial habitats showing the potential contribution of cyanobacteria in global CH4 cycling.
    • References (6671)

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