Termite mounds mitigate half of termite methane emissions

Philipp A. Nauer, Lindsay B. Hutley, Stefan K. Arndt

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Termites are responsible for ∼1 to 3% of global methane (CH4) emissions. However, estimates of global termite CH4 emissions span two orders of magnitude, suggesting that fundamental knowledge of CH4 turnover processes in termite colonies is missing. In particular, there is little reliable information on the extent and location of microbial CH4 oxidation in termite mounds. Here, we use a one-box model to unify three independent field methods—a gas-tracer test, an inhibitor approach, and a stable-isotope technique—and quantify CH4 production, oxidation, and transport in three North Australian termite species with different feeding habits and mound architectures. We present systematic in situ evidence of widespread CH4 oxidation in termite mounds, with 20 to 80% of termite-produced CH4 being mitigated before emission to the atmosphere. Furthermore, closing the CH4 mass balance in mounds allows us to estimate in situ termite biomass from CH4 turnover, with mean biomass ranging between 22 and 86 g of termites per kilogram of mound for the three species. Field tests with excavated mounds show that the predominant location of CH4 oxidation is either in the mound material or the soil beneath and is related to species-specific mound porosities. Regardless of termite species, however, our data and model suggest that the fraction of oxidized CH4 (fox) remains well buffered due to links among consumption, oxidation, and transport processes via mound CH4 concentration. The mean fox of 0.50 ± 0.11 (95% CI) from in situ measurements therefore presents a valid oxidation factor for future global estimates of termite CH4 emissions.

    Original languageEnglish
    Pages (from-to)13306-13311
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume115
    Issue number52
    Early online date26 Nov 2018
    DOIs
    Publication statusPublished - 26 Dec 2018

    Fingerprint

    Isoptera
    Methane
    Biomass
    Oil and Gas Fields
    Porosity
    Atmosphere
    Isotopes
    Habits
    Soil

    Cite this

    @article{02cf44475bf84f67ac3ca064c3a6ddb1,
    title = "Termite mounds mitigate half of termite methane emissions",
    abstract = "Termites are responsible for ∼1 to 3{\%} of global methane (CH4) emissions. However, estimates of global termite CH4 emissions span two orders of magnitude, suggesting that fundamental knowledge of CH4 turnover processes in termite colonies is missing. In particular, there is little reliable information on the extent and location of microbial CH4 oxidation in termite mounds. Here, we use a one-box model to unify three independent field methods—a gas-tracer test, an inhibitor approach, and a stable-isotope technique—and quantify CH4 production, oxidation, and transport in three North Australian termite species with different feeding habits and mound architectures. We present systematic in situ evidence of widespread CH4 oxidation in termite mounds, with 20 to 80{\%} of termite-produced CH4 being mitigated before emission to the atmosphere. Furthermore, closing the CH4 mass balance in mounds allows us to estimate in situ termite biomass from CH4 turnover, with mean biomass ranging between 22 and 86 g of termites per kilogram of mound for the three species. Field tests with excavated mounds show that the predominant location of CH4 oxidation is either in the mound material or the soil beneath and is related to species-specific mound porosities. Regardless of termite species, however, our data and model suggest that the fraction of oxidized CH4 (fox) remains well buffered due to links among consumption, oxidation, and transport processes via mound CH4 concentration. The mean fox of 0.50 ± 0.11 (95{\%} CI) from in situ measurements therefore presents a valid oxidation factor for future global estimates of termite CH4 emissions.",
    keywords = "Methane emissions, Methane oxidation, Methanotrophs, Termite biomass, Termite mounds",
    author = "Nauer, {Philipp A.} and Hutley, {Lindsay B.} and Arndt, {Stefan K.}",
    year = "2018",
    month = "12",
    day = "26",
    doi = "10.1073/pnas.1809790115",
    language = "English",
    volume = "115",
    pages = "13306--13311",
    journal = "Proceedings of the National Academy of Sciences of the United States of America",
    issn = "0027-8424",
    publisher = "National Academy of Sciences (USA)",
    number = "52",

    }

    Termite mounds mitigate half of termite methane emissions. / Nauer, Philipp A.; Hutley, Lindsay B.; Arndt, Stefan K.

    In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 115, No. 52, 26.12.2018, p. 13306-13311.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Termite mounds mitigate half of termite methane emissions

    AU - Nauer, Philipp A.

    AU - Hutley, Lindsay B.

    AU - Arndt, Stefan K.

    PY - 2018/12/26

    Y1 - 2018/12/26

    N2 - Termites are responsible for ∼1 to 3% of global methane (CH4) emissions. However, estimates of global termite CH4 emissions span two orders of magnitude, suggesting that fundamental knowledge of CH4 turnover processes in termite colonies is missing. In particular, there is little reliable information on the extent and location of microbial CH4 oxidation in termite mounds. Here, we use a one-box model to unify three independent field methods—a gas-tracer test, an inhibitor approach, and a stable-isotope technique—and quantify CH4 production, oxidation, and transport in three North Australian termite species with different feeding habits and mound architectures. We present systematic in situ evidence of widespread CH4 oxidation in termite mounds, with 20 to 80% of termite-produced CH4 being mitigated before emission to the atmosphere. Furthermore, closing the CH4 mass balance in mounds allows us to estimate in situ termite biomass from CH4 turnover, with mean biomass ranging between 22 and 86 g of termites per kilogram of mound for the three species. Field tests with excavated mounds show that the predominant location of CH4 oxidation is either in the mound material or the soil beneath and is related to species-specific mound porosities. Regardless of termite species, however, our data and model suggest that the fraction of oxidized CH4 (fox) remains well buffered due to links among consumption, oxidation, and transport processes via mound CH4 concentration. The mean fox of 0.50 ± 0.11 (95% CI) from in situ measurements therefore presents a valid oxidation factor for future global estimates of termite CH4 emissions.

    AB - Termites are responsible for ∼1 to 3% of global methane (CH4) emissions. However, estimates of global termite CH4 emissions span two orders of magnitude, suggesting that fundamental knowledge of CH4 turnover processes in termite colonies is missing. In particular, there is little reliable information on the extent and location of microbial CH4 oxidation in termite mounds. Here, we use a one-box model to unify three independent field methods—a gas-tracer test, an inhibitor approach, and a stable-isotope technique—and quantify CH4 production, oxidation, and transport in three North Australian termite species with different feeding habits and mound architectures. We present systematic in situ evidence of widespread CH4 oxidation in termite mounds, with 20 to 80% of termite-produced CH4 being mitigated before emission to the atmosphere. Furthermore, closing the CH4 mass balance in mounds allows us to estimate in situ termite biomass from CH4 turnover, with mean biomass ranging between 22 and 86 g of termites per kilogram of mound for the three species. Field tests with excavated mounds show that the predominant location of CH4 oxidation is either in the mound material or the soil beneath and is related to species-specific mound porosities. Regardless of termite species, however, our data and model suggest that the fraction of oxidized CH4 (fox) remains well buffered due to links among consumption, oxidation, and transport processes via mound CH4 concentration. The mean fox of 0.50 ± 0.11 (95% CI) from in situ measurements therefore presents a valid oxidation factor for future global estimates of termite CH4 emissions.

    KW - Methane emissions

    KW - Methane oxidation

    KW - Methanotrophs

    KW - Termite biomass

    KW - Termite mounds

    UR - http://www.scopus.com/inward/record.url?scp=85059213691&partnerID=8YFLogxK

    U2 - 10.1073/pnas.1809790115

    DO - 10.1073/pnas.1809790115

    M3 - Article

    VL - 115

    SP - 13306

    EP - 13311

    JO - Proceedings of the National Academy of Sciences of the United States of America

    JF - Proceedings of the National Academy of Sciences of the United States of America

    SN - 0027-8424

    IS - 52

    ER -