The interactive effect of temperature and humidity on the oxygen isotope composition of kangaroos

Brett Murphy, David Bowman, M Gagan

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    1. A strong relationship between the oxygen isotope composition (expressed as ?18O) of body water and relative humidity has been demonstrated for a number of mammalian herbivores with low drinking water requirements, including kangaroos. Consequently, it has been suggested that the oxygen isotope composition of preserved mammal remains may be used to reconstruct past relative humidity. Other physiological, environmental and ecological factors may also influence mammalian ?18O, thereby confounding the climatic signal, yet these factors have been rigorously examined in few taxa. 2. We examined sources of variation in the ?18O of tooth enamel, assumed to reflect ?18O of body water, of kangaroos (Macropus spp.) collected throughout Australia. 3. Relative humidity explained a large proportion of the variation in enamel ?18O, a finding that is consistent with previous studies. However, we also found a previously unreported interaction between mean annual temperature and relative humidity. At lower temperatures, the relationship between enamel ?18O and relative humidity was much steeper than at higher temperatures. 4. This may be a consequence of the Pecl�effect in plant leaves, whereby high transpiration rates diminish the 18O enrichment of bulk leaf water. It is likely that this interaction is also present in other herbivores with low drinking water requirements. 5. We found little evidence that ?18O varied consistently between molars, suggesting that a 'weaning effect' is either absent or swamped by seasonal variation in precipitation ?18O. 6. We suggest that the oxygen isotope composition of preserved kangaroo remains cannot be used to reconstruct relative humidity unless ambient air temperature can be reliably estimated. � 2007 The Authors.
    Original languageEnglish
    Pages (from-to)757-766
    Number of pages10
    JournalFunctional Ecology
    Volume21
    Issue number4
    Publication statusPublished - 2007

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    Macropodidae
    oxygen isotope
    relative humidity
    humidity
    isotopes
    oxygen
    enamel
    temperature
    water requirement
    body water
    drinking water
    herbivore
    herbivores
    Macropus
    tooth enamel
    weaning
    transpiration
    ambient air
    tooth
    effect

    Cite this

    @article{e47a5c24caab4024a6c5af4d9b2e1f59,
    title = "The interactive effect of temperature and humidity on the oxygen isotope composition of kangaroos",
    abstract = "1. A strong relationship between the oxygen isotope composition (expressed as ?18O) of body water and relative humidity has been demonstrated for a number of mammalian herbivores with low drinking water requirements, including kangaroos. Consequently, it has been suggested that the oxygen isotope composition of preserved mammal remains may be used to reconstruct past relative humidity. Other physiological, environmental and ecological factors may also influence mammalian ?18O, thereby confounding the climatic signal, yet these factors have been rigorously examined in few taxa. 2. We examined sources of variation in the ?18O of tooth enamel, assumed to reflect ?18O of body water, of kangaroos (Macropus spp.) collected throughout Australia. 3. Relative humidity explained a large proportion of the variation in enamel ?18O, a finding that is consistent with previous studies. However, we also found a previously unreported interaction between mean annual temperature and relative humidity. At lower temperatures, the relationship between enamel ?18O and relative humidity was much steeper than at higher temperatures. 4. This may be a consequence of the Pecl�effect in plant leaves, whereby high transpiration rates diminish the 18O enrichment of bulk leaf water. It is likely that this interaction is also present in other herbivores with low drinking water requirements. 5. We found little evidence that ?18O varied consistently between molars, suggesting that a 'weaning effect' is either absent or swamped by seasonal variation in precipitation ?18O. 6. We suggest that the oxygen isotope composition of preserved kangaroo remains cannot be used to reconstruct relative humidity unless ambient air temperature can be reliably estimated. � 2007 The Authors.",
    keywords = "air temperature, climate effect, enamel, isotopic composition, marsupial, oxygen isotope, relative humidity, seasonal variation, stable isotope, temperature effect, transpiration, weaning, Australasia, Australia, Macropodidae, Macropus, Mammalia",
    author = "Brett Murphy and David Bowman and M Gagan",
    year = "2007",
    language = "English",
    volume = "21",
    pages = "757--766",
    journal = "Functional Ecology",
    issn = "0269-8463",
    publisher = "Wiley-Blackwell",
    number = "4",

    }

    The interactive effect of temperature and humidity on the oxygen isotope composition of kangaroos. / Murphy, Brett; Bowman, David; Gagan, M.

    In: Functional Ecology, Vol. 21, No. 4, 2007, p. 757-766.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - The interactive effect of temperature and humidity on the oxygen isotope composition of kangaroos

    AU - Murphy, Brett

    AU - Bowman, David

    AU - Gagan, M

    PY - 2007

    Y1 - 2007

    N2 - 1. A strong relationship between the oxygen isotope composition (expressed as ?18O) of body water and relative humidity has been demonstrated for a number of mammalian herbivores with low drinking water requirements, including kangaroos. Consequently, it has been suggested that the oxygen isotope composition of preserved mammal remains may be used to reconstruct past relative humidity. Other physiological, environmental and ecological factors may also influence mammalian ?18O, thereby confounding the climatic signal, yet these factors have been rigorously examined in few taxa. 2. We examined sources of variation in the ?18O of tooth enamel, assumed to reflect ?18O of body water, of kangaroos (Macropus spp.) collected throughout Australia. 3. Relative humidity explained a large proportion of the variation in enamel ?18O, a finding that is consistent with previous studies. However, we also found a previously unreported interaction between mean annual temperature and relative humidity. At lower temperatures, the relationship between enamel ?18O and relative humidity was much steeper than at higher temperatures. 4. This may be a consequence of the Pecl�effect in plant leaves, whereby high transpiration rates diminish the 18O enrichment of bulk leaf water. It is likely that this interaction is also present in other herbivores with low drinking water requirements. 5. We found little evidence that ?18O varied consistently between molars, suggesting that a 'weaning effect' is either absent or swamped by seasonal variation in precipitation ?18O. 6. We suggest that the oxygen isotope composition of preserved kangaroo remains cannot be used to reconstruct relative humidity unless ambient air temperature can be reliably estimated. � 2007 The Authors.

    AB - 1. A strong relationship between the oxygen isotope composition (expressed as ?18O) of body water and relative humidity has been demonstrated for a number of mammalian herbivores with low drinking water requirements, including kangaroos. Consequently, it has been suggested that the oxygen isotope composition of preserved mammal remains may be used to reconstruct past relative humidity. Other physiological, environmental and ecological factors may also influence mammalian ?18O, thereby confounding the climatic signal, yet these factors have been rigorously examined in few taxa. 2. We examined sources of variation in the ?18O of tooth enamel, assumed to reflect ?18O of body water, of kangaroos (Macropus spp.) collected throughout Australia. 3. Relative humidity explained a large proportion of the variation in enamel ?18O, a finding that is consistent with previous studies. However, we also found a previously unreported interaction between mean annual temperature and relative humidity. At lower temperatures, the relationship between enamel ?18O and relative humidity was much steeper than at higher temperatures. 4. This may be a consequence of the Pecl�effect in plant leaves, whereby high transpiration rates diminish the 18O enrichment of bulk leaf water. It is likely that this interaction is also present in other herbivores with low drinking water requirements. 5. We found little evidence that ?18O varied consistently between molars, suggesting that a 'weaning effect' is either absent or swamped by seasonal variation in precipitation ?18O. 6. We suggest that the oxygen isotope composition of preserved kangaroo remains cannot be used to reconstruct relative humidity unless ambient air temperature can be reliably estimated. � 2007 The Authors.

    KW - air temperature

    KW - climate effect

    KW - enamel

    KW - isotopic composition

    KW - marsupial

    KW - oxygen isotope

    KW - relative humidity

    KW - seasonal variation

    KW - stable isotope

    KW - temperature effect

    KW - transpiration

    KW - weaning

    KW - Australasia

    KW - Australia

    KW - Macropodidae

    KW - Macropus

    KW - Mammalia

    M3 - Article

    VL - 21

    SP - 757

    EP - 766

    JO - Functional Ecology

    JF - Functional Ecology

    SN - 0269-8463

    IS - 4

    ER -