Oxygen, Hydrogen and Carbon Isotopes apaytan/290A_Winter2014/pdfs/290A Lecture 1 O...  Oxygen,...

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Transcript of Oxygen, Hydrogen and Carbon Isotopes apaytan/290A_Winter2014/pdfs/290A Lecture 1 O...  Oxygen,...

  • Oxygen, Hydrogen and Carbon Isotopes

    Fresh water -

    Rain, Lakes, Groundwater, Ice

    Plants

    Leaves and roots (also specific compounds)

    Animals

    bones and tissue

    Seawater

    Carbonate

    CaCO3 (other minerals)

  • Isotope Abundances

  • Hydrogen isotopes (D)Two stable isotopes of Hydrogen. 1H and 2H (Deuterium, D.) Expressed in

    notation as:

    D = [(2H/1H) sample

    (2H/1H) standard(SMOW)] x1000(2H/1H) standard(SMOW)

    -

    Big

    relative mass difference so big fractionations imposed by environmental and biological processes.

    Oxygen isotopes (18O)Three stable isotopes of O; we mostly care about 16O and 18O

    Expressed in

    notation as:

    18O = [18O/16O sample

    18O/16O standard(SMOW) ] x100018O/16O standard(SMOW)

    -

    Smaller relative mass difference so smaller fractionations imposed by environmental and biological processes.

  • Effectsoflatitude,aridity,altitudeandcontinentality

    onthehydrogenisotopecompositionof

    precipitation

    canbeclearlyseen.[reasonsforvariationareTemperatureandRainout]

    PrecipitationD

    Oxygen and Hydrogen in Precipitation

  • Globalmeteoricwaterline(GMWL)

    D =818O+10

    8 represents the ratio of the fractionation factors between D/H and 18O/16O.

    MostlyEquilibrium

    fractionation,buteffect

    ofKineticfractionation

    dragslineofftheorigin

  • Water Sources

    groundwater mixing, storm sources and history

    Evaporation in lakes and reservoirs

    Changes in the hydrological cycle over time

    Changes in sea level

    Peruvian stalagmite calcite 18O recordlinking northern and southern high latitudeice core records (Kammer* et al., 2012)

  • Lake Chichancanab

    and Mayan Collapse

  • Oxygen isotope fluctuations in seawater as recorded in marine sediments can be indicative of ice volume and thus sea level changes. Temperature effects will be included as well. Indicative of exchange among water reservoirs.

  • Siddall et al., 2000

  • Zachos

    et al., 2001

  • Plants, Animals, Soil Organic Matter

    1.

    Trace past climates/precipitation /environmentAssume plants take their O and H from the environment around them, as environmental changes influence the 18O and D of meteoric water we can examine fossil plants to reconstruct ancient climates/precipitation patterns [Compound-specific particularly].

    D and18Oinmeteoricwater.Influencedbyclimate,latitude,altitudeetc

    Fractionation?

    FixationofD and18Ointoplanttissue.

    AnalyzeplantD and18O

    Reconstructpastclimate,

    elevationetc

    Regional precipitation patterns, Latitude, altitude, continentality, intensity, source. -Relative humidity/ aridity-Seasonality-Temperature

  • 2. Investigate the biology of the plant. Determine what type of plants we are looking at (C3, C4, CAM etc).

    Cant always tell just by using 13C values

    DifferentfractionationsinC3,C4andCAMplants

    Determinebiosyntheticpathwayoftheplant

    Analyse

    celluloseD and18O

    ApplicationsformodernandfossilplantsMarineandterrestrialorganicmatterPetroleumsourcesPlantevolution

  • Sternberg,(1989)

    C4=lowmed

    Dandhigher

    18Ovalues

    CAM=highD

    andlowmed

    18Ovalues

    C3=lowerD

    andlower18O

    values

    D and18Ovalues

    fromplantcellulose

    of

    differentplants

    growinginsamesite

    inTexas.

    Samearea,therefore

    sameinputofsoil

    D,thereforesame

    baseline.

  • 3. Tracing water sources for plantsAre different plants in the same environment drinking from different

    pools of water in the soil?

    A

    B

    P =AP =fB +fA P =B

    Evapotranspiration Farquharetal.,(1989)

  • 18O in fluids (body water), tissues (hair, feather) and biological minerals (focus here on apatite, not calcium carbonate)

    18O in body water most tissues is 18O- enriched relative to environmental water

    Oxygen in PO4

    and CO3

    rapidly equilibrates with body water and temperature (carbonic anhydrase, pyrophosphatase

    and other

    enzymes)

  • Major Oxygen FluxesIN

    Ingested water: drinking water and water in food (not fractionated)

    Atmosphere O2 (globally constant value of +20, fractionated)

    Food dry matter

    OUT

    Respired CO2 (fractionated)

    Water in urine and feces

    Water lost in exhalation, sweat, evaporation (fractionated)

  • Rats with a change in drinking water D

    Body water Hair

    Ehleringer

    et al. 2008

  • Geographic patterns in human hair D

    Ehleringer

    et al. 2008

    Tap water D varies Diet constant: Dd

    -115

    27% hair H from drinking water85% variability explained

  • Changes in hair 18O, D with migration

    Ehleringer

    et al. 2008

  • Apatite 18O18O depends on the temperature and body fluid 18O value from which the biomineral precipitates

    For homeotherms

    (mammals, birds), there is a constant temperature dependent difference constant offset between 18O of body water and PO4

    (~18), between body water

    For heterotherms, as temp. , bioapatite

    18O values

    Changes in temperature, Habitat allocation, Migration (salmon), Seasonality

  • STABLE ISOTOPE COMPOSITIONS OF BIOLOGICAL APATITE; DINOSAUR THERMOREGULATION.

    ( M.J. KOHN, T.E. CERLING)

    Ectotherms maintain uniform temperature only in core areasEctotherms = Highly variable

    Endotherms

    = Less variable

  • The black numbers indicate how much carbon is stored in various reservoirs, in billions of tons (GigaTons, circa 2004). The purple numbers indicate how much carbon moves between reservoirs each year. The sediments, as defined in this diagram, do not include the ~70 million GtC

    of carbonate rock and kerogen.

    http://en.wikipedia.org/wiki/Image:Carbon_cycle-cute_diagram.jpeg

  • On geologic times scales, the carbon cycle model can be represented by 3 reservoirs, sedimentarycarbonate, sedimentary organic carbon, and the mantle, as well as fluxes between these reservoirs and the oceans and atmosphere.

  • When more C is removed into the reduced organic C reservoir residual C in the ocean and carbonates becomes enriched in 13C (heavy), atmospheric CO2

    is lower and O2

    is higher (less consumed for oxidation).

  • The long-term increases in 13Ccarb (e.g. more organic C burial) that began in the Mesozoic were accompanied by major evolutionary changes among the primary producers in the marine biosphere. Threegroups of eucaryotic

    marine phytoplankton (calcareous nannoplankton, dinoflagellates, and diatoms) began their evolutionary trajectories to ecological prominence at ~ 200 Ma. As Pangea

    fragmented and the Atlantic Ocean basin widened, the total length of coastline increased and sea level rose, flooding continental shelves and low-lyingcontinental interiors. Nutrients that were previously locked up in the large continental interior were transported to newly formed shallow seas and distributed over wider shelf areas and longer continental margins.

    Katz et al., 2005

  • The decline since the late Miocene in addition to changes in ocean circulation could be related to the evolution of C4 plants (less fractionation in organic C burial).

    Perturbations in the global C cycle.

  • McInerney

    and Wing 2011

  • Cerling

    et al. 97Nature

    13C

    Warm season grassArid adapted dicots

    Cool season grass most trees and shrubs

  • Food Sources for Coastal Marine Animals13C values of consumers can be

    used to indicate food source

    Fish:Offshore = primarily planktonic food sourceSeagrass

    = some primarily

    planktonic, some primarily benthic

    Invertebrates:Offshore = primarily planktonic food sourceSeagrass

    = primarily benthic food

    source [France, 1995]

  • Tracing organic matter sources and carbon burial in mangrove sediments over the past 160 years (Gonneea

    et al., 2004).

  • C3 -

    C4 balance varies with climate

    Tieszen

    et al.

    Ecol. Appl. (1997) Tieszen

    et al. Oecologia

    (1979)

  • 13C varies with environment within C3 plants

  • drought

    normal

    Diefendorf

    et al. (2010) PNAS

    Light matters too

  • QuantumYield

    (moles C fixed perphoton absorbed)

    Temperature (C)3 6 9 12 15 18 21 24 27 30

    C4 plants

    C3 plants

    Today (360 ppm)

    LGM (180 ppm)

    With equal water higher CO2

    is better for C3 plants but the temperature sensitivity changes

    At the LGM, was there less C4 biomass (because of lower temperatures) or more C4 biomass (because of lower pCO2)?

    Ehleringer

    et al. 1997 Oecologia

    C3 decreases in efficiency because of Photorespiration

  • Great Plains ecosystems

    Use isotopes in animals and soils to track CUse isotopes in animals and soils to track C33

    --toto--CC44

    balancebalance

  • AverageMeasured

    Enamel13C

    Enamel 13C value predicted from local vegetation

    For C you are what you eat

    Bison isotope values track C3

    -to-C4balance of grasslands

    -12

    -10

    -8

    -6

    -4

    -2

    0

    -14 -12 -10 -8 -6 -4 -2 0

    Y = -1.90 +0.78XR = 0.98

    CA OKMT SDND WYNE

  • %C4

    Grass Should Increase in the LGM Based on Temperature Model

  • Holocene -Late Glacial

    Last GlacialMaximum

    Pre-LGM

    Proboscidea