Oxygen, Hydrogen and Carbon Isotopes apaytan/290A_Winter2014/pdfs/290A Lecture 1 O... Oxygen,...
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Oxygen, Hydrogen and Carbon Isotopes
Fresh water -
Rain, Lakes, Groundwater, Ice
Leaves and roots (also specific compounds)
bones and tissue
CaCO3 (other minerals)
Hydrogen isotopes (D)Two stable isotopes of Hydrogen. 1H and 2H (Deuterium, D.) Expressed in
D = [(2H/1H) sample
(2H/1H) standard(SMOW)] x1000(2H/1H) standard(SMOW)
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
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.
Oxygen and Hydrogen in Precipitation
8 represents the ratio of the fractionation factors between D/H and 18O/16O.
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)
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
et al., 2001
Plants, Animals, Soil Organic Matter
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].
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
3. Tracing water sources for plantsAre different plants in the same environment drinking from different
pools of water in the soil?
P =AP =fB +fA P =B
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
rapidly equilibrates with body water and temperature (carbonic anhydrase, pyrophosphatase
Major Oxygen FluxesIN
Ingested water: drinking water and water in food (not fractionated)
Atmosphere O2 (globally constant value of +20, fractionated)
Food dry matter
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
et al. 2008
Geographic patterns in human hair D
et al. 2008
Tap water D varies Diet constant: Dd
27% hair H from drinking water85% variability explained
Changes in hair 18O, D with migration
et al. 2008
Apatite 18O18O depends on the temperature and body fluid 18O value from which the biomineral precipitates
(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
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
= 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.
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.
and Wing 2011
et al. 97Nature
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).
C4 balance varies with climate
Ecol. Appl. (1997) Tieszen
et al. Oecologia
13C varies with environment within C3 plants
et al. (2010) PNAS
Light matters too
(moles C fixed perphoton absorbed)
Temperature (C)3 6 9 12 15 18 21 24 27 30
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)?
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
Enamel 13C value predicted from local vegetation
For C you are what you eat
Bison isotope values track C3
-to-C4balance of grasslands
-14 -12 -10 -8 -6 -4 -2 0
Y = -1.90 +0.78XR = 0.98
CA OKMT SDND WYNE
Grass Should Increase in the LGM Based on Temperature Model
Holocene -Late Glacial