Stable Isotope Lab MTG

1
Stable Isotope Lab MTG

• September 13, 2006

2
Mass Spec Schedule

• Wed 9/13 - Rhonda Water
• Thurs 9/14 - Carbonate Switch
• RGF1 various sizes
• Fri 9/15 - Aurora
• Sat 9/16 - Rhonda
• Sun 9/17 - Rhonda
• Mon 9/18 - Aurora
• Tue 9/19 - JDW

3
Lab Maintenance

• Rhonda Quinn is the Associate Lab Director
• This provides students with one other person to
  contact when they have questions about the mass
  spec.
• This does not release students from the
  overseeing their run. More on this later.

4
Lab Maintenance

• You are expected to clean a set of vials for
  every run you make
• Rhonda or I will supervise the cleaning
• Be gentle with the V-vials

5
Lab Maintenance

• Kel-f septa and the seal it makes with the top of
  the vial is probably the single most common cause
  of poor data.
• Each sheet of Kel-f costs 100. Treat it with
  care.

6
Lab Maintenance

• If you have especially small samples, please
  notify me. There is no reason to waste
  foraminifera if I can predict with reasonable
  certainty that they wont run.
• Two bad things happen
• Waste of your picking time
• Waste of machine time and lab money

7
Lab Maintenance

• The mass spec should be started first thing in
  the morning
• If you have morning classes, then switch days
• Your responsibilities are
• Monitor the first three standards
• Watch the run throughout the day

8
Lab Maintenance

• Our reputation and scientific credibility is
  built on producing data of high quality.
• I would rather have fewer data of higher quality
  than more data of dubious quality

9
Requests for Sample Analyses

• Who needs them?
• How many?
• Urgency?

10
Recent Literature

• Science 8 September 2006
• Volcanism in Response to Plate Flexure
• Naoto Hirano et al.
• Implications for hot spots and the formation of
  intraplate volcanoes
• Marcia McNutt wrote Prespectives

11
Recent Literature

• Science 8 September 2006
• Tectonic Uplift and Eastern Africa Aridification
• Pierre Sepulchre, Gilles Ramstein, Frédéric
  Fluteau, Mathieu Schuster, Jean-Jacques
  Tiercelin, Michel Brunet
• The history of Eastern African hominids has been
  linked to a progressive increase of open
  grassland during the past 8 million years. This
  trend was explained by global climatic processes,
  which do not account for the massive uplift of
  eastern African topography that occurred during
  this period.

12
Recent Literature

• Science 8 September 2006
• Cold-Seep Mollusks Are Older Than the General
  Marine Mollusk Fauna
• Steffen Kiel and Crispin T. S. Little
• We used the fossil record of seep mollusks to
  show that the living seep genera have
  significantly longer geologic ranges than the
  marine mollusks in general, but have ranges
  similar to those of deep-sea taxa, suggesting
  that seep faunas may be shaped by the factors
  that drive the evolution of life in the deep sea
  in general. Our data indicate that deep-sea
  anoxic/dysoxic events did not affect seep faunas,
  casting doubt on the suggested anoxic nature
  and/or global extent of these events.

13
Recent Literature

• Science 25 August 2006
• Ice Sheets and Sea Level
• In the tandem papers on the stability of the
  Antarctic and Greenland Ice Sheets by J. T.
  Overpeck, B. L. Otto-Bliesner, and co-workers
  ("Paleoclimatic evidence for future ice-sheet
  instability and rapid sea-level rise," J. T.
  Overpeck et al., Reports, 24 Mar., "Simulating
  Arctic climate warmth and icefield retreat in the
  last interglaciation," B. L. Otto-Bliesner et
  al., firm statements are made about the possible
  contributions of these ice sheets to future
  sea-level change. Several doubtful assumptions
  are made, and the quality of model results seems
  to be overvalued.

14
Recent Literature

• Science 25 August 2006
• Ice Record of ?13C for Atmospheric CH4 Across the
  Younger Dryas-Preboreal Transition
• Hinrich Schaefer, Michael J. Whiticar, Edward J.
  Brook, Vasilii V. Petrenko, Dominic F. Ferretti,
  Jeffrey P. Severinghaus
• We report atmospheric methane carbon isotope
  ratios ?13CH4 from the Western Greenland ice
  margin spanning the Younger DryastoPreboreal
  (YD-PB) transition. Constant ?13CH4 during the
  rise in methane concentration at the YD-PB
  transition is consistent with additional
  emissions from tropical wetlands, or aerobic
  plant CH4 production, or with a multisource
  scenario. A marine clathrate source is unlikely.

15
Recent Literature

• Science 25 August 2006 1112-1115.
• Decoupled Plant and Insect Diversity After the
  End-Cretaceous Extinction
• Peter Wilf, Conrad C. Labandeira, Kirk R.
  Johnson, and Beth Ellis
• After the end-Cretaceous extinction, plants
  diversified without many insects in some places,
  whereas elsewhere insect herbivores diversified
  despite few plant species.

16
Recent Literature

• Nature 443, 71-75(7 September 2006)
• Methane bubbling from Siberian thaw lakes as a
  positive feedback to climate warming
• K. M. Walter, S. A. Zimov, J. P. Chanton, D.
  Verbyla F. S. Chapin, III
• Large uncertainties in the budget of atmospheric
  methane, an important greenhouse gas, limit the
  accuracy of climate change projections. Thaw
  lakes in North Siberia are known to emit
  methane3, but the magnitude of these emissions
  remains uncertain because most methane is
  released through ebullition (bubbling), which is
  spatially and temporally variable. Here we report
  a new method of measuring ebullition and use it
  to quantify methane emissions from two thaw lakes
  in North Siberia. We show that ebullition
  accounts for 95 per cent of methane emissions
  from these lakes, and that methane flux from thaw
  lakes in our study

17
Recent Literature

• Nature 19 July 2006
• Controls on tropical Pacific Ocean productivity
  revealed through nutrient stress diagnostics
• Michael J. Behrenfeld, Kirby Worthington, Robert
  M. Sherrell, et al.
• In situ enrichment experiments have shown that
  the growth of bloom-forming diatoms in the major
  high-nitrate low-chlorophyll (HNLC) regions of
  the world's oceans is limited by the availability
  of iron. We find that iron has a key function in
  regulating phytoplankton growth in both HNLC and
  oligotrophic waters near the Equator and further
  south, whereas nitrogen and zooplankton grazing
  are the primary factors that regulate biomass
  production in the north. Application of our
  findings to the interpretation of satellite
  chlorophyll fields shows that productivity in the
  tropical Pacific basin may be 1.22.5 Pg C yr-1
  lower than previous estimates have suggested, a
  difference that is comparable to the global
  change in ocean production that accompanied the
  largest El Niño to La Niña transition on record.

18
Recent Literature

• Nature 442, 908-911(24 August 2006)
• Sulphur isotope evidence for an oxic Archaean
  atmosphere
• Hiroshi Ohmoto, Yumiko Watanabe, Hiroaki Ikemi,
  Simon R. Poulson and Bruce E. Taylor

19
Recent Literature

• Paleoceanography, Vol. 21, No. 2, PA2022
• Rohling, E. J. Hopmans, E. C. Sinninghe Damsté,
  J. S.
• Water column dynamics during the last
  interglacial anoxic event in the Mediterranean
  (sapropel S5)
• Moros, Matthias Andrews, John T. Eberl, Dennis
  D. Jansen, Eystein
• Holocene history of drift ice in the northern
  North Atlantic Evidence for different spatial
  and temporal modes
• Damassa, Thomas D. Cole, Julia E. Barnett,
  Heidi R. Ault, Toby R. McClanahan, Timothy R.
• Enhanced multidecadal climate variability in the
  seventeenth century from coral isotope records in
  the western Indian Ocean
• Plewa, K. Meggers, H. Kasten, S.
• Barium in sediments off northwest Africa A
  tracer for paleoproductivity or meltwater events?
• Flückiger, Jacqueline Knutti, Reto White, James
  W. C.
• Oceanic processes as potential trigger and
  amplifying mechanisms for Heinrich events

20
Recent Literature

• Paleoceanography, Vol. 21, No. 2, PA2022
• Roche, D. M. Donnadieu, Y. Pucéat, E.
  Paillard, D.
• Effect of changes in d18O content of the surface
  ocean on estimated sea surface temperatures in
  past warm climate
• Mackensen, Andreas Wollenburg, Jutta Licari,
  Laetitia
• Low d13C in tests of live epibenthic and
  endobenthic foraminifera at a site of active
  methane seepage
• Marshall, Shawn J. Koutnik, Michelle R.
• Ice sheet action versus reaction Distinguishing
  between Heinrich events and Dansgaard-Oeschger
  cycles in the North Atlantic
• Greer, Lisa Swart, Peter K.
• Decadal cyclicity of regional mid-Holocene
  precipitation Evidence from Dominican coral
  proxies
• Sexton, Philip F. Wilson, Paul A. Norris,
  Richard D.
• Testing the Cenozoic multisite composite d18O and
  d13C curves New monospecific Eocene records from
  a single locality, Demerara Rise (Ocean Drilling
  Program Leg 207)

21
Recent Literature

• Geology Vol. 34, No. 9, pp. 753756.
• Heinrich H1 and 8200 yr B.P. climate events
  recorded in Hall's Cave, Texas
• Brooks B. Ellwood and Wulf A. Gose
• Measurements of magnetic susceptibility (MS)
  have been performed on a continuous set of
  samples from a well-dated 3 m sequence of
  sediments collected from Hall's Cave, Edwards
  Plateau, central Texas. Three major climatic
  events are represented by distinctive MS
  increases in the sequence (1) the Heinrich event
  H1 (from 17,500 to 17,000 yr B.P.) (2) the end
  of full glacial conditions on the Edwards Plateau
  at 14,200 yr B.P. and (3) the 8200 yr B.P.
  climatic event (from 8250 to 8050 yr B.P.). In
  addition, a minor event at 4400 yr B.P. is also
  well defined here and in Canada, indicating that
  it is a broadly regional event. These data
  indicate that all four events represent a shift
  toward milder climatic conditions accompanied by
  increased rainfall at this location.

22
Recent Literature

• Geology Vol. 34, No. 9, pp. 737740.
• Extreme warming of mid-latitude coastal ocean
  during the Paleocene-Eocene Thermal Maximum
  Inferences from TEX86 and isotope data
• J.C. Zachos, S. Schouten, S. Bohaty and T.
  Quattlebaum, A. Sluijs and H. Brinkhuis, S.J.
  Gibbs and T.J. Bralower
• Changes in sea surface temperature (SST) during
  the Paleocene-Eocene Thermal Maximum (PETM) have
  been estimated primarily from oxygen isotope and
  Mg/Ca records generated from deep-sea cores. Here
  we present a record of sea surface temperature
  change across the Paleocene-Eocene boundary for a
  nearshore, shallow marine section located on the
  eastern margin of North America. The SST record,
  as inferred from TEX86 data, indicates a minimum
  of 8 C of warming, with peak temperatures in
  excess of 33 C. Similar SSTs are estimated from
  planktonic foraminifer oxygen isotope records,
  although the excursion is slightly larger. The
  slight offset in the oxygen isotope record may
  reflect on seasonally higher runoff and lower
  salinity.

23
Brief Research Blurb

• 15JPC
• Why should we care?

24
(No Transcript)
25
(No Transcript)
26
Crest of Eirik Drift - southern tip of Greenland
27
Two Modes of Circulation

• Warm Mode
• N. Atlantic Deep Water
• Shallow Compensation
• Cold Mode
• N. Atlantic Intermediate and Upper Deep Water
• Deep Compensation

28
Two Modes of Circulation

• Warm Mode
• N. Atlantic Deep Water
• Shallow Compensation

29
Two Modes of Circulation

• Cold Mode
• N. Atlantic Intermediate and Upper Deep Water
• Deep Compensation

30
Two Modes of Circulation
31
Explore the Younger Dryas