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 won’t 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 Dryas–to–Preboreal (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 1.2–2.5 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 δ18O content of the surface ocean on estimated sea surface temperatures in past warm climate Mackensen, Andreas; Wollenburg, Jutta; Licari, Laetitia Low δ13C 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 δ18O and δ13C 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. 753–756. 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. 737–740. 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?

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