What is OG?

1. What is OG? What is "Organic Geochemistry?" • Most broadly: Study of Distribution and Transformation of organic matter (molecules) in the geosphere.

2. What is “Organic?” Historically: “Pertaining to Plants or Animals” Often heard: “containing C, or C-C bonds” So: how about CCl4NH4? How about Freons ( CxFy ) Firmest Basis: 1) oxidation state, and 2) complex C structure • C-H bonds = “reduced carbon” (flammable= storage for energy in biological/biogeochemical cycles) • C-C bonds: All natural products. What is Organic matter?

3. Organic Geochemistry / Biogeochemical Cycles • Sub discipline of Chemical Oceanography • Uses organic molecules as “tracers” for a wide range of processes • Tools: Typically analytical organic chemistry- but often adapted significantly. • Examples: Spectroscopy (e.g. NMR), molecular level analysis for specific compounds, organic isotopes = Stable 13C and 15N) and Radio (14C) isotopes.

4. Why do we care about these things? Large-scale cycles “Carbon Cycle” binds together life and the geosphere

5. Larger view (& slightly more quantitative… ) Large-scale cycles Atmosphere and rivers: links land to ocean in one great cycle

6. What is the “organic” part of the C-cycle? Large-scale cycles “Reduced carbon”: Biological & “fast” geochemical cycles

7. Cycling of OM: what are 1) fluxes and 2) controls? Large-scale cycles

8. “Reservoirs” or “Pools” of OM Organic C pools Relative Magnitudes of Active Organic Pools

9. Biota (alive) POC ? ? Organic C pools DOC Oceanic “Reservoir” and connections Sed OC (active=surficial)

10. Biota (alive) “Labile” & “Refractory” Sub-pools Organic C pools POC DOC

11. Biota (alive) POC ? ? How do you figure out? DOC HOW DO YOU FIGURE ALL THIS OUT? Sed OC (active=surficial)

12. POC 1. How big are the boxes? How big are these boxes? DOC • Bulk Organic measurements in vastly different matrixes. • (sounds easy right..) Sed OC (active=surficial)

13. Biota (alive) POC ? ? 2. What’s IN all the boxes? What’s in the boxes? DOC And: Where do all the arrows really go, and WHY? Sed OC (active=surficial)

14. Understand “Sources & Cycling” of Organic Matter What is it made of? Where did it originally come from? What processes produce specific pools or reservoirs? What processes cause them to be preserved?  Same framework of basic questions underlie essentially all OG research

15. Basic: Amimal & Vegitable vs Mineral: You can burn it! Historically: “Pertaining to Plants or Animals” • You can Burn it! • Means: Lots of stored chemical energy • Means: Unstable It is these chemical properties which essentially makes NOM a major player in biological and geochemical cycles.

16. “Non-Living” Organic matter Key point: Organic Geochemistry is (in general) concerned with non-living organic matter. This can go by a wide variety of names: eg: NOM, detrital OM, organic“detritus”, etc. The dividing line between living and non-living is often blurry, however in general its non-living material that comprises major C reservoirs & retains the most information.

17. Way back: Structural Organic chemistry heads out of the lab.. Triebs: origins of “Field I” Alfred Treibs, ~ 1930.

18. Porhyrine – Vanadium complex “e”” Triebs I: “Vanadium complex E”

19. Chllorophyll -a Triebs II: “Chlorophyll sources?”

20. Triebs III: “LINK?” Could one come from the other? ??

21. Triebs IV: “Triebs Mechanism”

22. Triebs III: “LINK?” ?? First unequivocal demonstration of organic origins of petroleum

23. Lessons from Triebs • Why was he interested in the first place? •  1. Understand Fundamental Geochemical cycles- • Oil, coal, OM in rocks (shales) = massive reduced C deposits • What are they made of? • Where did they originally come from? • What processes produce them & cause them to be preserved?

24. Lessons from Treibs Story: 2. Economic motivation: Post industrial revolution Organic matter- by its fundamental nature (ie reduced carbon= energy) has a primary place in anthopogenic biogeochemical cycles- Lessons from Triebs I: “Organic Matter”

25. Why are organics so good at unraveling?“Data Richness “of Organic Molecules Triebs searched for specific structures that would carry information about origins.  tip of iceberg vis a vis huge information potential in organic molecules!

26. Layers of information

27. Enormous number of information units ( isotopes, atoms, molecules, stereochemistry) Data richness 1 drink of water = 250 ml, at 4 mg/L of organic matter » 1 mg organic matter, at an average of 1000D/molecule » 10-6 moles of molecules, at 6 x 10E23 molecules/mole » 6 x 10E17 organic molecules in the cup.  Organic Structures: every 1000D molecule contains about 50% carbon  10-40 carbon atoms! = lots of potential for structural diversity (e.g. at least 10 structural variants for an acyclic 7-carbon hydrocarbon). Symmetry Each asymmetric carbon: has two possible stereoisometric forms. Isotopes 13C :40% of all molecules will have one 13- that one 13C could be in up to 40 different sites the individual molecules. 14Cabout 1/1012 carbons in the contemporary biosphere is a 14C,  4 x 10E 105 radioactive molecules in the cup of water, decaying at a predictable rate. f. organic matter has also:1H, 2H, 3H, 14N, 15N, 16O, 17O, 18O, P, and 32S, 33S 34S and 36S,

28. 15 N- Solid State NMR 13 d C, Functional-group Composition Spectroscopic Elemental Analysis Compound Classes Pyrolysis -N Degradative Diagenetic History Amino Acids Molecular Level Bacterial Biomass D vs L Chirality 13 15 d C, N Proteinaceous sources Stable Isotopes 14 C Cycling-Time Scale Radio Isotopes Specific Bacterial Sources/Cycles? Isotopic + Chirality ? D

29. Three main “Focus Areas” of Organic Geochemistry* 1. Bio-Focus 2. Geo-Focus & 3. “Tracers” * According to me.

30. Biota (alive) Bio focus 1. Bio-Focus: Information on biological processes (very short time scale) POC DOC

31. ? ? 2. Geo-Focus: Characterizing or Understanding Major Reservoirs Global cycles over long-time scales. “Geo-Focus “ POC

32. Tracers: 3. Tracer Focus: use organic molecules to understand many, many, many processes. (Possibly not even interested in organics per se, but all that information richness can be very useful to whatever you are interested in.)

33. The Concept of ‘molecular marker’ or Molecular “Fossil” • Origins: again 1930s, Alfred Treibs with establishment of the biological origin of petroleum • Central Idea: • Find a “unique” structure that can be traced to a specific source or process of interest • EG: Pollutant, Tributyl Tin = boat traffic (bottom paint) • EG: D/L amino acids in ancient middens = Heating (campfire) history • Eg: Lignin Phenols: contribution of terrestrial OM to an ocean sediment Molecular Markers

34. “biomarkers” Organic matter traces biological and geographic sources, as well as tranformations Eg: Biomarker Examples • 1. syringealdehyde  lignin  vascular plant angiosperms only • 2. vanillin  lignin  all vascular plants  only terrigenous origin

35. Example: Alkenone Paleo-thermometry C37:3 alkenone  coccolith marine • BUT Also temperature  number of C37:3 alkenone double bonds increases with decreasing water temperature • C37:3 alkenone  coccolith Cooler waters.. • C37:2 alkenone  coccolith  Warmer waters.. •  Paleo-Temperature proxy! • Other possiblities in same vein: paleosalinity paleooxicity  reflected by some pigments and lipids

36. Isotope Tracers ? How many 13C’s vs. 12C’s are in the molecule- can tell you about its ORIGIN

37. The Practice of OG research: • Finding/ the Molecules  Analytical organic chemistry. • Figuring out where they came from • Sources = biomarker potential  form of Natural products chemistry • Transformations = a path back to source, but also a captured history of environment. •  A form of biochemistry/ synthetic organic chemistry.... 3) Applications: is it a useful biomarker? • IF yes…then 4) Spend rest of career taking field samples & Measuring abundance! Practice of Orga nic geochem

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