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Sweetie

Sweetie. Lilly. Sonny. Nutrient Sources Supporting Ocean Productivity Deborah A. Bronk Department of Physical Sciences. Outline: A closer look at DON Methods to study regeneration Autochthonous sources Allochthonous sources. Southern California Bight. Bronk & Ward 2005 DSRI.

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Sweetie

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  1. Sweetie Lilly

  2. Sonny

  3. Nutrient Sources Supporting Ocean Productivity Deborah A. Bronk Department of Physical Sciences

  4. Outline: • A closer look at DON • Methods to study regeneration • Autochthonous sources • Allochthonous sources

  5. Southern California Bight Bronk & Ward 2005 DSRI

  6. Labile Semi-labile Refractory What is DON? Labile DFAA urea nucleic acids methylamines Semi-labile proteins DCAA amino polysaccharides (chitins & peptidoglycans) Refractory humic acids fulvic acids porphorins amides

  7. Labile Semi-labile Refractory What is DON? Labile DFAA urea nucleic acids methylamines NH4+ NO2- NO3- Semi-labile proteins DCAA amino polysaccharides (chitins & peptidoglycans) Refractory humic acids fulvic acids porphorins amides

  8. Months Days Years Weeks DON humic acids fulvic acids porphorins

  9. Months Days Years Weeks Hours Days DFAA urea NA semi-labile & refractory DON Minutes Seconds

  10. Allochthonous Autochthonous Months Days Years Weeks

  11. Months Days Years Weeks Estuarine High DIN

  12. Months Days Years Weeks

  13. Months Days Years Weeks

  14. Months Days Years Weeks

  15. Months Days Years Weeks

  16. Months Days Years Weeks Open Ocean DIN below detection

  17. Radiotracers (3H, 14C, 32P) Absolute amounts Methods for studying N sources: Stable isotope tracers (15N, 13C) Ratios (15N/14N or 13C/12C) Gross and net rates Uptake and regeneration simultaneously Bioassays Absolute amounts ~ Net rates

  18. Autochthonous sources of N Zooplankton Excretion Sloppy feeding Fecal pellet leaching DON and NH4+ Bactivory Bronk and Steinberg 2008 NITME

  19. Bioassays DON Conc. Time

  20. Saba, Steinberg and Bronk 2011 JEMBE

  21. Autochthonous sources of N Zooplankton Excretion Sloppy feeding Fecal pellet leaching Bactivory DON and NH4+ Bronk and Steinberg 2008 NITME

  22. [target] Target Pool Source pool atom % of target Rate = atom % Time of source  

  23. [ ] PN Isotope dilution 15N 15NH4+ 14NH4+ Net 15N in PN Uptake = Rate atom % NH4+ Time   

  24. Pt = P0 + (d - u)t ln(Rt - Ra) = ln(R0 - Ra) - [d/(d- u)][ln Pt/P0] Pt and P0 = ambient NH4+ conc at end and start of incubation Rt and R0 = atom % of the NH4+ pool at end and start of incub. u = absolute uptake rate d = regeneration rate Glibert et al. 1982 L&O

  25. Autochthonous sources of N Phytoplankton DON Passive diffusion Cell death & lysis

  26. Autochthonous sources of N Bacteria DON Exoenzyme release Cell death & lysis

  27. Excretion of organic matter by phytoplankton: Do healthy cells do it? Sharp 1977 L&O Active release outflow model Passive diffusion model Fogg 1966 OMBAR Fogg 1966 OMBAR Bacteria as ectoparasites Reduction of viruses Bjørnsen 1988 L&O Murray 1995 JPR

  28. Bronk 1999 JPR

  29. [DON] 15NH4+ O15N 15NH4+ DO15N atom % DON Release = Rate atom % ON Time * *

  30. Failure is an option so try something new!

  31. Bronk 1999 JPR

  32. Submit all chapters before you move on!!!!

  33. Trichodesmium ~50% N fixed gets released N2 NH4+  DON Glibert & Bronk 1994 Mulholland, Capone & Bronk 2006

  34. Viral lysis Phytopl. DON and NH4+ Bact. Viruses are unique in that they are “part” of the DOM pool (~<2%). Wommack and Colwell 2000 Microbiol. Mol. Bio. Rev.

  35. Viral infection DO15N 15NH4+ Sloppy feeding O15N 15NH4+ DO15N Cell death & lysis Leaky membranes DO15N DO15N Bronk 1999 JPR

  36. [ ] PN 15NH4+ O15N 15NH4+ DO15N Gross 15N in PN & DON Uptake = Rate (G) atom % NH4+ Time * * Bronk, Glibert, & Ward 1994 Science

  37. Gross Net DON Uptake Uptake Release - =

  38. Field Methods NH4+ NO3- /NO2- Urea DFAA DCAA Humic DON chl. a 15NO3- 15NH4+ DON DON

  39. When you incubate – be the cell!!

  40. Monterey Bay Bronk & Ward 1999 L&O

  41. Southern California Bight Bronk & Ward 2005 DSRI

  42. Slope = 0.24 Bronk & Steinberg 2008 N Bible

  43. Autochthonous sources of N DON or PN Bacterial Ammonification NH4+ DO15N or P15N

  44. Nitrification PN or DON NO2- NH4+ NO3-

  45. NO2- NH4+ Nitrification PN or DON NO3-

  46. Outline: • A closer look at DON • Methods to study regeneration • Autochthonous sources

  47. Proposals Quality over Quantity

  48. Months Days Years Weeks DON humic acids fulvic acids porphorins

  49. Allochthonous Autochthonous Months Days Years Weeks

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