Asignatura 2.07 Impacto del cambio global en los ciclos del N, P, C y metales

1. Asignatura 2.07 Impacto del cambio global en los ciclos del N, P, C y metales 1- Biological and geochemical CARBON cycle in the open ocean and coast (2 horas) 2- CARBON production during the Antropocene: sinks, sources, and storage. Anthropogenic carbon (1 hora) 3- CARBON cycle during the Antropocene: interaction between climate change and global change (1 hora) 3- The CARBON cycle in the 2070-2100 horizon: vulnerability of the carbon cycle in the oceans (1 hora) 4- Workshop - case study: CANT in the subtropical Indian Ocean (1.5 horas) IEO, A Coruña marta.alvarez@co.ieo.es Palma de Mallorca, October 2011

2. Asignatura 2.07 Impacto del cambio global en los ciclos del N, P, C y metales Biological and geochemical CARBON cycle in the open ocean and coast Marta Álvarez Rodríguez IEO, A Coruña marta.alvarez@co.ieo.es Palma de Mallorca, October 2011

3. http://press.princeton.edu/titles/8223.html

4. http://www.up.ethz.ch/people/ngruber/publications

5. ESQUEMA CICLO DEL C, N, O2, P EN EL OCÉANO Biological oceanography Physical oceanography Gruber 2004 Chemical Oceanography Definition: discipline studying the chemical reactions and processes within the ocean and those between the ocean and its borders Chemical oceanography mainly studies the cycles of the elements forming seawater, these are the biogeochemical cycles. => Movement of the elements and compounds within the organisms and the environment Geological oceanography

6. Carbon accumulation on real scales Antia, NATO Summer School, Ankara, 2006 Global carbon cycle in the oceans • Relevance: • inmense carbon reservoir, 50 times the carbon in the atmosphere, specially inorganic carbon • air-sea exchange of CO2 is relatively quick • the oceans absorb between 26 and 44% of the anthropogenic CO2 driven into the atmosphere • the CO2 uptaken by the ocean: => it does not affect the earth radiactive balance => mitigates the greenhouse effect => sequestered on long time scales, much longer than in the terrestial biosphere On a time scale of millenia: the oceans determine the CO2 concentration in the atmosphere

7. Global carbon cycle & the anthropogenic perturbation +161 1.9 Land sink 5.4 1.7 Land use change 21.9 20 -220 +65 -125 +18 1.6 +100 Global carbon cycle PgC/yr = 10 15 gC = 1 000 000 000 tons = 1 billón de kilos 1 tonelada = 1 000 000 gC = 1000 kilos

8. Carbon cycle in the oceans Fluxes in PgC/yr & stocks in PgC DIC: dissolved inorganic carbon; DOC: dissolved organic carbon POC: particulate organic carbon; PIC: particulate inorganic carbon = CaCO3 NPP: net primary production

9. weeks Temporal Scale Photic layer, epi-pelagic Who plays here? Primary Prod. 100 1 year Aphotic layer: meso & bati-pelagic 100-1000 years Export > 100m 10 Chisholm, Nature 2000 > 106 years Sediments 0.1 Carbon cycle in the oceans Biological pump Physical or solubility pump

10. 1 mol CaCO3=> 0.6 mol CO2 Carbon cycle in the oceans: euphotic zone Biological processes: + soft-tissue pump: photosynthesis/ remineralization of OM + carbonate pump: formation/dissolution of CaCO3

11. Carbon cycle in the oceans: euphotic zone Organic matter synthesis – stoichiometry - Redfield ratios: Redfield ratios: + C:N:P:O2 + 106:16:1:-138 + mean phyto composition (lipids + proteins + sugars + nucleid acids) in the ocean … BUT … it varies … + what else??

12. Carbon cycle in the oceans: euphotic zone Organic matter synthesis- limiting factors - nutrients

13. Chisholm, Nature 2000 Carbon cycle in the oceans: euphotic zone Organic matter synthesis- limiting factors - nutrients Where do they come from? + atmosphere + lateral transport + vertical transport: upwelling, winter mixing, vertical mixing

14. Carbon cycle in the oceans: euphotic zone Organic matter synthesis- limiting factors - nutrients ¿ De dónde vienen? + atmósfera + transporte lateral + transporte vertical: upwelling, winter mixing, vertical mixing

15. Carbon cycle in the oceans: euphotic zone Organic matter synthesis – limiting factors – nutrients - light + ???? Euphotic zone: area well iluminated, where photosynthesis takes place, but it depends on turbidity, hours of light, balance between photosynthesis and respiration

16. Carbon cycle in the oceans: euphotic zone More concepts: new, regenerated and export production N fixation Atmospheric input f ratio = New Prod / Primary production e ratio = export prod / PP over long time and space scales f ratio = e ratio Mainly production Definitions P= phytoplancton Z= zooplancton B= bacteria DON: dissolved organic nitrogen PON: particulate organic nitrogen Production & recycling Vertical input Export or import as dissolved Export as particulate

17. Carbon cycle in the oceans: euphotic zone Biological efficiency: capacity to consume the nutrients available in the photic zone

18. Carbon cycle in the oceans: euphotic zone OCEAN BIOMAS ICE: the marginal sea ice SP: subpolar ST-SS/PS: Subtropical Seasonally / Permanently Stratified EQ-D/EQ-U: Equatorial downwelling/upwelling LL-U: low-latitude upwelling biome

19. Carbon cycle in the oceans: euphotic zone aphotic zone The efficiency of the biological pump is inversely correlated to the efficiency in the export of organic matter out of the photic zone

20. Carbon cycle in the oceans: community structure The input of nutrients, light, physical conditions, etc.. Affect the efficiency of the biological pump, but the export mainly depends on the community structure, which organisms are in the photic zone. Export depends on temperature + nutrients input + Fe

21. Carbon cycle in the oceans: aphotic zone

22. 1 mol CaCO3=> 0.6 mol CO2 Carbon cycle in the oceans: aphotic zone Rain Ratio = POC / PIC export

23. Carbon cycle in the oceans: aphotic zone La eficiencia del secuestro depende del transporte de carbono por debajo de la capa de mezcla invernal (WML) Secuestro de C = Flujo POC · [(Rain Ratio-0.6)/ Rain Ratio]

24. Moderada PP- Bajo secuestro – WML profundo Alta PP- Alto secuestro – WML somero Carbon cycle in the oceans: aphotic zone Producción primaria Secuestro de C bajo WML Antia et al. (GBC, 2001)

25. Carbon cycle in the oceans: organic and inorganic carbon PgC/yr = 10 15 gC = 1 000 000 000 toneladas = 1 billón de kilos 1 tonelada = 1 000 000 gC = 1000 kilos

26. Mass balance CT=[CO2] + [HCO3-] + [CO32-] Charge balance TA = AT=[HCO3-]+2·[CO32-]+[B(OH)4-]+[OH-]-[H3O+] CO2 system in the ocean pCO2= [CO2]/0(S,T) Any two carbonate system parameters fix the values of all the rest K0 pH= -log [H3O+] K1 K2 CO2 / DIC / TIC / CT pH 5 species (unknowns) H2CO3* , HCO3– , CO3–2 , H+ , OH– 3 equilibrium equations K1, K2, Kw 1 concentration condition DIC 1 proton condition TA

27. TIC pH Carbon cycle in the oceans: inorganic carbon • Complex system: • Equilibrium system controlled by T, S & pressure • thanks to it, seawater is a weak alcaline buffer, pH varies within a 7.5 and 8.5 • 4 variables: TIC, pH, TA, fCO2

28. CO2 system in the ocean fCO2= x(CO2) patm = [CO2]/0(S,T) pH= -log [H3O+] Mass balance CT=[CO2] + [HCO3-] + [CO32-] Charge balance AT=[HCO3-]+2·[CO32-]+[B(OH)4-]+[OH-]-[H3O+]

29. CO2 system in the ocean fugacity or partial pressure fCO2= x(CO2) patm = [CO2]/0(S,T) General rule: more dissolved CO2 in cold waters

30. TIC pH CO2 system in the ocean total inorganic carbon Mass balance CT=[CO2] + [HCO3-] + [CO32-] 1% 85% 14% (CT a.k.a. SCO2 or DIC or TIC) Independent of T & Pr

31. CO2 system in the ocean THE CONCEPT OF ALKALINITY Zeebe and Wolf-Gladrow (2001) TA is balancing this excess of cations

32. Seawater with just CO2 & Borate as week acids CO2 system in the ocean THE CONCEPT OF ALKALINITY Seawater with just CO2 as week acid Zero Level of proton aceptors Zero Level of proton aceptors

33. Uptake protons Donate protons - [ACIDS] - [ACIDS] CO2 system in the ocean THE CONCEPT OF ALKALINITY REAL Seawater (with many weak basis and acids) Zero level of proton aceptors ??

34. CO2 system in the ocean THE CONCEPT OF ALKALINITY OPERATIONAL definition of TA

35. CO2 system in the ocean alkalinity

36. PAUSA

37. Zeebe and Wolf-Galdrow (2001) pH increase Chisholm, Nature 2000 pH increase CO2 system in the ocean variability factors • Three pumps: • gas-exchange: T + bio • Soft tissue • Carbonate

38. CO2 system in the ocean variability factors

39. CO2 system in the ocean variability factors

40. CO2 system in the ocean variability factors Factores físicos: + intercambio aire-agua + disolución en el agua

41. Piston velocity, units of velocity CO2 system in the ocean variability factors Physical factors: + air-sea exchange

42. CO2 system in the ocean variability factors ¿CO2 equilibration time in the mixed layer?

43. CO2 system in the ocean variability factors

44. CO2 system in the ocean partial pressure of CO2 Questions: + why are there sinks and sources of CO2 ? + what factors control pCO2? Takahashi et a. (DSRII, 2002)

45. CO2 system in the ocean partial pressure of CO2 Physical factors: + temperature + salinity • pCO2 = 300 uatm, T= 20, S=35 • 1ºC increase in T => +13 uatm • 1 unit increase in S => + 9 uatm

46. CO2 system in the ocean partial pressure of CO2 Quantification of the biological and physical factors: Seasonal variations in Temp are high in subtropical areas, tropical and polar areas have limited variability in T and so on pCO2temp

47. CO2 system in the ocean partial pressure of CO2 Quantification of the biological and physical factors: pCO2 decreases due to biological activity (photosynthesis) north of 40ºN, subpolar areas, upwelling areas.

48. CO2 system in the ocean partial pressure of CO2 Quantification of the biological and physical factors: Biology: green-blue, high north latitudes, Eq. Pacific, SO Temp: temperate & subtropical areas !!: areas of water mass formation, biology predominates.

49. The Royal Society (2005) CO2 system in the ocean surface pH

50. CO2 system in the ocean water column pH 25 T