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1- Biological and geochemical CARBON cycle in the open ocean and coast (2 horas) 2- CARBON production during the Antropocene: sinks, sources, and storage.

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Presentation on theme: "1- Biological and geochemical CARBON cycle in the open ocean and coast (2 horas) 2- CARBON production during the Antropocene: sinks, sources, and storage."— Presentation transcript:

1 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 horizon: vulnerability of the carbon cycle in the oceans (1 hora) 4- Workshop - case study: CANT in the subtropical Indian Ocean (1.5 horas)

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5 Definition 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 Gruber 2004 ESQUEMA CICLO DEL C, N, O 2, P EN EL OCÉANO Physical oceanography Biological oceanography Geological oceanography

6 Relevance 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 Carbon accumulation on real scales Antia, NATO Summer School, Ankara, 2006 On a time scale of millenia: the oceans determine the CO2 concentration in the atmosphere

7 Global carbon cycle Land use change Land sink & the anthropogenic perturbation PgC/yr = gC = tons = 1 billón de kilos 1 tonelada = gC = 1000 kilos

8 Fluxes in PgC/yr & stocks in PgC DIC: dissolved inorganic carbon; DOC: dissolved organic carbon POC: particulate organic carbon; PIC: particulate inorganic carbon = CaCO 3 NPP: net primary production

9 Chisholm, Nature 2000 Biological pump Physical or solubility pump Primary Prod. 100 Export > 100m 10 Sediments0.1 Temporal Scale 1 year years > 10 6 years weeks Photic layer, epi-pelagic Who plays here? Aphotic layer: meso & bati-pelagic

10 Biological processes: + soft-tissue pump: photosynthesis/ remineralization of OM + carbonate pump: formation/dissolution of CaCO 3 1 mol CaCO 3  => 0.6 mol CO 2 

11 Organic matter synthesis – stoichiometry - Redfield ratios: Redfield ratios: + C:N:P:O :16:1: mean phyto composition (lipids + proteins + sugars + nucleid acids) in the ocean … BUT … it varies … + what else??

12 Organic matter synthesis- limiting factors - nutrients

13 Where do they come from? + atmosphere + lateral transport + vertical transport: upwelling, winter mixing, vertical mixing winter mixing, vertical mixing Chisholm, Nature 2000 Organic matter synthesis- limiting factors - nutrients

14 ¿ De dónde vienen? + atmósfera + transporte lateral + transporte vertical: upwelling, winter mixing, vertical mixing Organic matter synthesis- limiting factors - nutrients

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

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

17 Biological efficiency: Biological efficiency: capacity to consume the nutrients available in the photic zone

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

19 The efficiency of the biological pump is inversely correlated to the efficiency in the export of organic matter out of the photic zone

20 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

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22 1 mol CaCO 3  => 0.6 mol CO 2  Rain Ratio = POC / PIC export

23 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 Producción primaria Secuestro de C bajo WML Moderada PP- Bajo secuestro – WML profundo Alta PP- Alto secuestro – WML somero Antia et al. (GBC, 2001)

25 PgC/yr = gC = toneladas = 1 billón de kilos 1 tonelada = gC = 1000 kilos

26 pH  CO 2 / DIC / TIC / C T K0K0 K1K1 K2K2 pH= -log [ H 3 O + ] C T = [ CO 2 ] + [ HCO 3 - ] + [ CO 3 2- ] Mass balance TA = A T =[HCO 3 - ]+2· [ CO 3 2- ] + [ B(OH) 4 - ] + [ OH - ] - [ H 3 O + ] Charge balance pCO 2 = [CO 2 ]/  0 (S,T) 5 species (unknowns) H 2 CO 3 *, HCO 3 –, CO 3 –2, H +, OH – 3 equilibrium equations K 1, K 2, K w 1 concentration condition DIC 1 proton condition TA Any two carbonate system parameters fix the values of all the rest fix the values of all the rest

27 pH TIC Complex system 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 variables: TIC, pH, TA, fCO2

28 fCO 2 = x(CO 2 )  p atm = [CO 2 ]/  0 (S,T) A T =[HCO 3 - ]+2· [ CO 3 2- ] + [ B(OH) 4 - ] + [ OH - ] - [ H 3 O + ] C T = [ CO 2 ] + [ HCO 3 - ] + [ CO 3 2- ] Mass balance Charge balance pH= -log [ H 3 O + ]

29 fCO 2 = x(CO 2 )  p atm = [CO 2 ]/  0 (S,T) General rule: more dissolved CO2 in cold waters

30 C T = [ CO 2 ] + [ HCO 3 - ] + [ CO 3 2- ] Mass balance (C T a.k.a.  CO 2 or DIC or TIC) Independent of T & Pr pH TIC 1% 85% 14%

31 THE CONCEPT OF ALKALINITY Zeebe and Wolf-Gladrow (2001) TA is balancing this excess of cations

32 Zero Level of proton aceptors THE CONCEPT OF ALKALINITY Zero Level of proton aceptors Seawater with just CO 2 as week acid Seawater with just CO 2 & Borate as week acids

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

34 THE CONCEPT OF ALKALINITY OPERATIONAL definition of TA

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37 pH increase Zeebe and Wolf-Galdrow (2001) Three pumps: - gas-exchange: T + bio - Soft tissue - Carbonate Chisholm, Nature 2000

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40 Factores físicos: + intercambio aire-agua + disolución en el agua

41 Physical factors: + air-sea exchange Piston velocity, units of velocity

42 ¿CO2 equilibration time in the mixed layer?

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44 Takahashi et a. (DSRII, 2002) Questions: + why are there sinks and sources of CO2 ? + what factors control pCO 2 ?

45 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 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 pCO 2 temp

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

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

49 The Royal Society (2005)

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51 Caldeira & Wickett (2003) Oceanography (Vol 17, 2004)

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53 Global mean profiles of the three main carbon pumps. Sarmiento & Gruber (2006)

54 NTA = TA*35 / Sal

55 Relevance of the coast LOICZ, 2006

56 Relevancia costas:  ocupan ± 20% de la superficie del océano  contienen más de un 40% de la población mundial  proveen de 75% de las capturas de pesca  representan un 25% de la PP  directamente afectadas por la actividad humana (contaminación, eutrofización): ríos, aerosoles en atmósfera,  interacción tierra-océano-atmósfera-sedimentos en escalas de años.  muy heterogéneas y dinámicas, vehículo conductor de carbono hacia el interior del océano.  proyectos: LOICZ ( ), CARBOOCEAN ( )

57 0.24 PIC 0.32 POC 33.6 DIC, 1.44 DOC, PIC, 0.26 POC DIC, 0.84 DOC POC CARBON budget (PgC y -1 ) in the continental margins 0.18 PIC 0.18 POC River, drainage & ice Primary Prod: 0.48 PIC, 6.19 POC New Prod.: 0.28 DOC, 0.23 PIC, 0.50 POC Coast & open platforms0.38 DIC, 0.32 DOC, 0.18 PIC, 0.22 POC CH 4 from sediments DMS from biolog. Act. Sediments & fishery Open ocean Mixed layer Deep layer Sediments C Precipitation & dust Atmosphere Chen (2004) Chen & Borges (2009) 0.31 IC (DIC) 0.81 OC (74% DOC) Net sink of CO 2 CONTINENTAL SHELF PUMP ?????????? ????? ????? Wollast (1998) 0.36 CO 2 New Prod 0.25 PIC DMS

58 Net air-sea CO 2 flux on european coasts Borges et al., ECSS, 2006 Frankingnoulle & Borges GBC 2001

59 Borges et al., ECSS, 2006 Golfo de Vizcaya -0.8 molC m -2 yr -1 Net air-sea CO 2 flux on european coasts

60 Typology of (a) estuarine environments (modified from Dürr et al. [Estuaries & Coasts 2010]) and (b) continental shelf seas. In Laruelle et al. (GRL, 2010)

61 Latitudinal distribution of the (a–c) air-water CO2 fluxes (in g C yr−1) and (d–f) surface areas (in 10 6 km2) in estuaries (Figures 2a and 2d) and continental shelf seas (Figures 2b and 2e) and the global coastal ocean (Figures 2c and 2f). A positive value represents a source of CO2 to the atmosphere.

62 Evaluation of sinks and sources of CO2 in the global coastal ocean using a spatially-explicit typology of estuaries and continental shelves. Laruelle et al (GRL, 2010). The computed emission of CO 2 to the atmosphere from estuaries (+0.27 ± 0.23 PgC yr −1 ) is ~26% to ~55% lower than previous estimates while the sink of atmospheric CO 2 over continental shelf seas (−0.21 ± 0.36 PgC yr −1 ) is at the low end of the range of previous estimates (−0.22 to −1.00 PgC yr −1 ). The air-sea CO 2 flux per surface area over continental shelf seas (−0.7 ± 1.2 molC m −2 yr −1 ) is the double of the value in the open ocean based on the most recent CO 2 climatology. The largest uncertainty of scaling approaches remains in the availability of CO 2 data to describe the spatial variability, and to capture relevant temporal scales of variability.

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