Algae and theAlgae and theCalcium Carbonate Calcium Carbonate

CycleCycle

Natalie LeeNatalie Lee

AtmosphereAtmosphere CO CO22

Atmospheric exchangeAtmospheric exchange

OceanOcean HCOHCO33--

CalcificationCalcification

MarineMarine CaCO CaCO33

organismsorganisms

Sinking/SedimentationSinking/Sedimentation

MarineMarine

sedimentssediments CaCO CaCO33

Acidification of water forms carbonic acid, HAcidification of water forms carbonic acid, H22COCO33, which , which

dissolves CaCOdissolves CaCO33

Lysocline = distinct increase in dissolution rateLysocline = distinct increase in dissolution rate

Carbonate Compensation Depth (CCD) = equilibrium Carbonate Compensation Depth (CCD) = equilibrium between precipitation and dissolution of CaCObetween precipitation and dissolution of CaCO33

CaCa2+2+ lost to sedimentation is recycled by rock weathering lost to sedimentation is recycled by rock weathering

COCO2 2 + Ca+ Ca2+2+ + H + H22O O CaCO CaCO3 3 + 2H+ 2H++

CALCIFICATIONCALCIFICATION

2H2H+ + + 2HCO+ 2HCO33- - 2CO 2CO2 2 + 2H+ 2H22OO

BICARBONATE UTILIZATIONBICARBONATE UTILIZATION

COCO2 2 + 2H+ 2H22O + >8 photons O + >8 photons CH CH22O + HO + H22O + OO + O22

PHOTOSYNTHESISPHOTOSYNTHESIS

2HCO2HCO33-- + Ca + Ca2+2+ CaCO CaCO33 + H + H22O + COO + CO22

NETNET

CalcificationCalcification

CaCa2+2+ transport across membrane coupled transport across membrane coupled with Hwith H+ + exportexport

HH+ + reacts with HCOreacts with HCO33- - in water to form CO in water to form CO22

COCO2 2 used in photosynthesis and binds used in photosynthesis and binds

with Cawith Ca2+2+ to form CaCO to form CaCO33

Calcification is an adaptation that allows Calcification is an adaptation that allows algae to obtain sufficient inorganic carbon algae to obtain sufficient inorganic carbon for photosynthesisfor photosynthesis

Calcareous AlgaeCalcareous Algae

CyanobacteriaCyanobacteria Green algaeGreen algae Brown algaeBrown algae Red algaeRed algae Coccolithophores Coccolithophores

HalimedaHalimeda

Discosphaera tubiferaDiscosphaera tubifera

Pneophyllum conicumPneophyllum conicum

Focus On: Distribution of Crustose Coralline AlgaeFocus On: Distribution of Crustose Coralline Algae Fabricius & De’ath, 2001Fabricius & De’ath, 2001

Observational study of 144 reef sites at Great Barrier Observational study of 144 reef sites at Great Barrier ReefReef

Which factors correlate with CCA percent cover?Which factors correlate with CCA percent cover? Thickness of sediment depositsThickness of sediment deposits VisibilityVisibility Reef slope angleReef slope angle Distances across and along shelfDistances across and along shelf

Focus On: Distribution of Crustose Coralline AlgaeFocus On: Distribution of Crustose Coralline Algae Fabricius & De’ath, 2001Fabricius & De’ath, 2001

Focus On: Distribution of Focus On: Distribution of Crustose Coralline AlgaeCrustose Coralline Algae

Fabricius & De’ath, 2001Fabricius & De’ath, 2001

CCA cover has strong inverse relationship with cross-shelf distance and with sediment deposit

CCA cover has weak relationship with visibility and with slope

All variables strongly related to cross-shelf distance, therefore it is the single variable that best explains variability in CCA cover

Focus On: Calcification in CoccolithophoresFocus On: Calcification in Coccolithophores Satoh Satoh et al.,et al., 2009 2009

What factors induce calcification in What factors induce calcification in Emiliania huxleyiEmiliania huxleyi?? Cold stressCold stress Phosphate deprivationPhosphate deprivation

Temperature decrease from 20°C to 12°C suppressed Temperature decrease from 20°C to 12°C suppressed growth, caused Pgrowth, caused Pi i depletion and increase in alkaline depletion and increase in alkaline

phosphatase activity, and increase in coccolith phosphatase activity, and increase in coccolith productionproduction

Important to our understanding of the relationship Important to our understanding of the relationship between phosphate availability and temperature to between phosphate availability and temperature to oceanic carbon flux.oceanic carbon flux.

ReferencesReferences

Fabricius, K., and G. De’ath. (2001). Environmental factors associated with the distribution of Fabricius, K., and G. De’ath. (2001). Environmental factors associated with the distribution of crustose coralline algae on the Great Barrier Reef. crustose coralline algae on the Great Barrier Reef. Coral ReefsCoral Reefs 19:303–309. 19:303–309.

Graham, L. E., J. M. Graham, and L. W. Wilcox. (2009). Graham, L. E., J. M. Graham, and L. W. Wilcox. (2009). AlgaeAlgae (2 (2ndnd ed.). San Francisco: ed.). San Francisco: Pearson Benjamin Cummings.Pearson Benjamin Cummings.

Ridgwell, A., and R. E. Zeebe. (2005). The role of the global carbonate cycle in the regulation Ridgwell, A., and R. E. Zeebe. (2005). The role of the global carbonate cycle in the regulation and evolution of the Earth system. and evolution of the Earth system. Earth and Planetary Science Letters Earth and Planetary Science Letters 234:299-315.234:299-315.

Satoh, M., K. Iwamoto, I. Suzuki, Y. Shiraiwa. (2009). Cold stress stimulates intracellular Satoh, M., K. Iwamoto, I. Suzuki, Y. Shiraiwa. (2009). Cold stress stimulates intracellular calcification by the Coccolithophore, calcification by the Coccolithophore, Emiliania huxleyiEmiliania huxleyi (Haptophyceae) under phosphate- (Haptophyceae) under phosphate-deficient conditions. deficient conditions. Marine Biotechnology Marine Biotechnology 11:327-333.11:327-333.

““The Marine Carbon Cycle.” The Marine Carbon Cycle.” http://earthguide.ucsd.edu/virtualmuseum/climatechange1/06_3.shtmlhttp://earthguide.ucsd.edu/virtualmuseum/climatechange1/06_3.shtml