malaysia_ioc-westpac 2016 new
TRANSCRIPT
CurrentstatusofimplementationforOAstudiesinMalaysia
LocationoftheproposedstudysiteN
400km
Pulau Gaya
STUDYSITE
Sumatra
PulauPayar
TarutaoNationalPark
SOUTHCHINASEA
PulauBidong
P.Payar
P.Lembu
P.Kaca
N
STRAITOFMALACCA
1km
MarineParkCentre
PulauPayarMarinePark
Pulau Bidong (UMTMarineResearchStation)
UMTMarineResearchStation
N
SOUTHCHINASEA
1km
InvestigatingthediurnalvariationoftheseawaterpHandalkalinityinshallowwatercoralreefofPulau Payar (StraitofMalacca),Pulau Bidong andPulau Gaya(SouthChinaSea)astheproposedsitesoftheocean
acidificationstudy.
DiurnalvariabilityofpHandtotalalkalinity
3dayperiodofobservationatashallowwater coralreefarea
In-situmeasurement&watersamplecollection
Every3hours,watersamplewerecollectedandmeasuredfortheTotalAlkalinity(AT)
HydrolabDS5Xrecordedreadingevery15minute(pH,Temperature,Salinity,DissolvedOxygen,DO)
AragonitesaturationweredeterminedusingtheCO2SYSprogram(LewisandWallace,1998)throughinsituAT,pH,
salinity,temperaturedata.
Methodsthatwereusedtodeterminetheseawatercarbonateparameter
Parameters Unit MeasurementMethods
Temperature °C HydrolabDS5X
Salinity ppt HydrolabDS5X
pH HydrolabDS5X
DissolvedOxygen(DO) mg/L HydrolabDS5X
TotalAlkalinity µmol/kg PotentiometricTitration(Dicksonetal.2007)
AragoniteSaturation ΩAragonite CO2SYSprogram(LewisandWallace,1998)
DiurnalvariationinseawaterpHatthestudyarea
day day daynight night night
• pH trend fluctuates daily following the diurnal pattern which is regulated by the biological activity such as photosynthesis and respiration
Payar(SOM)
Bidong(SCS)
Gaya(SCS)
SeawaterpHatPulauPayar,PulauBidongandPulauGaya
• Decreasing surface seawater pH trend from the Strait of Malacca to the South China Sea
morebasic
lessbasic
Diurnalvariationoftotalalkalinity
day day daynight night night
Payar(SOM)
Bidong(SCS)
Gaya(SCS)
• Total alkalinity (AT) did not show any diurnal trend through out this study.• However, the largest difference of AT was recorded at Payar with the value of 28.92 μmol/kg.• Changes in AT are attributed to calcification or carbonate dissolution (Murillo et al., 2014)
Relationshipbetweentotalalkalinityandsalinity
• Precipitation and evaporation mainly controls the AT variability of surface ocean (Brewer et al., 1986; Millero et al., 1998a)
• Concentrations of the key chemical species (i.e., HCO3
-
CO32-) that contribute to AT
proportionally increase with increasing salinity (Lee et al., 2006)
CO2 ParameterVariation
• pH ranged 7.21 to 7.81°C• Lower pH observed at the southern
region
pH
• ρCO2 ranged 710 to 3151 µatm
• Higher ρCO2 observed at the southern region
ρCO2 (µatm)
• Aragonite saturation ranged 0.57 to 2.26• Low saturation state observed at the
southern region• At extremely marginal state
Aragonite Saturation (ΩAra)
CO2 ParameterVariation
Hoegh-Guldberg et al. 2007: Ωarag = 3.3
Shamberger et al. 2011
Saturation States in the Pacific
(Shambergeretal.2011)
(ReefsatRiskRevisited 2011)
Saturation state in our region
Carbonateenvironmentcomparison• Pulau Bidong and Pulau Gaya
– Higher AT were recorded at these sites, 2161.78 μmol kg-1 and2160.45 μmol kg-1 respectively.
– The pH at both sites are lower than Payar as denoted by the higherH+ concentration in the seawater.
– Aragonite saturation in the seawater at both sites were recorded atadequate (3.41) and marginal (2.99) level respectively.
• Pulau Payar– Lower AT (2140.77 μmol kg-1) means the capacity of the seawater
buffer system to neutralize acidic pollution is reduced.– At present, the seawater carbonate system is maintained because of
the pH value (pH 8.14).– Only a small amount of acidic pollution is needed to disrupt the
carbonate system equilibrium.– Optimal aragonite saturation state in Payar contributes to the high
coral calcification rate in the area.
CurrentstatusofimplementationforOAstudiesinMalaysia
• AllrequiredCAUs,BMUsandARMshavebeenmanufacturedbutasyetnotdeployed
• diurnalvariationsurveyofselectedstationhasbeencompletedfortemperature,salinity,pHDO,aragonitesaturationandtotalalkalinity
• Coralcoveranddiversitystudiesareplannedfor2016-2017).Bioticsurvey(georeferenced,cover,diversity)iscurrentlybeinganalysed.
• Localorganizingcommittee• IOC/WESTPAC• Mr.WenxiZhu• PhuketMarineBiologicalStation