Implication of biogeochemical change driven by global warming in the East Sea

- 1 - PHYSICAL CLIMATOLOGYPHYSICAL CLIMATOLOGY

Implication of biogeochemical change Implication of biogeochemical change

driven by driven by global warmingglobal warming

in the in the East SeaEast Sea

Implication of biogeochemical change Implication of biogeochemical change

driven by driven by global warmingglobal warming

in the in the East SeaEast Sea

Il Nam KimIl Nam KimIl Nam KimIl Nam Kim

Department of Marine ScienceDepartment of Marine ScienceUniversity of Texas at AustinUniversity of Texas at Austin

Department of Marine ScienceDepartment of Marine ScienceUniversity of Texas at AustinUniversity of Texas at Austin

EAST SEA STUDYEAST SEA STUDY


INTRODUCTION INTRODUCTION

BACKGROUNDBACKGROUND

MATERIAL & METHODMATERIAL & METHOD

RESULTSRESULTS

CONCLUSIONCONCLUSION


• INTRODUCTIONINTRODUCTION


■■ The East SeaThe East Sea

▲▲ a semi-closed marginal seaa semi-closed marginal sea

17 June – 21 July 22 July – 11 August

depth (m)

▲▲ frequently referred to as frequently referred to as ‘ ‘ miniature ocean miniature ocean ’’

▲▲ The maximum depth – 4,049mThe maximum depth – 4,049m average depth – 1,600maverage depth – 1,600m

▲▲ Study areaStudy area


■■ Dissolved Oxygen distribution at 1000mDissolved Oxygen distribution at 1000m

[Talley et al. 2006]


■■ Warming evidencesWarming evidences

▲▲ Temperature changesTemperature changes

[Min and Kim, 2006][Min and Kim, 2006]

VladivostokVladivostok

Sea Surface Temp.Sea Surface Temp.

[Kim et al., 2004][Kim et al., 2004]


▲▲ Oxygen changesOxygen changes

[Kang et al., 2004][Kang et al., 2004][Kim et al., 2001][Kim et al., 2001]

box modelingbox modeling


• BACKGROUNDBACKGROUND


■■ DenitrificationDenitrification

▲▲ In the presence of oxygenIn the presence of oxygen

▲▲ In the absence of oxygenIn the absence of oxygen

☞ ☞ nitrification (NHnitrification (NH44+ + → NO→ NO22

- - → NO→ NO33--))

☞ ☞ denitrification (NOdenitrification (NO33- - → NO→ NO22

- - → N→ N22O/NO/N22))

[Sarmiento and Gruber, 2006][Sarmiento and Gruber, 2006]


▲▲ The major areasThe major areas

FIG. 4

In the eastern tropical North Pacific

In Saanich Inlet

[Devol, 1978][Devol, 1978]

The Arabian SeaThe Arabian Sea

[Hupe and Karstensen, 2000][Hupe and Karstensen, 2000]


• MATERIALMATERIAL


■■ Study MapStudy Map

▲▲ Cruise: CREAMS II expedition (1999)Cruise: CREAMS II expedition (1999)

▲▲ Parameters used : T, S, DO, nutrients, TAlk, DICParameters used : T, S, DO, nutrients, TAlk, DIC lat, long, depth (lat, long, depth (≥300m≥300m))

• ≥ 200 m

• ≥ 300 m


• METHODMETHOD


■■ Linear Inverse Mixing Model Linear Inverse Mixing Model

▲▲ Model equationsModel equations

• T : TemperatureT : Temperature• S : Salinity S : Salinity • DO : Dissolved OxygenDO : Dissolved Oxygen• P : PhosphateP : Phosphate

• N : Nitrate N : Nitrate • Si : SilicateSi : Silicate• TALK : Total Alkalinity TALK : Total Alkalinity • DIC : Dissolved Inorganic CarbonDIC : Dissolved Inorganic Carbon

[Hupe and Karstensen 2000][Hupe and Karstensen 2000]


▲▲ Matrix formMatrix form

※ rD (Gruber and Sarmiento 1997)

AA xx dd RR•• -- ==

• AA : source water types : source water types• xx : mixing ratio : mixing ratio • dd : observed data : observed data• RR : residual : residual

knownknown knownknownunknownunknown unknownunknownKim and Lee (2004)Kim and Lee (2004)TMWTMW ( (TTsushima sushima MMiddle iddle WWater)ater)LCWLCW ( (LLiman iman CCold old WWater)ater)ESIWESIW ( (EEast ast SSea ea IIntermediate ntermediate WWater)ater)ESPWESPW ( (EEast ast SSea ea PProper roper WWater)ater)


▲▲ Redfield ratiosRedfield ratios

▲▲ Solution Solution

※ MATLAB is available to calculate non-negative solutions ☞ function of NNLS

▲▲ Weights Weights


• RESULTS IRESULTS I- some evidences- some evidences


■■ N:P ratioN:P ratio


■■ Vertical profiles of NOVertical profiles of NO33--, NO, NO22

--, O, O22, and N/P ratio, and N/P ratio


• RESULTS IIRESULTS II- linear inverse modeling- linear inverse modeling


■■ Expected denitrification locations Expected denitrification locations ▲▲ CASE 1 CASE 1 ▲▲ CASE 2 CASE 2

▲▲ CASE 3 CASE 3 ▲▲ CASE 4 CASE 4


■■ Vertical profiles of Vertical profiles of ∆∆NNdenideni ▲▲ CASE 1 CASE 1 ▲▲ CASE 2 CASE 2



■■ How to derive the unit of time ? How to derive the unit of time ?

▲▲ Estimation of pseudo-age using oxygenEstimation of pseudo-age using oxygen

▲▲ ExampleExample


■■ Horizontal distributions of Horizontal distributions of ∆∆NNdenideni - CFCs - CFCs▲▲ CASE 1 CASE 1 ▲▲ CASE 2 CASE 2


(µmol/m(µmol/m22dayday))


■■ Horizontal distributions of Horizontal distributions of ∆∆NNdenideni - MBBM - MBBM▲▲ CASE 1 CASE 1 ▲▲ CASE 2 CASE 2


(µmol/m(µmol/m22dayday))


SUMMARYSUMMARYSUMMARYSUMMARY

Area = Area = 7.0926e+3 km7.0926e+3 km22


• RESULTS IIIRESULTS III- feedback loop- feedback loop


■■ The feedback loop based on biogeochemical changesThe feedback loop based on biogeochemical changes

Global Warming ↑Global Warming ↑ Water formation Water formation ↓↓

low Oxygen Environment ↑low Oxygen Environment ↑Denitrification Denitrification ↑↑ NN2O ↑O ↑

POSITIVEPOSITIVE

Gamo (1999)

Postlethwaite et al. (2005)

Kang et al. (2003b)

Kang et al. (2004)

Kim et al. (2004)

Chen et al. (1999)

Gamo (1999)

Kim et al. (2001)

Kim and Kim (1996)

Min and Kim (2006)

Chae et al. (2005)

?

Gamo et al. (2001)

SST ↑SST ↑


• CONCLUSION CONCLUSION


☞ The denitrification in the East Sea is estimated The denitrification in the East Sea is estimated

approximately to be approximately to be 9 to 16 9 to 16 µmol·µmol·mm-2-2··dd-1-1 through the through the

linear mixing inverse model.linear mixing inverse model.

☞ New finding ? New finding ? vsvs Warming event ? Warming event ?

☞ Therefore, we need to have Therefore, we need to have deep concerndeep concern about the about the

phenomenon that is occurring though the oxygen phenomenon that is occurring though the oxygen

content high. It might be content high. It might be a signala signal of of global warmingglobal warming..


Thank you for your time !Thank you for your time !

Implication of biogeochemical change driven by global warming in the East Sea

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