- 1 - PHYSICAL CLIMATOLOGY Implication of biogeochemical change driven by global warming in the East Sea Implication of biogeochemical change driven by global warming in the East Sea Il Nam Kim Department of Marine Science University of Texas at Austin Department of Marine Science University of Texas at Austin EAST SEA STUDY

- 2 - PHYSICAL CLIMATOLOGY INTRODUCTION INTRODUCTION BACKGROUND BACKGROUND MATERIAL & METHOD MATERIAL & METHOD RESULTS RESULTS CONCLUSION CONCLUSION

- 3 - PHYSICAL CLIMATOLOGY INTRODUCTION INTRODUCTION

- 4 - PHYSICAL CLIMATOLOGY ■ The East Sea ▲ a semi-closed marginal sea 17 June – 21 July 22 July – 11 August depth (m) ▲ frequently referred to as ‘ miniature ocean ’ ‘ miniature ocean ’ ▲ The maximum depth – 4,049m average depth – 1,600m average depth – 1,600m ▲ Study area

- 5 - PHYSICAL CLIMATOLOGY ■ Dissolved Oxygen distribution at 1000m [Talley et al. 2006]

- 6 - PHYSICAL CLIMATOLOGY ■ Warming evidences ▲ Temperature changes [Min and Kim, 2006] Vladivostok Sea Surface Temp. [Kim et al., 2004]

- 7 - PHYSICAL CLIMATOLOGY ▲ Oxygen changes [Kang et al., 2004] [Kim et al., 2001] box modeling

- 8 - PHYSICAL CLIMATOLOGY BACKGROUND BACKGROUND

- 9 - PHYSICAL CLIMATOLOGY ■ Denitrification ▲ In the presence of oxygen ▲ In the absence of oxygen ☞ nitrification (NH 4 + → NO 2 - → NO 3 - ) ☞ denitrification (NO 3 - → NO 2 - → N 2 O/N 2 ) [Sarmiento and Gruber, 2006]

PHYSICAL CLIMATOLOGY ▲ The major areas FIG. 4 In the eastern tropical North Pacific In Saanich Inlet [Devol, 1978] The Arabian Sea [Hupe and Karstensen, 2000]

PHYSICAL CLIMATOLOGY MATERIAL MATERIAL

PHYSICAL CLIMATOLOGY ■ Study Map ▲ Cruise: CREAMS II expedition (1999) ▲ Parameters used : T, S, DO, nutrients, TAlk, DIC lat, long, depth (≥300m) lat, long, depth (≥300m) ≥ 200 m ≥ 300 m

PHYSICAL CLIMATOLOGY METHOD METHOD

PHYSICAL CLIMATOLOGY ■ Linear Inverse Mixing Model ▲ Model equations T : Temperature T : Temperature S : Salinity S : Salinity DO : Dissolved Oxygen DO : Dissolved Oxygen P : Phosphate P : Phosphate N : Nitrate N : Nitrate Si : Silicate Si : Silicate TALK : Total Alkalinity TALK : Total Alkalinity DIC : Dissolved Inorganic Carbon DIC : Dissolved Inorganic Carbon [Hupe and Karstensen 2000]

PHYSICAL CLIMATOLOGY ▲ Matrix form ※ r D (Gruber and Sarmiento 1997) AxdR -= A : source water types A : source water types x : mixing ratio x : mixing ratio d : observed data d : observed data R : residual R : residual knownknown unknownunknown Kim and Lee (2004) TMW (Tsushima Middle Water) LCW (Liman Cold Water) ESIW (East Sea Intermediate Water) ESPW (East Sea Proper Water)

PHYSICAL CLIMATOLOGY ▲ Redfield ratios ▲ Solution ※ MATLAB is available to calculate non-negative solutions ☞ function of NNLS ▲ Weights

PHYSICAL CLIMATOLOGY RESULTS I RESULTS I - some evidences

PHYSICAL CLIMATOLOGY ■ N:P ratio

PHYSICAL CLIMATOLOGY ■ Vertical profiles of NO 3 -, NO 2 -, O 2, and N/P ratio

PHYSICAL CLIMATOLOGY RESULTS II RESULTS II - linear inverse modeling

PHYSICAL CLIMATOLOGY ■ Expected denitrification locations ▲ CASE 1 ▲ CASE 2 ▲ CASE 3 ▲ CASE 4

PHYSICAL CLIMATOLOGY ■ Vertical profiles of ∆N deni ▲ CASE 1 ▲ CASE 2 ▲ CASE 3 ▲ CASE 4

PHYSICAL CLIMATOLOGY ■ How to derive the unit of time ? ▲ Estimation of pseudo-age using oxygen ▲ Example

PHYSICAL CLIMATOLOGY ■ Horizontal distributions of ∆N deni - CFCs ▲ CASE 1 ▲ CASE 2 ▲ CASE 3 ▲ CASE 4 (µmol/m 2 day)

PHYSICAL CLIMATOLOGY ■ Horizontal distributions of ∆N deni - MBBM ▲ CASE 1 ▲ CASE 2 ▲ CASE 3 ▲ CASE 4 (µmol/m 2 day)

PHYSICAL CLIMATOLOGY SUMMARYSUMMARY Area = e+3 km 2

PHYSICAL CLIMATOLOGY RESULTS III RESULTS III - feedback loop

PHYSICAL CLIMATOLOGY ■ The feedback loop based on biogeochemical changes Global Warming ↑ Water formation ↓ low Oxygen Environment ↑ Denitrification ↑ NO ↑ N 2 O ↑ POSITIVE 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 ↑

PHYSICAL CLIMATOLOGY CONCLUSION CONCLUSION

PHYSICAL CLIMATOLOGY ☞ The denitrification in the East Sea is estimated approximately to be 9 to 16 µmol·m -2 ·d -1 through the approximately to be 9 to 16 µmol·m -2 ·d -1 through the linear mixing inverse model. linear mixing inverse model. ☞ New finding ? vs Warming event ? ☞ Therefore, we need to have deep concern about the phenomenon that is occurring though the oxygen phenomenon that is occurring though the oxygen content high. It might be a signal of global warming. content high. It might be a signal of global warming.

PHYSICAL CLIMATOLOGY Thank you for your time !