IEG 환경지질연구정보센터

지구화학│기타

2010 추계지질과학연합학술발표회 초록집 243

Understanding carbon exchange processes in headwater streams draining silicate and carbonate catchments based on δ ¹³ C DIC values

Woo-Jin Shin

․Gong Soo Chung

․Dongho Lee

․Kwang-Sik Lee

1

Korea Basic Science Institute, [email protected]

2

Chungnam National University

3

Yonsei University

4

Graduate School of Analytical Science and Technology

We report isotopic compositions of dissolved inorganic carbon (δ

C

) in waters derived from catchments underlain by silicate and carbonate rocks. Spring and stream waters were sampled from each catchment to understand carbon exchange processes along the hydrological pathways from the subsurface (spring) to surface (stream) reservoirs. The δ

C

value was controlled by catchment lithology with spring waters howing low δ

C

values (-16.7±2.4‰) in the silicate catchment and higher values (-9.9±1.3‰) in the carbonate catchment. Seasonal variation in the δ

C

was characterized by decreasing values during summer and early fall and increasing values during winter and early spring due to seasonality in rainfall and bioproductivity. The seasonal variation in the δ

C

of stream samples generally followed the pattern observed in the springs. Despite the considerable difference in δ

C

between spring waters in the two catchments, both streams exhibited higher and rather similar δ

C

values, -6.7±1.5‰ and -7.9±1.4‰ insilicate and carbonate catchments, respectively.

Both streams underwent prolific CO

exchanges with the atmosphere, and therefore the distinct source signatures were eradicated in the carbon isotopic compositions of DIC.

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