210 likes | 366 Views
Implications of C/N Ratios from Two USGS Sediment Trap Samples Recovered from the Kaoping Canyon. Saulwood Lin , Institute of Oceanography Natioanal Taiwan University James Liu Institute of Marine Geology and Chemistry National Sun-Yat-Sen University.
E N D
Implications of C/N Ratios from Two USGS Sediment Trap Samples Recovered from the Kaoping Canyon Saulwood Lin, Institute of Oceanography Natioanal Taiwan University James Liu Institute of Marine Geology and Chemistry National Sun-Yat-Sen University 「International Sediment Trap Workshop」 National Sun Yat-sen University, Kaohsiung, Taiwan. March 23-27, 2009
(Huh et al., 2007) Dadson et al. (2003)
Modes of SS transport: Normal river plume Densityflow
Wet season Annual rainfall Dry season From Taiwan Central Weather Bureau
High frequency of typhoon invasion (~4 per year) Total 436 typhoons invaded Taiwan during 1897 to 2007 From Central Weather Bureau
(Boutton et al., 1991) ( Kendall et al., 2001)
Sediment Mooring T6KP: Winter (Dry) Season (January 10-March 20, 2008) T7KP: Summer (Wet) Season (July 7-September 11, 2008) (From J. Liu)
T7KP T6KP USGS Sediment Trap (From J. Liu)
Samples from T7KP 25 cm Timer (a) (b) a1: 21cm a2: 23cm 108.5 cm 5.4 cm b: 49cm 5.85 cm 5.85 cm (0cm) 6.8 cm Sediment length in the coreliner: 192cm 191 cm 6.8 cm Time marker 02 at (186~188cm) Time marker 01 at (188~190cm) (From J. Liu)
Calmagi Fung Wong Kammuri Nuri (From J. Liu)
Objective • To study particulate (%TOC, %TON, C/N ratio, 13COrg) passing through the KP Canyon during wet and dry season, • To delineate source(s) of particle transport through the KP canyon, • To examine the effect of typhoon on types of organic carbon passing the canyon, • To compare short event driven and seasonal variations on organic carbon deposition and transport.
Analytical Method Grind sample Remove Carbonate (2N HCl for 8 hrs) Freeze dry (5 days) Elemental Analyzer (%TOC, %TON) C/N molar ratio CHN Analyzer Thermo Flash 2000
Problems may encounter using Elemental Analyzer 1. Sample Weight 2. Homogenized Sample
T7KP Sediment Trap: wet season Sep 11, 2008 Aug 3, 2008 Trap funnel typhoon floods 2-m Core liner Jul 13, 2008 Jul 8, 2008 (from CA Huh)
T7KP Sediment Trap: wet season Typhoon Flood ? Typhoon Flood ● Sand ▲ Clay ■ Silt (Grain size data from J Liu) Plant Debris
Summary . Particulate organic carbon, nitrogen contents and grain sizes showed semi-cyclic oscillation during dry season, while extreme values were observed for wet season, . Distinct C/N ratios are found for sediments collected during dry and wet season; . C/N ratios are mostly marine in sediments collected during dry season, probably a result of periodical tide/current winnowing into the KP canyon; . C/N ratios fluctuate rapidly during wet season, but, mostly terrigenous, a result of typhoon event . Particular organic matter were carried into the canyon during both season but probably through different transport mechanism, tide vs flood (hyperpycnal ?).
Thanks for your attention Comments and suggestions