Implications of C/N Ratios from Two USGS Implications of C/N Ratios from Two USGS Sediment Trap Samples Recovered from the Sediment Trap Samples Recovered from the

Kaoping CanyonKaoping Canyon

Saulwood LinSaulwood Lin, , Institute of OceanographyInstitute of Oceanography

Natioanal Taiwan UniversityNatioanal Taiwan UniversityJames LiuJames Liu

Institute of Marine Geology and ChemistryInstitute of Marine Geology and ChemistryNational Sun-Yat-Sen UniversityNational Sun-Yat-Sen University

「「 International Sediment Trap WorkshopInternational Sediment Trap Workshop 」」National Sun Yat-sen University, Kaohsiung, Taiwan. March 23-27, 2009National Sun Yat-sen University, Kaohsiung, Taiwan. March 23-27, 2009

(Hedges et al., 1995)

Dadson et al. (2003)

(Huh et al., 2007)

1. Normal river plume2. Density flow

Modes of SS transport :

From Taiwan Central Weather Bureau

Annual rainfallAnnual rainfallWet season

Dry season

High frequency of typhoon invasion (~4 per year)

From Central Weather Bureau

Total 436 typhoons invaded Taiwan during 1897 to 2007

(Boutton et al., 1991)

( Kendall et al., 2001)

Sediment MooringSediment MooringT6KP: Winter (Dry) Season (January 10-March 20, 2008)T7KP: Summer (Wet) Season (July 7-September 11, 2008)

(From J. Liu)

T7KPT6KPUSGS Sediment TrapUSGS Sediment Trap

(From J. Liu)

Samples from T7KPSamples from T7KP

6.8 cm

108.5 cm

191 cm

25 cm

a1: 21cm a2: 23cm

Timer

Sediment lengthin the coreliner:192cm

Time marker 02 at (186~188cm)Time marker 01 at (188~190cm)

(0cm)

5.85 cm5.85 cm

5.4 cm

6.8 cm

(a) (b)

b: 49cm

(From J. Liu)

Typhoon Invasion (July 7-Sept. 11, 2008)Typhoon Invasion (July 7-Sept. 11, 2008)

Calmagi Fung Wong Kammuri Nuri

(From J. Liu)

ObjectiveObjective

1. To study particulate (%TOC, %TON, C/N ratio, 13COrg) passing through the KP Canyon during wet and dry season,

2. To delineate source(s) of particle transport through the KP canyon,

3. To examine the effect of typhoon on types of organic carbon passing the canyon,

4. To compare short event driven and seasonal variations on organic carbon deposition and transport.

Analytical MethodAnalytical 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 2000CHN Analyzer Thermo Flash 2000

Problems may encounter using Elemental AnalyzerProblems may encounter using Elemental Analyzer

1. Sample Weight

2. Homogenized Sample

T6KP Sediment Trap: Dry SeasonT6KP Sediment Trap: Dry Season

2-mCore liner

Trapfunnel

Jul 8, 2008

Sep 11, 2008

Aug 3, 2008

Jul 13, 2008

typhoonfloods

T7KP Sediment Trap: wet seasonT7KP Sediment Trap: wet season

(from CA Huh)

T7KP Sediment Trap: wet season T7KP Sediment Trap: wet season

● Sand ▲ Clay ■ Silt

(Grain size data from J Liu)

TyphoonFlood

Plant DebrisPlant Debris

TyphoonFlood ?

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

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