01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0232 |
| Title of Abstract | Spatial Distribution and Isotopic Signatures of Particulate Organic Carbon in the Western Indian Ocean and Their Interannual Variability |
| Authors | Sujin Kang*, Tae Keun Rho, Dong-Jin Kang |
| Organisation | Korea Institute of Ocean Science and Technology |
| Address | 385 Haeyang-ro, Yeongdo-gu Busan, Busan, Korea, Rep. Pincode: 49111 E-mail: sjkang@kiost.ac.kr |
| Country | Korea, Rep. |
| Presentation | Oral |
| Abstract | The particulate organic carbon (POC)produced by primary producers in the surface ocean through atmospheric CO⿿ uptake, plays a central role in the biological carbon pump and is closely linked to vertical carbon fluxes. The Seychelles⿿Chagos Thermocline Ridge (SCTR) in the tropical western Indian Ocean is an open-ocean upwelling system with relatively high productivity, making it an important area for studying biogeochemical and carbon cycles. However, studies on POC in this region remain scarce. We investigated POC concentrations and stable carbon isotopes (δ¹³C) in the western Indian Ocean (65°E, 5°N to 65°E, 20°S) in 2023 and 2025 to examine spatial distribution patterns and source variations. POC concentrations ranged from 12.8 to 57.8 μg L⁻¹, with higher values in the SCTR. δ¹³C values ranged from ⿿20.0⿰ to ⿿25.0⿰. In 2023, a strong upwelling in the SCTR core produced higher POC concentrations, enriched δ¹³C values, and lower C/N ratios, indicating enhanced productivity and contributions from fresh marine organic matter. In contrast, weaker upwelling year led to reduced POC and PN, lighter δ¹³C signatures, and slightly higher C/N ratios, suggesting lower productivity and degraded organic matter. These results indicate that variations in upwelling intensity control both concentration and source of POC in the tropical Western Indian Ocean. |
| Are you part of IIOE-2 endorsed project | yes |
| Endorsed Project Number | IIOE2-EP51 |
| Keywords | POC, SCTR, Stable carbon isotope |
| For Awards | no |