| 20 Jan 2026
Resolving distribution and controls of terrigenous and marine particulate organic matter across an energetic shelf
Abstract. We assess the sources, distribution and controls of particulate organic matter (POM) across the northeastern Taiwan Strait, where monsoonal forcing, water-mass mixing, riverine inputs and sediment resuspension modulate particle dynamics. By integrating lignin biomarkers, bulk geochemistry, and sedimentary constraints within a two-step quantification approach, we demonstrate the influence of river discharge, plume intrusions, and seafloor resuspension on the distribution of terrigenous POM. Terrigenous particulate organic carbon (POCterr) represents a minor component in most water samples but becomes substantial in resuspension-dominated layers. Combining estimated POCterr with modeled current velocities yields an export flux of ~243 ± 56 kt C yr‒1, consistent with the regional imbalance between riverine input and sedimentary burial. After correction for terrigenous influence, bulk POM properties exhibit features reflecting nutrient supply, photoacclimation, and temperature-dependent variation in stable carbon isotopic (δ13C) composition. Comparisons with co-sampled surface sediments show that biomarker signals are preserved more faithfully than δ13C of organic matter, which is strongly modulated by lateral transport. This study provides a practical framework for quantifying terrigenous and marine POM in continental-shelf settings and offers improved constraints for interpreting source-to-sink processes and sedimentary archives.
General comments:
In this contribution, the authors investigated suspended particles collected from the northeastern Taiwan Strait to provide full-water column assessment of the sources, distribution, and controls of POM in the study area. They quantified terrigenous particulate OC, the sum of biospheric and petrogenic OC using lignin and the stable C isotopic composition of OC. Based on the results, the authors established source to sink coherence by comparing POM characteristics.
Taiwan Strait is a dynamic, shallow strait with an average depth of 60 m and hydrography is shaped by the interplay of complex bathymetry, monsoonal forcing and riverine inputs. The authors are keen to establish the sources distribution and POM controls in such a dynamic area. I appreciate their attempt, but I feel that the current version of manuscript is blurred in some aspects, as given below.
Specific major comments:
I feel that a clarity is needed for how much published data were taken from Lin et al. (2025a, 2025b), as the authors refer often these publications apart from some other sources. In addition, what is really new in this contribution is unclear while reading. Moreover, why the authors have used 2 step estimation of terrigenous OC using lignin and δ13C of organic carbon and how it is understood that lignin is appropriate than δ13C and in what capacity. In their previous publication, Lin et al. (2025a), the authors described source to sink processes, OM composition and oxygen consumption. This should be categorically explained to understand the importance of already published one from the present manuscript content, not to mention that the hydrographic, POM and carbonate chemistry data for the present study were taken from Lin et al. (2025b). My question is why not the authors can focus on new, unpublished data to revise the manuscript?
After using lignin and δ13C, the authors mentioned in lines 300-305 that “the available evidence does not allow us to resolve which process is chiefly responsible for the low 𝝠8 values”. This part shows some incorrect handling of data and interpretation. The authors should know what their data can or cannot reveal; after so many corrections and recalculations and re-estimations in the manuscript, such a vague statement bespeaks that the authors have no clear-cut idea to understand or reconcile lignin and δ13C data in this manuscript. This needs more vigorous approach of data reconciliation and that is missing in the manuscript.
Minor comments:
Section 2.1
Lines 75-80: The authors mentioned that the shelf off SE China or through the funnel-shaped Penghu Channel, which serves as the primary pathway for volume transport (Jan et al., 2002). If any estimate on the volume transport is available, it is better to include here with reference(s).
In the same paragraph, it is mentioned that tidal current velocities decreased progressively. Any estimate of tidal velocities may be included here.
Line 143: Change to Andrew
Lines 295-310:
Terrigenous POM persists during both alongshore and cross-shelf transport. Any reason from biomarker data why land-derived POM survives during the both transport?
The authors said that “Seabed sediments on this region are dominated by terrigenous OM (Lin et al., 2025a)”. However, they also mentioned that “subsurface shelf waters contained negligible lignin consistent with SCSW receiving a greater contribution from Pacific-origin waters. From this line, I understood that negligible lignin is derived from Pacific waters. The study area is proximal to both Taiwan and mainland China terrestrial fluxes that dominated likely by lignin. Given this, the above statement seems to me “odd” in the study area, which is shallow and dynamic strait.
In Fig. C6, why just one data has not been included in the regression analysis, though given r2 value is low?