The study by Healey et al., investigates the water column 234Th – 238U disequilibrium and surficial sediment inventory of excess 234Th to constrain the particulate organic carbon (POC) export and burial in Bedford Basin. The integration of water column and sediment data to quantify the POC fluxes is appreciable.

Authors conducted quasi-season sampling from 2021 – 2024, capturing the seasonal dynamics over three-year period. The water column and sedimentary 234Th fluxes and POC fluxes along with bottom sediment depositional POC fluxes are in close agreement which verifies the estimates of POC fluxes in water column and mostly contributed by the vertical setting of particles. The study is comprehensive with proper methodology.

Though the Bedford Basin is relatively small, the data from a single central station might not capture the lateral heterogeneity or edge effects. In the center, as shown by the data, the POC contribution is mostly from the primary production or vertical setting of particles, however, the lateral contribution of the particles cannot be ignored, especially in this shallow fjord. It can be discussed in the manuscript in general regarding the overall basin for wider implications.

The hydrological parameters of the basin show similar patterns for different years and seasonal variations. The mixing and stratification are seasonal and the importance of absence of winter mixing and spring blooms in relation with steady state 1D Model needs to be further discussed. The limited direct measurements of nepheloid layers and primary production weakened mechanistic interpretation of persistent 234Th deficits. Although 1-D steady state model is assumed in this study, the system shows several seasonal dynamic features, especially intrusion and spring bloom. The authors have included a paragraph of discussion about the NSS contribution for <3%, but it doesn’t justify this datasheet. The authors should describe how the absence of NSS might impact the fluxes especially during different seasons and spring bloom for this study.

I appreciate the authors for nice graphs and figures; however, the authors should include the 234Th profile data along with errors even if it’s in supplementary data.

Fig 6 a. There is no need to include the R2 value as this is cumulative fluxes and R2 values doesn’t have any meaningful essence. 

Overall, the manuscript is valuable, relevant and methodologically sound. Incorporating these suggestions, addressing spatial heterogeneity would provide clarity and enhance the impact of this manuscript.