Year: 2025
Type: article
Abstract: . Demersal fishing is a major anthropogenic disturbance to marine sediments, with global implications for benthic carbon cycling and greenhouse gas emissions. Resuspension of sediment organic carbon during bottom trawling enhances oxic mineralisation, converting stored organic matter into aqueous CO2 and reducing the long-term carbon storage potential of the seafloor. Sediment heterogeneity likely plays a role in the vulnerability of sedimentary organic carbon to resuspension, but spatial estimates of trawling-induced CO2 release from resuspended sediment rarely account for this heterogeneity. In this study, we conducted a large-scale survey in the Hauraki Gulf, New Zealand, to assess how sediment characteristics affect resuspension-induced CO2 production (RCO2P). Using a resuspension assay at 57 sites, we quantified RCO2P and it with measurements of sediment grain size, organic matter content and quality, and phytopigments. Boosted regression tree modelling revealed that organic matter content has the strongest influence, with a non-linear relationship to RCO2P and interaction effects with water depth and medium sand content. Vulnerability to CO2 release was highest in sediments with > 3 % organic matter and < 27 % medium sand, particularly at depths between 55 – 95 m. Our results demonstrate that sediment heterogeneity must be accounted for in regional assessments of seafloor carbon storage and disturbance impacts. For this, the resuspension assay offers a practical tool to empirically assess carbon storage vulnerability and can complement model-based approaches to inform spatial management of demersal fisheries.
Source: Biogeosciences
Authors: Ines Bartl, Simon Thrush
Institution: University of Auckland
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,628
OpenAlex ID: W4416783476