Meeting Documents

Improving Seafloor Representation in Ocean Models from the Shore to the Abyss: A Computationally Efficient and Universal Approach

Abstract

Ocean biogeochemistry is currently subject to a number of alterations driven by human activities, including warming and acidification, eutrophication, and deoxygenation. The ocean’s ability to sequester anthropogenic carbon dioxide over large timescales has given it a prominent role in proposed marine carbon dioxide removal (mCDR) strategies, and it is set to play a significant role in the renewable energy transition via the rapid build-up of offshore renewable energy. However, the biogeochemical implications of such activities on marine and benthic environments remain debated. Ocean models provide an ideal tool for studying the potential impacts, but benthic ecosystems and environments in these models are often underrepresented or completely lacking. The seafloor, which covers 70% of the earth’s surface, modulates the transfer of materials and energy from the biosphere to the geosphere and is thus an integral component in any biogeochemical cycle. To simulate the seafloor’s response to natural or anthropogenic environmental perturbations, we have improved RADI, an early diagenetic model initially targeted at deep-sea sediments, to be applicable in all marine environments — from the beach to the abyss. We use our improved version of RADI to construct a universal set of equations that approximate solute and solid exchange across the sediment-water interface in deep-sea and coastal environments. These equations provide a simplified, yet accurate approximation of the primary benthic biogeochemical fluxes and are computationally efficient, enabling their implementation in any ocean model. Here, we review the main characteristics of our model, present a few selected applications and case studies, and discuss future developments. Ultimately, this work provides a pathway forward for improved representation of bottom-sediment biogeochemistry in ocean models, which will aid in improving estimates of the global carbon cycle.