Biogenic methane production and gas hydrate distribution during the Last Glacial Maximum: estimates utilizing machine learning and model-based inputs
Abstract
Since the Last Glacial Maximum (LGM), the effects of rising sea levels, reduced glaciation, and ocean warming are inducing gas hydrate dissociation and seabed methane release in the Arctic. However, the Arctic-wide geospatial extent of this dissociation and methane release is not fully quantified, because this process is a function of the hydrate and methane distribution during the LGM and the extent under contemporary environmental conditions. Here, we estimate the maximum gas hydrate and biogenically-derived methane extent across the Arctic region during the LGM. By comparing these estimates to contemporary distributions, we identify potential regions of methane release across the Arctic. Quantifying the distributions during the LGM requires estimates of the past environmental conditions (i.e., seafloor temperature, heat flux, glaciation extent and thickness, etc.); we use a combination of previously published measurements, machine learned values, and physics-derived quantities to constrain these past conditions. Subsequently, using a hybrid stochastic and deterministic model we estimate the maximum carbon available for methanogenesis in the seabed sediments. We then quantify the microbial methane generated and sequestered in the gas hydrate stability zone as a function of location and depth. The difference in distributions estimated from the LGM and contemporary conditions quantifies the possible extent of hydrate dissociation and methane release since the Holocene across the Arctic region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMOS12C0761P