| Abstrakt: |
The meridional overturning circulation influences the deep‐sea carbon reservoir, global carbon cycle, and climate change on century to millennium time scales. However, the influence of deep‐sea circulation on sedimentary carbonate accumulation and thus deep‐sea carbonate system in the North Pacific Ocean is difficult to quantify owing to the complicated geometry of deep ocean ventilation attributed to its topographic complexity. In this study, we reanalyzed the distribution patterns of sedimentary calcium carbonate contents (wtCaCO3%) in the deep Northeast Pacific in a quantitative manner. Our results in conjunction with data from the Northwest Pacific Ocean, suggest that the deep ocean circulation plays a critical role in elucidating the basin‐scale features of sedimentary CaCO3 distribution in the North Pacific Ocean, despite elevated non‐carbonate dilution exerted by detritus from active geological processes on the topographic structure. Moreover, enhanced carbonate dissolution in the Guatemala and Panama Basins, controlled by higher flow rates of deep currents, influences the depth‐profiles of sedimentary wtCaCO3% in that region. These findings suggest a novel avenue to reconstruct past changes in ocean circulation and carbon cycling in the Northeast Pacific Ocean based on the wtCaCO3% records in sediments. Plain Language Summary: Accumulation and dissolution of calcium carbonate (CaCO3) in surface sediments in the deep sea dominates changes in the carbonate system in the ocean and ultimately the global carbon cycle and climate change over decadal to millennial time scales. However, these processes occurring at great depths are difficult to observe and model; thus, features of sedimentary CaCO3 distribution remain to be quantified. Here, we constrained the distribution features of (sub)basinal sedimentary wtCaCO3% in the Northeast Pacific Ocean using a new data compilation and a carbonate accumulation model and found that the thermohaline circulation largely influences the distribution of sedimentary wtCaCO3% in the North Pacific Ocean. Elevated flow rates of currents at depths between 2.5 and 3 km in the Guatemala and Panama Basins causes in‐situ enhanced carbonate dissolution. Our results show that the distribution patterns of wtCaCO3% records in the Pacific sediments could be potentially used to reconstruct changes in ocean circulation and marine carbon cycles in the Pacific Ocean in the past. Key Points: The distribution patterns of sedimentary CaCO3 contents in the deep Northeast Pacific Ocean are reanalyzed in a quantitative mannerDeep ocean circulation governs the basin‐scale features of sedimentary CaCO3 distribution in the North Pacific OceanEnhanced carbonate dissolution in the Guatemala and Panama Basins is attributed to higher flow rates of deep currents between 2.5 and 3 km [ABSTRACT FROM AUTHOR] |
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