Emmanuel C. Laurenceau-Cornec, Mathieu Mongin, Thomas W. Trull, Matthieu Bressac, Emma L. Cavan, Lennart T. Bach, Frédéric A. C. Le Moigne, Frédéric Planchon, Philip W. Boyd
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引用次数: 1
Abstract
The gravitational sinking of organic debris from ocean ecosystems is a dominant mechanism of the biological carbon pump (BCP) that regulates the global climate. The fraction of primary production exported downward, the e-ratio, is an important but poorly constrained BCP metric. In mid- and high-latitude oceans, seasonal and local variations of sinking particle fluxes strongly modulate the e-ratio. These locally specific e-ratio variations and their ecological foundations are here encapsulated in the term “export systems” (ES). ES have been partly characterized for a few ocean locations but remain largely ignored over most of the ocean surface. Here, in a fully conceptual approach and with the primary aim to understand rather than to estimate ocean carbon export, we combine biogeochemical (BGC) modeling with satellite observations to map ES at fine spatio-temporal scales. We identify four plausible ES with distinct e-ratio seasonalities across mid- and high-latitude oceans. The ES map confirms the outlines of traditional BGC provinces and unveils new boundaries indicating where (and how) the annual relationship between carbon export and production changes markedly. At six sites where ES features can be partially inferred from in situ data, we test our approach and propose key ecological processes driving carbon export. In the light of our findings, a re-examination of 1,841 field-based e-ratios could challenge the conventional wisdom that e-ratios change strongly with latitude, suggesting a possible seasonal artifact caused by the timing of observations. By deciphering carbon export mechanistically, our conceptual ES map provides timely directions to emergent ocean robotic explorations of the BCP.
期刊介绍:
Global Biogeochemical Cycles (GBC) features research on regional to global biogeochemical interactions, as well as more local studies that demonstrate fundamental implications for biogeochemical processing at regional or global scales. Published papers draw on a wide array of methods and knowledge and extend in time from the deep geologic past to recent historical and potential future interactions. This broad scope includes studies that elucidate human activities as interactive components of biogeochemical cycles and physical Earth Systems including climate. Authors are required to make their work accessible to a broad interdisciplinary range of scientists.