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| Tang, Weiyi; Li, Zuchuan; Cassar, Nicolas. |
| Marine nitrogen (N2) fixation supplies “new” nitrogen to the global ocean, supporting uptake and sequestration of carbon. Despite its central role, marine N2 fixation and its controlling factors remain elusive. In this study, we compile over 1,100 published observations to identify the dominant predictors of marine N2 fixation and derive global estimates based on the machine learning algorithms of random forest (RF) and support vector regression (SVR). We find that no single environmental property predicts N2 fixation at global scales. Our RF and SVR algorithms, trained with sampling coordinates and month, solar radiation, wind speed, sea surface temperature, sea surface salinity, surface nitrate, surface phosphate, surface excess phosphorus, minimum... |
| Tipo: Text |
Palavras-chave: N-2 fixation; Machine-learning; Ocean. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00483/59501/62371.pdf |
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| Lin, Yajuan; Cassar, Nicolas; Marchetti, Adrian; Moreno, Carly; Ducklow, Hugh; Li, Zuchuan. |
| Despite our current realization of the tremendous diversity that exists in plankton communities, we have little understanding of how this biodiversity influences the biological carbon pump other than broad paradigms such as diatoms contributing disproportionally to carbon export. Here we combine high-resolution underway O-2/Ar, which provides an estimate of net community production, with high-throughput 18 S ribosomal DNA sequencing to elucidate the relationship between eukaryotic plankton community structure and carbon export potential at the Western Antarctica Peninsula (WAP), a region which has experienced rapid warming and ecosystem changes. Our results show that in a diverse plankton system comprised of similar to 464 operational taxonomic units... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00409/52099/52810.pdf |
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