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Groupama et ses cinq concurrents se bagarrent avec un Indien compliqué : un creux barométrique leur barre le chemin. « Les routages s'affolent, » écrit ce matin Yann RIOU, l'équipier média.

Le sixième concurrent de la Volvo Ocean Race a annoncé hier qu'il allait boucler à la voile la première partie de l'étape 2. Team Sanya avait cassé un hauban dans l'océan Indien et est en escale technique à Madagascar.

Et les concurrents peuvent respirer. Ils ont chargé leurs bateaux hier, juste après la ligne d'arrivée du port secret, sur le cargo qui transportera la flotte jusqu'au nord des Émirats. Récit d'une opération tendue.

Après 12 jours de course, c'est la veille de Noël et les concurrents de la Volvo Ocean Race se rapprochent du port secret, arrivée du premier acte de cette étape. Entre les leaders et leurs poursuivants, la fête n'a pas le même gout.

Ocean primary production is the basis of the marine food web, sustaining life in the ocean via photosynthesis, and removing carbon dioxide from the atmosphere. Recently, a small but significant decrease in global marine primary production has been reported based on ocean color data, which was mostly ascribed to decreases in primary production in the northern Indian Ocean, particularly in the Bay of Bengal. Available reports on primary production from the Bay of Bengal (BoB) are limited, and due to their spatial and temporal variability difficult to interpret. Primary production in the BoB has historically been described to be driven by diatom and chlorophyte clades, while only more recent datasets also show an abundance of smaller cyanobacterial primary producers visually difficult to detect. The different character of the available datasets, i.e., direct counts, metagenomic and biogeochemical data, and satellite-based ocean color observations, make it difficult to derive a consistent pattern. However, making use of the most highly resolved dataset based on satellite imaging, a shift in community composition of primary producers is visible in the BoB over the last 2 decades. This shift is driven by a decrease in chlorophyte abundance and a coinciding increase in cyanobacterial abundance, despite stable concentrations of total chlorophyll. A similar but somewhat weaker trend is visible in the Arabian Sea, where satellite imaging points towards decreasing abundances of chlorophytes in the north and increasing abundances of cyanobacteria in the eastern parts. Statistical analysis indicated a correlation of this community change in the BoB to decreasing nitrate concentrations, which may provide an explanation for both the decrease in eukaryotic nitrate-dependent primary producers and the increase in small unicellular cyanobacteria related to Prochlorococcus, which have a comparably higher affinity to nitrate. Changes in community composition of primary producers and an