Temporal changes in ventilation and the carbonate system in the Atlantic sector of the Southern Ocean

Variability of nutrients and carbon dioxide in the Antarctic Intermediate Water between 1990 and 2014

“…The hypothesis of an increase in upwelling is supported by the decrease in potential temperature (−0.15 ±0.1 • C decade −1 ) that could be related to the increase in the subduction rate (Downes et al 2011). This is in line with the findings of Tanhua et al (2017) who reported a speed-up of ventilation in the upper intermediate waters of the Atlantic sector of the SO between 1998 and 2012 based on the analysis of transient tracers (SF 6 /CFC-12). The increase of nitrate due to stronger upwelling of nutrient-rich deep water is in accord with Hoppema et al (2015) who reported an increase in nutrient concentration in the surface waters of the Weddell Sea between 1996 and 2011 and linked the changes observed in nutrients to the increase in upwelling.…”

“…Also, we found that the amplitude of DIC change that varies spatially between 0.2 and 1.2 μmol kg −1 year −1 between 44 and 50 • S in the period 1990 to 2012 (Fig. S11) compares well with the amplitude of anthropogenic carbon change (0.4-1.2 μmol kg −1 year −1 ) estimated by Tanhua et al (2017). All these observations suggest that the more probable scenario is the one where 75% of the DIC change are explained by anthropogenic carbon uptake.…”

“…Recently, a speed-up in the transport of surface and intermediate waters in the Atlantic sector of the SO was reported based on the observations of transient tracers, leading to more sequestration of anthropogenic carbon dioxide in this water mass (Tanhua et al 2017). Salt et al (2015) reported rapid acidification of the AAIW in the southwest Atlantic.…”

Influência das variações de baixa frequência da Circulação de Revolvimento Meridional na concentração de clorofila - a no Atlântico Sul

“…Tal hipótese explicaria não só o padrão observado das variáveis biogeoquímicas como das variáveis físicas. Essa hipótese também parece corroborar outros achados na literatura com relação ao nutrientes e a temperatura na mesma região (Pardo et al 2017;Tanhua et al 2017;Hoppema et al 2015).…”

“…A tendência da concentração de clorofila menos a sua média (anomalia) e a taxa de variação temporal da mesma próximo a região de estudo de Panassa et al (2018) Palter et al (2010). Também está de acordo com achados na literatura como Panassa et al (2018, Ayers andStrutton (2013) e os estudos que estão de acordo com estes como (Pardo et al 2017;Tanhua et al 2017;Hoppema et al 2015).…”