Possible Relationship Between Atmospheric Conditions and the Great Atlantic Sargassum Belt

Using multivariate analysis in three zones of the Great Atlantic Sargassum Belt (GASB), we found close associations between the density of sargassum, dust deposition, and surface iron concentration on the sea surface during 2002–2010, before the appearance of the GASB in 2011. Combined with a statistical analysis of dust depositions during 1980–2023 in these zones, the results imply increases in each, concomitant with the behavior of the GASB in recent times, such as its appearance in 2011 in the northern tropical Atlantic and its reach in the Mexican Caribbean in 2015. Given indications that sargassum growth is limited by iron and the close association between dust deposition and iron concentration in the sea surface, we infer that the increase in dust deposition, which is generated mainly in the African Sahara and Sahel deserts, may have contributed to the sargassum growth in the GASB. Although the results of this study showed statistical significance, they remain hypothetical due to the lack of field data. Further surveys measuring chemical compositions and stable isotope rates of samples of Saharan dust, phytoplankton, and sargassum may explain the relevance of dust deposition to the development of the GASB.