Study of the process of dissolution of nutrients in contact with water

The nutrients contained in mineral aerosols can only be used by the marine food web in soluble form and their solubility depends on the first order nature of the minerals that contain them [Journet et al., 2008]. Experiences of laboratory simulation on aerosols collected in the field or analogues of aerosols can describe the mechanism and the kinetic of dissolution for various conditions of the aqueous phase (pH, light, complex organics).

Moreover, rain samples collected in West Africa allowed quantifying particulate fractions and iron dissolved in rains charged in mineral aerosols and to highlight the increase in solubility linked to the presence of complex organics brought by monsoon flow (Desboeufs et al., 2010).

Dissolution experiments in laboratory are also used to produce analogues of mineral aerosol modified by their passage in cloud systems. These analogs have been used to conduct controlled experiments of seeding of the marine environment (DUNE project, Guieu et al., 2010). The objective is to study the biological response of an addition of modified dust or not in a controlled environment (Mesocosms) depleted in nutrients and micronutrients.

The experiments of dissolution of aerosols are conducted in controlled laboratory conditions, by varying the composition of the aqueous medium and taking into account the illumination conditions.