Water-bouyant particulate materials containing micronutrients for phytoplankton

A process for preparing an aqueous dispersion of a composition comprising water-buoyant particles containing about 0.1% to 90% by weight of a micronutrient for photosynthetic phytoplankton growth selected from the group consisting of Fe, Co, Mn, Zn, and mixtures thereof, said particles having an average length in the range of about 0.001 mm to 100 mm, provided that when the average length is greater than 10 mm, the average largest cross-sectional length perpendicular to the length cannot be more than 10% of the average length, which process comprises admixing and impregnating a water-buoyant, relatively water insoluble particulate substrate material with an aqueous solution or dispersion of one or more compounds that are a source of the micronutrient.

A process for stimulating photosynthetic phytoplankton growth in a ocean, lake, or river devoid of, or deficient in, such growth, said process comprising supplying iron to the surface of said ocean, lake, or river areas by deploying water-buoyant particles containing about 0.01% to 90% by weight of iron on said ocean, lake, or river surface, said particles having an average length in the range of about 0.001 mm to 100 mm, provided that when the average length is greater than 10 mm, the average largest cross-sectional length perpendicular to the length cannot be more than 10% of the average length.

A process for preparing a particulate, water-buoyant composition containing about 0.01% to 90% by weight of a micronutrient for photosynthetic phytoplankton growth selected from the group consisting of Fe, Co, Mn, Zn, and mixtures thereof, which process comprises the following steps:

• (a) obtaining particles of an insoluble micronutrient source in an aqueous media containing a soluble sealing agent by either (i) admixing particles of an insoluble micronutrient source in an aqueous media containing a soluble sealing agent, or (ii) precipitating a soluble micronutrient source from an aqueous media containing a soluble sealing agent;
• and
• (b) drying the mixture from (a) and, if step (a)(i) was previously carried out, then in addition fusing the particles at a temperature of at least about 1000.degree. C., thereby forming free-flowing, water-buoyant particles coated with said sealing agent for temporarily sealing the surfaces of the particles.