Ocean Nourishment - Techniques and Motivation

Techniques and Motivation

The marine food chain is based on photosynthesis by marine phytoplankton which combine carbon with inorganic nutrients to produce organic matter. The production of organic matter is limited in general by the availability of nutrients, most commonly nitrogen or iron. Numerous experiments have been carried out demonstrating how iron fertilization can increase phytoplankton productivity. Nitrogen is a limiting nutrient over much of the ocean and can be supplied by from a number of sources including fixation by cyanobacteria. Carbon-to-iron ratios in phytoplankton are much larger than carbon-to-nitrogen or carbon-to-phosphorus ratios, so iron has the highest potential for sequestration per unit mass added.

Ocean fertilization offers the prospect of both reducing the concentration of atmospheric greenhouse gases with the aim of avoiding dangerous climate change and at the same time increasing the sustainable fish stocks. It promises to do this by increasing the ocean primary production.

Ocean fertilization may be a way of creating low cost protein in sufficient quantity to supply the needs of the additional two billion people expected to populate the earth before the population stabilizes at values near eight billion. While manipulation of the land ecosystem in support of agriculture for the benefit of humans has long been accepted it is a new concept to enhance the large scale ocean productivity and so creates some apprehension.