Iron Fertilisation in the Southern Ocean

Abstract

The Southern Ocean (below 60°S) surrounds Antarctica. This ocean is known as a highnutrient low-chlorophyll (HNLC) environment where there is an excess of macronutrients but little primary productivity (Wadley, Jickells, & Heywood, 2014). This is due to the deficit of iron in this region as iron is a limiting micronutrient in phytoplankton growth (Nicol et al., 2010). There have been many studies that have examined this area and experimented by injecting iron into the waters. These identified that artificial fertilisation significantly increases biological productivity (Joos, Sarmlento, & Siegenthaler, 1991; Nishioka et al., 2005; Oschlies, Koeve, Rickels, & Rehdanz, 2010; Williamson et al., 2012; Martin et al., 2013). This leads to an increase in the sequestration of atmospheric CO2 as the phytoplankton utilise the dissolved carbon in the ocean water during their enhanced photosynthetic rates. These artificial fertilisation experiments have been considered as a long-term method to reduce the anthropogenic atmospheric carbon, however, based on the current literature, the risks of damaging the surrounding environment (ocean acidification, anoxic waters, nutrient deficit, and greenhouse gas emission) exceed the potential benefits. To be able to consider artificial ocean iron fertilisation as a method for carbon sequestration there must be much more comprehensive research done about the consequences and the risks to the environment.