This review proposes a novel method to accurately gauge the full ecological impact of manmade iron fertilization upon local environments not through direct experimentation, but by observing similar natural manifestations of fertilization in volcanic eruptions. Two case studies of specific volcanoes - Kilauea in Hawaii and Eyjafjallajökull in Iceland - show that firstly, ocean iron fertilization is capable of self-sustainment after ocean iron fertilization deployments in HNLC (High Nutrient Low Chlorophyll) regions, and secondly, ocean fertilization can be extended beyond the usage of iron dust fertilizer in ideal situations. For example, simple physical disturbances under the shores of one of Hawaii's islands propelled the large-scale development of phytoplankton colonies, in a process called "organic nitrate displacement". Kilauea's volcanic breakouts contributed to greenhouse gas emissions but were proportionally absorbed (7:1 ratio) by local phytoplankton growth. In another case of post-eruption phytoplankton development at Eyjafjallajökull in Iceland, while the volcanic eruptions dispersed a relatively small amount of iron-infused tephra through atmospheric injection and way of local winds, the airborne nutrients heavily stimulated phytoplankton colonies throughout surrounding waters and generated large biomasses of algae that were visible from space. After consecutive months of eruptions by Eyjafjallajökull in 2010, the airborne spread of iron-rich tephra particles lead to visible growths in phytoplankton colonies bordering other nearby countries. Through multiple comparative case studies of post volcanic eruption phenomena, ocean iron fertilization demonstrates its efficiency in initiating phytoplankton growth while revealing unexpected safety concerns in its deployment.