Fertilizing for Fish – Fraud or the Future?


One of the most contentious discussion issues that blends scientists with policymakers revolves around the question: “Can we geoengineer the ocean to alleviate climate change?” This case introduces students to the process of enriching oceanic regions (specifically High Nutrient, Low Chlorophyll; HNLC regions) with iron to alleviate trace metal limitation of phytoplankton primary productivity—potentially leading to more productive fisheries and carbon sequestration into the ocean depths. The case exposes students to the science behind ocean iron fertilization (OIF) efforts—knowledge gained from thirteen (13) OIF experiments conducted by scientists since 1993, but equally important the controversies associated with OIF efforts to date.

Specifically, whether OIF will: 1) serve as an effective climate change mitigation mechanism to enhance the sequestration of anthropogenic carbon dioxide (CO2) into the deep sea, 2) increase the productivity of the base of the marine food chain—thus possibly leading to enhancement of fish yields, and/or 3) cause deleterious impacts on ocean ecology such as enhancement of microalgae that produce toxins leading to Harmful Algal Blooms (HABs).

The case is designed to introduce the basic concepts of biological oceanography to students with limited formal exposure to the processes of the surface ocean. To achieve this, we provide them with a debate and decision-making exercise that evokes discussion on the level of our biological, chemical and ecological knowledge of marine systems, our ability to modify the environment to ameliorate elevated concentrations of CO2 in the atmosphere, and a discussion of the ethics and responsibilities of scientists that propose or conduct large-scale ecological manipulations of the oceans. 

This case is appropriate for upper-division undergraduates or beginning graduate students; it is particularly useful in interdisciplinary problem solving courses, and has been used in a case-based ‘Sustainable Environmental Health’ course in the Master of Public Health (MPH) program at Western University, and in a course entitled, ‘Foundations in Global Change in Urbanized Coasts and Estuaries’ in the Master of Science program in Interdisciplinary Marine & Estuarine Science (IMES) at San Francisco State University.

William P. Cochlan
Charles G. Trick
Course/Class Size
1) interdisciplinary MS graduate course, Fall 2019, Estuary & Ocean Science Center, San Francisco State University; 2) a variation in a ‘Sustainable Environmental Health’ course in MPH program; 3) undergrad environmental science course at Western Univ.