An international consortium has been formed to study the potential effects of adding iron to the ocean to promote the growth of phytoplankton. Phytoplankton use carbon dioxide from the atmosphere and ocean fertilization might therefore be a way of mitigating the effects of global warming. When phytoplankton die, organic carbon sinks to the seafloor where it may remain for decades, centuries or even longer – we still do not now much about the time-line.

Iron fertilization of the ocean is far from uncontroversial, since it is very difficult to foresee the long term effects of such a project. The international consortium, which has been named In-Situ Iron Studies (ISIS) consortium , will carry out iron fertilization experiments in the open ocean in an effort in to answer some of the questions regarding how iron affects the ocean’s capacity for dragging carbon dioxide from the air and into the water. All experiments will adhere to the London Convention/London Protocol regarding ocean iron fertilization research.

“A great deal remains to be learned about ocean iron fertilization and how effective it could be in storing carbon dioxide in the oceans, and the formation of this consortium is an important first step,” says Lewis Rothstein, professor of oceanography at the University of Rhode Island. “This is not a call for climate engineering; on the contrary this is a research consortium. It is premature to advocate for large-scale ocean iron fertilization, but it is time to conduct a focused research experiment that will examine the concept as comprehensively as we can. We want to make sure that it doesn’t generate harmful side effects that might negatively affect the marine ecosystem.”

The twelve ISIS-members are the following:
University of Rhode Island, USA
University of Hawaii, USA
University of Illinois at Urbana-Champaign, USA
University of Maine, USA
University of Massachusetts Boston, USA
University of Plymouth, UK
Xiamen University, Fujian, China
The Antarctic Climate and Ecosystems Cooperative Research Centre, Australia
Netherlands Institute for Sea Research, The Netherlands
The National Oceanography Centre, UK
Moss Landing Marine Laboratories, California, USA
Woods Hole Oceanographic Institution, Massachusetts, USA

The oceans of the world absorb a large part of the carbon dioxide released into the atmosphere by us burning fossil fuels, burning forests to make room for fields, etc. This have helped slow down global warming, but new studies shows that it might have a devastating effects on certain fish species such as clown fish. Tests performed on clown fish larvae have shown that increased levels of carbon dioxide can make them disoriented an unable to find a suitable home and avoid predators. The pH level in the ocean has dropped 0.1 since pre-industrial times due to the absorption of carbon dioxide and researchers believe that it will fall another 0.3-0.4 before the end of this century.

This increased acidicy of the water can cause serious problems for clown fish larvae, since clownfish larvae lose the ability to sense vital odours in more acidic waters – probably owing to the damage caused to their olfactory systems. Kjell Døving (Oslo University), co-author of the rapport that was published in US journal Proceedings of the National Academy of Sciences, says “They can’t distinguish between their own parents and other fish, and they become attracted to substances they previously avoided. It means the larvae will have less opportunity to find the right habitat, which could be devastating for their populations.“

The research indicates that other species might be affected in a similar way and might have a hard time finding their way to suitable habitats if carbon dioxide levels raises in the oceans.

About the study

The study was executed in such a way that the researchers checked how well clownfish larvae could detect smells in normal sea water (pH 8.15) and how well they could detect odours in more acidic water (at levels predicted to be a reality around the year 2100 and later). The test showed that at pH 7.8 the larvae stopped following scent trails released by reefs and anemones and started following sent trails they would normally avoid; scents that are associated with environments not suitable for clown fish. The larvae also lost the ability to use smell to distinguish between their parents and other fish. At pH 7.6 the larvae were unable to follow any kind of odour in the water, and instead swam in random directions.