By Eden Placer, Contributing Writer ‘24

The issue of ocean acidification as a result of global warming is not a topic concealed from the public eye, and it most certainly is not to the scientists who have been following the issue for years. However, a new study, carried out by the University of Adelaide in December of 2021, offers new insight into how climate and atmospheric alterations may be disrupting the species in the waters below.

As carbon dioxide levels rise within the atmosphere, ocean surface temperatures spike as a direct result. Levels of acidification in the oceans have increased upwards of 25% since before the Industrial Revolution. It is true that warming and acidification are two different phenomena; however, their simultaneous occurrence poses a catastrophe for the marine environment.

Prior to the study, research determined that fish shoals, or clusters of fish, tend to travel in such a formation as a survival tactic in order to acquire food or elude danger with the utmost protection against predators on the prowl. Clustering offers fish the ability to generate strong cohesion and coordination to make decisions crucial to their survival. Tropical and temperate species tend to travel in the direction to their right when ‘spooked’ or confused. Interestingly enough, Angus Mitchell, the PhD student from the University of Adelaide who conducted the experiments, found that this pattern significantly diminished after coming into contact with ocean acidification effects. 

The shoals’ lateral travels and seemingly poleward angles of direction shifted and altered to a slower, less cohesive style which resulted in slower escape responses. Likely, this obstruction was caused as a result of warmer waters making the oceans an ideal location of growth for harmful microbial algae and bacteria. The bacteria known as Clostridium botulinum has the ability to produce the very potent, natural Botulinum toxin which, when orally ingested, blocks nerve functions and may even prompt respiratory and musculoskeletal paralysis, thus explaining the shoals’ slower reaction times. This impairment to the tropical and temperate fish species puts them in danger as they are more susceptible to potential threats around them. 

Professor David Booth from the University of Technology, Sydney, an associate on the study, clarified that, “[These] findings highlight the direct effect of climate stressors on fish behavior and interplay with the indirect effect of new species interactions.” 

In other words, the study’s findings determined that if the ability for fish to function in the way they are accustomed to is compromised, it could alter the chances of survival for any particular species in the oceans of the future.

Findings from the team of researchers who worked on this study are published in the journal titled Global Change Biology, which is ranked third for most cited journals in climate change research.

As for the further implications of climate change and its effects on the food supply chain, there are more than a billion people across the globe who rely on aquatic species as their primary protein source. With such drastic changes in the state of the oceans and the creatures who reside within, not only are harvests decreased and a need for alternatives more dire than ever, but many workers who derive income from the fishing industry are now unemployed as a result. These challenges may lead to migration from more agricultural regions to those more urban, which may influence social structure or even cause conflict.

Only negative effects can come from continued ocean acidification and global warming. Beyond   detriments to ecotourism and the food supply chain, the list of consequences includes decreased storm protection of the many coral reefs. Organizations such as the National Oceanic and Atmospheric Administration (NOAA) are working relentlessly to develop an early warning system to urge the public of this impending issue before it truly is too late.