Say Goodbye to Your Tuna Melts Because We've Ruined the Ocean
According to a study published in Nature, oceanic mercury levels have tripled since the beginning of the Industrial Revolution.
Far surpassing earlier estimates, data collected during research cruises from 2006-2011 in both the Atlantic and Pacific oceans has revealed a 340% increase in surface-level mercury content. During the cruises, deep seawater samples (depths up to 5km) were compared to surface water samples. The analysis implicates the burning of fossil fuels as the primary culprit of this dramatic rise, with mining activities thought to have also contributed a significant amount.
Ocean circulation patterns have mitigated the increase, to some extent, as the density of mercury-rich water causes it to sink, drawing it away from the more-inhabited shallower waters. Co-author Carl Lamborg expressed concern that the circulation patterns will not continue to protect marine life as humans are expected to pour as much mercury into the environment over the next 50 years as we have over the previous 150.
The marine life most heavily affected by this change are apex predators, such as tuna. Mercury levels in a tuna can be up to 10 million times higher than in the surrounding seawater. The levels in predators increase because they absorb (and do not excrete) the mercury from the fish that they ate… and the fish that those fish ate… etc. This means that humans need to practice safe fish-eating because you aren’t just eating your fish- you are eating all of the fish that your meal ever ate.
The NRDC recommends that children under the age of six and pregnant women (or soon-to-be pregnant), restrict or eliminate fish such as ahi, swordfish, shark, bigeye tuna, and other fish caught in water subject to a mercury advisory. The NRDC maintains a list of sushi fish to avoid and the Monterey Bay Aquarium has this helpful site (and an app) that you can use to check the safety of fish you plan to eat. There is also a helpful graphic based on this data published by FIX if you prefer things to be explained to you with pretty pictures.
As if we really needed another reason to decrease our reliance on fossil fuels, pescetarians, sushi-files, and the protein-conscious are all now at a greater risk of mercury poisoning- a risk that is bound to increase in the coming years as we continue to dump horrible things into our air and waters. P.s. mercury poisoning really does suck- just ask Jeremy Piven.
Photo credit: Stu Spivack on Flickr