How to Monitor for Chemicals in Ocean Food with a Little Help from Dolphins!

Recently, we looked at how a new ‘Robo-fish’ could combat water pollution. So what’s next? Could dolphins be the key to monitoring the chemical content of the marine food web? According to researchers at UC San Diego’s Scripps Institution of Oceanography, the answer is yes! As part of the university’s research programme the eating patterns of eight dolphins are currently being used to gain rare information on chemicals found throughout the ocean’s food web.

So how was this new information sourced? Over a period of 15 years researchers have been analysing the chemical content of blubber sourced from eight Bottlenose Dolphins. They then used advanced equipment to separate and analyse each individual chemical found in the tissue. Disclaimer: all dolphins died of natural causes and were found washed up on Southern Californian beaches! It’s an interesting area to study given the fact that the region is notorious for its storm and wastewater discharge, as well as contamination from commercial chemicals such as dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB).

Thanks to their position at the top of the marine food chain dolphins provide accurate insight into the chemical content of the food they ingest, as well as the food that their prey eats. As plenty of their meals end up on our dinner tables the research could prove to be incredibly valuable to the food industry, and the health of the population.

“These dolphins are giving us a better idea of what chemicals are out there, and they are showing us what’s inside some of our own food sources,” explains Lihini Aluwihare, a chemical oceanographer at Scripps Institution of Oceanography and co-author of the dolphin study.

Alarmingly, over 300 chemicals were found in the blubber, with a large portion originating from human sources. 29 were clearly linked to DDT pesticide while a further 17 polybrominated diphenyl ethers (PBDEs) were identified. Not to mention a myriad of unknown compounds that could be toxic to both dolphins and humans.

Nellie Shaul, Scripps Institution of Oceanography graduate and head author of the dolphin study explains that “ninety-four of the 327 unique chemicals in the new library at this point are unknown.” She maintains that she was surprised by the results and “because it tells us that not only are these chemicals currently not on our monitoring radar, there is a lot of stuff out there that we really need to learn more about.”

Now that we know the extent of the chemical content of our food chain scientists are urging people to be more aware of the impact we have on the environment, and ultimately, ourselves. 

“We know many of these compounds are made by humans and they are going through the food web and accumulating. It really does powerfully demonstrate how connected we are to our environment,” says Aluwihare.