By Manasi Desai
Our blue beautiful ocean provides numerous benefits to our planet and all the organisms that live here. But it faces many environmental threats created by humans. Oil spills caused by oil rigs and tankers is one of them.
When an oil droplet is introduced into the ocean it releases toxins called polycyclic aromatic hydrocarbons or PAHs. These toxins are hydrophobic in nature so they try to attach onto other particles. Recent studies have shown that microplastics are some of the particles that PAHs adsorb to. These plastics are less than 5mm in diameter and have been detected in the ocean due to a large influx of plastic waste from land and pose a risk to marine species’ health.
We have seen images of how oil and larger plastics affect animals like birds, turtles etc. But how do these affect smaller marine species like plankton?
Let me introduce the real MVP of the ocean – copepods. These tiny critters eat almost anything and everything that even remotely looks like their food, which includes microplastics. Ingestion of PAH adsorbed microplastics by copepods leads to accumulation of the toxin in the animal’s body through leaching.
When copepods are eaten by larger species such as fish and even whales, the PAH accumulation can increase in toxicity leading to biomagnification of the toxin up the marine food web. This could be potentially harmful to industries like fisheries and also impact human health. Therefore, there is a need to understand if microplastics provide an ecologically important route for PAHs to enter the food web through ingestion by copepods.
Manasi Desai is a student from The College of Wooster in the 2020 Sea Change Semester Program at Bigelow Laboratory. This intensive experience provides an immersion in ocean research with an emphasis on hands-on, state-of-the-art methods and technologies.