How Plastic Chemicals Are Harming Coral Reefs

A variety of chemicals used to manufacture plastic packaging each causes harm to different organisms of tropical coral, say researchers.

They tested the effects of four plastic additives on the reproductive process and larvae development of corals and other organisms in the coral reef at Eilat, southern Israel. And they identified the specific harm caused by each of them.

They focused on four organisms, which play an important role in the ecology of tropical coral reefs: three types of coral (stony, soft, and fire corals) and a solitary ascidian, which is a marine invertebrate filter feeder. Damage to their reproduction and development may affect the coral reef’s structure. 

A chemical called 4-Nonylphenol, used to stabilize plastic packaging, was found to harm the fertilization and development of all studied organisms. And a high concentration of phthalate chemicals, which soften and increase the flexibility of plastics, was found to damage the settlement of stony coral larvae. 

These findings add to existing evidence that plastic pollution has a selective effect on different species. 

Prof Noa Shenkar, of Tel Aviv University’s School of Zoology, and one of the researchers who led the study, said: “Our findings demonstrate plastic additives’ negative and selective effects on the development and reproduction of coral reef organisms.

“The environmentally-relevant concentrations used in our experiments were concentrations found in seawater; alarmingly, some had deleterious effects on organisms’ reproduction. 

“Nevertheless, concentration within organisms’ tissues may reach higher levels as these compounds can potentially bioaccumulate.

“To better understand the impact of plastic additives on this endangered ecosystem, we suggest developing better methods for measuring the actual concentrations within the tissues of the organisms to produce relevant risk assessments.

The researchers concluded: “We emphasize the importance of proper waste management that will reduce the presence of plastic waste from reaching the marine environment, as well as the need for methods to measure the concentration of chemicals inside the bodies of organisms, in order to assess the possible risk to their reproductive and developmental processes.”

The study was published in the prestigious journal Environmental Pollution.