Microplastics impact protozoan fauna in marine environments

Microplastics pose a serious threat to small marine living beings

by Lorenzo Ciotti
Microplastics impact protozoan fauna in marine environments
© Ed Wray / Stringer Getty Images

Microplastics have been found to persist in the environment in large quantities, especially in marine and aquatic ecosystems. This is because plastic deforms but does not break down for many years, can be ingested and accumulate in the body and tissues of many organisms.

The entire cycle and movement of microplastics in the environment has not yet been studied in depth, mainly due to the difficulty of analyzing a mixture of various types of more or less inert plastic. 77% of the blood of people tested by researchers at Vrije University in Amsterdam in 2022 was found to contain microplastics as they can travel through the body and settle in organs.

But let's get back to talking about microplastics in marine environments. Microplastics pose a serious threat to small marine living beings, which tend to feed on them by mistaking them for plankton. These minor organisms are in turn inserted into the food chain and ingested by larger living beings and their predators.

The chain can continue until it reaches our tables. Controlling the release of these plastics into the environment therefore means safeguarding marine fauna. Many marine animals such as seagulls or seals have ingested microplastics, having repercussions on their health.

Microplastics impact protozoan fauna in marine environments

The study Microplastics drive community dynamics of periphytic protozoan fauna in marine environments, published on the Environmental science and pollution research international, made an interesting retrospective on the topic.

The researchers expained: "The pollution of microplastics (MPs) to the marine environment has become a widespread focus of attention. To assess MP-induced ecotoxicity on marine ecosystems, periphytic protozoan communities were used as test organisms and exposed to five concentrations of MPs: 0, 1, 5, 25, and 125 mg l-1. Protozoan samples were collected using microscope slides from coastal waters of the Yellow Sea, northern China.

A total of 13 protozoan species were identified and represented different tolerance to MP-induced ecotoxicity Inhibition effects of MPs on the test protozoan communities were clearly shown in terms of both the species richness and individual abundance and followed linear relationships to MP concentrations.

The community patterns were driven by MPs and significantly shifted at concentrations over 5 mg l-1. Our findings demonstrated that MPs may induce the community-level ecotoxic response of periphytic protozoan fauna and followed significant community dynamics. Thus, it is suggested that periphytic protozoan fauna may be used as useful community-based test model organisms for evaluating MP-induced ecotoxicity in marine environments."