Microplastic ingestion in Otariids

Transportation of microplastics along the food chain is no surprise. Trophic transfer from prey to predators is a fairly common source of microplastics, especially in top predators. A recently published research by Perez-Venegas et al. (2020) evidenced the ingestion of microplastics in Otariids from the coast of Chile and Peru by analyzing their scats.

Fig. 1. Arctocephalus sp. 

As reported in the study, the occurrence of micro-fibres (ranging from 63 to 100%) was much bigger than fragments (1 to 14%). Higher concentrations in samples from the Juan Fernández Archipielago may be due to the influence of the South Pacific subtropical gyre, an area of high plastic debris concentration. The presence of these particles can potentially be harmful to these animals, although this requires further research.

Reference
Perez-Venegas, D.J., Toro-Valdivieso, C., Ayala, F., Brito, B., Iturra, L., Arriagada, M., Seguel, M., Barrios, C., Sepúlveda, M., Oliva, D., Cárdenas-Alayza, S., Urbina, M.A., Jorquera, A., Castro-Nallar, E., Galbán-Malagón, C., 2020. Monitoring the occurrence of microplastic ingestion in Otariids along the Peruvian and Chilean coasts. Mar. Pollut. Bull. 153, 110966. https://doi.org/10.1016/j.marpolbul.2020.110966

How much micro- and mesoplastics can seaweed retain?

During a microplastic sampling campaign in Lima, Perú, we noticed in an extremely polluted beach, seaweed inhabiting intertidal rock formations were retaining high amounts of micro- and mesoplastics (Fig. 1, 2).

Fig. 1. First photo of microplastics retained in seaweed in a sandy beach of Lima, Perú

Fig. 2. Second photo of microplastics retained in seaweed in a sandy beach of Lima, Perú

It is noticeable that MPs are trapped in seaweed formations, rather than rock surface. A question comes: How much MP and mesoplastic can seaweed retain under extreme pollution conditions? 

We are looking forward to do some research regarding these observations. 

Commercial bivalves contaminated with microplastics in Peru

The mussel Aulacomya atra, also known as "choro", is one highly consumed bivalve species of commercial importance. The second most consumed after the Peruvian scallop Argopecten purpuratus. A. atra is commonly served fresh and eaten as a whole, thus presenting a higher chance of microplastic ingestion. 

We investigated the abundance and characteristics of microplastics in A. atra from fishery markets in three Peruvian provinces: Huarmey, Lima and Pisco (Fig. 1). 

Fig.1 Map of the three Peruvian provinces. S1: Huarmey, S2: Lima and S3: Pisco

Results indicated that microplastics were ubiquitous in A. atra from fishery markets. Microplastics of different sizes, shapes and colors were found and recorded (Fig. 2).

Fig. 2 Microplastics found in A. atra. A: Red microbead, B: Blue fiber, C: White fragment, D: Green line, and E: White film. Scale bar indicated 1 mm.

This is the first evidence of microplastic contamination in A. atra. The presence of microplastics in the last step of the supply chain confirms that the Peruvian population are subject to microplastic intake through contaminated seafood. Further research must continue surveying markets and fishery markets aiming to contribute to the microplastic human intake estimation. 

This manuscript is currently under review by the Journal of Food Science and Technology, once it gets published, I will make sure to share the research entirely. Questions regarding this research, feel free to send me an email: gabriel.e.dltp@gmail.com 

Plasticrusts: A new potential threat in the Anthropocene's rocky shores

The new term 'plasticrusts' have been coined in a recent article published in Science of the Total Environment by Gestoso et al. (2019). This type of plastic pollution refers to plastic pieces of blends encrusting the texture of intertidal rocks forming crusts that could vary in color and forms.

Fig. 1. Pictures showing (A, B) a general overview of mid-upper intertidal rocky shore in Madeira Island encrusted by plastic; (C) detail of ‘plasticrusts’ on the surface of the rocks; and (D, E) view of ‘plasticrusts’ surrounded by the littorinid gastropod Tectarius striatus.

Plasticrusts could expose marine rock grazers, like gastropods, to plastic debris ingestion. This type of plastic pollution could be considered as a new litter category for monitoring guidelines.

Reference
Gestoso, I., Cacabelos, E., Ramalhosa, P., & Canning-Clode, Joao. (2019). Plasticrusts: A new potential threat in the Anthropocene's rocky shores. Science of The Total Environment, 687, 413-415. https://doi.org/10.1016/j.scitotenv.2019.06.123

Marine macroinvertebrates inhabiting marine debris

During a sampling campaign, we found many stranded marine debris along the coast. In many cases, these items were inhabited by many marine macroinvertebrates, among sessile species and other species that seemed to be entangled.

Fig. 1. Stranded red fishing net inhabited by marine macroinvertebrates

In this example (Figure 1), we found a quite large fishing net, having bivalves, gastropods, a crustacean and even an echinoderm.

Fig. 2. Ocypode occidentalis

Fig. 3. Semimytilus algosus

Fig. 4. Tetrapygus niger

These findings suggest a potential invasion of non-native species and invasive species to foreign marine ecosystems due to rafting.

Microplastics in the marine environment

I've been researching microplastic (MP) presence and abundance for about two years now. It is interesting to see how these particles smaller than 5 mm in diameter or length are ubiquitous in the marine environment. After doing some research, we found MPs in different molluscs, fish and even in marine otter scats from the coast of Peru. Determining the exact sources is quite hard, but it is most likely that the poor waste water treatments promote the dispersal of microfibers (which are, by the way, the most common MP morphological type I've found here and many studies agree with this).

Fig. 1. Blue microfibers found in the stomach of Cheilodactylus variegatus from the coast of Lima, Peru

The MPs in figure 1 are about larger than 100um. I'm looking forward to investigate MP bioaccumulation in Peruvian bivalves through the correlation between MP content and valve length and wet weight of each individual. It sound very interesting to me.