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. 

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.