Plastic waste, an agent for the spread of invasive species in the Caribbean

tons of plastic which are dumped daily in the oceans not only contaminate your waters but also cause some organisms to move to others ecosystems and put them at risk by becoming invasive species, as is the case on the island of Salamanca, a biosphere reserve in the north of Colombia.

This was revealed by an investigation by experts from the Universidad del Atlántico, led by the marine biologist Adriana Gracia and the geologist Nelson Rangel, who determined that garbage, and especially plastic, is the vehicle in which these species are transported from a place to another.

“Although the research is focused on the Colombian Caribbean coast, this is a problem that extends to all marine ecosystems”explained Gracia, who gave the Asian green mussel as an example of an invasive species (‘Perna viridis‘), on which the research is based.

The work indicates that the dispersal of larvae by itself may not be the only process responsible for the presence on the Colombian Caribbean coast of this bivalve mollusk native to the Pacific Ocean.

Displacement by oceans

Gracia adds that these mollusks appeared in ports because they arrived attached to the hulls of ships, but today “We are finding evidence that these organisms and groups of marine organisms are using these substrates (garbage) as a movement mechanism in the oceans.”

“In the case of ‘Perna viridis’, it is a mollusk of about ten centimeters, but the species that adhere to the plastic can range from microorganisms to macrofauna and megafauna, that is, much larger ones,” said Gracia.

The expert clarifies that not all the organisms that travel in the plastic that moves through the oceans are invasive species, but they do increase the possibility of affecting the ecosystem where they arrive.

In addition to Asian mussels, polychaete tubes (a species of worm), bryozoans (similar to corals) and three more unidentified species were found colonizing remains of wood, seeds, plastic bottles and glass on the study beaches.

“It turns out that we found them associated with some plastics, not only in the port of Cartagena but also in the area of ​​Puerto Velero (Atlántico) and on the road to Parque Isla de Salamanca. That is to say, that the plastic is serving as a dispersal mechanism and that species has gone a little further north, which is dramatic in itself.”added the biologist.

The island of Salamanca is classified as an Important Bird Conservation Area (AICA) and, together with the Ciénaga Grande de Santa Marta Fauna and Flora Sanctuary, was declared a Ramsar Site of global importance in 1998. Later, in November 2000, Unesco declared them Biosphere Reserves.

damage from invaders

Invasive species are organisms that develop outside their natural range, altering the ecosystems they reach because they reproduce without restrictions, they do not have predators to control their population, or they simply compete with advantage for food.

Some organisms, like the “Perna viridis”can persist in the marine environment, but do not necessarily have the rafting ability to move long distances.

“Floating structures, as well as debris, can serve as optimal substrates in the marine environment, contributing to increasing non-native species problems at sites with a high degree of susceptibility to species invasion”said.

The investigation by Gracia and Rangel also found that in 16 of the 26 beaches that were studied “the marine fauna uses garbage and woody debris as a substrate for possible ‘rafting’ and dispersal” of herself.

Source: EFE