Garbage is found at the bottom of the ocean in Brazil – 02/29/2024 – Environment

The presence of large amounts of trash in the ocean is a topic that is gaining more and more attention and study, however, there are few assessments regarding the deep ocean (more than 200 meters deep).

A first report on the presence of persistent marine litter on the continental slope of the South and Southeast of Brazil was published in the magazine Marine Pollution Bulletin and brings alarming data: litter was found in 28 of the 31 sampled locations (90% of the total) in two different areas of the South/Southeast coast of Brazil and, in some of them, the amount of waste was greater than that of fish and invertebrates.

“Our project aims to study fish and other animals in the deep sea, between 200 and 1,500 meters deep, and we noticed that in practically all collections there was also a large amount of garbage”, explains Marcelo Melo, from the Diversity Laboratory, Ecology and Evolution of Fish at the Oceanographic Institute of the University of São Paulo.

The research team then decided to save and study all the garbage collected.

For Flávia Masumoto, the group’s researcher and first author of the article, the amount of trash found was astonishing, which led to the decision to save, dry, weigh, quantify and analyze the material found.

“It was surprising that we did not find any article analyzing the presence of garbage in the Brazilian deep ocean. We did find some analyzes about garbage in the ocean, but only on the Brazilian coast, and this reinforced the importance of the work we were carrying out”, he states.

The research, financed by Fapesp through two projects linked to the Biota Program, collected material at 16 points in São Paulo and 15 stations in Santa Catarina. In only three locations in São Paulo, no trash was found. A total of 603 items were obtained, with a mass of 13.78 kilograms.

“Although the deep ocean is a very vast area, sunlight does not reach it efficiently to produce photosynthesis, so there are no plants or algae. It is, therefore, an area with little biomass. It is important to keep this in mind when analyzing these 13 kilos of garbage found, because in some areas we collect a larger mass of garbage than fish and invertebrates”, explains Melo.

Type and origin of waste

The predominant material was plastic, present at all collection points, representing 58.5% of the total collected. Fabrics and metals were also common, corresponding to 14% and 11% of the waste collected, respectively. Catalyzed paints for boats, glass and concrete were also identified.

“We did not observe any pattern in the distribution of garbage along the depth, however, we observed a greater amount of garbage in São Paulo than in Santa Catarina”, says Melo.

According to Masumoto, this difference may be related to the proximity of more urbanized coastal areas, the port of Santos and the Santos Basin, where there is greater ship traffic and the presence of oil platforms.

There are two main sources of marine litter: material that is discarded in coastal regions and transported by rivers and/or wind to the coast or dumped directly on the beach or material generated by oil and gas platforms, vessels, ships and others facilities that is dumped directly into the ocean.

“It is very difficult to determine the origin of the trash, but we assess, based on the type of trash found and the distance from the mainland, that most of it came from vessels or platforms”, points out Masumoto.

“We found many cans of corn and peas, for example, and products from at least eight foreign countries that we identified by the label. In other words, we were able to determine with certainty where the material was produced, but not where it was discarded, this is one of the challenges for ocean trash analysis.”

Despite Law 9,966, dated April 28, 2000, which prohibits the direct disposal of waste at sea by vessels and platforms, the results of the research indicate the need for awareness and more effective supervision.

Unknown garbage

The deep ocean is difficult to access and little known. “We think that these regions are exempt from human action, but there are industrial activities there, such as oil and gas exploration, and fishing”, comments Melo.

The researchers found, for example, animals growing associated with the trash, such as sea sponges, polychaetes and barnacles attached to the remains.

The presence of corn and soy residues in the stomach contents of a grenadier fish (family Macrouridae) indicates that the fauna is consuming food remains that are being dumped directly into the ocean, another type of impact that still needs to be further studied.

Furthermore, research is in a new phase to assess the presence of microplastics in the stomach contents of fish already collected.

“We found that garbage is arriving in these areas as well. This has a huge impact on the organisms that live in this region and we still need to study this”, concludes Masumoto.

The group’s article can be read, in English, here.