Washington: In an alarming report, scientists in the US have claimed that over the past 40 years there has been a 100-fold increase of small plastic fragments floating in the north Pacific Ocean.
A team at Scripps Institution of Oceanography documented the big rise when they trawled the waters off California. And, it compared the latest plastic "catch" with previous data for the region, the `Biology Letters` journal reported.
"We did not expect to find this. When you go out into the North Pacific, what you find can be highly variable. So, to find such a clear pattern and such a large increase was very surprising," team leader Miriam Goldstein told `BBC`.
All the plastic discarded into the ocean that does not sink will eventually break down. Sunlight and the action of the waves will degrade and shred the material over time into pieces the size of a fingernail, or smaller.
An obvious concern is that this micro-material could be ingested by marine organisms, but the Scripps team has noted another, perhaps unexpected, consequence.
The fragments make it easier for the marine insect Halobates sericeus to lay its eggs out over the ocean. These "sea skaters" or "water striders" -- relatives of pond water skaters -- need a platform for the task.
The team found a strong association between the presence of Halobates and the micro-plastic in a way that was just not evident in the data from 40 years ago.
Goldstein explained: "We thought there might be fewer Halobates if there`s more plastic -- that there might be some sort of toxic effect. But, actually, we found the opposite. In tareas that had the most plastic we found the most Halobates."
The team, which accumulated their information on the abundance of micro-plastic in 2009, compared their data with those from other scientific cruises, including records dating back to the early 1970s.
Goldstein said: "The study raises an important issue, which is the addition of hard surfaces to the open ocean. In the North Pacific, for example, there`s no floating seaweed like there is in the Sargasso Sea in the North Atlantic.
"And we know that the animals, the plants and the microbes that live on hard surfaces are different to the ones that live floating around in the water. So, what plastic has done is add hundreds of millions of hard surfaces to the Pacific Ocean. That`s quite a profound change."