Plastic in sea alters marine ecology

May 9th, 2012 by Scripps Institution of Oceanography

A 100-fold upsurge in human-produced plastic garbage in the ocean is altering habitats in the marine environment, according to a new study led by Ph.D. graduate student researcher Miriam Goldstein at Scripps Institution of Oceanography at UC San Diego.

SEAPLEX chief scientist Miriam Goldstein in New Horizon's science laboratory on 5 August 2009 (click image to expand - ©Scripps Institution of Oceanography).

In 2009 an ambitious group of graduate students led the Scripps Environmental Accumulation of Plastic Expedition (SEAPLEX) to the North Pacific Ocean Subtropical Gyre aboard the Scripps research vessel New Horizon.

The Scripps Institution of Oceanography research vessel New Horizon exploring the North Pacific Ocean Gyre on 11 August 2009 as part of the SEAPLEX voyage (click image to expand - ©Scripps Institution of Oceanography).

During the voyage the researchers, who concentrated their studies a thousand miles west of California, documented an alarming amount of human-generated garbage, which was mostly broken down bits of plastic the size of a fingernail floating across thousands of miles of open ocean.

Tiny pieces of plastic from the Pacific Ocean including a 'nurdle' (raw industrial preproduction plastic pellet second from left (click image to expand - ©Scripps Institution of Oceanography)

The paper, “Increased oceanic microplastic debrid enhances oviposition in an endemic pelagic insect,” published in the 9 May 2012 online issue of the journal Biology Letters, reveals that plastic debris in the area popularly known as the “Great Pacific Garbage Patch” has increased by 100 times over in the past 40 years, leading to changes in the natural habitat of animals such as the marine insect Halobates sericeus.

These “sea skaters” or “water striders”-relatives of pond water skaters-inhabit water surfaces and lay their eggs on flotsam.

Naturally existing surfaces for their eggs include such items as seashells, seabird feathers, tar lumps and pumice.

In the new study, researchers found that sea skaters have exploited the influx of plastic garbage as new surfaces for their eggs. This has led to a rise in the insect’s egg densities in the North Pacific Subtropical Gyre.

The sea skater or water strider, Halobates sericeus, has increased in population due to the presence of small plastic particles in the upper surface of the Pacific Ocean (click image to expand - image courtesy of Scripps Institution of Oceanography and ©Anthony Smith)

Such an increase, documented for the first time in a marine invertebrate in the open ocean, may have consequences for animals across the marine food web, such as crabs that prey on sea skaters and their eggs.

“Our paper shows a dramatic increase in plastic over a relatively short time period and the effect it’s having on a common North Pacific Gyre invertebrate,” said Miriam Goldstein, lead author of the study and chief scientist of SEAPLEX, a UC Ship Funds-supported voyage. “We’re seeing changes in this marine insect that can be directly attributed to the plastic.”

The new study follows a report published last year by Scripps researchers in the journal Marine Ecology Progress Series showing that nine percent of the fish collected during SEAPLEX contained plastic waste in their stomachs.

That study estimated that fish in the intermediate ocean depths of the North Pacific Ocean ingest plastic at a rate of roughly 12,000 to 24,000 tons per year.

The Goldstein et al. study compared changes in small plastic abundance between 1972-1987 and 1999-2010 by using historical samples from the Scripps Pelagic Invertebrate Collection and data from SEAPLEX, a NOAA Ship Okeanos Explorer cruise in 2010, information from the Algalita Marine Research Foundation as well as various published papers.

In April, researchers with the Instituto Oceanográfico in Brazil published a report that eggs of Halobates micans, another species of sea skater, were found on many plastic bits in the South Atlantic off Brazil.

“Plastic only became widespread in late 1940s and early 1950s, but now everyone uses it and over a 40-year range we’ve seen a dramatic increase in ocean plastic,” said Goldstein.

Beach litter including a large amount of plastic collected from the shore at Champ Rouget, Chouet, Guernsey on 26 June 2011 (click image to expand - ©RLLord)

“Historically we have not been very good at stopping plastic from getting into the ocean so hopefully in the future we can do better,” she said.

Marci Rosenberg, a UCLA student, and Scripps Research Biologist Emeritus Lanna Cheng, were coauthors of the study.



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