Climatide

Photo by Miriam Goldstein

Plastic debris is small and spread over a vast area. As this fall 2010 photo from the "Eastern Pacific Garbage Patch" shows, even in the areas with the highest concentrations of plastic, most of the ocean just looks like ocean.

Miriam Goldstein – a scientist who studies marine plastic debris in the Pacific Ocean – says that a study by Oregon State University’s Angelicque White debunking many common plastic pollution myths has left people confused and questioning whether plastic pollution is even a problem. So she set out to clarify a few points from the study, starting with the “plastic outweighs plankton” myth (starting quotes are from Dr. White’s meta-analysis):

“…it is simply inaccurate to state that plastic outweighs plankton, or that we have observed an exponential increase in plastic.”

Reports that plastic outweighs plankton stem from a 2001 study by Moore et al., published in Marine Pollution Bulletin. Most oceanographers, including myself, do not think that comparing the dry weight of plankton and plastic is a helpful way of understanding what is going on in the ocean. The reasons for this are somewhat technical, but you can read about them in this blog entry, which I wrote a year before I starting doing my own research on plastic in the North Pacific. I believe that this method is no longer much used – in a recent post at the Plastic Pollution Coalition’s blog, Marcus Eriksen of Algalita Marine Research writes “…it’s important to describe plastic to plankton ratios as an anecdote, but not worth quantifying.”

As for the idea that there’s a Garbage Patch twice the size of Texas:

“The studies have shown is that if you look at the actual area of the plastic itself, rather than the entire North Pacific subtropical gyre, the hypothetically “cohesive” plastic patch is actually less than 1 percent of the geographic size of Texas.”

In order to understand this, I emailed Dr. White directly, and she was happy to explain her calculations. First, remember that the vast majority, more than 90%, of the plastic found in the [North Pacific Gyre] are tiny – less than the size of your pinky fingernail. These pieces are spread out over the surface making them very hard to see with the naked eye. Mostly, the ocean just looks like ocean… But when you tow a fine-meshed plankton net through this same area, there are thousands of tiny plastic crumbs. They’re just really small, and fairly spread out on the surface of the ocean… Dr. White was looking at the area of the ocean’s surface covered by solid plastic, not where plastic pieces could be found. She calculated the area that would be covered by plastic if all tiny pieces were squished together into a solid “island.” Since the pieces are so small, that’s not very much area.