Miriam Goldstein of Scripps Institution of Oceanography recently sat down with the NOAA Marine Debris Program to talk about her October 2010 work aboard NOAA’s Okeanos Explorer during its EX1006 trans-Pacific cruise through what is commonly referred to as the “Eastern Garbage Patch” in the north Pacific ocean west of California.
About Miriam C. Goldstein:
Miriam C. Goldstein is a Ph.D. student in biological oceanography at the Scripps Institution of Oceanography in Mark Ohman’s lab. She is currently working on the abundance and ecological effects of plastic debris in the North Pacific Central Gyre. In August 2009, she served as chief scientist on the Scripps Environmental Accumulation of Plastic Expedition (SEAPLEX), a 20-day expedition to study accumulation of plastic debris in the central Pacific. This Q&A took place following her work on the NOAA Okeanos Explorer’s cruise from Honolulu to San Francisco, which concluded in November 2010.
How did you become interested in this subject?
About 3 years ago, I started seeing headlines about the “Great Pacific Garbage Patch.” I became really intrigued and invited Marcus Eriksen of the Algalita Marine Research Foundation to speak at Scripps Institution of Oceanography, where I am a graduate student. I found Dr. Eriksen’s talk fascinating and realized that there was lots of scientific work to do on this topic. So I got together with several other Scripps graduate students and wrote a grant to the UC Ship Funds to take one of the Scripps research vessels out to the North Pacific to look for plastic.
Have there been other scientific studies conducted in this part of the ocean before on plastics? Who did this and when did they take place?
The Algalita Marine Research Foundation, founded by Charles Moore, has been going out there for about a decade. They are the ones who have really raised awareness of plastic in the open ocean. The Sea Education Association is an educational group that has been monitoring plastic in both the Atlantic and the Pacific from their tall ships for a number of years. They have a particularly nice dataset on plastic in the Atlantic, collected over 22 years and just recently published in Science. Project Kaisei is another nonprofit that went out to the North Pacific Central Gyre in 2009 (in collaboration with our group at Scripps) and again in 2010. Their mission is to find ways to clean up the plastic. This is definitely not a comprehensive list – thanks to the hard work of Charles Moore and his group in particular, there are now many conservation groups and scientists who are becoming interested in this issue.
What was unique or different about the October 2010 NOAA EX1006 trans-Pacific cruise from other(s) you’ve been on?
I had never been on a NOAA ship before, and I am embarrassed to say that I had no idea that NOAA had a uniformed officer corps. I enjoyed learning about the NOAA Commissioned Officer Corps and getting to know some of the officers and the paths their careers had taken. I had also never been on a bathymetric mapping ship before. It was incredibly cool to see how the mapping team used sonar to map the seafloor. They may have even discovered a new seamount or two!
What goes into deploying your equipment on a vessel as large as the Okeanos Explorer?
Every deployment requires a lot of teamwork! The manta tow is deployed on a piece of equipment called the “J-frame,” which allows us to pull the net on the starboard (right) side of the ship. In order to do this the officer in charge needs to slow down the ship, a trained person needs to operate the J-frame, and two people need to attach the net to the J-frame wire and make sure it enters and leaves the water correctly. Each team constantly talks to each other over the radio to make sure that everyone is coordinated. It takes about a half-hour to do one manta tow.
How many samples were you able to collect?
We were able to do 40 manta tows. Some of the samples went to the NOAA Northwest Fisheries Science Center for chemical analysis, some went back to my lab at Scripps to count and measure the plastic, and a few stayed on the Okeanos Explorer for outreach and education.
What was the lab like aboard the Okeanos Explorer?
There are three labs on the Okeanos Explorer – the wet lab, the dry lab, and the control room. Since I was working with plankton and seawater, it probably isn’t much of a surprise that I spent most of my time in the wet lab. Every time we did a tow, I would wash all the plankton into the end of the net, which is a removable part called a “cod end.” I would then take the cod end into the wet lab and wash the plastic and plankton into a jar. I would then fill the jar with ethyl alcohol, which preserves the plankton so that I can look at it in the lab back at Scripps. Preservation is absolutely necessary because rotting plankton is VERY unpleasant!
What did you use to collect the samples? Why the manta net?
We collected two types of samples. We used the manta net to look at plastic on the ocean’s surface. The manta net captures what’s called the air-sea interface – the very top of the ocean. Past trips to the Gyre suggest that most of the plastic is floating up there. We also collected seawater in a bucket, then filtered it through very fine filters to see if we could find plastic particles that were too small to be captured by the manta net.
Were there specific collection protocols you followed for this cruise?
Definitely! It is very important to collect samples the exact same way every time. That way, when we see changes in the amount or type of plastic, we can be sure that it is because something is happening in the ocean and not because we collected the samples in a different way.
What types of plastic samples were collected?
I can’t answer this since we haven’t analyzed the samples yet.
Where can one find data from past samples collected in this area of the ocean?
An arbitrary and very incomplete list…
Gilfillan, L., M. Ohman, M. Doyle, and W. Watson. 2009. Occurrence of plastic micro-debris in the southern California Current system. CalCOFI Report 50. Retrieved from http://www.calcofi.org/publications/ccreports/251-vol50-2009.html.
Moore, C. J., S. L. Moore, M. K. Leecaster, and S. B. Weisberg. 2001. A comparison of plastic and plankton in the North Pacific central gyre. Marine Pollution Bulletin 42:1297-1300.
Pichel, W. G., J. H. Churnside, T. S. Veenstra, D. G. Foley, K. S. Friedman, R. E. Brainard, J. B. Nicoll, Q. Zheng, and P. Clemente-Colon. 2007. Marine debris collects within the North Pacific Subtropical Convergence Zone. Marine Pollution Bulletin 54:1207-1211.
Shaw, D. G., and R. H. Day. 1994. Colour- and form-dependent loss of plastic micro-debris from the North Pacific Ocean. Marine Pollution Bulletin 28:39-43.
Venrick, E. L., T. W. Backman, W. C. Bartram, C. J. Platt, M. S. Thornhill, and R. E. Yates. 1973. Man-made objects on the surface of the central North Pacific ocean. Nature 241:271-271.
Wong, C. S., D. R. Green, and W. J. Cretney. 1974. Quantitative tar and plastic waste distributions in Pacific Ocean. Nature 247:30-32.
What was the most difficult part of your work on this cruise?
Usually I get seasick for the first few days, and that’s never any fun. I was really lucky onboard the Okeanos Explorer – we had great weather, and for the first time ever, I didn’t feel sick at all! But the most difficult part was still anticipating that I would spend some time “feeding the fish.”
How will the samples be processed?
We will sort the plastic out under a dissecting microscope, then use a specialized scanner called Zooscan to count and measure each piece. I’m working with NOAA and with Sea Education Association to find the best way to monitor plastic pollution.
What do you hope to find out from these samples?
The cruise on board the Okeanos Explorer was a wonderful opportunity to look at plastic abundance in the fall. The North Pacific Central Gyre does undergo some seasonal changes, and we don’t have very much data from times other than the summer. So we’re really excited to see how the samples vary from season to season and year to year.
When do you think results might be available on your samples analysis? Do you plan to publish your results?
We will definitely do our best to get our findings out as fast as we can. The laboratory process does take time – collecting the samples is actually the easier part. We plan to publish in the scientific literature, as well as communicating our findings directly to the public through blogs like this one!
What would you say was the most surprising thing you discovered during your work on this vessel?
I was really surprised how much the amount of plastic we found seemed to change with the season. This may be because of the wind – there is less wind in the summer, so all the plastic is floating right on the surface. During the Okeanos Explorer cruise there was more wind, so the plastic may have been mixed deeper, in the first six feet of water or so. Changes like this are why monitoring plastic is so important – if we don’t understand where the plastic is, it’s really hard to understand what its impact on marine ecosystems might be.