After making it outside of the Marshall Islands we officially began our research. As I mentioned in an earlier post, the purpose of this research trip was to study plastic pollution of the Western Garbage Patch, an area in the North Pacific Ocean that had not been surveyed in nearly a quarter of a century. This historic research incorporated several data retrieval methods. Our main collection samples came from our trawls, a device used to skim the surface of the water. Once research commenced we launched three different trawls of different speeds and mesh sizes into the water for varying times, speeds and distances. This was our primary data set; our secondary set came from fifty minute debris surveys and random debris sightings.
Our first trawl-The High Speed Trawl-was used at you guessed it, high speeds! This elongated mesh trawl with a 500 micron mesh cod end was deployed before and after setting the Manta Trawl.
The Manta Trawl was the most scientific of all the trawls. Deployment and retrieval of the manta was very important as this was a 60 minute timed sample that travelled at a speed of 2 knots. Although similar in appearance to the high speed trawl the manta had elongated wings like a manta ray, making it more streamlined in the water. Its 333 micron mesh screen allowed for capture of small organisms.
The folding manta, a spin-off design of the manta, was used for educational purposes. Once the manta was deployed the folding manta went out as well.
All trawls were deployed on the leeward side of the boat off of the spinnaker boom, where they were monitored by different watch teams on board. After pulling in the trawls by hand all samples had to be processed, this was one of my main jobs; processing a majority of the samples before turning them over to Marcus for further analyzing and labelling.
Apart from collecting data for the 5 GYRES organization we were also collecting data for several other research agencies like NOAA, Woods Hole and Scripps Institutes. Woods Hole is looking at microbes in the water column versus microbes on pieces of plastic debris and determining their comparisons. The collection method for this process was quite intricate and timely; it was also another task I took pleasure in being responsible for. After grabbing a bucket of water from the side of the boat, I began the sampling process by forcing 4000ml of water through a syringe into a vile filled with a cotton material (trapping the microbes) followed by adding a preserving solution to the vile. Another form of data collection that I was often responsible for was collecting Halobates for Scripps Research Institute. Halobates are tiny micro organisms that reside in the water column. At Scripps, they are testing if these organisms are indicator species for marine debris, which is ironic because the more debris we had in a sample the more Halobates we found. Very neat stuff!
Pulling in the manta at night
About to process a sample Credit: Hank Carson
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