Deadliest Catch: Man-Made Pollution

Cruising around the Scandinavian coastline in November might not sound like the most ideal place to conduct an environmental impact study, but for Norway’s Institute of Marine Research it was necessary in order to investigate the levels of anthropogenic particles in the Skagerrak strait. As you can imagine, this setting presented some unique challenges for the research team. In order to gather and analyze microscopic samples from this body of water, which is located between Norway, Denmark and Sweden, researchers had to come up with some new sampling methods and fashion their own equipment to solve problems that had plagued previous studies.

Norwegian Researchers Hard at Work^

One key obstacle that these scientists needed to overcome was how to distinguish between anthropogenic particles, which are man-made bits of matter that impact the environment (i.e. oil-spill droplets, asphalt, rubber tire wear, fly ash), from those particles with similar characteristics which appear naturally (volcanic ash, peat). To make this distinction, the samples were subjected to morphology analysis of their color and texture to first determine their origin before being counted. The second major challenge was how to prevent contamination, which is easier said than done considering the harsh and unpredictable nature of the sea. One of the steps the researchers took to solve this was to develop control samples, free of any contaminants, which they could actually bring on board the ship with them. To further reduce the potential of contaminating samples, they also created new methodology and constructed their own customized sampling apparatus. You can see a schematic of the sampling equipment the Institute researchers built in their published study. Their setup involved a submersible water pump that was positioned inside a waterproof case connected to the sampling filter (10 ?m hydrophobic polycarbonate membrane filters, along with a 30 ?m square mesh nylon filter as a support) which was placed directly in the sea. To protect the filter from wave turbulence they modified one of our filter holders (this one) with a new outlet fitting and a larger, semi-enclosed inlet with a smooth surface. The filters were also placed in protective holders before and after filtration for protection and to reduce the risk of contamination. As an added protective measure, the filter apparatus was ultrasonically cleaned prior to use. The entire sampling apparatus was held 2 meters outside the boat (to further prevent contamination) and the sampling depth was limited to between 0.1 and 1.5 meters to protect it from large waves. While it will take many more studies before conclusions can be drawn about the state of this particular body of water, the scientists were encouraged by the results of the new methodology they created. They note in the conclusion how these improvements have standardized the sampling and reduced the risk of contamination. The scientists also suggest that this sampling equipment could be adapted for larger particles. To read the full study, visit here. ^Image from Survey of microscopic anthropogenic particles in Skagerrak. Lysekil and Flødevigen 2010-11-20, Institute of Marine Research.