Thursday, July 19, 2012

Data on data on data (and you do not need to be a scientist to get it)

Rozalia Project for a Clean Ocean is about halfway through our 2012 season and, with the help of many excellent people on the coast and in Vermont, we have already collected over 143,000 pieces of marine debris!  18,101 pieces were collected since early June with our interns aboard American Promise. Here is a quick list of the top ten items we picked up along the coast of New England:

Top Ten
Foam Pieces
Food Wrappers/Containers
Small Plastic (5-30mm)
Plastic Bottles
Microplastic (<5mm)
Caps/Lids/Bottle Tops
Rubber Pieces
Large Plastic (>30mm)

The above list accounts for 5,410 pieces of collected trash, over a quarter of the total number collected this far (we picked up over 12,000 pieces of trash on Frenchboro - there was so much that we only counted the number but did not fill out our specific data cards).

There are three main ways in which we collect this trash, each of which is effective in its own way.  Land cleanups account for the majority of debris removal.  Like the name claims, this involves picking up garbage found on the ground near bodies of water.  This is important because trash on land can be blown into the water by wind or swept in with runoff after heavy rains.  The other two methods are used for removing debris directly from the water.  We use various nets (Neuston, dip-nets, and our own Baleen Basker) and drag them along the surface of the water while we sail in order to pick up anything that may be floating or near the very top of the water column.  Lastly, we use our ROV (Remotely Operated Vehicle) to explore and clean the ocean floor.  This underwater robot can be flown through the water using a control box that is very similar to a video game controller.  It has a camera on the front so that we can see everything the robot sees as well as a claw to grab any trash we find.

No matter which method we use, we fill out a data card every time we go trash hunting.  This ensures that we have a more detailed record of items we find so we can identify any trends in debris accumulation.  We break up the data card into five main categories (food-related waste, personal waste, fishing debris, industrial debris, other pieces), each with several sub-categories for more specific labeling.  With a little data manipulation, we are able to compare the percent debris removal of each category by each method to see which technique is most effective for a given trash category.  From the graph, we can see that collected trash during land cleanups is pretty much even across the five categories.  Surface tows, on the other hand, appear to yield small percentages of everything except “Other Debris”.  By digging a little deeper, we found that this could be a result of large amounts of microplastic that are found farther from the shoreline as larger items break down.  Surface towing is the most reliable method to collect these tiny pieces of plastic that we may otherwise not be able to see easily.  The ROV shows the highest collection rate for food-related waste.  This also makes sense because we often launch the robot off the side of docks where people dump either their trash or it blows from overflowing garbage cans.

As we continue to analyze our data, we are finding many interesting trends.  Check back in soon to see what else we have learned! If you are interested in helping Rozalia Project and your local waterway, we will be happy to send you a copy of our data card. Fill it out each time you and your friends and family do a clean up, send it to us and we will keep records to see how what you find compares to what we find.

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