This research was performed and written by all women(!!) at different career stages including: volunteer, lab technician, master’s student, PhD student, academic faculty, and long-term conservation researcher.
Tiny bits of human-made debris, called microparticles (less than 5 mm in size), are found almost everywhere in the ocean. In the Salish Sea, WAm changes in weather (precipitation), river flow (Duwamish discharge), sewage overflow (wastewater), and tourism (TSA) are all thought to influence how many of these particles end up in the water.
To better understand this, we collected seawater samples every two weeks from 2019 to 2020 at the Seattle Aquarium, just offshore in Elliott Bay. We used a special oil-based method to separate out the microparticles from the water. In total, we sampled 100 liters of seawater each time at a depth of about 9 meters.
What did we find? Most of the microparticles were fibers, and concentrations ranged from 0 to 0.64 particles per liter. We found that tourism had the strongest correlation to the number of microparticles. Fewer tourists seemed to mean less pollution. But something interesting happened in April 2020—right around the start of COVID-19 lockdowns— we documented a breakpoint and a significant decline in microparticle concentration. The fewer people were traveling to Seattle (documented with TSA at SEATAC), the fewer microparticles we found in our waters.
Decline in tourism and activity on the waterfront decreased the quantity of microparticles observed; however, the long-term Covid effects on marine debris remain unknown. The microparticles found in the present study were primarily fibers and likely not from single!use plastics but rather from textile washing and shedding. While the quantity of microparticles found in the present study decreased with the onset of Covid and stay-at-home orders, global single use plastic consumption and subsequent pollution increased substantially. The volume of personal protective equipment and takeout containers, as two examples, skyrocketed. We fully expect to see an uptick in microparticle volume in the future because of the increase in these single-use plastics. While our research reveals a good immediate outcome, it is not likely long-term.
In the end, our project showed that long-term monitoring is essential. It helps us catch important shifts—like those caused by big events such as a pandemic—and better understand when and why our oceans are most at risk from human pollution.
This research was featured on
Lyda Harris, PhD 
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