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Great Marsh Macroplastics Mapping

Macroplastics are plastics that are easily visible to the human eye and are often what we first think of when we consider plastic pollution.

The 25,500 acres of saltwater marsh, mudflats, beaches, and various bodies of water that make up the Great Marsh are subject to the ebb and flow of daily tides, and the debris they carry.

Seaside works with volunteers and organizations to not only clean up these bodies of water of macroplastics and other debris, but to also record the types of debris collected. In surveying the variable topography this expansive marsh consists of, we hope to make distinct correlations between characteristics of the landscape and the debris that is deposited there. The patterns derived from these correlations can then be applied toward informing local organizations or individuals in the development of their land management procedures.

Great Marsh Macroplastics Surveys

Seaside is actively working to clean up the shores and waterways of the Great Marsh on the North Shore. Through surveys of the coastal lands, we hope to record the types and locations of macroplastics in order to inform land management decisions and practices.

In collecting data, areas of the marsh are walked by foot and the wrack line is surveyed for plastic debris accumulation. The assessed area is recorded using a GPS unit, making distinctions between clean and dirty areas during the survey. Areas that have a high density of debris are uploaded in contrast to their clean counterparts on Google Earth Pro. Using these tools allows the clean and dirty acreage to be accurately measured.

Areas that have a large accumulation of debris are cleaned by volunteers, removing only commercial and consumer plastics. The plastic debris collected at each location is weighed and sorted, with photographic representations of their groupings being taken if possible.

While the removal of only plastic does not provide a complete analysis of the area, it serves as an accurate representation of the volume of debris that can accumulate. The breakdown of debris by composition, item, and origin (commercial or consumer) provides a means of quantifying each source of macroplastic debris in marine environments. Having quantifiable data on the debris can serve as a tool to make predictive assessments of debris deposition in areas that are hard to access or privately owned.

Final Mudflat Acidification Infographic.