Spatial-temporal growth, distribution, and diffusion of marine microplastic research and national plastic policies

Plastic accounts for 80% of material waste in the ocean. The field of
marine microplastic research is relatively new and is growing rapidly, in
terms of published papers as well as institutions and countries conducting
research. To combat plastic pollution, there is sufficient evidence that
policies can lead to reduced plastic production and consumption both
locally and globally. We aim to understand how marine plastics research
and policies have grown and spread. Specifically, we used scientometric
and spatial diffusion methods to best explain how ideas (in this case
science and policy) clustered and spread geographically through time. We
performed systematic literature searches to determine the spatial and
temporal growth of marine microplastic publications and national plastic
policies from 1900-2019. We found that more countries adopted national
plastic policies than those that have conducted marine plastic research.
Doubling times of each temporal growth rate analyzed (research paper,
institution, country, and national policy) ranged from 1.1 – 4.05 years.
Further, each temporal growth rate had a break point where doubling time
changed significantly. Marine microplastic research has grown
exponentially since 2006, and the topics of inquiry have increased
steadily. Marine microplastic publication spread at the institution level
is best explained by a hybrid of expansion and relocation diffusion while
national plastic policy spread is best explained by expansion diffusion.
Marine microplastic research activity was not a good indicator of a
country’s resources or motivation toward national plastic policies.