University of Washington
Marine microplastic pollution: An interdisciplinary approach to understanding the effects on organisms, ecosystems, and policy.
Degree: PhD, 2021, University of Washington
Microplastics (plastic < 5mm) are ubiquitous in marine environments, from surface waters to benthic sediments. Microplastic in the oceans was first documented in 2004 and our current knowledge of potential biological implications is limited and rapidly growing. Thus far, we know marine organisms are exposed to microplastics in natural settings, ingest microplastics, and experience negative physiological impacts. Many aspects of microplastics such as ingestion fate, extent of trophic transfer, and effect on marine ecosystems remain unknown. Motivated by the need to understand the impact microplastic pollution has on our environment and our lives, I investigated three aspects of the marine microplastic problem: impacts on marine organisms, the ecosystem they support, and the linkages between scientific research and public policy. In nature, mussels experience a wide range of particle types and concentrations, readily filtering microalgae and abiotic particles other than microplastic. Mussel clearance rate is sensitive to stress, making it a good indicator of stressful conditions and polluted environments. In Chapter 1, I compare mussel (Mytilus trossulus) clearance rates when exposed to two different abiotic particles, microplastic and silt, across multiple concentrations. I measure the clearance rates of mussels exposed to increasing concentrations of three particle treatments: Algae, microplastic + algae, and silt + algae. I found that mussel clearance rate was inhibited by high concentrations of microplastics but not silt. In the absence of microplastic, mussel clearance rate was not dependent on the addition of silt, total particle concentration, or algal concentration.
Mussels readily ingest microplastics in natural and laboratory settings, raising concerns about particle fate. Mussels are key benthic-pelagic couplers, concentrating particles from the water column into dense and nutrient rich biodeposits. In Chapter 2, I evaluate how microplastic changes the benthic-pelagic coupling role of marine mussels (M. trossulus). I expose mussels to feeding regimes with and without microplastic and measure four attributes of biodeposits: morphology, quantity of algal and microplastic particles, sinking rate, and resuspension velocity. I found biodeposits from the algae treatment contained more algal cells on average than those from the microplastic treatment. Further, biodeposits from the microplastic treatment sank slower and resuspended at slower water velocities than biodeposits from the algae treatment.
To combat plastic pollution, there is sufficient evidence that policies can lead to reduced plastic production and consumption both locally and globally. In Chapter 3, I examine global growth and spread of the marine microplastic field in conjunction with growth and spread of national plastic policies using scientometric and diffusion methods. I conduct systematic literature reviews of marine microplastic papers and national plastic policies through 2019. At a global level, marine microplastic research and…
Advisors/Committee Members: Carrington, Emily (advisor).
Subjects/Keywords: Benthic-Pelagic; Marine debris; Microplastic; Mussel; Physiology; Policy; Ecology; Environmental science; Biology
to Zotero / EndNote / Reference
APA (6th Edition):
Harris, L. (2021). Marine microplastic pollution: An interdisciplinary approach to understanding the effects on organisms, ecosystems, and policy. (Doctoral Dissertation). University of Washington. Retrieved from http://hdl.handle.net/1773/46738
Chicago Manual of Style (16th Edition):
Harris, Lyda. “Marine microplastic pollution: An interdisciplinary approach to understanding the effects on organisms, ecosystems, and policy.” 2021. Doctoral Dissertation, University of Washington. Accessed April 22, 2021.
MLA Handbook (7th Edition):
Harris, Lyda. “Marine microplastic pollution: An interdisciplinary approach to understanding the effects on organisms, ecosystems, and policy.” 2021. Web. 22 Apr 2021.
Harris L. Marine microplastic pollution: An interdisciplinary approach to understanding the effects on organisms, ecosystems, and policy. [Internet] [Doctoral dissertation]. University of Washington; 2021. [cited 2021 Apr 22].
Available from: http://hdl.handle.net/1773/46738.
Council of Science Editors:
Harris L. Marine microplastic pollution: An interdisciplinary approach to understanding the effects on organisms, ecosystems, and policy. [Doctoral Dissertation]. University of Washington; 2021. Available from: http://hdl.handle.net/1773/46738