Project Description
The accumulation of micro-nano-plastics and the effects these have on organisms, food webs, nutrient and energy transfers, ecosystem function, and ultimately ecosystem services are a global concern. Plastic debris has been found in sensitive ecosystems such as Antarctica, the deep oceans, and across a plethora of freshwater, terrestrial and marine organisms (1). Several actions have been taken to reduce or ban the use of conventional plastics. The plastics industry has pivoted towards the production of compostable biodegradable bioplastics with >2.11 million tonnes manufactured in 2018 alone (2,3). The environmental and ecological effects of BMNPs, the adsorption and release of toxic substances, and the role of BMPs in transporting legacy contaminants remains to be elucidated. In the aquatic environment, not all biodegradable plastics exhibit the same rates of decay and consequently, biodegradation can take an extended time. Many legacy compounds, such as polychlorinated naphthalene (PCN), can interact with BMNP making synergistic effects highly likely. The goal of this QUADRAT PhD is to assess the implications of switching from oil-based plastics to newer biodegradable plastics. The objective is to exploit a sentinel fish species the shanny (Lipophrys pholis) informed by the zebrafish toxicology model to assess the impacts of the two most-produced biodegradable plastics, biobased (PLA – polylactic acid) and non-biobased (PBAT – polybutylene adipate terephthalate) and a legacy contaminant (PCN) that is widespread in in the Irish Sea. This approach is based on pilot studies at QML showing shanny is easy to manipulate, and amenable to exposure experiments with various plastics, both ambient and in the diet. The PhD candidate will assess the impacts of BMNP exposure via dietary intake on fish physiology, organismal stress, endocrine disruption, behavioural alterations, alterations in commensal gut microbial flora, and hepatic and gonadal transcriptional perturbations. These data will provide key insights into the potential toxic mechanisms of action of BMNP in comparison to traditional oil-based plastic and controls. The rationale is that once the key mechanisms of toxicity have been elucidated, a systems-level comprehension of bioplastics exposure will be possible, and this will guide the development of risk assessment frameworks using the Adverse Outcome Pathway framework.
The overall aims of this project, ‘Biodegradable plastics as emerging environmental pollutants’ are to establish the biological impacts of biodegradable plastics exposure in a sentinel marine species the shanny (Lipophrys pholis) informed by the zebrafish toxicology model. This project will be carried out under the guidance of Profs Gary Hardiman and Jaimie Dick at Queen’s University Belfast/Queen’s Marine Laboratory and Prof Stuart Piertney at the University of Aberdeen and Dr. Tim Mackie, Department of Agriculture, Environment and Rural Affairs (DAERA), Marine & Fisheries Division Monitoring & Assessment Team.
The plastics industry has pivoted towards the production of ‘compostable’ and ‘degradable’ plastics in response to environmental concerns surrounding conventional plastics. The slow decomposition rate and the accumulation of traditional macro and microplastics are now a global concern particularly as the waste material is inert and persistent in the environment. Plastic debris has been found in sensitive ecosystems such as Antarctica and in a plethora of freshwater, terrestrial and marine organisms. Several actions have been taken in Europe and the UK to reduce the use of conventional plastics and many countries have banned their use. The European Commission plans that all plastic will be reusable or recyclable by 2030. Biodegradable bioplastics use has increased exponentially across the globe, with >2.11 million tonnes manufactured in 2018 alone. A concern with bioplastics is that they may not degrade completely in natural ecosystems. Most bioplastics are comprised of organic polymers (e.g., polylactic acid, polyhydroxyalkanoate) and as they degrade, have the potential to release carbon as well as other chemicals that could affect organisms, food webs, nutrient and energy transfers, ecosystem function, and ultimately ecosystem services. This PhD project will take an interdisciplinary approach that encompasses aquatic biology, marine genomics, metagenomics, toxicology, and fish behaviour and physiology to allow a holistic understanding of the impacts of BMNPs on aquatic organisms using the shanny as a ‘canary in a coal mine’. This intertidal fish combines many characteristics required in sentinel species. It is abundant and easy to catch, has a wide geographical distribution and a restricted home range. This species is commonly encountered in rockpools in Ireland and the UK. We have piloted, at QML, the use of shanny in ambient and dietary plastics exposure and found the species amenable to such experimental treatments. In the Irish sea a recent study demonstrated that fish and shellfish are highly contaminated with PCN. In addition, mesopelagic fish collected near this region had high gut loads of microplastics, therefore demonstrating the critical need for studying the combination of both pollutants.
To date, much work has been done to understand the effects of conventional plastic pollution in the aquatic environment. It is well established that plastics are a source of endocrine-disrupting chemicals (EDCs) and that they can release or transfer these contaminants to organisms. Based on previous studies from our group, we know that conventional plastics and their additives (e.g., bisphenol A, phthalates) alter hepatic miRNA expression profiles, perturb hepatic metabolism, and energy balance, and decrease reproductive performance. Ingestion of marine microplastic debris impacts intestinal flora disrupting symbiosis between the host and its microbiome. This dysbiosis may interfere with animal health and promote disease onset. At present, there is a lack of information about the potential health effects of biodegradable plastics in marine organisms. Despite their promise, it remains unclear whether they cause environmental damage, and this PhD project will address this gap in our knowledge.
Taking into account the low biodegradation rate of bioplastic polymers in the marine environment, and the fact that bioplastics will be ubiquitous in the environment in a few short years the student will focus on the impacts of two bioplastic polymer micro and nanoparticles; 1) A biodegradable biobased polymer: PLA (poly(lactic)acid) derived from corn and a promising candidate to replace conventional plastics and 2) a biodegradable non-biobased plastic: PBAT (polybutylene adipate terephthalate), derived from fossil resources and, after PLA, is the most manufactured biodegradable polymer. This project will undertake a comprehensive research program consisting of four independent, yet complementary objectives to assess the impacts of bioplastics micro-nano particles (BMNP) on fish physiology and behaviour, organismal stress, endocrine disruption, alterations in commensal gut microbial flora, and transcriptional perturbations. The first objective (O1) will assess the impacts of BMNPs on the hepatic-gonadal axis of the shanny and zebrafish after chronic BMNP ingestion. The second objective (O2) will examine the gut microbiota and potential dysbiosis following BMNPs ingestion. The third objective (O3) will assess transcriptomic responses in the hepatic-gonadal axis and integrate findings with data from O1 and O2 (including behavioural observations, e.g., swimming, aggression, feeding rates, hiding, exploring, and correlates with physiology) to allow risk assessment. The fourth objective (O4) will survey the impacts of BMNPs toxicant levels using FTIR and a targeted q-PCR panel (guided by O3) to monitor effects on natural populations. These data will ultimately provide key insights into the toxic mechanisms of action of biodegradable plastics. The rationale is that once the key mechanisms have been elucidated, a systems-level comprehension of phenotypic, behavioural, metagenomic, and transcriptional perturbations in response to bioplastics exposure will be possible and this will guide the development of risk assessment frameworks using advanced machine learning models.
This transdisciplinary approach will leverage supervisory expertise in Big Data, genomics, toxicology, and marine biology at QUB/QML and UoA and world-class research infrastructure for computing, analytical chemistry, genomics, and marine research at the Institute for Global Food Security (IGFS) QUB and the Queen’s Marine Laboratory (QML) and DAERA. The project’s multidisciplinary approach provides an excellent opportunity for training in various aspects of ecotoxicogenomics and advanced environmental and risk assessment analysis. Moreover, it provides an exceptional opportunity for research training in both Northern Ireland and Scotland whereby the successful candidate will work collaboratively across disciplines and research cultures to generate new insights that transcend traditional boundaries. The project will combine aspects of marine biology, environmental chemistry, genetics, bioinformatics, and systems biology. Consequently, subject-specific training will be offered in each of these areas. This will comprise a mix of appropriate postgraduate level training (e.g., molecular biology, bioinformatics, genetics, biogeochemistry, computer science, environmental change) and ‘hands-on’ training in the advanced systems-level methods.
Essential & desirable candidate skills
Essential: Basic laboratory and field work skills in the areas of fish biology / ecology / behaviour / genetics.
Desirable: Experience with fish models e.g., shanny or zebrafish, and training in bioinformatics
Supervisors
Gary HardimanPrimary Supervisor: | Profile: Gary Hardiman Email: g.hardiman@qub.ac.uk Institution: Queen's University, Belfast Department/School: School of Biological Sciences |
Stuart PiertneySecondary Supervisor: | Profile: Stuart Piertney Email: s.piertney@abdn.ac.uk Institution: University of Aberdeen Department/School: School of Biological Sciences |
Jaimie TA DickAdditional Supervisor: | Profile: Jaimie TA Dick Email: j.dick@qub.ac.uk Institution: Queen's University, Belfast Department/School: School of Biological Sciences |
Additional Supervisor: | Dr. Tim Mackie Senior Scientific Officer at DAERA Marine & Fisheries Division |
References
Wang et al. Biodegradable microplastics (BMPs): a new cause for concern?. Environ Sci Pollut Res 28, 66511–66518 (2021). https://doi.org/10.1007/s11356-021-16435-4
Huff M, da Silveira W, Starr Hazard E, Courtney SM, Renaud L, Hardiman G. Systems analysis of the liver transcriptome in adult male zebrafish exposed to the non-ionic surfactant nonylphenol. Gen Comp Endocrinol. 2019 Jan 15;271:1-14. doi: 10.1016/j.ygcen.2018.10.016. Epub 2018 Oct 25. PMID: 30563618.
Fernandes AR, Mortimer D, Holmes M, Rose M, Zhihua L, Huang X, Smith F, Panton S, Marshall L. Occurrence and spatial distribution of chemical contaminants in edible fish species collected from UK and proximate marine waters. Environ Int. 2018 May;114:219-230. doi: 10.1016/j.envint.2018.02.047. Epub 2018 Mar 6. PMID: 29522986.
Wieczorek, Alina M., et al. “Frequency of microplastics in mesopelagic fishes from the Northwest Atlantic.” Frontiers in Marine Science (2018): 39.
Huff M, da Silveira WA, Carnevali O, Renaud L, Hardiman G. Systems Analysis of the Liver Transcriptome in Adult Male Zebrafish Exposed to the Plasticizer (2-Ethylhexyl) Phthalate (DEHP). Sci Rep. 2018 Feb 1;8(1):2118. doi: 10.1038/s41598-018-20266-8. PMID: 29391432; PMCID: PMC5794889.
Renaud L, Silveira WAD, Hazard ES, Simpson J, Falcinelli S, Chung D, Carnevali O, Hardiman G. The Plasticizer Bisphenol A Perturbs the Hepatic Epigenome: A Systems Level Analysis of the miRNome. Genes (Basel). 2017 Oct 13;8(10):269. doi: 10.3390/genes8100269. PMID: 29027980; PMCID: PMC5664119.
Michael E Baker, L James Sprague, Cataldo Ribecco, Barbara Ruggeri, Narimene Lekmine, Colleen Ludka, Ivan Wick, Laura Soverchia, Massimo Ubaldi, Roman Šášik, Daniel Schlenk, Kevin M Kelley, Jesus A Reyes & Gary Hardiman (2014) Application of a targeted endocrine q-PCR panel to monitor the effects of pollution in southern California flatfish, Endocrine Disruptors, 2:1, DOI: 10.4161/23273739.2014.969598
Expected Training Provision
This transdisciplinary approach will leverage supervisory expertise in Big Data, genomics, toxicology, and marine biology at QUB/QML and UoA and world-class research infrastructure for computing, analytical chemistry, genomics, and marine research at the Institute for Global Food Security (IGFS) QUB and the Queen’s Marine Laboratory (QML) and DAERA. The project’s multidisciplinary approach provides an excellent opportunity for training in various aspects of ecotoxicogenomics and advanced environmental and risk assessment analysis. Moreover, it provides an exceptional opportunity for research training in both Northern Ireland and Scotland whereby the successful candidate will work collaboratively across disciplines and research cultures to generate new insights that transcend traditional boundaries. The project will combine aspects of marine biology, environmental chemistry, genetics, bioinformatics, and systems biology. Consequently, subject-specific training will be offered in each of these areas. This will comprise a mix of appropriate postgraduate level training (e.g., molecular biology, bioinformatics, genetics, biogeochemistry, computer science, environmental change) and ‘hands-on’ training in the advanced systems-level methods.
Impact
In the past few years, marine plastic pollution has become one of the most commented environmental issues in the media, NGOs, and academic circles. Reduction of plastic pollution has turned into a global societal priority. Several agencies have stressed the importance of reducing plastics use. For example, in the list of Sustainable Development Goals of the United Nations ‘Life below water: avoid plastic bags to keep the oceans clean’ is currently the 14th goal; the European Commission has banned single-use plastic under the EU Strategy for Plastics in a Circular Economy and Environmental America has selected plastic pollution as one of its legislative agenda priorities. The current focus on plastics is slowly shifting to encompass a new class of biodegradable plastics to ameliorate plastic contamination, however, no information is available regarding the potential impacts on the environment, particularly the micro and nano plastics derived from biodegradable plastics. In the aquatic environment, not all biodegradable plastics exhibit the same rates of decay and consequently, biodegradation of bioplastics can take an extended time. A comprehensive understanding of the potentially toxic effects of BMNPs under natural conditions is urgently required to understand the implications of switching from legacy plastics to BMNPs. This research is important as it will address this knowledge deficit. The impact of this PhD will be the delivery of comprehensive data set using a sentinel species which will facilitate the development of risk assessment frameworks.
Proposed Timetable
The 42-month project is based on a research strategy with four key objectives. In Y1 the candidate will carry out a literature review and become proficient in sampling of the fish and the QML environment.
O1 will involve biodegradable bioplastics (BMNP) exposure and assessment of fish for endocrine, behavioural, and physiological alterations. The exposure experiments will commence at the beginning of the shanny breeding season (March-April Y1). Exposure to BMNPs will be adapted to 28 days, to balance chronic exposure. Y1 deliverables will include sampling, exposure via diet to BMNPs; collection of tissues for lab analysis; health status and behavioural assessments; plasma concentrations of steroid hormones; and assessment of reproductive performance.
O2 is a comprehensive Gut microbiota study which will start at the beginning of Y2. DNA will be extracted from fecal samples and fish intestines. 16S rRNA library construction will be carried out to allow metagenomics comparative analysis of control and BMNPs diets. The milestone from O2 will be a comprehensive analysis of microbial gut community dysfunctionality in response to BMNPs.
O3 will assess transcriptomic responses in hepatic and gonadal tissue in response to BMNP exposures. This will commence in late Y2. Data analysis will be a major focus in Y3 examining hepatic and gonadal deregulated biological pathways. O3 will perform an integrative analysis of the transcriptomic, metagenomics, and phenotypic data and provide a risk assessment for the impacts of BMNPs. Milestones will be a correlative analysis of metagenomic and transcriptomic data with adverse behavioural & phenotypic endpoints.
O4 will commence midway through Y3 and will survey the impacts of BMNPs toxicant levels using FTIR and a targeted q-PCR panel (guided by O3) to monitor effects on natural populations.
The remainder of Y3 and partial Y4 will involve thesis writing, dissemination, & an internship at DAERA.
QUADRAT Themes
- biodiversity
- environmental-management
Partners
A CASE Partnership has been confirmed with DAERA (Marine & Fisheries Division)
