Session Chairs: Chelsea Rochman, University of Toronto; Matthew Cole, Plymouth Marine Laboratory; Amy Lusher, Norwegian Institute for Water Research (NIVA)

This session focuses on new experimental evidence regarding the impacts of microplastics on fish and invertebrates in aquatic ecosystems.

Microplastic pollution has been identified in habitats and animals, in both freshwater and marine ecosystems, from all over the world. Microplastics contaminate every level of aquatic foodchains, from the smallest zooplankton to the largest vertebrates. This begs the question: how does microplastic impact animals that become contaminated via ingestion or absorption? The weight of evidence regarding impacts is rapidly increasing. This session aims to highlight new findings that demonstrate the effects that microplastic (and associated co-contaminants) can have upon fish and invertebrates. This session will highlight both field and laboratory research investigating how microplastic exposure can affect fish and invertebrates at multiple levels of biological organization. Scientific presentations in this session will contribute novel findings, work to close some of the key research gaps relating to plastic pollution, and address topics relevant to policy change.



Distribution and ecotoxicological effects of microplastics in Mediterranean marine organisms

presenting: Carlo Giacomo Avio (Department of Life and Environmental Sciences, Italy); authors: Francesco Regoli (Dep. Life and Environmental Sciences, Polytechnic University of Marche, Italy), Lucia Pittura (Department of Life and Environmental Sciences), Daniele Fattorini (Department of Life and Environmental Sciences), Marta Di Carlo (Department of Life and Environmental Sciences), Stefania Gorbi (Department of Life and Environmental Sciences), Francesco Regoli (Department of Life and Environmental Sciences)

Microplastics (MPs) are widely diffused in the oceans and their ingestion by marine organisms is raising concern for potentially adverse effects. In this study, the distribution of MPs along Mediterranean trophic webs was evaluated, in approximately 600 specimens representative of the main invertebrate and vertebrate species. MPs were characterized in terms of size, shape and polymer typology trough microscopy and µFT- IR analyses. The results indicated that ingestion of MPs is widespread, with their occurrence in approximately 30% of Mediterranean specimens, and much higher frequencies in some species; fragments, lines, films and pellets are the more represented particles, while polyethylene, polystyrene and polyamide are the dominant polymers. However, no clear relationship with trophic position, feeding strategy or habitat preference can be easily observed.

The ecotoxicological effects of MPs were further investigated in Mediterranean mussels, Mytilus galloprovincialis, focussing on biological interactions of these particles when contaminated by PAHs. After ingestion, MP were observed in different tissues causing a significant bioaccumulation of B(a)P. The analysis of a wide range of molecular and cellular biomarkers, including immunological and antioxidant systems, neurotoxic responses, genotoxic damages and lipid peroxidation showed a different susceptibility of analysed pathways, depending on time of exposure, tissue and treatment typology. Toxicity of MPs alone was slight, but increased for contaminated particles. Even in the absence of strong toxicity, the downregulation of the immune system might have long-term consequences on organisms health status. In conclusion, this study provided new insights on the distribution of MPs in marine food webs, and on the mechanisms for their potential toxicity.


Microplastic fiber uptake, ingestion, and egestion rates in the blue mussel (Mytilus edulis)

presenting: Madelyn Woods (Marine & Environmental Research Institute, United States); authors: Madelyn Woods (Marine & Environmental Research Institute, United States), Margaret Stack (Marine & Environmental Research Institute), David Fields (Bigelow Laboratory for Ocean Sciences), Patricia Matrai (Bigelow Laboratory for Ocean Sciences)

Microplastics are a ubiquitous contaminant in the marine environment. Microplastic fibers, which make up to 90% of microplastics in coastal systems, are consumed by more than 200 marine species. However, the fate of these fibers and their effects once ingested remain largely unknown. Here, we present the effects of polyethylene terephthalate microplastic fibers (MPF) on blue mussel (Mytilus edulis) feeding rates, using imaging flow cytometry—a tool we have quantitatively adapted and applied to MPF. Mussels were fed a diet of Rhodomonas salina and experimental treatments ranged from 3,000 to 30,000 MPF/L, or 0.0004–0.004% of available seston. Microalgal uptake rates were greatly reduced in mussels exposed to levels of 15,000 MPF/L or higher. Pseudofeces production showed a positive correlation with MPF uptake rates at 30,000 MPF/L. Up to 70 MPF were isolated in a single fecal pellet and an average of approximately 300 to 1000 MPF accumulated in the digestive track. Based on our results, it is possible that mussels act as microplastic sinks in Gulf of Maine coastal waters where MPF concentrations average 10.16±0.54 MPF/L in summer and fall (2014-2017). Depuration times of exposed mussels were also examined to assess MPF egestion rates and may be an important processing step for commercial farmers. Ecological implications of MPF intake and egestion by filter feeders will be discussed.


Understanding scleractinian microplastic ingestion: size limits, retention, and calcification effects

presenting: Cheryl Hankins (U.S. Environmental Protection Agency, United States); authors: Cheryl Hankins (U.S. Environmental Protection Agency, United States), Allyn Duffy (student), Kathryn Drisco (U.S. Environmental Protection Agency)

The prevalence of microplastics in the marine environment has been of increasing concern in the past decade. Microplastics have been shown to be ingested by aquatic organisms, however the physical and toxic effects of microplastic ingestion in marine organisms, including coral, are not well understood. Two laboratory experiments were conducted on the coral species, montastraea cavernosa and Orbicella faveolata. The first experiment measured calcification rates of corals exposed to three sizes of cured microplastics: 90-106, 425-500, and 850-1000 µm. Both species ingested all size classes, however, O. faveolata did not retain many of the 425-500 or 850-1000 µm size range. Calcification was measured by using the alkalinity anomaly principle per experimental chamber. Calcification was qualitatively lower in corals exposed to microplastics, however there was no significant difference from control treatment. This may be explained by potential species-specific retention times and an artifact of exposing both species at the same time as the amount of microplastics recovered was greater in M. cavernosa than in O. faveolata fragments. Hence, a second experiment was performed to determine retention times of various size classes (425-500 µm, 850-1000 µm, 1.7-2.0 mm, and 2.4-2.8 mm) of microplastic in individual fragments of M. cavernosa and O. faveolata. The largest size range ingested by both M. cavernosa and O. faveolata was 2.4-2.7 mm, with ingestion rates of 100% and 20%, respectively. At 48 hours, the majority of microplastics (>82%) were released by both species. It is clear that there are varying responses of ingestion rates and retention times for different coral species. These results are the first step to providing threshold values for better land-based management practices, especially around coral reef habitats.


Effects of acute exposure of microplastics on the physiology of blue mussels

presenting: J. Evan Ward (Department of Marine Sciences, United States); authors: J. Evan Ward (Department of Marine Sciences, United States), Cate Herrick (Sacred Heart Academy), Maria Rosa (Department of Ecology and Evolution), Vena Haynes (Department of Marine Sciences), Bridget Holohan (Department of Marine Sciences)

As sedentary organisms, suspension-feeding bivalves are particularly vulnerable to anthropogenic contaminants that enter coastal environments. To understand the full range of impacts that contaminants such as microplastics have on these animals, sub-lethal effects must be assessed. In this study we exposed the blue mussel, Mytilus edulis, to microspheres composed of polystyrene divinylbenzene (ca. 3-30 µm; 1500 microspheres ml-1, Bangs Labs) for a period of 12 hours. Prior to exposure, mussels were delivered a microalgal diet for 1 day and then divided into two groups: a microplastic-exposed group and an unexposed control group. Mussels in each group were then placed in individual feeding chambers supplied with the microalgal diets and microspheres as appropriate. After exposure, three physiological parameters were measured including diet absorption efficiency (AE; Conover 1966), oxygen consumption, and ammonium excretion (phenolhypochlorite method). Each mussel was then sacrificed and soft tissues isolated and dried to a constant mass. All physiological parameters were standardized to a 1-g dry tissue mass using appropriate allometric equations. Absorption efficiency of mussels exposed to microplastics (55.6%) was significantly lower than AE of control mussels delivered only the microalgal diet (73.6%). No significant differences in oxygen consumption or ammonium excretion were found between treatments. Results indicate that acute exposure of mussels to polystyrene-divinylbenzene microplastics can have significant impacts on digestive processes, but not on respiration or ammonium excretion rates.


Hepatic gene expression in the European sea bass (Dicentrarchus labrax) experimentally exposed to PVC microplastics

presenting: Cristina Panti (University of Siena, Department of Environmental, Earth and Physical Sciences, Italy); authors: Cristina Panti (University of Siena, Department of Environmental, Earth and Physical Sciences, Italy), Erica de Rysky (University of Siena, Department of Environmental, Earth and Physical Sciences), Cristina Pedà (Institute for Environmental Protection and Research, Laboratory of Milazzo), Giulia Maricchiolo (National Research Council, Institute for Coastal Marine Environment), Lucrezia Genovese (National Research Council, Institute for Coastal Marine Environment), Francesco Gai (CNR, Institute of Science of Food Production), Teresa Romeo (Institute for Environmental Protection and Research, Laboratory of Milazzo), Maria Cristina Fossi (Department of Environmental, Earth and Physical Sciences, University of Siena)

The effects of microplastics (MPs; <1 mm) on fish species are still under debate. Few species have shown toxicological or physical impact due to the ingestion of MPs, as liver toxicity or alteration of intestinal tissues. The European seabass (Dicentrarchus labrax) is one of the most consumed fish species in Europe and it is potentially exposed to the ingestion of MPs both in its natural habitat and in the aquaculture plants. We measured, by quantitative Real-Time PCR, the variation of four different early warning signals in the liver of the European sea bass exposed for 90 days to virgin (MPV) and marine polluted PVC (MPI) MPs supplemented with food. The selected genes are: the TNF receptor associated factor 3 (TRAF3), the Peroxisome Proliferators Activator Receptors (PPARα/γ), the Estrogen Receptor alpha (ERα). The mRNA levels were quantified on 66 fish at time 0, after 30, 60 and 90 days of exposure to the two treatments (MPV and MPI) and control. The expression of TRAF3 is down-regulated with increasing time of exposure. The ERα mRNA levels are higher in the control compared to MPI and MPV for all the exposures, suggesting an upregulation of the gene related to contaminated food pellets. On the contrary, the PPARα gene expression increases over the time from 60 to 90 days of exposure. The PPARγ seems to be mostly affected by the MPV exposure, suggesting an effect due to leaching of plastic additives from PVC. This study represents one of the first investigation on the effects of the exposure to virgin and marine polluted PVC MPs on an edible species, which shows an early warning signal on the chemical and physical hepatic stress on this species. Further data are needed to better understand the role of the partitioning of chemicals from and to MPs and the related effects on fish and, potentially, on human health.


The fate of microplastics ingested by the Mediterranean mussel: biochemical biomarkers and histopathology

presenting: Cátia Gonçalves (FCT-NOVA, Portugal); authors: Paula Sobral (FCT-NOVA, Portugal), Marta Martins (FCT-NOVA), Paula Sobral (FCT-NOVA), Pedro Costa (FCT-NOVA), Maria Helena Costa (FCT-NOVA)

The concerns over the effects of microplastics (MP) in marine ecosystems has increasingly emerged in scientific community as shown by the high number of toxicological studies, regarding micro-sized plastics (<5 mm) and marine fauna. Although several studies reported that organisms ingest and excrete microplastics, the potential effects at organ and tissue level remain unclear, especially considering different microplastics sizes and concentrations. The present study investigates the potential toxicological effects of the ingestion of polystyrene microparticles (size range 2 – 10 µm) by the Mediterranean mussel (Mytilus galloprovincialis) over short-, mid- and long-term exposure periods, single and combined sizes, at two concentrations (10 and 1000 MP.·mL-1) using the biomarkers GST, LPO and histology. Overall, the results indicate that microparticles are promplty ingested regardless of size, are detected in the lumen of gut (mostly in midgut region) and, posteriorly, excreted through faeces. After 48h, higher levels of LPO were measured both in the gill and in the digestive gland in mixed size (2, 6 and 10 µm) exposures, and GST response was higher in the digestive gland than in the gill especially for the 2µm particles, but no correlation was found. After 21d exposure histopathological analysis of the whole digestive tract, revealed small foci of haemocytic infiltration in gastric epithelium, though this inflammatory response was not significantly correlated with the ingested microparticles. and no other tissue alterations were detected such as abrasion of the digestive epithelia. After 7 d in clean water microplastics could still be found in the digestive gland of the mussel.


Effects of plasticizers on the immune system of juvenile salmon.

presenting: Patty Zwollo (The College of William and Mary, United States); authors: Patty Zwollo (The College of William and Mary, United States), Kelly Martins (The College of William and Mary), Lidia Epp (The College of William and Mary), Birgit Hagedorn (University of Alaska Anchorage), Chris Pallister (Gulf of Alaska Keeper), John Kentish (University of Alaska Anchorage)

Phthalate esters are commonly used plasticizers that help make polymer products more flexible and durable. They are non-covalently bound to their polymer products and therefore slowly migrate into the environment. Phthalates have been shown to dysregulate the immune system of mammals, birds, and fish. We have shown in a previous study that phthalate exposure reduces the abundance and inhibits the proliferation of rainbow trout (Oncorhynchus mykiss) IgM+ B lymphocytes and expression of secreted immunoglobulin heavy chain mu transcripts in an in vitro culture system. We proposed that phthalates modify the normal B cell activation pathways by accelerating B cell differentiation while suppressing cell expansion, resulting in fewer IgM-secreting plasma cells. This hypothesis was tested here in an in vivo field study of juvenile Dolly Varden (Salvelinus malma) collected from a plastic-polluted lake in the Gulf of Alaska. Fish tissues were analyzed both for phthalate levels, using liquid chromatography-coupled ion trap mass spectrometry, and for changes in immune gene expression, using RT-qPCR. Results revealed that fish with higher accumulated levels of di(2-ethylhexyl) phthalate, di(n-butyl) phthalate, and/or dimethyl phthalate, expressed significantly fewer secreted and membrane-bound immunoglobulin heavy chain mu and Blimp1 transcripts in their hematopoietic tissue. This suggests that chronic in vivo exposure of phthalates in wild juvenile fish leads to changes in expression of B cell-specific genes, and further, that this likely dysregulates normal B lymphoid function and antibody responses. Insufficient production of protective antibodies will make fish more susceptible to infection, and predictably increases their risk for disease and mortality in polluted waters.


Exploring the effects of nylon microplastic on the development and energy reserves in coldwater copepods

presenting: Matthew Cole (Plymouth Marine Laboratory, United Kingdom); authors: Matthew Cole (Plymouth Marine Laboratory, United Kingdom), Rachel Coppock (Plymouth Marine Laboratory), Pennie Lindeque (Plymouth Marine Laboratory), Dag Altlin (Biotrix), Andy Booth (SINTEF Ocean), Tamara Galloway (University of Exeter)

Microplastic debris is a pervasive and widespread pollutant that poses a risk to aquatic biota and healthy marine ecosystems. Copepods are an abundant and ecologically important class of zooplankton, common to marine ecosystems across the globe. Field studies and laboratory exposures have identified that copepods readily consume microplastic particulates. In the copepod Calanus helgolandicus, prolonged exposure to polystyrene microbeads resulted in significant reductions in feeding, egg size, hatching success and survival. We hypothesise exposure to microplastics reduces feeding in copepods, resulting in energetic shortfalls for which lipids can act as a proxy. The coldwater copepod Calanus finmarchicus is a keystone species, common to the North Atlantic. During maturation, these copepods rapidly build-up their wax-ester store (oil sac); this lipid reserve is essential to the copepod’s buoyancy regulation and energetic budget when overwintering, and is of high nutritional value to predators. Following a 48-hour acclimation period, juvenile C. finmarchicus were incubated in natural seawater containing a mixed assemblage of cultured algae (control), with the addition of either nylon granules (10-30 µm) or fibres (10×30 µm) at a concentration of 100 microplastics mL-1. Algal ingestion rates and developmental stage were monitored daily, while prosome length, oil sac size and lipid profiles were assessed following the six-day experiment. No significant differences in growth, sex-ratios or oil-sac size were identified, however we observed juvenile copepods moulted into adults significantly earlier (ANOVA, P<0.05) when exposed to microplastic. We discuss the impact microplastic exposure can have on feeding and energetics of animals, in relation to the individual and marine food webs as a whole.


Effects of micro- and nanoplastics on fertilization, embryo-larval development and metamorphosis success of the Pacific oyster Crassostrea gigas

presenting: Kevin Tallec (Ifremer, France); authors: Kevin Tallec (Ifremer, France), Ika Paul-Pont (LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer), Carole Di Poi (Ifremer), Christophe Lambert (LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer), Nelly Le Goïc (LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer), Philippe Soudant (LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer), Arnaud Huvet (Ifremer)

To date, limited information is available for small plastic debris (< 330 μm) concentrations in oceans but recent studies showed significant impacts of small microplastics (< 20 μm) and nanoplastics (< 100 nm) on behaviour, metabolism, reproductive success and physiology of various marine organisms (fish, bivalve, zooplankton, phytoplankton). Thus, it is important to clearly evaluate the risks and define the toxicity thresholds. Here we investigated the effects of micro-sized (500 nm and 2 μm) and nano-sized polystyrene particles (50 nm) on three reproductive steps of the Pacific oyster Crassostrea gigas: (i) Fertilization (ii) Embryogenesis and (iii) Metamorphosis. Plain nanoplastics (no coating) and nanoplastics coated with carboxylic (PS-COOH) and amine groups (PS-NH2) were used to observe a possible charge-effect. All particles were used at four concentrations (0.1, 1, 10 and 25 μg/mL) to identify toxicity thresholds. Impacts on fertilization and embryogenesis were size, charge and dose dependent. Microplastics presented lower toxicity than nanoplastics, while amino-nanopolystyrene exhibited the highest toxicity (PS-NH2 > PS-COOH > PS-Plein). In contrast, no effects of plastic particles were observed on the metamorphosis. Thus, we demonstrated in our conditions that plastic particles may rapidly impair early life stages of oysters, which could have consequences on their overall life cycle. Next goals will be the analysis of the molecular and cellular pathways underlying the nanoplastics toxicity.


A New Digestible Fluorescent Coating Method for Quantification of Cumulative Microplastic Ingestion

presenting: Evan Karakolis (University of Toronto, Canada); authors: Evan Karakolis (University of Toronto, Canada), Brian Nguyen (University of Toronto), Jae Bem You (University of Toronto), Percival Graham (University of Toronto), Chelsea Rochman (University of Toronto), David Sinton (University of Toronto)

The ubiquitous presence of microplastics in the environment makes it imperative to understand their impact. First, we must understand exposure – i.e., how many microplastics are ingested by organisms. This has proved difficult because counting microplastics in the gut content provides only a snapshot in time. Here, we developed a method that uses a digestible fluorescent coating (DFC) to enable the quantification of cumulative microplastic ingestion. The method works by coating microplastic particles with a digestible fluorophore-conjugated protein that is removed from microplastics upon passing through the digestive tract of an organism. When an organism ingests microplastics with a digestible fluorescent coating the peptide bonds in the protein coating are hydrolyzed by proteases in the gut and the attached fluorophore is released allowing identification of an ingested plastic by loss of fluorescence. Our method enables automated enumeration of microplastic ingestion using fluorescence microscopy coupled with particle counting software and the flexibility to track different microplastic types and sizes with distinct fluorescent tracers. The method is compatible with different polymer types, sizes and shapes, in varying water quality parameters and with different species. We demonstrate proof-of-concept with four zooplankton species with varying feeding strategies and different native habitats to confirm the coating is non-toxic and is not preferentially ingested by these species. This method provides a unique and reliable approach to quantify microplastic ingestion over time, and can be used to advance our understanding of the impact of microplastics on wildlife.


A Platform for High-Throughput Assessments of Environmental Multi-stressors: A first look at the combined impacts of climate change and microplastics on zooplankton

presenting: Brian Nguyen (Department of Mechanical and Industrial Engineering and Institute for Sustainable Energy, University of Toronto, Canada); authors: Brian Nguyen (Department of Mechanical and Industrial Engineering and Institute for Sustainable Energy, University of Toronto, Canada), Percival Graham (Department of Mechanical and Industrial Engineering and Institute for Sustainable Energy, University of Toronto), Evan Karakolis (Department of Mechanical and Industrial Engineering and Institute for Sustainable Energy, University of Toronto), Chelsea Rochman (Department of Ecology and Evolutionary Biology, University of Toronto), David Sinton

Marine debris occurs in complex environments. Despite this, most experimental studies do not consider the effects of differing environments. Here, we introduce a platform, compatible with microtiter plates, for measuring complex interactions between multiple stressors, including parameters relevant to climate change and point source pollutants. Our platform (Figure 1) leverages (1) the high rate of purely diffusive gas transport in aerogels to produce well-defined centimeter-scale gas concentration gradients, (2) spatial light control and (3) established automated liquid handling. As a result, hundreds of treatments can be run in parallel with our platform. Previously, we validated the platform by conducting proof-of-concept experiments with single and multi-cellular organisms including: Chlamydomonas reinhardtii, Lemna gibba, and Artemia salina. We are applying our platform to marine debris research by applying it to explore the effect of acidification and warming on microplastic ingestion by the copepod, Tisbe biminiensis. Our initial tests (Figure 2) suggest that ocean acidification potentially increases the ingestion of microplastics by Tisbe biminiensis while warming only increases algae consumption, suggesting that ocean acidification may impact prey selectivity.


Trophic transference of microplastics under a low exposure scenario: insights on the likelihood of particles cascading along marine food-webs

presenting: Marina Ferreira Mourão Santana (James Cook University, College of Science and Engineering Australian Tropical Science and Innovation Precinct, Australia); authors: Marina Ferreira Mourão Santana (James Cook University, College of Science and Engineering Australian Tropical Science and Innovation Precinct, Australia), Fabiana M. Tavares (University of São Paulo, Oceanographic Institute (IO), Department of Biological Oceanography), Alexander Turra (University of São Paulo, Oceanographic Institute (IO), Department of Biological Oceanography)

Microplastic (mp) transference and persistence along trophic levels are key processes to understand the risks of this pollutant to marine food webs. The goal of this published work was to asses the potential occurrence of these processes considering a less extreme scenario of predator’s exposure than used previously. For that, mps were only present in the hemolymph of prey (mussel Perna perna). Predators were the crab Callinectes ornatus and the puffer fish Spheoeroides greeleyi. The experiment showed the transference of mps from prey to predators but without evidences of persistence after 10 days of exposure. This suggests a reduced likelihood of particle’s trophic cascading along the studied food web and low risks of mp impacts on higher trophic levels. However, the simplest transference of mps along food webs is still concerning, despite the particle persistence. We suggest that the risks of mps cascade along food webs are modulated by the concentration of particles in prey and by the predators’ depuration capacity and rate.


Ingestion, bioaccumulation and depuration of nano- and micro-plastic particles by marine bivalves

presenting: Kayla Mladinich (University of Connecticut- Avery Point, United States); authors: Kayla Mladinich (University of Connecticut- Avery Point, United States), Vena Haynes (University of Connecticut- Avery Point), Bridget Holohan (University of Connecticut- Avery Point), J. Evan Ward (University of Connecticut- Avery Point)

Plastics debris are introduced into the oceans, through industrial production and as anthropogenic waste. Larger plastics breakdown into nanoplastics (NP) and microplastics (MP) via weathering. Benthic animals, such as suspension-feeding bivalves, are exposed to NP and MP pollutants in coastal waters. MP also are capable of adsorbing dissolved pollutants in the surface waters and transferring them to benthic organisms when ingested. Studies have shown that NP and MP negatively affect marine animals on an organ and cellular level. Despite the potential for exposure and toxicological effects, the uptake, accumulation, and depuration of NP and MP by bivalves is largely unexplored. This study examined the ingestion, bioaccumulation and depuration of fluorescent polystyrene NP and MP by the blue mussel (Mytilus edulis). NP and MP were aged in seawater for 3 days prior to exposure experiments. Mussels were exposed to a 0.1 mg/L/hr concentration of NP or MP for two weeks and then allowed to depurate for one week in filtered seawater. Mussels were fed a standard microalgal diet throughout the 3-week experiment. Whole animals were frozen for later analysis of NP or MP concentrations at the end of each week and feces were collected daily for all 3 weeks and frozen. Tissue and feces samples were analyzed via a scanning fluorescence spectrophotometer for fluorescent plastic quantification. Results from this study will aid in developing biokinetic models of NP uptake and bioaccumulation in shellfish, and help elucidate the potential for these materials to be passed to higher trophic levels including humans.


A comparison of microplastic contamination characteristics among marine invertebrates inhabiting in urban, rural, and aquaculture areas

presenting: Mi Jang (Korea Institute of Ocean Science & Technology (KIOST), South Korea); authors: Mi Jang (Korea Institute of Ocean Science & Technology (KIOST), South Korea), Sang Hee Hong (Korea Institute of Ocean Science & Technology (KIOST)), Won Joon Shim (Korea Institute of Ocean Science & Technology (KIOST)), Gi Myung Han (Korea Institute of Ocean Science & Technology (KIOST)), You Na Cho (Korea Institute of Ocean Science & Technology (KIOST))

Microplastics have become a global environmental concern because of their widespread presence in coastal areas, the open ocean, and polar regions. Microplastics in the environment originate from a variety of land- and sea-based sources. Regional industrial and human activities may affect the abundance and contamination characteristics of microplastics in their surrounding environment, which may be reflected to marine species living in its water body and transfer through their food web. This study investigated the contamination characteristics of microplastics in abiotic matrices such as seawater and sediment, and biotic matrices such as oyster, mussel, and lugworm in urban, aquafarm, and rural areas. In abiotic matrices, different polymer composition of microplastic was found among three regions. High diversity was found from urban area, implying diverse sources of microplastic in this area. Polystyrene was relatively abundant in aquafarm area, reflecting well the wide use of expanded polystyrene buoys. In rural area, polypropylene is relatively abundant, probably related with the wide use of polypropylene rope in fishing activity. Microplastic compositions in marine invertebrates followed well those in abiotic matrices. This result implies that the accumulation profile of microplastics by marine invertebrates reflects regional human activities.


Ingestion of microplastics by zooplankton in the natural environment

presenting: Penelope Lindeque (Plymouth Marine Laboratory, United Kingdom); authors: Penelope Lindeque (Plymouth Marine Laboratory, United Kingdom), Alice Wilson McNeal (University of Exeter), Matthew Cole (Plymouth Marine Laboratory), James Clark (Plymouth Marine Laboratory), Elaine Fileman (Plymouth Marine Laboratory), Amanda Beesley (Plymouth Marine Laboratory)

Microplastics have been documented in marine environments worldwide where they pose a potential risk to a range of biota. Of particular susceptibility are zooplankton, small ubiquitous marine animals that provide an essential link between primary producers and higher trophic levels (e.g. commercial fish species). Laboratory studies have established that zooplankton, such as copepods, readily ingest microplastics, and that such ingestion decreases their energy budget and negatively impacts reproduction, health and survival. It is imperative to understand the extent to which zooplankton encounter and ingest plastic particles and fibres within their natural environment, as there is potential to not only disrupt the link between primary producers and higher trophic levels but also for trophic transfer and bioaccumulation of microplastics within the marine food web. Hydrodynamic models were developed to identify areas where zooplankton and microplastics were most likely to overlap. Guided by these models, we sampled six sites in the western English Channel over the course of one year. Sampling was conducted using 50 μm nets to target microplastic debris at risk of being ingested by zooplankton, and 200 μm horizontal hauls to sample zooplankton. After each trawl, cohorts of different zooplankton taxa (i.e. copepods, decapod larvae) were enzymatically digested to determine the types and amount of anthropogenic debris ingested. Our results demonstrate that zooplankton routinely encounter and ingest microplastics under natural conditions. Encounter rates resulting from ingestion ranged from 1 particle/every 6-125 zooplankton. The incidence of ingestion of different zooplankton at different temporal and spatial locations and potential impact on the health of the population and higher trophic levels will be discussed.


Microplastics on sessile invertebrates in the eastern coast of Thailand: the effect and coastal zone management

presenting: Suchana Chavanich (Chulalongkorn University, Thailand); authors: Suchana Chavanich (Chulalongkorn University, Thailand), Gajahin Thushari (Uva Wellassa University), Jayan Senevirathna (Uva Wellassa University), Amararatne Yakupitiyage (Asian Institute of Technology)

This study assessed the microplastic contamination of 3 most abundant sessile and intertidal invertebrates (Rock Oyster: Saccostrea forskalii, Striped Barnacle: Balanus amphitrite, Periwinkle: Littoraria sp.) in 3 beaches of the eastern coasts of Thailand. The results showed a significant accumulation of microplastics in the invertebrates at rates of 0.2–0.6 counts/g indicating higher pollution levels along the coastline. Filter feeding organisms showed comparatively higher accumulation rates of microplastics. Thus, contaminated bivalves pose potential health risks for seafood consumers. The plastic pollutant prevalence in sessile and intertidal communities was corresponded with pollution characteristics of contaminated beach habitats where they live. Thus, bivalves, gastropods and barnacles can be used as indicators for contamination of microplastics in the areas. This study also demonstrated the need for controlling plastic pollution in Thai coastal areas.


A long term exposure experiment tests the effects of clean and contaminated microplastics on juvenile blue mussels Mytilus edulis

presenting: Thea Hamm (GEOMAR, Helmholtz Center for Ocean Research, Germany); authors: Thea Hamm (GEOMAR, Helmholtz Center for Ocean Research, Germany), Mark Lenz (GEOMAR Helmholtz Center for Ocean Research)

Evidence grows that marine benthic filter feeders take up microplastic particles together with their food frequently, while our knowledge about the possible effects of this is still small. In addition to mechanical impacts such as clogging and damaging, microplastics presumably have negative effects because they accumulate persistent organic pollutants. They could therefore serve as vectors that increase the bioavailability of chemical compounds for marine invertebrates. So far, very few experimental approaches investigated this potential role of microplastics over a longer time period and with realistic particle concentrations. Therefore, we are currently investigating the effects of clean and contaminated microplastics (irregularly shaped PVC particles, 20-60 µm) on juvenile individuals of the blue mussel Mytilus edulis over the course of 12 months. For this, we will use particle concentrations of 0, 100, 1000 and 10 000 particles per liter. Furthermore, since marine organisms in coastal waters are commonly exposed to multiple stressors, we will test whether possible negative effects of microplastic pollution are aggravated when heat stress is induced. This will be done by simulating a summer heat wave with a magnitude that is expected for the Western Baltic by the end of the 21st century. We intend to answer two questions: (1) At which particle density and after which time span do effects of clean or contaminated microplastics become detectable in the blue mussel M. edulis? (2) Are possible effects enhanced when they co- occur with a further environmental stressor? We will present first data and would like to discuss our approach with other researchers who focus on the biological effects of microplastic pollution.