Ingestion of microplastics by natural zooplankton groups in the northern South China Sea

The ingestion of microplastics by five natural zooplankton groups in the northern South China Sea was studied for the first time and two types of sampling nets (505 μm and 160 μm in mesh size) were compared. The microplastics were detected in zooplankton sampled from 16 stations, with the fibrous microplastics accounting for the largest proportion (70%). The main component of the found microplastics was polyester. The average length of the microplastics was 125 μm and 167 μm for Nets I and II, respectively. The encounter rates of microplastics/zooplankton increased with trophic levels. The average encounter rate of microplastics/zooplankton was 5%, 15%, 34%, 49%, and 120% for Net I, and 8%, 21%, 47%, 60%, and 143% for Net II for copepods, chaetognaths, jellyfish, shrimp, and fish larvae, respectively. The average abundance of microplastics that were ingested by zooplankton was 4.1 pieces/m3 for Net I and 131.5 pieces/m3 for Net II.

Xiaoxia Sun, Qingjie Li, Mingliang Zhu, Junhua Liang, Shan Zheng, Yongfang Zhao, Marine Pollution Bulletin, Volume 115, Issues 1–2, 15 February 2017, Pages 217–224

The article

Changes in the composition of ichthyoplankton assemblage and plastic debris in mangrove creeks relative to moon phases

Lunar influence on the distribution of fish larvae, zooplankton and plastic debris in mangrove creeks of the Goiana Estuary, Brazil, was studied over a lunar cycle. Cetengraulis edentulus, Anchovia clupeoides and Rhinosardinia bahiensis were the most abundant fish larvae (56·6%), independent of the moon phase. The full moon had a positive influence on the abundance of Gobionellus oceanicus, Cynoscion acoupa and Atherinella brasiliensis, and the new moon on Ulaema lefroyi. The full and new moons also influenced the number of zoeae and megalopae of Ucides cordatus, protozoeae and larvae of caridean shrimps, and the number of hard and soft plastic debris, both <5 and >5 mm. Micro and macroplastics were present in samples from all 12 creeks studied, at densities similar to the third most abundant taxon, R. bahiensis. Cetengraulis edentulus and R. bahiensis showed a strong positive correlation with the last quarter moon, when there was less zooplankton available in the creeks and higher abundance of microplastic threads. Anchovia clupeoides, Diapterus rhombeus, U. lefroyi and hard microplastics were positively associated with different moon phases, when calanoid copepods, Caridean larvae and zoeae of U. cordatus were highly available in the creeks. Cynoscion acoupa, G. oceanicus and A. brasiliensis were strongly associated with the full moon, when protozoeae of caridean shrimps and megalopae of U. cordatus were also highly available, as were hard and soft macroplastics, paint chips (<5 mm) and soft microplastics. The results reinforce the role of mangrove creeks as nursery habitats. The moon phases influenced the distribution of fish larvae species, zooplankton and plastic debris by changing their compositions and abundances in the mangrove creeks of the Goiana Estuary when under the influence of different tidal current regimes.

Lima, A. R. A., Barletta, M., Costa, M. F., Ramos, J. A. A., Dantas, D. V., Melo, P. A. M. C., Justino, A. K. S. and Ferreira, G. V. B., J Fish Biol, Volume 89, Issue 1, July 2016, Pages 619–640

The article

Microplastic pollution in the Greenland Sea: Background levels and selective contamination of planktivorous diving seabirds

Microplastics have been reported everywhere around the globe. With very limited human activities, the Arctic is distant from major sources of microplastics. However, microplastic ingestions have been found in several Arctic marine predators, confirming their presence in this region. Nonetheless, existing information for this area remains scarce, thus there is an urgent need to quantify the contamination of Arctic marine waters. In this context, we studied microplastic abundance and composition within the zooplankton community off East Greenland. For the same area, we concurrently evaluated microplastic contamination of little auks (Alle alle), an Arctic seabird feeding on zooplankton while diving between 0 and 50 m. The study took place off East Greenland in July 2005 and 2014, under strongly contrasted sea-ice conditions. Among all samples, 97.2% of the debris found were filaments. Despite the remoteness of our study area, microplastic abundances were comparable to those of other oceans, with 0.99 ± 0.62 m−3 in the presence of sea-ice (2005), and 2.38 ± 1.11 m−3 in the nearby absence of sea-ice (2014). Microplastic rise between 2005 and 2014 might be linked to an increase in plastic production worldwide or to lower sea-ice extents in 2014, as sea-ice can represent a sink for microplastic particles, which are subsequently released to the water column upon melting. Crucially, all birds had eaten plastic filaments, and they collected high levels of microplastics compared to background levels with 9.99 and 8.99 pieces per chick meal in 2005 and 2014, respectively. Importantly, we also demonstrated that little auks took more often light colored microplastics, rather than darker ones, strongly suggesting an active contamination with birds mistaking microplastics for their natural prey. Overall, our study stresses the great vulnerability of Arctic marine species to microplastic pollution in a warming Arctic, where sea-ice melting is expected to release vast volumes of trapped debris.

F. Amélineau, D. Bonnet, O. Heitz, V. Mortreux, A.M.A. Harding, N. Karnovsky, W. Walkusz, J. Fort, D. Grémillet, Environmental Pollution, Volume 219, December 2016, Pages 1131–1139

The article

Microtrophic project: microplastic incorporation in marine food webs

Small pieces of plastic are accumulating in the oceans. Because they are smaller than 5 mm they are called microplastics. They are produced by many different processes of degradation and fragmentation, and can be found washed up on every beach of the world ocean. Recently their size is getting smaller and their abundance increasing. A recent evaluation finds five trillion particles weighing 268,940 tons floating at sea. However, these values are 10 orders of magnitude lower than the total plastic debris dumped into the sea since 1970. Thus, a significant portion of plastic waste has disappeared and one likely cause is ingestion by marine zooplankton and subsequent transfer up the marine food web. There, they pose a biohazard because microplastics absorb persistent organic pollutants (POP’s), including polychlorinated biphenyls (PCB’s) that, via marine fisheries, get transferred to people. Once in people’s bodies, these POPs can penetrate cells, chemically interact with important biomolecules, and disrupt the endocrine system. Because of this danger, it is imperative to estimate microplastic ingestion and egestion rates in zooplankton. Here at the University of Las Palmas on Gran Canaria in the MICROTROPHIC Project, we are determining microplastic abundance and temporal variability. In laboratory cultures of zooplankton, we are determining the ingestion and egestion rates of microplastics. In mesocosm experiments we are investigating microplastic transfer through the food chain and we are studying the relationship between the ingestion of microplastics contaminated with PCBs and the concentration of PCB’s in animal tissues.

Alicia Herrera, Maite Asensio, Ico Martínez, Ted Packard, May Gómez, Ecofisiología de Organismos Marinos (EOMAR), Univ. de Las Palmas de Gran Canaria, 2016

The poster

Microplastics in the marine environment. A threat to marine biota?

Microplastics in marine environments are an emerging environmental problem of international concern. This review focuses on the sources, quantities and effects of microplastics, to assess whether or not they pose a threat to marine biota. Microplastics are ubiquitous in marine environments, and have been reported along shorelines, in surface waters, seabed sediments, watercolumn and in a wide range of biota, from the Arctic to Antarctic. Particularly high concentrations have been measured in sub-tropical ocean gyres, close to population centers and in enclosed seas, like the Mediterranean. Measurements over time have also revealed that the smaller fragments are increasing. These have more surface area per unit mass, and are therefore likely to exhibit more intrinsic toxicity. Their small size also makes them bioavailable to a much wider variety of organisms, than larger plastic debris. Microplastics can therefore act as a carrier of chemicals ( either adsorbed from surrounding seawater, or incorporated in the plastic ) to marine biota. Few field studies have attempted to investigate the effects of microplastic exposure, however, indications of harmful effects have been revealed in several laboratory studies. These include reduction in the function and health of zooplankton, hindered algal photosynthesis and accumulation in mussels, causing a strong inflammatory response. The potential impact on the base of the food chain represents a primary concern, as it could affect the productivity of the entire ecosystem.

Gudmundsdottir Birna, M2 – Bachelor Degree, Studies in Environmental Science, LUND University, 2016

The document

Short-term exposure with high concentrations of pristine microplastic particles leads to immobilisation of Daphnia magna

Recent studies revealed that freshwaters are not only polluted by chemicals, but also by persistent synthetic material like microplastics (plastic particles <1 mm). Microplastics include a diverse range of characteristics, e.g. polymer type, size or shape, but also their tendency to sorb pollutants or release additives. Although there is rising concern about the pollution of freshwaters by microplastics, knowledge about their potential effects on organisms is limited. For a better understanding of their risks, it is crucial to unravel which characteristics influence their effects on organisms. Analysing effects by the mere particles is the first step before including more complex interactions e.g. with associated chemicals. The aim of this study was to analyse potential physical effects of microplastics on one representative organism for limnic zooplankton (Daphnia magna). We investigated whether microplastics can be ingested and whether their presence causes adverse effects after short-term exposure. Daphnids were exposed for up to 96 h to 1-μm and 100-μm polyethylene particles at concentrations between 12.5 and 400 mg L−1. Ingestion of 1-μm particles led to immobilisation increasing with dose and time with an EC50 of 57.43 mg L−1 after 96 h. 100-μm particles that could not be ingested by the daphnids had no observable effects. These results underline that, considering high concentrations, microplastic particles can already induce adverse effects in limnic zooplankton. Although it needs to be clarified if these concentrations can be found in the environment these results are a basis for future impact analysis, especially in combination with associated chemicals.

 

Saskia Rehse, Werner Kloas, Christiane Zarfl, Chemosphere, Volume 153, Pages 91–99, June 2016