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  • 1
    Publication Date: 2016-11-22
    Description: Careless use of plastic products leads to massive litter accumulations in natural environments. Due to the river runoff and gradual degradation of larger plastic pieces into micro-sized particles, microplastics enter to the marine environment. Recently it was demonstrated, that subtidal marine isopods Idotea emarginata, readily ingested and excreted microplastics, without clogging the digestive system. In the present study, we focused on physiological effects of food quality and microplastics, by applying different feeding treatments. Digestive enzymes and protein content in the midgut gland and gut were investigated. Feeding rates differed significantly between natural and artificial diets, but have not changed when microplastics were added to diets. Enzyme activities showed high scatter and inconsistent results. Esterase activity was enhanced in the midgut gland and suppressed in the gut tissue, by microplastics in the agarose. Microplastics further suppressed lipase activity in the midgut of fresh algae fed isopods. Exopeptidase activity was suppressed and endopeptidase enhanced in the midgut gland, due to microplastics in agarose. Microplastics increased protein content of the gut tissue. Our results indicate, that microplastics may differently affect digestive processes of marine isopods. Further research is needed to verify whether these alterations affect nutrient assimilation and nutritional health of the isopods.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Thesis , NonPeerReviewed
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  • 2
    Publication Date: 2018-07-13
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 3
    Publication Date: 2018-11-29
    Description: Plastic litter is gaining attention in environmental science, public perception, and, finally, in politics. Macro- and microplastic pollution of rivers, oceans, and beaches are regularly reported. However, to our knowledge nobody studied the temporal dynamics of plastic pollution at beaches. This study is a re-investigation of a former work done in 2012 on the occurrence, distribution and composition of microplastic at Slovenian beaches. Similar methods in field sampling and particle isolation were applied. The study was extended by including additional beaches, addressing seasonal aspects (winter and summer) and introducing quality assurance/quality control checks. Furthermore, the chemical composition of isolated plastic items was verified by ATR-FTIR spectroscopy. Only about 10 % of the putative microplastic items were decisively recognised as synthetic material. Secondary microplastics were present as fragments, fibers, films, and foams. Primary microplastics were absent at all. The microplastic concentrations of the present study were distinctly lower than in the former study. The low pollution of Slovenian beaches could be the result of regular beach clean-ups of touristic beaches, or an improved environmental consciousness of citizens and tourists. This study emphasize the importance of continuous microplastic monitoring to understand the annual microplastic contamination and its’ seasonal and inter-annual dynamics.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 4
    Publication Date: 2019-04-09
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 5
    Publication Date: 2016-06-01
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 6
    Publication Date: 2017-05-03
    Description: Plastic is an integral part of modern lifestyle. However, due to versatile use and poor recycling management, plastic litter is meanwhile spoiling almost all habitats on earth. Larger plastic pieces can harm animals by entanglement, suffocation, stranding, or they simply provoke injuries when animals try to escape from getting trapped. Gradual degradation of bigger plastic pieces generates micro-sized particles which can become vulnerable to small organisms. Recent studies indicated that ingestion of microplastics can impair the nutritive state of marine invertebrates. In a laboratory study we tested whether microplastics affect food quality and, in turn, nutrition in peracarid crustaceans. Marine isopods, Idotea emarginata, were fed for eight days with natural food, the brown alga Fucus vesiculosus, and an artificial diet which contained freeze dried algae embedded in agarose. Additionally, both diets were blended with microplastic particles at a concentration of 40 items per mg of food. The isopods accepted both types of food but consumed significantly (3.6-fold) more of the agar based artificial food. Addition of microplastics did not significantly alter feeding rates on both diets. Enzyme ac tivities showed high scatter and inconsistent results. Esterase (C4) and lipase (C18) activities decreases in the gut and in the midgut gland when microplastics were added to fresh algae. Activities of phosphoesterase exo-and endopeptidase showed no distinct changes in activity. Idotea emarginata compensated for impaired food quality by increasing the ingestion rates by exactly that factor by which the amount of digestible organic matter was reduced. The amount of microplastics was apparently too low to provoke such kind compensation. However, our results indicate that microplastic may differently affect digestive enzyme activities in the gut and the midgut gland of marine isopods. Further research is needed to verify whether the observed alterations affect food digestion and nutrient assimilation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 7
    Publication Date: 2017-09-19
    Description: Plastic litter in the marine environment is receiving increasing attention. Namely, through rivers, ship traffic and recreation is anthropogenically produced litter introduced into the marine environment. Sun radiation and mechanical impact degrade plastic items into smaller pieces, i.e. secondary microplastic. Alternatively, primary microplastics from cosmetic products can enter the environment through waste water drains. The number of microplastics at beaches can vary substantially. In this study, the occurrence and the quantity of the microplastic in the Slovenian beach sediments was investigated. Samples were taken in March 2017. Microplastic particles were isolated by density separation in an aqueous solution of common salt (NaCl). The floating particles were separated and filtered over a 100-µm metal filter. Assumed microplastics were photographed and their characteristics were noted (i.e. source, form, color) and stored in glass vials with a Teflon lid. Potential contamination during the processing of the samples was controlled with a white filter in petri dish exposed to air. The reliability of the separation method was confirmed by a recovery experiment which yielded 86-90% recovery of intentionally added microplastic. Secondary microplastic were present as fragments, films, and fibers. However, the present study showed lower concentrations of microplastic at the Slovenian beaches than previously reported by Laglbauer et al. (2014, Marine Pollution Bulletin 89: 356-366). The differences in the concentrations are probably due to seasonal fluctuations of microplastic concentration. Moreover, contamination was not considered in the former study. Potential pollutants of the Slovenian coast are tourism, industry, sea- and road traffic, wastewater treatment plant, port, and agriculture. Since Laglbauer et al. (2014) excluded tourism as the contributor of the microplastic pollution the real contributors need to be identified. Polluted beaches are not attractive and may scare tourists and, thus, impair economy.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 8
    Publication Date: 2018-07-13
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 9
    Publication Date: 2018-11-05
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 10
    Publication Date: 2018-11-30
    Description: In coastal areas, and especially in estuaries, organisms are constantly exposed to a variety of suspended particles. The particles are mostly of natural origin, i.e. fine sand grains, diatoms shells, cellulose fibres or chitinous fragments. Since several decades, however, man-made synthetic plastic particles are accumulating in the environment. The later are of great interest in environmental and toxicological sciences as they are suspected to induce cellular modifications and stress in organisms upon ingestion. This situation raises a number of questions whether natural and synthetic microparticles induce similar effects and damage in cells and organisms. In order to investigate this issue, marine organisms with different feeding modes will be subjected to natural and synthetic particles. Blue mussels (Mytilus edulis) and brown shrimps (Crangon crangon) will be collected from the field, acclimatized to laboratory conditions, and exposed to natural and synthetic particles for 6, 24, and 48 hours. Microscopic analysis will be done to localize the particles in digestive organs. Histochemical and biochemical analyses will be used to detect stress markers in cells and tissues. The goal of this doctoral project is to understand the hazardous effects of microparticles and to differentiate between anthropogenic and natural items. The findings will be beneficial in estimating the actual hazard potential of microplastics and in defining actual threat boundaries for marine invertebrates.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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