The physiological Impact of Microplastics on Holothuria leucospilota

Abstract

Nowadays plastic debris are found in oceans.Various processes lead to a transformation of macroplastics into microplastics (i.e. particles < 5mm). Sunlight and the action of the waves can degrade plastic and shred the material over time into smaller pieces. Furthermore, they can be found as ingredients of different products e.g. cosmetics and therefore enter the marine environment. Microplastics could have negative effects on marine organisms, especially for benthic organisms but up to now little is known about potential consequences. This study aims to investigate the physiological impact of microplastics on marine deposit-feeding invertebrates like sea cucumber Holothuria leucospilota. Polyvinylchloride (PVC) and fluoranthene was selected as a representative model plastic and model pollutant. The size range of PVC particles were 50-200 μm and have been previously polluted with fluoranthene. In laboratory, groups of sea cucumbers (n=15) were exposed to 6 different pollution scenarios (i.e. 0%; 0.03%; 0.3%; 1%; 3% and 3% non polluted with fluoranthene) which differed regard to the microplastics density (% by weight of sediment). Futhermore, after exposed from PVC particles polluted and non polluted with fluoranthene, H. leucospilota would faced hypoxia condition used as a common response variable to investigate if H. leucospilota has a lower resistance to environmental stress due to previous microplastics ingestion. The study revealed that after 60 days exposure to microplastic PVC particles polluted and non polluted with fluoranthene is not given any negatively influence on physiological parameters (respiration rate, faeces production and survival rate) of black sea cucumber H. leucospilota. This study clearly indicates that H. leucospilota is susceptible to oxygen depletion. Probably, long-term experiments will reveal negative impacts that were not detected in the present study. Another aspects from this study, microplastics particles were collected and found in all sediment samples, depths and sampling locations at Rambut Island which also took H. leucospilota but in different site. The diverse composition of microplastics particularly on type at the sampling location Rambut Island were found fibers, foamed particles, films and fragments. Further, these findings revealed a possible threshold of marine organisms on the marine biodiversity especially in Rambut Island, one of closest island to Jakarta Bay.