Potential Threat of Microplastics to Zooplanktivores in the Surface Waters of the Southern Sea of Korea

Abstract

The potential impact of microplastic to zooplanktivores was assessed by measuring a ratio of neustonic microplastics to zooplankton by abundance in the southern sea of Korea. Neustonic microplastics and zooplankton (0.33-2 mm) were collected using a 330-μm mesh Manta trawl in Geoje eastern Bay and Jinhae Bay before and after the rainy season in 2012 and 2013. The mean microplastic to zooplankton ratios were 0.086 (May) and 0.022 (July) in 2012, and 0.016 (June) and 0.004 (July) in 2013, indicating that zooplanktivores could be more likely to feed on microplastics than natural preys before the rainy season in 2012 and 2013. In particular, the relatively high ratio occurred in a semi-enclosed bay characterized by a shipyard and a beach resort in Geoje Bay, and at stations close to a wastewater treatment plant and an aquaculture facility in Jinhae Bay before the rainy season. Among dominant microplastics and zooplankton before the rainy season, meroplankton of macrobenthos could be confused with paint particles in Geoje Bay, 2012, whereas Styrofoam could be mistaken as immature copepods by predators in Jinhae Bay, 2013. These observations suggest that zooplanktivores could be more likely to feed on microplastics than natural preys around Geoje and Jinhae Bays before the rainy season.

Microplastics in the Ocean

“…Pretreatment method was proposed to identify microplastics in fish stomach using Raman spectroscopy, and microplastics were detected in three fish from European seas (Collard et al 2015). The potential impact of microplastics on zooplankton feeders also was assessed by measuring the ratio by abundance of neustonic microplastics to zooplankton in the Southern Sea of Korea (Kang et al 2015). More than 200 chemicals were detected in marine plastic debris and their original products, and a comparison of them indicated the leaching or absorption of chemicals from or to plastic debris (Rani et al 2015).…”

Can Zooplankton Be Entangled by Microfibers in the Marine Environment?: Laboratory Studies

“…The "encounter rate" used in the present study means that the opportunity that zooplankton encounter microplastics in the water column, comparing the ratio of microplastics to zooplankton based on abundance [22,[31][32][33]. The concept meant that the higher the encounter rate is, the worse risk of microplastic to zooplankton is.…”

“…Until recently, the ratios reported in marine environments, which indicate the 'rate of encounter' between microplastics and zooplankton, ranged from 0.004 (Jinhae Bay, Korea) to 0.6 (southern California coast, USA) [17,28,32], corresponding to the relatively low microfiber to high zooplankton ratios in the experiment simulating the environmentally relevant concentration of microfibers, as well as those observed at stations where zooplankton entangled in microfibers were found in archived samples from the Yellow Sea (Tables 3 and 4). These results suggest that abundances of copepods entangled with microfibers can occur at negligible values in current marine environments.…”

Adaptation of a laboratory protocol to quantity microplastics contamination in estuarine waters

“…The characteristics of estuarine waters differ greatly from seawater samples, mainly in terms of organic matter content that can vary significantly. Furthermore, other studies refer the use of different concentrations of H 2 O 2 or even other reagents [2,3] as being more effective in degrading all the organic matter present in the sample (phase 2). These studies also refer that sodium chloride might not be efficient in the density separation step (phase 3) of NOAA protocol, decreasing the protocol’s efficiency and resulting in an underestimation of MPs concentration [4].…”