Quantification of microplastics in the stomach content of krill in the Southern Ocean

• Main Author: Falcou-Préfol, Mathilde
• Format: Thesis
• Language: unknown
• Published: Mathilde Falcou-Préfol 2019
• Subjects: Antarctic; Southern Ocean; The Antarctic; Antarctic Peninsula; Weddell Sea; Bransfield Strait; Weddell; Elephant Island; Antarc*; Antarctic Krill; Euphausia superba
• Online Access: https://epic.awi.de/id/eprint/52182/; https://hdl.handle.net/10013/epic.3290fc47-ca3d-43d7-a792-e864a6afbd07

Microplastics (< 5 mm) have become ubiquitous in global oceans, posing a threat for a wide range of marine species. Recent publications have described the presence of microplastics in the water column and sediments in the Southern Ocean. This study aimed to investigate the occurrence of microplastics in the gut content of the keystone species Antarctic Krill (Euphausia superba). Specimens were collected around the Antarctic Peninsula during the PS112 expedition (March to May 2018) in three regions: Elephant Island, Bransfield Strait West and the Weddell Sea. Twenty krill stomachs were analysed per region: 10 pooled, 5 pooled and 5 single stomachs. Microplastics were extracted through a 24-hour 10% potassium hydroxide (KOH) digestion step and the particles were identified using focal plane array (FPA) Fourier transform infrared (FTIR) microscopy. Abundance, chemical nature, and size distribution of the microplastics were also analysed. All analysed samples contained microplastics except one individual in the Bransfield Strait West region that did not show any plastic contamination. Krill collected in Elephant Island showed a higher number of plastic particles per stomach than the two other regions. Twelve polymer types were found across the three areas. The main polymers identified were polyethylene (34.47%), polypropylene (27.68%) and polyamide (26.51%) in Elephant Island, polyamide (64.52%) in Bransfield Strait West, and polyamide (66.65%) and polycarbonate (23.51%) in the Weddell Sea. All microplastics were below 100 μm in size, with 98.14% smaller than 50 μm.