Effects of Microplastics in the Cryosphere

Abstract

Microplastics have been found in most parts of the world including the cryosphere, the part of the Earth’s surface characterized by frozen water. Surprisingly, high concentration of microplastics has been observed in some cryosphere areas. Shrinking of the cryosphere could release considerable amount of microplastics entrapped in sea ice and glaciers, posing serious threat to the already vulnerable ecosystems in these extreme habitats. Microplastics, and their associated contaminants, can be assimilated by biota in number of ways, such as filter feeding, suspension feeding, inhalation at air-water surface, consumption of prey exposed to microplastics, or via direct ingestion. Microplastics may bioaccumulate within individual organisms over time and be transferred up the food chain. Ingestion or even exposure to microplastics may pose a threat to the ecosystem. Leaching of chemical additives and contaminants from microplastics may alter community compositions of microbiota (e.g., bacteria, microalgae, and protozoa), and affect lower (e.g., invertebrates) and higher tropic level organisms such as fish, birds, and seals with unknown consequences for top predators, such as polar bears, and killer whales. In the first part of this review, the abundance and distribution of microplastics in the realm of the cryosphere is discussed. In the latter part, a comprehensive examination of scientific data regarding consumption of microplastics and the potential impact on organisms of the cryosphere, in particular marine organisms in the polar regions, is presented.