Microplastics, small plastic particles less than five millimetres in size, are affecting the ability of the Earth’s oceans to absorb carbon dioxide, according to a new study published in the Journal of Hazardous Materials: Plastics.
The study, From pollution to ocean warming: The climate impacts of marine microplastics, gathered findings from various sources to examine how plastic pollution interacts with marine ecosystems and climate change, suggesting that the impact of microplastics on carbon dioxide absorption has received ‘limited attention’.
‘Climate disruption and plastic pollution are two major environmental challenges that intersect in complex ways. MPs (microplastics) influence biogeochemical processes, disrupt oceanic carbon pumps, and contribute directly to greenhouse gas emissions,’ the authors write.
‘In marine ecosystems, MPs alter the natural carbon sequestration by affecting phytoplankton and zooplankton, which are key agents of carbon cycling. Additionally, the plastisphere, a microbial community colonising MPs, plays a significant role in GHG production due to its diverse microbial networks.’
Biological carbon pump
According to the study, microplastics interfere with the ocean’s ‘biological carbon pump’, where carbon dioxide is absorbed by phytoplankton during the photosynthesis process, and transported to deeper waters as organic matter sinks.
“Over time, these changes could lead to ocean warming, acidification, and biodiversity loss, threatening food security and coastal communities worldwide,” commented Dr. Ihsanullah Obaidullah, associate professor of integrated water processing technologies at the University of Sharjah and the study’s corresponding author.
Knowledge gaps
As part of their research, the authors examined 89 studies published mainly between 2010 and 2015, as well as drawing on reports from international organisations and peer-reviewed literature. As they state, the aim of the report is to address ‘knowledge gaps’ that exist around microplastics and climate change.
‘The extent to which microplastics affect climate change, ocean health, and associated systems is currently unknown,’ the authors note. ‘This can be mostly because the issue is novel, intricate, and multifaceted. The significant ecological effects of plastic pollution in the oceans are well recognised, but its exact connections to these extensive environmental processes are not well understood.’ Read more here and here.
