Volatile Organic Compounds Released by Oxyrrhis marina Grazing on Isochrysis galbana
Zooplankton grazing is a crucial process in marine ecosystems as it supports the transfer of energy and nutrients from primary producers to higher trophic levels. Recent research has shown that this process also results in the release of volatile organic compounds (VOCs) into the atmosphere, having important ecological implications and highlighting the importance of considering VOCs in studies of marine plankton interactions and the broader marine ecosystem. There is still a limited understanding of the suite of VOCs produced during grazing and their potential contribution to oceanic emissions.
A new study published in the MDPI Oceans journal seeks to provide more insights into the production of VOCs by marine organisms and their ecological implications. By investigating the release of VOCs from the marine planktonic organism Oxyrrhis marina when grazing on the microalga Isochrysis galbana. The researchers used a Vocus proton-transfer-reaction time-of-flight mass spectrometer, coupled to a segmented flow coil equilibrator, which allowed for fast and sensitive measurements of VOCs released during grazing. They also investigated the effect of antibiotic treatment on the VOC production to assess the role of bacteria in the process.
The study found that VOCs beyond dimethyl sulfide, a well-known biogenic gas, were released during grazing. Specifically, toluene and xylene increased by about 30 pmol dm−3 and 10 pmol dm−3, respectively, during grazing only, indicating a biological source for these compounds. Moreover, alternative increases of dimethyl sulfide by up to 0.2 nmol dm−3 and methanethiol by up to 10 pmol dm−3 were observed depending on the presence or absence of bacteria, suggesting that microbial processes play a role in VOC production during grazing.
These findings have significant implications for our understanding of VOC cycling in the surface ocean and the impact of zooplankton grazing on global ocean emissions and interlinked atmospheric chemistry. The authors highlight the need for further quantification of this source in budgets and process-based understanding of VOC cycling in the surface ocean.
Overall, this study adds to the growing body of research on the role of marine ecosystems in VOC production and their potential impact on atmospheric chemistry and climate. By shedding light on the VOCs produced during zooplankton grazing, this research highlights the complex and interconnected nature of marine ecosystems and the need for a holistic approach to understanding their functioning and response to environmental change.