Abstract
AbstractMethane (CH4) production in the ocean surface mixed layer is a widespread but still largely unexplained phenomenon. In this context marine algae have recently been described as a possible source of CH4in surface waters. In the present study we investigated the effects of temperature and light intensity (including daylength) on CH4formation from three widespread marine algal speciesEmiliania huxleyi,Phaeocystis globosa,andChrysochromulinasp. Rates ofE. huxleyiincreased by 210% when temperature increased in a range from 10°C to 21.5°C, while a further increase in temperature (up to 23.8°C) showed reduction of CH4production rates. Our results clearly showed that CH4formation ofE. huxleyiis controlled by light: When light intensity increased from 30 to 2,670 μmol m−2 s−1, CH4emission rates increased continuously by almost 1 order of magnitude and was more than 1 order of magnitude higher when the daylength (light period) was extended from 6/18 hr light‐dark cycle to continuous light. Furthermore, light intensity is also an important factor controlling CH4emissions ofChrysochromulinasp. andP. globosaand could therefore be a species‐independent regulator of phytoplankton CH4production. Based on our results, we might conclude that extensive blooms ofE. huxleyicould act as a main regional source of CH4in surface water, since blooming ofE. huxleyiis related to the seasonal increase in both light and temperature, which also stimulate CH4production. Under typical global change scenarios,E. huxleyiwill increase its CH4production in the future.
Highlights
Huge amounts of methane (CH4) are formed in the oceans, but only a small proportion is released to the atmosphere (Weber et al, 2019)
In the present study we investigated the effects of temperature and light intensity on CH4 formation from three widespread marine algal species Emiliania huxleyi, Phaeocystis globosa, and Chrysochromulina sp
Our results clearly showed that CH4 formation of E. huxleyi is controlled by light: When light intensity increased from 30 to 2,670 μmol m−2 s−1, CH4 emission rates increased continuously by almost 1 order of magnitude and was more than 1 order of magnitude higher when the daylength was extended from 6/18 hr light‐dark cycle to continuous light
Summary
Huge amounts of methane (CH4) are formed in the oceans, but only a small proportion is released to the atmosphere (Weber et al, 2019). In this context the biogeochemical cycle of CH4 in the oceans is of great interest, and in particular, the frequently observed CH4 production within the ocean surface mixed layer is challenging our previous understanding of biogeochemical CH4 formation processes. It is thought that CH4 in the oceans is either produced by geological processes (abiotic) or by methanogenic archaea (biotic). Journal of Geophysical Research: Biogeosciences (Lenhart et al, 2015) and algae (Klintzsch et al, 2019; Lenhart et al, 2016), animals (Ghyczy et al, 2008), and humans (Keppler et al, 2016) and even in the presence of oxygen
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
