Abstract
Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1–5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.
Highlights
Anthropogenic activities have almost doubled the atmospheric carbon dioxide (CO2) concentration, and have driven both global warming and ocean acidification (OA) due to the greenhouse effect
Fatty acid composition was significantly affected by warming
The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures
Summary
Anthropogenic activities have almost doubled the atmospheric carbon dioxide (CO2) concentration, and have driven both global warming and ocean acidification (OA) due to the greenhouse effect. The uptake of CO2 by the surface ocean has caused profound changes in marine carbonate chemistry: increased aqueous CO2, bicarbonate (HCO3-), and hydrogen ion (H+) concentrations, while the concentration of carbonate ions (CO32-) declined [1]. Contemporary surface ocean pH has declined by 0.1 units since pre-industrial time [2]. Ocean sea surface temperature is predicted to increase up to 3–5°C by the year 2100 [3]. The consequences of ocean warming and OA for planktonic organisms remain unclear as only a few studies to-date have experimentally tested their combined effects on natural plankton communities [4,5,6,7,8]. The effects on plankton phenology (directly modifying food quantity) and physiology (modifying food quality) remain unresolved
Sign-in/Register to view highlights & summary 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.
