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Will elevated atmospheric CO2 boost the growth of an invasive submerged macrophyte Cabomba caroliniana under the interference of phytoplankton?
- Liu, Xin, Han, Yanqing, Zhu, Jinge, Deng, Jiancai, Hu, Weiping, da Silva, ThomazEdson Veloso
- Environmental science and pollution research international 2018 v.25 no.2 pp. 1809-1821
- Cabomba caroliniana, basins, biomass, carbon, carbon dioxide, carbon dioxide enrichment, electron transfer, macrophytes, photosynthesis, phytoplankton
- The growth of most submerged macrophytes is likely to be limited by the availability of carbon resource, and this is especially true for the obligatory carbon dioxide (CO₂) users. A mesocosm experiment was performed to investigate the physiological, photophysiological, and biochemical responses of Cabomba caroliniana, an invasive macrophyte specie in the Lake Taihu Basin, to elevated atmospheric CO₂ (1000 μmol mol⁻¹); we also examined the possible impacts of interferences derived from the phytoplankton proliferation and its concomitant disturbances on the growth of C. caroliniana. The results demonstrated that elevated atmospheric CO₂ significantly enhanced the biomass, relative growth rate, and photosynthate accumulation of C. caroliniana. C. caroliniana exposed to elevated atmospheric CO₂ exhibited a higher relative maximum electron transport rate and photosynthetic efficiency, compared to those exposed to ambient atmospheric CO₂. However, the positive effects of elevated atmospheric CO₂ on C. caroliniana were gradually compromised as time went by, and the down-regulations of the relative growth rate (RGR) and photosynthetic activity were coupled with phytoplankton proliferation under elevated atmospheric CO₂. This study demonstrated that the growth of C. caroliniana under the phytoplankton interference can be greatly affected, directly and indirectly, by the increasing atmospheric CO₂.