Effect of elevated pCO2 on trace gas production during an ocean acidification mesocosm experiment
A mesocosm experiment was conducted in Wuyuan Bay (Xiamen), China, to investigate the effects of elevated p CO 2 on the phytoplankton species Phaeodactylum tricornutum ( P. tricornutum ), Thalassiosira weissflogii ( T. weissflogii ) and Emiliania huxleyi ( E. huxleyi ) and their production ability o...
Published in: | Biogeosciences |
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Main Authors: | , , , , , , |
Format: | Text |
Language: | English |
Published: |
2019
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Subjects: | |
Online Access: | https://doi.org/10.5194/bg-15-6649-2018 https://www.biogeosciences.net/15/6649/2018/ |
Summary: | A mesocosm experiment was conducted in Wuyuan Bay (Xiamen), China, to investigate the effects of elevated p CO 2 on the phytoplankton species Phaeodactylum tricornutum ( P. tricornutum ), Thalassiosira weissflogii ( T. weissflogii ) and Emiliania huxleyi ( E. huxleyi ) and their production ability of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), as well as four halocarbon compounds, bromodichloromethane ( CHBrCl 2 ), methyl bromide ( CH 3 Br ), dibromomethane ( CH 2 Br 2 ) and iodomethane ( CH 3 I ). Over a period of 5 weeks, P. tricornuntum outcompeted T. weissflogii and E. huxleyi , comprising more than 99 % of the final biomass. During the logarithmic growth phase (phase I), mean DMS concentration in high p CO 2 mesocosms (1000 µ atm) was 28 % lower than that in low p CO 2 mesocosms (400 µ atm). Elevated p CO 2 led to a delay in DMSP-consuming bacteria concentrations attached to T. weissflogii and P. tricornutum and finally resulted in the delay of DMS concentration in the high p CO 2 treatment. Unlike DMS, the elevated p CO 2 did not affect DMSP production ability of T. weissflogii or P. tricornuntum throughout the 5-week culture. A positive relationship was detected between CH 3 I and T. weissflogii and P. tricornuntum during the experiment, and there was a 40 % reduction in mean CH 3 I concentration in the high p CO 2 mesocosms. CHBrCl 2 , CH 3 Br , and CH 2 Br 2 concentrations did not increase with elevated chlorophyll a (Chl a ) concentrations compared with DMS(P) and CH 3 I , and there were no major peaks both in the high p CO 2 or low p CO 2 mesocosms. In addition, no effect of elevated p CO 2 was identified for any of the three bromocarbons. |
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