Mesocosm Facility

The pH of the world’s oceans is falling as a result of anthropogenic CO2 emissions to the atmosphere. Such an ocean acidification phenomenon is progressive at an unprecedented rate in Earth’s history. The rate of change has been estimated to be faster than at any time in the last 300 million years.  The acidity of surface oceans is predicted to increase by 150% by the end of this century. The far-reaching effects of ocean acidification on food webs, biodiversity, fisheries and aquaculture and then societies are of general concerns to scientific communities and the general public. Predicting how organisms and ecosystems will change in response to ocean acidification remains challenging.

To explore mechanistic influences of ocean acidification, Mesocosm Facility for Ocean Acidification Impact Study of State Key Laboratory of Marine Environmental Science (MEL, Xiamen University) (FOANIC-XMU)has been successfully set up in Wuyuan Bay (N24°3148, E118°1047). The floating platform, with the dimension of 35×7 m, has three independent rooms (9 m2 each ) and nine  4-m3 mesocosms, and is fully solar-powered, for all instruments on board.  Activities on the platform are monitored and recorded continuously.  Different levels of CO2 in the mesocosms can be achieved by the commercially available CO2-enriching device (CO2 enrichlor, Ruihua, Wuhan, China).  Ocean acidification (OA) conditions can be induced gradually with aeration from the CO2 enrichors.  Effects of OA on phytoplankton species competition, primary productivity, food chain effect and microbial processes will be examined by MEL group and their collaborating scientists to look into the OA impacts on species, community, and ecosystem levels.

The first experiment has been carried out during May - July, 2013 to understand the competition of different phytoplankton groups, mainly diatoms and coccolithorphores under ambient and elevated CO2 concentrations, which are achieved with a CO2-enriching device. Another mesocosm experiment is planned in 2014 to investigate the effects of OA on shellfish development and shellfish farming ecosystem processes.