Effects of ocean warming and acidification on Thalassia hemprichii

• Main Authors: Hung-Feng Chang, 張宏逢
• Other Authors: Hsing-Juh Lin
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/50820535204907694667

碩士 === 國立中興大學 === 生命科學系所 === 103 === Since the Industrial Revolution, a huge amount of anthropogenic carbon dioxide have been discharged into both atmospheric and oceanic reservoirs. The increase in CO2 concentration has caused ocean acidification and warming. Previous research indicated that seagrass beds have good carbon capture and storage capacity. Most previous research focused on the single effect of acidification or warming instead of the combined effect. It is not known whether seagrass beds can benefit under the condition of ocean acidification and temperature rising. This study used a mesocosm system to examine the single and combined effects of temperature rising and acidification on the seagrass Thalassia hemprichii and quantify carbon budgets. Results showed that acidification would increase seagrass productivity, carbon sequestration, belowground biomass and the carbon content of rhizomes. Rising temperature increased the maximum quantum yield, productivity, relative dry weight increase rate, growth rate, carbon sequestration and decomposition rate, but reduced the shoot density change rate, the carbon content of root and leaf. Compared with current marine environment(25℃ normal group), Thalassia hemprichii at 31℃ acidification group had the highest productivity (1.78±0.24 mg DW shoot-1 d-1), relative dry weight increase rate (9.41 mg DW g-1 d-1), maximum quantum yield (0.81±0.00), growth rate (1.78±0.24 mm shoot-1 d-1), belowground biomass (128±24 mg DW shoot-1), carbon content of shoot(6.55±0.91 g C shoot-1) and carbon sequestration (0.59±0.05 mg C shoot-1 d-1). The results of carbon budgets showed that seagrass bed had highest leaf production(32.6±2.5 g C m-2 month-1), belowground production(128±24 mg DW shoot-1), and aboveground and belowground carbon storage(15.6±1.3 g C m-2 month-1 + 239±18 g C m-2 month-1). In addition, we found rising temperature led corals to bleach and increased herbivory on seagrasses by sea urchins. This research predict that Thalassia hemprichii could benefit from the scenario of ocean environments under climate change in the case of the exclusion of other disturbance, and able to absorb and store more carbon in the shoot and sediments.