Effects Of Ocean Acidification On Active Metabolites Of Macroalgae

Ocean acidification is becoming more and more serious due to human activitiessuch as burning of fossil fuels such as coal and oil and the production of cement make the concentration of CO₂ in the atmosphere continue to rise.The reduction of sea water pH will break the balance system of sea water carbonate,which will have an important influence on the physiological and biochemical processes of algae,but the study on the effect of ocean acidification on the active metabolites of algae is still in the blank stage.The following works are carried out:1.Research on the effects of ocean acidification on the metabolites of G. lemaneiformis and G.chouae.First,the components of normal and acidified G.lemaneiformis and G.chouae were extracted.The results showed that the acidification made the physiological concentration of all the components of G.lemaneiformis and G.chouae declined.The results of TLC and GC-MS analysis were carried out on the normal and acidified G.lemaneiformis and G.chouae,and the results showed that the marine acidification environment could reduce the unsaturated fatty acids in the body of G.lemaneiformis and G.chouae,and the volatile hydrocarbons,ketones and alcohols increased,while the unsaturated fatty acids on the surface of the algae rose.The secondary metabolites of petroleum ether phase were isolated and purified, and 4 monomeric compounds were isolated and identified from normal G.lemaneiformis,including two fatty acids:hexadecanoic acid,oleic acid and two steroid compounds:cholesterol and cholesteryl cis,cis-9,12-octadecadienoate.Hexadecanoic acid,cholesterol and cholesteryl cis,cis-9,12-octadecadienoate were also isolated from acidified G.lemaneiformis,and the physiological concentration of two steroids decreased greatly,indicating that acidification could reduce the cell membrane fluidity and affect the normal physiological function of the cells.Anti Artemia and antibacterial activity were tested in the crude extract components of the normal and acidified G.lemaneiformis and G.chouae.The results showed that the activity of the essential oil was the highest,and the direct-volatile oil,indirect-volatile oil and petroleum ether components were decreased in the acidation of G.lemaneiformis and G.chouae,but the activity of the ethyl acetate was improved.Acidification reduced the antibacterial activity of petroleum ether and ethyl acetate components to 5 common food pathogenic bacteria.The experimental results show that the ocean acidification environment will have an important effect on the active components of G.lemaneiformis and G.chouae,which will decrease the unsaturated fatty acids in the algae,increase the volatile hydrocarbons,ketones,alcohols,and increase the unsaturated fatty acids on the surface of the algae.This may be because the acidification environment causes a part of fatty acids in the algae to produce volatile components such as hydrocarbons,ketones and alcohols through a series of biochemical reactions,and part of the unsaturated fatty acids are released to the surface of the algae,which reduces the fluidity of the cell membrane and forms oil film on the surface of the algae to resist the effect of acidification on the algae.This may be the main cause of the reduction of the anti Artemia and antibacterial activity of some components of acidified algae,so acidification will also have an important effect on the ecological effects of G.lemaneiformis and G.chouae in the sea.2.The research on Enteromorpha prolifera metabolites.TLC and GC-MS of the normal E.prolifera were analyzed and tested for the activity of anti Artemia.7 monomeric compounds were isolated from the petroleum ether phase of E.prolifera,including two fatty acids:linolenic acid,hexadecanoic acid,two lipid compounds:1,3-stearin-2-olein and monopalmitin,a steroid compound:5-avenasterol,phytol and nonadecanoic acid phytol ester.