Ge Xianping

Characteristics of carbon cycles and mechanism of carbon sink in inland fishery ecosystem

Inland fishery carbon sink(IFCS)refers to the process and mechanism in which fishery organ-isms absorb and sequestrate CO2 sequestrate CO2 in the water and remove it from the water,and conse-quently,inland carbon sink fishery(ICSF) will be any fishery activity that effectively promotes a relative increase of IFCS.Phytoplankton fixes CO2 through photosynthesis and converts it into organic carbon.Quite much of it is taken up by major freshwater herbivorous and filter-feeding fish and mussels,and ac-cordingly,carbon can be cascaded through aquatic food webs and removed by capture fisheries and aqua-culture.Therefore,ICSF can not only provide large quantities of nutritious food,but also play a critical role in carbon sequestration and removal.Carbon in freshwater ecosystems can be made up of different chemical components,like particulate organic and inorganic carbon,dissolved inorganic and organic car-bon,which are convertible with high dynamics.It is noteworthy that unsustainable fishing related activities will jeopardize the potential capacities and even ecosystem services of IFCS.Therefore,the importance of IFCS and ICSF must be highlighted.A more recent study suggested that aquaculture ponds(110 830 km2) sequester an estimated 16.6 million tonnes/year of carbon globally,and the most carbon sequestration oc-curs in Asia and particularly in China(94% and 55.9% of global aquaculture pond area,respectively).Fishery will be the only controllable industry that is possible to effectively increase the carbon sink capac-ity in aquatic ecosystem,and the carbon sink fishery will be the only carbon sink industry in aquatic eco-system.To better understand the mechanism of carbon sink/source,the current focus of study should be on the natural laws of carbon cycles in inland fishery ecosystem(including natural waters and ponds),form conversion between different chemical components,the carbon footprint for each of the different inland fisheries and aquaculture activities,and the corresponding assessment methods and models.At the same time,attention should also be paid to calculating realistic estimates of CO2 fluxes in inland fishery waters and at the water-atmosphere interface,understanding the dynamics of carbon sink/source,and establish-ment of the information platform for environmental carbon/biological carbon/carbon fluxes of ICSF.

Effects of anthraquinones extract from Rheum officinale Baill on the hepatopancreas antioxidative capacity and HSP70 gene expresssion under high temperature of Macrobrachium rosenbergii

Macrobrachium rosenbergii,also known as the giant river prawn,the giant freshwater prawn or the Malaysian prawn,is the most important cultivated species of freshwater shrimp in the world.This species(as well as other Macrobrachium) is commercially important for its value as a food source.In China,the production of M.rosenbergii has been increasing in recent year.However,cultured M.rosenbergii in China as well as in other parts of the world have suffered from various stress factors such as ambient temperature,stocking density,physicochemical parameters,transport,and storage.Stress means the sum of nonspecific responses of organisms to various acute stimuli inside and outside.It is a physiological response of any organisms in the long evolution process to extend its adaptation,but excess response,which inhibits immunity,improves the free radical contents,destroys the homeostasis between producing and cleaning-up of free radical,and attacks the double bond of polyunsaturated fatty acid in plasma membrane,the last leading to increase the lipid peroxidation contents and lipid peroxidation injury.So these are many disadvantageous impacts on organisms and it causes fish to infect diseases even to die.Therefore,how to alleviate stress response is the research focus in this field.The present research falls on substances,which can strengthen immunity of organisms and alleviate stress,e.g.vitamin C,vitamin E,lipid acid,metal ion,fructose,astacin.Chinese herbal medicines have many merits:natural,highly effective,low toxicity,low side effects,and rich in resources.Chinese herbal medicines have many effective components,such as organic acids,alkaloid,saccharide,volatile oil,wax,glycoside,tannic acid substance and some unknown factors that can elevate fish immunity and enhance the growth.However,few reports have been found in studying the effects of Chinese herbal medicines on the hepatopancreas antioxidative capacity and the level of HSP70 mRNA under high temperature of M.rosenbergii.In view of this,M.rosenbergii were divided into 5 groups randomly.The control were fed with basal diet,the others the treated groups were fed with basal diet supplemented with 0.05%,0.10%,0.20%,0.40% anthraquinone extracts for 10 weeks,respectively.After that,shrimp were stressed by high temperature at 35 ℃ for 48 h continuously.The changes of total antioxidative capacity(T-AOC),catalase(CAT),superoxide dismutase(SOD),nitrogen oxide(NO),malondialdehyde(MDA) and the mRNA level of heat shock protein 70(HSP70) in hepatopancreas before and after the stress were investigated.The results showed that compared with the control,0.05% dose of anthraquinone extract could elevate CAT,SOD activities and reduce MDA concentration,0.20% dose group improved T-AOC and NO content and reduced MDA concentration,and 0.10%,0.20% doses groups improved also the relative content of HSP70 mRNA before the stress.After 35 ℃ high temperature stress,T-AOC,CAT activities,SOD activities,and NO concentrations in hepatopancreas were decreasing in all groups of which the control relatively lower and 0.10%-0.20% doses groups were relatively higher,while MDA contents were increasing trend in all groups of which the control was relatively higher and 0.10%-0.20% doses groups were relatively lower.The relative content of HSP70 in hepatopancreas 6 h after the stress in 0.10% and 0.20% doses groups were higher than those of the control.It is concluded that ingestion of 0.10%-0.20% doses of anthraquinones extracts could improve the antioxidative capacity,elevate the relative content of HSP70 mRNA and help prevent negative effects of high temperature stress to a certain degree.