The Ecological Benefits Of Grateloupia Lanceolata And Mytilus Edulis In Marine Ranching

Grateloupia lanceolata belongs to the genus Rhodophycophyta,Cryptonemiales,Halymeniaceae,and Grateloupia C.Agardh which is the warm temperate algae.Grateloupia lanceolata is a kind of seaweed which is widely grown in the sea of Gouqi Island,it can be used for edible and algin extraction,and has high medicinal and economic value.It has certain development and utilization prospect.Mytilus edulis is one of the most important marine shellfish in China whose cultivation is mainly concentrates in Shengsi Islands,Zhoushan City,Zhejiang Province,and the scale is expanding year by year.However,due to the continuous expansion of mussels breeding area,in recent years,the breeding density is so large that the eutrophication of the mariculture area is serious,and the red tide frequently breaks out.Therefore,this paper mainly studies the optimum growth environment of Grateloupia lanceolata,its N and P absorption capacity,and its optimum proportion to ecological polyculture of Mytilus edulis,which are the artificial breeding and artificial construction of Grateloupia lanceolata.The algae field provides theoretical basis and technical support;it provides theoretical basis and technical support for the use of Algae-coated Algae to control the eutrophication of water bodies;and it provides a theoretical basis for changing Mussel Island mussel breeding mode,and thus improves under a well-preserved marine ecological environment.Mussel production,while harvesting a large number of large-scale economic algae,bring greater economic benefits to local fishermen,and realize the sustainable development of the mussel farming industry in the region.The main results of the study are as follows:1.Effects of different light,temperature and salinity on the growth and photosynthesis of Grateloupia lanceolataWe studied the effects of different light intensities:20,40,60,80,100,200?mol·m^-2·s^-1?other culture conditions were temperature 20?,salinity 30?,different temperatures:10,15,20,25,30,35?(other culture conditions are light intensity 60?mol·m^-2·s^-1,salinity 30)and different salinities:10,20,25,30,35,40,50(other cultures Under conditions of temperature of 20?and light intensity of 80?mol·m^-2·s^-1)on the effects of growth,photosynthetic pigment content and Fv/Fm on the maximum fluorescence activity of Grateloupia lanceolata.The results showed that the suitable light intensity for the growth of Grateloupia lanceolata was 60¹00?mol·m^-2·s^-1,and the optimal light intensity was 80?mol·m^-2·s^-1.The suitable growth temperature was 20²5?,the optimal growth temperature is 25?;the suitable growth salinity is 20³5,and the optimal salinity is 30.2.Effects of Different N,P Concentrations on the Growth and Nutrient Absorption of Grateloupia lanceolataDifferent concentrations of N were studied:0,50,100,150 and 200?mol/L?P concentration was 10?mol/L?and different P concentrations:0,1,5,10 and 15?mol/L?N concentration was 100?mol/L?the effect of Grateloupia lanceolata on growth,photosynthetic pigment content and Fv/Fm of the maximum fluorescence activity of Algae.The results showed that when the concentration of P in water is 10?mol/L,the concentration of N suitable for the growth of Grateloupia lanceolata is100 to 150?mol/L,and the limit of the maximum N concentration that can be absorbed by the growth of Grateloupia lanceolata is 50¹00?mol/L;when the concentration of N in the water is 100?mol/L,the concentration of P suitable for the growth of Grateloupia lanceolata is 5 to 20?mol/L,and the maximum P concentration limit for growth of Grateloupia lanceolata can be absorbed.1⁵?mol/L.3.Effect of different culture densities on theecological polyculture of Mytilus edulis and Grateloupia lanceolataGrateloupia lanceolata is a kind of seaweed which is widely grown in the sea of Gouqi Island,it can be used for edible and algin extraction,and has high medicinal and economic value.It has certain development and utilization prospect.Mytilus edulis is one of the most important marine shellfish in China whose cultivation is mainly concentrates in Shengsi Islands,Zhoushan City,Zhejiang Province,and the scale is expanding year by year.However,due to the continuous expansion of mussels breeding area,in recent years,the breeding density is so large that the eutrophication of the mariculture area is serious,and the red tide frequently breaks out.This paper studied on the polyculture of Mytilus edulis and Grateloupia lanceolata in order to improve the environment of the region's aquaculture area.Polyculture systems of Mytilus edulis and Grateloupia lanceolata were set as 5 treatment groups and the polyculture of the Mytilus edulis with the Grateloupia lanceolata densities were G1?1:0?,G2?1:0.25?,G3?1:0.5?,G4?1:1?and G5?1:2?.The Mytilus edulis was reared at the density of 0.63 ind/L in each group,but the Grateloupia lanceolata were cultivated at the densities of 0 g/L,1.25 g/L,2.5 g/L,5 g/L and 10 g/L.After 36 days,the specific growth rate of Mytilus edulis in G3 was 0.21±0.03%·d^–1,significantly higher than those in the other polyculture groups(0.11±0.028⁰.21±0.03%·d^–1,P<0.01),and the specific growth rate of Mytilus edulis monoculture was only 0.063±0.022%·d^–1?P<0.01?.The specific growth rate of Grateloupia lanceolata in G3group was 0.96±0.20%·d^–1,which was significantly higher than those of the other polyculture groups(0.62±0.16⁰.96±0.20%·d^–1,P<0.01).The removal rates of nutrients?NO₃^--N,NO₂^--N,NH₄⁺-N,PO₄^--P?in G3 were 91.38±1.40%,96.79±1.97%,98.38±2.06%and 96.86±3.16%respectively,which were significantly higher than G2?P<0.05?and no signicant difference between G4 and G5?P>0.05?.In conclusion,the polyculture of Mytilus edulis with the Grateloupia lanceolata can take reasonable ecological effects when the density ratio is 1:0.5.4.Effect Investigation and analysis of algae,mussels and water quality in mussel culture area of Gouqi islandThe impact of mussel culture on the environment in the Gouqi island was investigated by investigating the nutrient content of water in the mussel culture area,the biomass of the algal biomass on mussel oysters,and the production of mussels.The results are as follows:Eutrophication occurred in the aquatic environment of mussel culture area in June,August and December.The biomass of algae in the four seasons of spring,summer,autumn and winter was 0.9,0.21,0.55 and 0.33 million tons,respectively.The water environment in the area showed a negative correlation trend;the production of the purple mussel breeding showed a decrease while the production of the thick shell mussels showed an increasing phenomenon.In order to achieve the sustainable development of the continuously expanding scale of mussel culture in the region,it is the most effective,environmentally-friendly,and cheapest way to supplement the biomass of algae in the region.