Changes In Seagrass Blue Carbon Storage And Its Management In Xincun Bay,Hainan

With the massive emission of greenhouse gases and the continuous increase of global CO₂ concentration,climate change has become the biggest environmental problem faced by human beings in the 21st century,and the"blue carbon"of coastal ecosystems has been paid more and more attenti on.According to the Blue carbon report,seaweed plays an important role in the storage and sequestration of organic carbon.The carbon sealed by the global seagrass ecosystem is one of the main components of"blue carbon".The total amount of carbon captured and sealed in the sediments every year is second only to the coastal salt marshes,but the global blue carbon data relate to the sediment carbon pool of the seagrass ecosystem in China.in particular,there are few changes in carbon increment and carbo n reserves of seagrass beds.In this study,the carbon increment and carbon loss of Xincun Bay were analyzed by comparing the seagrass carbon reserves of Xincun Bay seagrass growth dense area,empty spot area and light beach area,combined with the change of Xincun Bay seagrass bed.（1）The results show that the seagrass of Xincun Bay is mainly distributed in the southern part of the lagoon in 2004 to 2021,were in 2 families5 genera 6 kids,the area of seaweed decreased from 4.82 km² in 2007 to 2.82km² in 2020.The OC value of Xincun Bay in 2022（0.06～0.63mg/g,0.08～0.82mg/g）was significantly lower than that in 2018（0.80～1.86 mg/g,0.47～1.06mg/g）.The surface OC density（3.2,4.4Mg C/ha）at R and M stations in2022 was lower than that in 2018（3.4,5.4 Mg C/ha）.It is estimated that the carbon storage of Xincun Bay seagrass bed in 2022 is 1027.95Mg C,and the annual carbon loss of Xincun Bay seagrass is 0.21 Mg C.（2）In Xincun Bay,the deposition area and amount of the main body of lagoon are larger than the scouring area and scouring amount,and the whole lagoon is mainly silted,which will lead to the decrease of seagrass bed abundance and seaweed coverage in some areas.as a result,the organic carbon stored by seaweed escapes in the atmosphere,resulting in the reduction of seagrass bed carbon sequestration in Xincun Bay.Human activities mainly lead to the reduction of seagrass bed area and carbon reserves through land development,reclamation activities,the preva lence of aquaculture ponds,the rapid development of deep-sea aquaculture technology and the input of land-based pollutants.Based on the results,this study suggests to carry out basic investigation and evaluation of carbon reserves of coastal blue carbon ecosystem in Hainan Island,to formulate incentive policies and innovative incentive mechanisms for protection and restoration of important coastal blue carbon ecosystem,to carry out research on the restoration of seagrass bed ecosystem and to strengthen climate change research on coastal blue carbon ecosystem.Reasonable management of carbon sequestration resources in Xincun Bay and Hainan.