Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of...Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a14C dated （AD 990±40） fossil giant clam,Tridacna gigas, from Shidao Island, South China Sea. Theδ18O profile of theT. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with theδ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of theTridacna specimen was stable after the onset of sexual ma-turity. Spectral analysis of theδ18O and blue color intensity time series suggested that the El Ni？o-Southern Oscillation （ENSO） period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.展开更多
In Egypt, Tridacna Maxima are found in Gulf of Suez, Gulf of Aqaba and Red Sea. Tridacna Maxima are very important ecological species as seafood source and as a substrate for reef-associated organisms;therefore we sho...In Egypt, Tridacna Maxima are found in Gulf of Suez, Gulf of Aqaba and Red Sea. Tridacna Maxima are very important ecological species as seafood source and as a substrate for reef-associated organisms;therefore we should protect it from extinction. Recently, these species are exposed for many factors of pollution (human activities, tourism and natural resources) that affect the distribution and abundance of it. The main objective of this research is to shed some light on the origin, stratigraphic position, systematic palaeontology and geographic distribution of Tridacna Maxima. In addition to their ecologic and environmental conditions were discussed. Finally, a proposed rules for protection these species from extinction were listed. Individuals of Tridacna Maxima were collected from different sites along the red Sea coast.展开更多
基金The National Basic Research Program of China(973 Program)under contract Nos 2010CB428902 and 2013CB955900the National Natural Science Foundation of China under contract No.41176042+1 种基金the West Light Foundation of The Chinese Academy of Sciences under contract No.29Y42909101the Key Programs of the Chinese Academy of Sciences under contract No.55ZZBS1304101
文摘Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a14C dated （AD 990±40） fossil giant clam,Tridacna gigas, from Shidao Island, South China Sea. Theδ18O profile of theT. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with theδ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of theTridacna specimen was stable after the onset of sexual ma-turity. Spectral analysis of theδ18O and blue color intensity time series suggested that the El Ni？o-Southern Oscillation （ENSO） period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.
文摘In Egypt, Tridacna Maxima are found in Gulf of Suez, Gulf of Aqaba and Red Sea. Tridacna Maxima are very important ecological species as seafood source and as a substrate for reef-associated organisms;therefore we should protect it from extinction. Recently, these species are exposed for many factors of pollution (human activities, tourism and natural resources) that affect the distribution and abundance of it. The main objective of this research is to shed some light on the origin, stratigraphic position, systematic palaeontology and geographic distribution of Tridacna Maxima. In addition to their ecologic and environmental conditions were discussed. Finally, a proposed rules for protection these species from extinction were listed. Individuals of Tridacna Maxima were collected from different sites along the red Sea coast.
