Coastal lagoons with small catchment basins are highly sensitive to natural processes and anthropogenic activities. To figure out the environmental changes of a coastal lagoon and its contribution to carbon burial, tw...Coastal lagoons with small catchment basins are highly sensitive to natural processes and anthropogenic activities. To figure out the environmental changes of a coastal lagoon and its contribution to carbon burial, two sediment cores were collected in Xincun Lagoon, southeastern Hainan Island and (210) ~Pb activities, grain size parameters, total organic carbon(TOC), total nitrogen(TN), total inorganic carbon(TIC) and stable carbon isotopes(δ^(13)C) were measured. The results show that in 1770–1815, the decreasing water exchange capacity with outer open water, probably caused by the shifting and narrowing of the tidal inlet, not only diminished the currents and fined the sediments in the lagoon, but also reduced the organic matter of marine sources. From 1815 to 1950, the sedimentary environment of Xincun Lagoon was frequently influenced by storm events. These extreme events resulted in the high fluctuation of sediment grain size and sorting, as well as the great variation in contributions of terrestrial(higher plants, soils) and marine sources(phytoplankton, algae, seagrass). The extremely high content of TIC, compared to TOC before 1950 could be attributed to the large-scale coverage of coral reefs. However, with the boost of seawater aquaculture activities after 1970, the health growth of coral species was severely threatened, and corresponding production and inorganic carbon burial flux reduced. The apparent enhanced inorganic carbon burial rate after 1990 might result from the concomitant carbonate debris produced by seawater aquaculture. This result is important for local government long-term coastal management and environmental planning.展开更多
Knowledge of the biodiversity of Brazilian reef ecosystems has expanded in recent years with several new species. Brazil is considered an important province because it has the only true reefs in the South Atlantic. Th...Knowledge of the biodiversity of Brazilian reef ecosystems has expanded in recent years with several new species. Brazil is considered an important province because it has the only true reefs in the South Atlantic. This study identified the endemism of benthic invertebrate species of the Brazilian reefs. The reef coast is approximately 600 km long and extends from the state of Rio Grande do Norte to south coast of the Bahia state, with many coral and sandstone reefs near the shoreline and in the offshore zone, where the platform top remains exposed during low tides; and also on the Abrolhos region has isolated columns and offshore banks. Four offshore sites within the EEZ （Exclusive Economic Zone） were also included in this review. This study was based on the invertebrate benthic diversity existing on the northeastern coast, represented by Porifera with 450 spp, Cnidaria Scleractinia 16 spp and Echinodermata 51 spp. Of these, 102 species are endemic to Brazilian reefs, including Porifera with 86 spp （18,44%）, Cnidaria Scleractinia 8 spp （50%）, and Echinodermata 8 spp （2.93%）. The results reflect the recent increase in taxonomic studies, and identify a large number of endemic species among the benthic invertebrate fauna of the Brazilian reefs.展开更多
Symbiodinium sp. occurs in a symbiotic association with various marine invertebrates, including the seleractinian corals. Understanding the flexibility and specificity in coral-algal symbiosis can have important impli...Symbiodinium sp. occurs in a symbiotic association with various marine invertebrates, including the seleractinian corals. Understanding the flexibility and specificity in coral-algal symbiosis can have important implications for predicting the future of coral reefs in the era of global climate change. In the present study, we conducted Symbiodinium phylotype analysis, based on polymerase chain reaction and restriction fragment length polymorphism （PCR-RFLP）, in the scleractinian coral, Galaxeafascicularis, from a tropical fringing reef in Hainan Island, over a 1-yr period. Our results showed that Galaxea fascicularis could associate with Symbiodinium clade C and D either individually or simultaneously. However, during the sampling period, the Symbiodinium phylotype did not change significantly in the scleractinian coral Galaxeafascicularis, although the seawater temperature decreased sharply in the winter season. This study further suggests that the shift in Symbiodinium communities in response to seasonally fluctuating environments might not be a universal feature of coral-algal associations.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41530962)
文摘Coastal lagoons with small catchment basins are highly sensitive to natural processes and anthropogenic activities. To figure out the environmental changes of a coastal lagoon and its contribution to carbon burial, two sediment cores were collected in Xincun Lagoon, southeastern Hainan Island and (210) ~Pb activities, grain size parameters, total organic carbon(TOC), total nitrogen(TN), total inorganic carbon(TIC) and stable carbon isotopes(δ^(13)C) were measured. The results show that in 1770–1815, the decreasing water exchange capacity with outer open water, probably caused by the shifting and narrowing of the tidal inlet, not only diminished the currents and fined the sediments in the lagoon, but also reduced the organic matter of marine sources. From 1815 to 1950, the sedimentary environment of Xincun Lagoon was frequently influenced by storm events. These extreme events resulted in the high fluctuation of sediment grain size and sorting, as well as the great variation in contributions of terrestrial(higher plants, soils) and marine sources(phytoplankton, algae, seagrass). The extremely high content of TIC, compared to TOC before 1950 could be attributed to the large-scale coverage of coral reefs. However, with the boost of seawater aquaculture activities after 1970, the health growth of coral species was severely threatened, and corresponding production and inorganic carbon burial flux reduced. The apparent enhanced inorganic carbon burial rate after 1990 might result from the concomitant carbonate debris produced by seawater aquaculture. This result is important for local government long-term coastal management and environmental planning.
文摘Knowledge of the biodiversity of Brazilian reef ecosystems has expanded in recent years with several new species. Brazil is considered an important province because it has the only true reefs in the South Atlantic. This study identified the endemism of benthic invertebrate species of the Brazilian reefs. The reef coast is approximately 600 km long and extends from the state of Rio Grande do Norte to south coast of the Bahia state, with many coral and sandstone reefs near the shoreline and in the offshore zone, where the platform top remains exposed during low tides; and also on the Abrolhos region has isolated columns and offshore banks. Four offshore sites within the EEZ （Exclusive Economic Zone） were also included in this review. This study was based on the invertebrate benthic diversity existing on the northeastern coast, represented by Porifera with 450 spp, Cnidaria Scleractinia 16 spp and Echinodermata 51 spp. Of these, 102 species are endemic to Brazilian reefs, including Porifera with 86 spp （18,44%）, Cnidaria Scleractinia 8 spp （50%）, and Echinodermata 8 spp （2.93%）. The results reflect the recent increase in taxonomic studies, and identify a large number of endemic species among the benthic invertebrate fauna of the Brazilian reefs.
基金Supported by the National Natural Science Foundation of China(No.40830850)the Knowledge Innovation of Chinese Academy of Sciences(No.KZCX2-YW-227)
文摘Symbiodinium sp. occurs in a symbiotic association with various marine invertebrates, including the seleractinian corals. Understanding the flexibility and specificity in coral-algal symbiosis can have important implications for predicting the future of coral reefs in the era of global climate change. In the present study, we conducted Symbiodinium phylotype analysis, based on polymerase chain reaction and restriction fragment length polymorphism （PCR-RFLP）, in the scleractinian coral, Galaxeafascicularis, from a tropical fringing reef in Hainan Island, over a 1-yr period. Our results showed that Galaxea fascicularis could associate with Symbiodinium clade C and D either individually or simultaneously. However, during the sampling period, the Symbiodinium phylotype did not change significantly in the scleractinian coral Galaxeafascicularis, although the seawater temperature decreased sharply in the winter season. This study further suggests that the shift in Symbiodinium communities in response to seasonally fluctuating environments might not be a universal feature of coral-algal associations.
