The monitoring survey and health assessment for benthic community were carried out in Luhuitou fringing reef of Sanya, Hainan, China in 2002. Monitoring survey included manta tow, line intercept transect, video transe...The monitoring survey and health assessment for benthic community were carried out in Luhuitou fringing reef of Sanya, Hainan, China in 2002. Monitoring survey included manta tow, line intercept transect, video transect and digital photograph. The mean live coral cover was 23.40%. Comparison of used monitoring methods showed that video transect can replace line intercept transect, and 50 m transect is better than 20 m transect in uneven coral region. Survey data and comparison with previous research work showed that Luhuitou fringing reef has been damaged severely and has a general declining trend with live coral cover from about 85% in the 1960s down to 20% in 2004, but it still has quite high biodiversity and therefore has special protection value. Main factors of Luhuitou fringing reef declining were human activities including reef rock digging and curios collecting, destructive fishing, sediment and pollutant from coastal land, and recent marine aquaculture. Only strengthening integrated management can reach improvement and restoration of Luhuitou declining coral reef ecosystem.展开更多
The migration and transformation of nitrogen(N)in sediments play an important role in regulating the N concentration and nutrient structures in shallow seas.However,studies of sedimentary N dynamics are rarely focused...The migration and transformation of nitrogen(N)in sediments play an important role in regulating the N concentration and nutrient structures in shallow seas.However,studies of sedimentary N dynamics are rarely focused on carbonate sediments,although these account for about 40%of the continental shelf area.Thus,the regulation mechanisms of the N dynamics in the carbonate sands of coral reefs are not clear.Taking the coral reef area of Weizhou Island,which has a relatively high N concentration,as the research object,we conducted a series of flow-through reactor experiments to investigate the fluxes of different N forms at the interface of sediment and seawater and their regulation mechanism by environmental factors.The fluxes of dissolved inorganic and organic N(DIN and DON)at different stations were-0.39-0.12 mmol/(m^(2)·h) and-0.18-0.39 mmol/(m^(2)·h),respectively.Denitrification(0.11-0.25 mmol/(m^(2)·h) was closely coupled to nitrification,which was limited by the availability of organic matter and its degradation product(i.e.,NH_(4)^(+)).Thus,the excessive NO_(3)^(-) might be reduced to NH4+by dissimilatory nitrate reduction to ammonium,rather than to N_(2) by denitrification.NO_(3)^(-) reduction peaked at intermediate advection rates(96 L/(m^(2)·h)) and flow path lengths(10 cm),but the release of DON also peaked at the same condition.In addition,climate warming would significantly affect sedimentary N dynamics at Weizhou Island.These results may help address the broader issue of the N cycle in coral reef eco systems under the dual pressure of climate warming and anthropogenic activities,and these results are beneficial to coral reef protection and local ecological management.展开更多
The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral ...The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition.The estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very poor.Totally,12 genera were recorded,of which Porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(p<0.05).The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble.The reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.展开更多
基金Acknowledgements The authors would like to thank Hainan Sanya National Coral Reef Natural Reserve Administration, International Cooperation Division of State 0ceanic Administration of China, and Marine Environment protection Division of Department of Marine and Fishery of Hainan Province, for their powerful help. This work was supported by Chinese Ministry of Science ＆ Technology Special Scheme （Grant No. 2002CCA02700）, National Natural Science Foundation of China （Grant Nos. 40231009, 40406018）, UNEP Small Grant Fund Project （Grant No. MT/1010-01-03） and the Knowledge Innovation Project of South China Sea Institute of 0ceanology, Chinese Academy of Sciences.
文摘The monitoring survey and health assessment for benthic community were carried out in Luhuitou fringing reef of Sanya, Hainan, China in 2002. Monitoring survey included manta tow, line intercept transect, video transect and digital photograph. The mean live coral cover was 23.40%. Comparison of used monitoring methods showed that video transect can replace line intercept transect, and 50 m transect is better than 20 m transect in uneven coral region. Survey data and comparison with previous research work showed that Luhuitou fringing reef has been damaged severely and has a general declining trend with live coral cover from about 85% in the 1960s down to 20% in 2004, but it still has quite high biodiversity and therefore has special protection value. Main factors of Luhuitou fringing reef declining were human activities including reef rock digging and curios collecting, destructive fishing, sediment and pollutant from coastal land, and recent marine aquaculture. Only strengthening integrated management can reach improvement and restoration of Luhuitou declining coral reef ecosystem.
基金The Guangxi Natural Science Foundation under contract Nos 2019GXNSFAA185001 and 2019GXNSFAA185022the National Natural Science Foundation of China under contract Nos 41976059 and 42166002.
文摘The migration and transformation of nitrogen(N)in sediments play an important role in regulating the N concentration and nutrient structures in shallow seas.However,studies of sedimentary N dynamics are rarely focused on carbonate sediments,although these account for about 40%of the continental shelf area.Thus,the regulation mechanisms of the N dynamics in the carbonate sands of coral reefs are not clear.Taking the coral reef area of Weizhou Island,which has a relatively high N concentration,as the research object,we conducted a series of flow-through reactor experiments to investigate the fluxes of different N forms at the interface of sediment and seawater and their regulation mechanism by environmental factors.The fluxes of dissolved inorganic and organic N(DIN and DON)at different stations were-0.39-0.12 mmol/(m^(2)·h) and-0.18-0.39 mmol/(m^(2)·h),respectively.Denitrification(0.11-0.25 mmol/(m^(2)·h) was closely coupled to nitrification,which was limited by the availability of organic matter and its degradation product(i.e.,NH_(4)^(+)).Thus,the excessive NO_(3)^(-) might be reduced to NH4+by dissimilatory nitrate reduction to ammonium,rather than to N_(2) by denitrification.NO_(3)^(-) reduction peaked at intermediate advection rates(96 L/(m^(2)·h)) and flow path lengths(10 cm),but the release of DON also peaked at the same condition.In addition,climate warming would significantly affect sedimentary N dynamics at Weizhou Island.These results may help address the broader issue of the N cycle in coral reef eco systems under the dual pressure of climate warming and anthropogenic activities,and these results are beneficial to coral reef protection and local ecological management.
文摘The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition.The estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very poor.Totally,12 genera were recorded,of which Porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(p<0.05).The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble.The reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.
