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Catch organism assemblages along artificial reefs area and adjacent waters in Haizhou Bay
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作者 Shike Gao Bin Xie +3 位作者 Chengyu Huang Xiao Zhang Shuo Zhang Wenwen Yu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第2期34-42,共9页
To better understand the community patterns mediated by connectivity in artificial reefs of coastal areas, it is necessary to understand the distribution and coexistence of organisms with artificial reefs area and adj... To better understand the community patterns mediated by connectivity in artificial reefs of coastal areas, it is necessary to understand the distribution and coexistence of organisms with artificial reefs area and adjacent waters. This study was conducted to examine main catches assemblages collected by trawls in Haizhou Bay,which included five habitats: the artificial reef area(AR), aquaculture area(AA), natural area(NA), estuary area(EA) and comprehensive effect area(CEA). The result shows that the total abundances of species in the five habitats were highly different(univariate PERMANOVA: P = 0.001, n = 24), but some species were also unique in their habitat(e.g. Scapharca subcrenata and Glossaulax didyma in AA). The body size distribution of specific species between habitats are different. For Collichthys lucidus, their body size in AR(14.63 cm ± 1.64 cm) and EA(14.3 cm ± 0.85 cm) is higher than that in NA(10.65 cm ± 1.64 cm), CEA(11.28 cm ± 1.85 cm) and AA(12.1 cm ±0.43 cm), which indicates the potential connection from AR to EA mediated by their adult population. We concluded that artificial reefs in AR can be considered key components that have the ability to support species assemblages in adjacent habitats. This study has implications for the conservation and monitoring of species assemblages in coastal areas in terms of that artificial reefs can be applied in different stages of habitat protection implementation and in different combinations of scenarios. 展开更多
关键词 ASSEMBLAGE artificial reefs adjacent water Haizhou Bay
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Simulation of global ocean acidification and chemical habitats of shallow-and cold-water coral reefs 被引量:1
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作者 ZHENG Mei-Di CAO Long 《Advances in Climate Change Research》 SCIE 2014年第4期189-196,共8页
Using the UVic Earth System Model, this study simulated the change of seawater chemistry and analyzed the chemical habitat surrounding shallow- and cold-water coral reefs from the year 1800 to 2300 employing RCP2.6, R... Using the UVic Earth System Model, this study simulated the change of seawater chemistry and analyzed the chemical habitat surrounding shallow- and cold-water coral reefs from the year 1800 to 2300 employing RCP2.6, RCP4.5, RCP6.0, and RCP8.5 scenarios. The model results showed that the global ocean will continue to absorb atmospheric CO2. Global mean surface ocean temperature will rise 1.1-2.8 K at the end of the 21st century across RCP scenarios. Meanwhile, the global mean surface ocean pH will drop 0.14--0.42 and the ocean surface mean con- centration of carbonate will decrease 20%--51% across the RCP scenarios. The saturated state of sea water with respect to calcite carbonate minerals (t2) will decrease rapidly. During the pre-industrial period, 99% of the shallow-water coral reefs were surrounded by seawater with t2 〉 3.5 and 87% of the deep-sea coral reefs were surrounded by seawater with aragonite supersaturation. Within the 21st century, except for the high mitigation scenario of RCP2.6, almost none shallow-water coral reefs will be surrounded by seawater with g2 〉 3.5. Under the intensive emission scenario of RCP8.5, by the year 2100, the aragonite saturation horizon will rise to 308 m under the sea surface from 1138 m at the pre- industrial period, thus 73% of the cold-water coral reefs will be surrounded by seawater with aragonite undersaturation. By the year 2300, only 5% of the cold-water coral reefs will be surrounded by seawater with aragonite supersaturation. 展开更多
关键词 Simulation research Aragonite saturation state Ocean acidification Shallow-water coral reefs Cold-water coral reefs
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Paleogene and Early Neogene Lacustrine Reefs in the Western Qaidam Basin, China 被引量:16
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作者 ZHONGJianhuat WENZhifeng GUOZeqing WANGHaiqiao GAOJianbo 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第3期736-743,共8页
Typical reefs in the Paleogene and early Neogene strata of the Qaidam Basin, Tibetan Plateau, China, reveal their internal structures and sedimentation environments and consist mainly of algal reef, stromatolite reef ... Typical reefs in the Paleogene and early Neogene strata of the Qaidam Basin, Tibetan Plateau, China, reveal their internal structures and sedimentation environments and consist mainly of algal reef, stromatolite reef and thrombolite reef with distinct reef structures, fore-reef, back-reef and reef-plateau. The fore-reef is characterized by a combination of pinnacle reef, thrombolite and algal reef. The back reef is composed of stromatolite reef and algal reef. The pinnacle reefs (micro-atoll), most of which are several tens of centimeters in diameter (whereas some exceptionally big ones are over 200 cm in diameter), and several tens of centimeter to 2 m in height, are situated on the far front-edge of the reef; the pinnacle reef is also often of recumbent form with a gravel-filled circular hole in the center. The algal reef is in the form of dome and irregular beds, and filled with algal detritus, ostracodes, spirorbis fossils, ooid and terrigenous debris, and worm traces; cavities and scour marks are often developed. The algal reef is gray commonly when fresh and weathers to a brown color. The lacustrine thrombolite in the Qaidam Basin is light gray or deep gray when fresh, white-gray or brown when weathered, dense and homogeneous with abundant pores filled by oil and bitumen. Observed under the microscope, the thrombolite consists mainly of brown or brown-black clots with a little algal debris, ooid, pellet, ostracodes, spirorbis fossils and terrigenous debris, in some cases, terrigenous debris, even gravel, is abundant. Many features of the thrombolite suggest that it is formed in a high-energy envkonment. The stromatolite reefs developed on the lacustrine algal reef in the Qaidam Basin are very complex whether in shape or in internal structure. The simplest ones form laminated layers and the most complex ones have intensely branching structures. The size is also variable. 展开更多
关键词 reefs STROMATOLITE thrombolite LACUSTRINE PALEOGENE early Neogene Qaidam Basin
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Studies on Factors Influencing Hydrodynamic Characteristics of Plates Used in Artificial Reefs 被引量:7
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作者 TANG Yanli YANG Wenzhao +3 位作者 SUN Liyuan ZHAO Fenfang LONG Xiangyu WANG Gang 《Journal of Ocean University of China》 SCIE CAS CSCD 2019年第1期193-202,共10页
As a simplified model of artificial reefs, a series of plate models punched with square or circular openings are designed to investigate the effects of openings on the hydrodynamic characteristics of artificial reefs.... As a simplified model of artificial reefs, a series of plate models punched with square or circular openings are designed to investigate the effects of openings on the hydrodynamic characteristics of artificial reefs. The models are grouped by various opening numbers and opening-area ratios. They are physically tested in a water flume or used in the numerical simulation to obtain the drag force in the uniform flow with different speeds. The simulation results are found in good agreement with the experimental measurements. By the non-dimensional analysis, the drag coefficient specified to each model is achieved and the effects of openings are examined. It is found that the key factor affecting the drag coefficient is the open-area ratio. Generally, the drag coefficient is a linear function of the open area ratio with a minus slope. The empirical formulae for the square and circular openings respectively are deduced by means of the multiple regression analysis based on the measured and numerical data. They will be good references for the design of new artificial reefs. As a result of numerical simulation, the vorticity contours and pressure distribution are also presented in this work to better understand the hydrodynamic characteristics of different models. 展开更多
关键词 artificial reefs drag COEFFICIENT HYDRODYNAMIC characteristics model EXPERIMENT
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Survey of reefs based on Landsat 8 operational land imager(OLI)images in the Nansha Islands, South China Sea 被引量:6
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作者 DUAN Yuewei LIU Yongxue +2 位作者 LI Manchun ZHOU Minxi YANG Yuhao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第10期11-19,共9页
A detailed survey of the reefs in the Nansha Islands' sea that are of strategic importance is conducive to their future development. In this study, a total of 50 Landsat 8 operational land imager(OLI) images were u... A detailed survey of the reefs in the Nansha Islands' sea that are of strategic importance is conducive to their future development. In this study, a total of 50 Landsat 8 operational land imager(OLI) images were used to analyze the geological features and spectral characteristics of the Nansha reefs. The exposed islands/sandbanks,reef flats and sub-tidal reefs were identified with the near-infrared band, the red and green bands, and the blue band, respectively. Based on the relationships among various characteristics and bands illustrated in the OLI images, the maximum between-cluster variance threshold algorithm(OTSU method) and the mathematical morphology were employed to extract characteristic parameters of the spatial geometry of the reefs from top to bottom, which were subsequently operated by a series of post-processing methods such as vectorization,simplification and topological analysis. Among the 132 standalone reefs and 16 atolls that are identified in the study, four reefs have yet to be named in the Standard Names of Various Islands in the South China Sea and the website Nansha Islands Online(http://www.nansha.org/). Another 24 ones are exposed to the atmosphere even during high tides. Taiping Island with an area of 0.57 km^2 represents the largest exposed geological feature. This study demonstrated the applicability of medium-resolution satellite images to derive the coral reef information effectively and thus provided information for the related departments that are responsible to manage the coast.An improved resolution of multispectral bands with the panchromatic band in higher spatial resolution(15 m for OLI image) is expected to provide an optimum satellite based approach to map marine habitats. 展开更多
关键词 remote sensing coral reefs OLI imagery Nansha Islands
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Underwater topography detection of Shuangzi Reefs with SAR images acquired in different time 被引量:6
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作者 YANG Jungang ZHANG Jie MENG Junmin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2007年第1期48-54,共7页
Imaging mechanism of underwater topography by SAR and a underwater topography SAR detection model built on the theory of underwater topography detection with SAR image presented by Yuan Yeli are used to detect the und... Imaging mechanism of underwater topography by SAR and a underwater topography SAR detection model built on the theory of underwater topography detection with SAR image presented by Yuan Yeli are used to detect the underwater topography of Shuangzi Reefs in the Nansha Islands with three scenes of SAR images acquired in different time. Detection results of three SAR images are compared with the chart topography and the detection errors are analyzed. Underwater topography detection experiments of Shuangzi Reefs show that the detection model is practicable. The detection results indicate that SAR images acquired in different time also can be used to detect the underwater topography, and the detection results are affected by the ocean conditions in the SAR acquiring time. 展开更多
关键词 Shuangzi reefs underwater topography SAR image topography detection
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A Comparative Study of Numerical Models for Wave Propagation and Setup on Steep Coral Reefs 被引量:4
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作者 ZHANG Shan-ju ZHU Liang-sheng ZOU Kai 《China Ocean Engineering》 SCIE EI CSCD 2019年第4期424-435,共12页
Complex factors including steep slopes, intense wave breaking, large bottom friction and remarkable wave setup should be considered while studying wave propagation over coral reefs, and how to simulate wave propagatio... Complex factors including steep slopes, intense wave breaking, large bottom friction and remarkable wave setup should be considered while studying wave propagation over coral reefs, and how to simulate wave propagation and setup on coral reefs efficiently has become a primary focus. Several wave models can be used on coral reefs as have been published, but further testing and comparison of the reliability and applicability of these models are needed. A comparative study of four numerical wave models (i.e., FUNWAVE-TVD, Coulwave, NHWAVE and ZZL18) is carried out in this paper. These models’ governing equations and numerical methods are compared and analyzed firstly to obtain their differences and connections;then the simulation effects of the four wave models are tested in four representative laboratory experiments. The results show that all four models can reasonably predict the spectrum transformation. Coulwave, NHWAVE and ZZL18 can predict the wave height variation more accurately;Coulwave and FUNWAVE-TVD tend to underestimate wave setup on the reef top induced by spilling breaker, while NHWAVE and ZZL18 can predict wave setup relatively accurately for all types of breakers;NHWAVE and ZZL18 can predict wave reflection by steep reef slope more accurately. This study can provide evidence for choosing suitable models for practical engineering or establishing new models. 展开更多
关键词 CORAL reefs STEEP slope BOUSSINESQ equations WAVE propagation and SETUP WAVE breaking numerical simulation comparative study
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Geomorphology and sediment dynamics of the Liyashan oyster reefs,Jiangsu Coast,China 被引量:3
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作者 Hangjie Lin Qian Yu +3 位作者 Zhiyun Du Yiyang Fan Yunwei Wang Shu Gao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第10期118-128,共11页
Oyster reefs and their spatial patterns are deemed to change the local hydrodynamic condition and exert profound impacts on the grain size,concentration and transportation of suspended sediments.Meanwhile,high suspend... Oyster reefs and their spatial patterns are deemed to change the local hydrodynamic condition and exert profound impacts on the grain size,concentration and transportation of suspended sediments.Meanwhile,high suspended sediment concentration often results in excess mortality among oysters.Oyster reefs are rare and vital ecosystem in Liyashan national marine park,Jiangsu Coast,China.However,urgent conservation efforts should be made on account of the drastic reduction in reef areas.To investigate the sediment dynamics and the geomorphology,two tripod observation systems were deployed and UAV aerial surveys with elevation measurement using Real Time Kinematic(RTK)were also carried out.High mud content(60%)was found in the bed sediment at the reef ridge,causing much lower drag coefficient than other recorded values of living oyster reefs,indicating the death of oysters and the degradation of reefs in Liyashan.Ridgelines of the string reefs at 45°to the current direction and high suspended sediment concentration in the water body(50–370 mg/L)that exceeds the threshold(200 mg/L),which would affect nutrient uptake efficiency and further result in gill saturation,decrease of clearance rate and associated deposition,were probably crucial causes of the death of oysters.The findings are useful for restoring natural oyster reefs and designing artificial reefs for nature-based coastal defense. 展开更多
关键词 oyster reefs suspended sediment concentration HYDRODYNAMICS drag coefficient spatial patterns
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Depositional Architecture and Evolution of Late Permian Reefs in Ziyun County,Southern Guizhou, China 被引量:1
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作者 Lu Yongchao Li Sitian Xie Xinong (Faculty of Earth Resources, China University of Geosciences, Wuhan 430074) Zhou Yaoqi (Department of Geology, University of Petroleum, Dongying 257062) 《Journal of Earth Science》 SCIE CAS CSCD 1996年第1期95-100,共6页
The uppermost Permian reef complex in Ziyun County, southern Guizhou occurs as a third-order depositional sequence developed in the platform marginal break zone during the Late Permian transgressive period This paper ... The uppermost Permian reef complex in Ziyun County, southern Guizhou occurs as a third-order depositional sequence developed in the platform marginal break zone during the Late Permian transgressive period This paper deals with the evolution of the third-order sequence and depositional arthitecture of the sequence stratigraphic units with the analysis of outcrop sequence stratigraphy and chemostratigraphy. Thirteen parasequences which belong to four system tracts are recognized. According to their genetic facies features,three growth strategies of reef accrete from the systems tracts during sea level changes are distinguished as keep-up reefs, give-up reefs and catch-up reefs. In combination with an absolute water depth analysis by chemostratigraphic method, we establish an entire sea level curve of the third-order sequence and discuss its evolution and depositional response. 展开更多
关键词 sequence stratigraphy reef growth strategy aggrading reefs sea level curve.
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Remote sensing composite information's trend surface analysis of Nansha Islands coral islets and reefs' top 被引量:1
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作者 Liu Baoyin and Wang Yanfeng 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1999年第1期87-96,共10页
Based on the remote sensing information feature of Nansha coral islets and reefs that controlled by the Nansha Islands local area's goological structure and growth law, by means of mathematical model and PC, the N... Based on the remote sensing information feature of Nansha coral islets and reefs that controlled by the Nansha Islands local area's goological structure and growth law, by means of mathematical model and PC, the Nansha Islands coral islets and reefs' top geological data' spatial distribution and local change trend are simulated by using the trend surface system on the remote sensing composite information, and an scientific interpretation and local comparison of Nansha coral islands and islets' spatial distribution feature are made. 展开更多
关键词 Nansha Islands coral reefs remote sensing GEOMORPHOLOGY trend surface mathematical model
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Community structure of planktonic copepods in artificial reefs of Wenchang,Hainan 被引量:2
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作者 XIE Fuwu PANG Qiaozhu 《Marine Science Bulletin》 CAS 2020年第2期61-77,共17页
To understand the characteristics of population structure of planktonic copepods and their response mechanisms to marine environmental factors in different seasons,the community structure of planktonic copepods in sam... To understand the characteristics of population structure of planktonic copepods and their response mechanisms to marine environmental factors in different seasons,the community structure of planktonic copepods in samples obtained from 7 stations in artificial reefs of Wenchang,Hainan Province in March and September 2019 were investigated.A total of 33 species of planktonic copepods belonging to 23 genera within 17 families were identified in artificial reefs,with 27 species and 21 genera in spring,and 23 species and 19 genera in fall,respectively.The identified planktonic copepods were further categorized into estuarine groups,warm temperate groups,warm water coastal groups,and warm water widespread groups.The predominant species in spring were mainly composed of Temora turbinata and Canthocalanus pauper,whereas Tortanus gracilis and Subeucalanus subcrassus were dominant species in fall.The species and abundance of planktonic copepods in spring were higher than that in fall,while the diversity index and evenness were vice versa,with obvious seasonal differences.In addition,there was a correlation between the population of copepods and physicochemical environmental factors.The major warm water group of copepods in spring showed different degree of correlation with environmental factors,such as NO2-N,NH3-N,pH,water depth,temperature etc.,while the population of copepods in fall was affected by limiting factors such as dissolved oxygen,pH,and temperature.In conclusion,copepods species inartificial reefs were rich and diverse,and their community structure tended to be stable.In addition,the surrounding water quality was generally good,and the whole marine ecosystem and ecological environment were in good condition. 展开更多
关键词 Planktonic copepods community structure artificial reefs Hainan Wenchang
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A Study of Devonian Reefs from Southern China
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作者 G.FLAJS 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2000年第4期727-739,共13页
Three Devonian reefs (bioherms) from Yunnan and Guangxi, southern China, are studied in detail. Six microfacies types are differentiated. Colonial rugose corals (Columnaria, Disphyllum and Hexagonaria) at Qujing, tabu... Three Devonian reefs (bioherms) from Yunnan and Guangxi, southern China, are studied in detail. Six microfacies types are differentiated. Colonial rugose corals (Columnaria, Disphyllum and Hexagonaria) at Qujing, tabulate corals (Alveolites) with massive stromatoporoids (Actinostroma and Stromatoporella) and sponges at Panxi, and massive stromatoporoids (Actinostroma, Trupetostroma and Stromatoporella) at Yangshuo belong to the most important reef builders. All the three reefs studied clearly reveal a successive evolution history. They developed on the carbonate banks, shallow carbonate platforms and platform margins in the Late Givetian and terminated in the Frasnian due to sea-level falls related to local uplifts of platforms. This coincides with a eustatic fall of relative sea level at the Frasnian/Famennian transition. 展开更多
关键词 MICROFACIES reefs DEVONIAN southwestern China
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Experimental Investigation of Local Scour Around Artificial Reefs in Steady Currents
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作者 TANG Yanli WEI Shuangwu +2 位作者 YANG Mingda WANG Xinxin ZHAO Fenfang 《Journal of Ocean University of China》 SCIE CAS CSCD 2022年第2期445-456,共12页
Artificial reef is a man-made object that is deployed purposefully on the seafloor to restore the offshore fishery resources and the ecological environment.To secure its ecological effects,it is important to study the... Artificial reef is a man-made object that is deployed purposefully on the seafloor to restore the offshore fishery resources and the ecological environment.To secure its ecological effects,it is important to study the possible instability of artificial reefs,like drifting and reversing caused by burial and scour in different seafloor conditions.In the present study,experiments of local scour around an artificial reef are carried out in steady currents.The effect of the open-area ratios and the open-hole heights of the cubic reefs,and the bottom angles of the triangular reefs on the time-scale of the scour process and the equilibrium scour depth are investigated.The results indicate that for the cubic artificial reef,the scour depth decreases with the increasing open-area ratios,and increases with the increasing open-hole heights.In the present study,the optimal prototype of the cubic reef with an open-area ratio of 0.49 and open-height of 0.7 m produces the minimum scour depth.For the triangular reef,the scour depth increases when the bottom angle increases.Moreover,based on the experimental results,empirical equations of the effects of the cut-opening and the bottom angle on the maximum equilibrium scour depth are proposed.The formulas will provide theoretical support and practical guidance for the optimized design and construction of artificial reefs. 展开更多
关键词 local scour artificial reefs open-area ratios open-hole heights bottom angles
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Scleractinian Corals and Reefs of Vietnam as a Part of the Pacific Reef Ecosystem
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作者 Yuri Ya Latypov 《Open Journal of Marine Science》 2011年第2期50-68,共19页
The paper analyzes both published and unpublished results of the investigations of Vietnamese reef building corals and reefs performed in the last decades of the twentieth century and first decades twenty-first. The s... The paper analyzes both published and unpublished results of the investigations of Vietnamese reef building corals and reefs performed in the last decades of the twentieth century and first decades twenty-first. The state of the art in the study of reef-building scleractinian corals and reefs is presented. The scleractinian fauna of Vietnam is shown to match in species diversity (350 species of 80 genera) the tropical coral fauna of the Indonesian–Malacca fertile center, from which Indo-Pacific reef-building corals originated. The whole Vietnam coast from the Gulf of Tonkin to the Gulf of Siam is a biogeographically single whole and is a part of the Indo-Polynesian Province of the Indo-Pacific Area. 展开更多
关键词 VIETNAM reefs Reef-Building Corals PACIFIC REEF ECOSYSTEM
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Sedimentology of the Redang Island Coral Reefs Environment
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作者 Nor Antonina Binti Abdullah Noor Azhar Mohd Shazili +1 位作者 Norhayati binti Mohd . Tahir Siti Zauyah binti Darus 《Journal of Chemistry and Chemical Engineering》 2010年第2期41-47,共7页
A study on the sedimentology of the Redang Island coral reefs environment was conducted. Sediments were collected on board UNIPERTAMA VII during the pre and post monsoon seasons. Twenty and seven sediments samples wer... A study on the sedimentology of the Redang Island coral reefs environment was conducted. Sediments were collected on board UNIPERTAMA VII during the pre and post monsoon seasons. Twenty and seven sediments samples were collected using a Smith McIntyre grab on board UNI PERTAMA VII and put in labelled plastic bags then brought back to the laboratory for analysis. The sediments were analyzed for their sedimentological characteristics (mean size, skewness, standard deviation and kurtosis) using dry sieving method. Results showed that the highest mean size value of the sediments during the pre and post monsoons seasons are 2.14 ~ and 2.37 O. respectively and the lowest are -0.40 q~ and -0.10 ~, respectively. Based on the results, sediments can be classified as medium sand (34%), poorly sorted (67%), strongly negative skewed (36%) and extremely leptokurtic (56%) during the pre monsoon season, while during the post monsoon season sediments can be classified as medium sand (38%), poorly sorted (73%), strongly negative skewed (41%) and very leptokurtic (62%). Results revealed that the sediments in the whole study area are relatively coarse. No relationship was observed between mean size and other sedimentological characteristics (R2= 0.05 pre-monsoon. R2 =0.0017 post monsoon) with seasons. 展开更多
关键词 SEDIMENTOLOGY redang island coral reefs sediment.
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The evolution of the coral reefs in the middle and north parts of the South China Sea and its relation with tectonic and eustatic movements
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《Acta Oceanologica Sinica》 SCIE CAS CSCD 1990年第2期283-292,共10页
In this paper, the morphogenesis, stratigraphic sequences and dates of the coral reefs in the middle and north parts of the South China Sea are discussed, the position of the distributary regions of Cenozoic coral ree... In this paper, the morphogenesis, stratigraphic sequences and dates of the coral reefs in the middle and north parts of the South China Sea are discussed, the position of the distributary regions of Cenozoic coral reefs in plate tectonics, the relationships of coral-reef evolutionary characteristics and dates with sea-basin spreading. Neogene sea-water transgression and Quaternary global climate-eustatic fluctuation are expounded and proved, and the latitudinal variation of the distribution of coral reefs in various geologic times are summed up. 展开更多
关键词 The evolution of the coral reefs in the middle and north parts of the South China Sea and its relation with tectonic and eustatic movements
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Quantitative Evaluation of the Sea-level Drop at the End-Permian: Based on Reefs 被引量:15
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作者 WU Yasheng and FAN Jiasong Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2003年第1期95-102,共8页
The amplitude of pre-Quaternary sea level drop, H, can be calculated by usingthe formula H = D + To, where To is the original thickness from the top of the tidal deposits onthe reef core to the bottom of the tidal dep... The amplitude of pre-Quaternary sea level drop, H, can be calculated by usingthe formula H = D + To, where To is the original thickness from the top of the tidal deposits onthe reef core to the bottom of the tidal deposits on the reef front, or to the bottom of the ancientmeteoric vadose zone, or to the edge of the mixed-water dolostone zone. The identity and similaritybetween the sea-level drop amplitudes calculated from different reefs far away from each otherindicates that such sea-level changes are eustatic rather than relative changes. Evidence of anend-Permian sea-level drop has been found on the Changxingian (i.e. the end of the Palaeofusulinazone) reefs at Ziyun in South China, including algal laminated deposits, sabkha-related dolostone,desiccation cracks, dissolution collapse breccia. According to calculation based on the meteoricdissolution zone of the reef-core sequence at Ziyun, Guizhou province, the amplitude of thesea-level drop at the end-Permian is about 89.3 m. Calculation via the dolomitized upper part of theChangxingian reef in Lichuan, Hubei Province, yields an 88.9 m amplitude of the sea-level drop atthe end-Permian. Comparison shows that the sea-level drop recorded in the two distantly locatedreefs may be of eustatic type. So the amplitude of the sea level drop of the Tethys Sea at theend-Permian might be at least 89.3 m. 展开更多
关键词 sea-level drop eustatic REEF PERMIAN Changxingian
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Habitat values for artificial oyster (Crassostrea ariakensis) reefs compared with natural shallow-water habitats in Changjiang River estuary 被引量:7
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作者 全为民 郑麟 +1 位作者 李备军 安传光 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第5期957-969,共13页
Oyster reefs have an equivalent, complex 3-dimensional structure to vegetated habitats and may provide similar functions in estuarine environments. Nevertheless, few studies have compared oyster reefs with adjacent na... Oyster reefs have an equivalent, complex 3-dimensional structure to vegetated habitats and may provide similar functions in estuarine environments. Nevertheless, few studies have compared oyster reefs with adjacent natural shallow-water habitats. Here the resident benthic macroinvertebrate communities in an artificial oyster (Crassostrea ariakensis) reef and in adjacent natural estuarine shallow-water habitats (salt marsh, intertidal mudflat, and subtidal soft bottom) in the Changjiang (Yangtze) River estuary were described. The mean total densities and biomass, Margalef's species richness, Pielou's evenness and Shannon-Weaver biodiversity indices of the resident benthic macroinvertebrate communities differed significantly among the habitats. Significantly higher densities and biomass of benthic macroinvertebrates occurred in the oyster reef compared with the other three habitats. Ordination plots showed a clear separation in benthic macroinvertebrate communities among the four habitat types. The results demonstrated that the artificial oyster reef supported distinct and unique benthic communities, playing an important role in the complex estuarine habitat by supplying prey resources and contributing to biodiversity. In addition, the results suggested that the oyster reef had been restored successfully. 展开更多
关键词 oyster reef habitat complexity biodiversity MACROINVERTEBRATES estuaries Changjiang River
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Post-Rifting Magmatism and the Drowned Reefs in the Xisha Archipelago Domain 被引量:6
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作者 WANG Hongli ZHAO Qiang +2 位作者 WU Shiguo WANG Dawei WANG Bin 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第1期195-208,共14页
Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three d... Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three different accelerated tectonic subsidence periods. The drowning of the Xisha reefs is the result of the combined action of tectonic subsidence and sea level fluctuations, and the tectonic subsidence rate had to remain above 0.2 mm yr^(-1 )for a long time. Three abrupt accelerated tectonic subsidence events that occurred in the late Miocene, Pliocene and early Quaternary in the Xisha Uplift were closely related to the thermal subsidence processes after three stages of post-rifting magmatism. The magmatism of the middle Miocene and the following thermal subsidence resulted in the drowning of reefs in the northwestern Xisha uplift(Zone A). During the early Pliocene, massive magmatic intrusions and volcanic eruptions occurred in the Xisha Uplift. Then, the subsequent thermal subsidence started the drowning process of reefs in the northeastern and western regions of the Xisha Uplift(Zone B and C). During the early Quaternary, large-scale magmatism also occurred in the Xisha Uplift. The subsequent thermal subsidence resulted in a new rapid tectonic subsidence, which caused the reefs in the southern and southeastern regions of the Xisha Uplift to drown(Zone D and E). 展开更多
关键词 MAGMATISM tectonic SUBSIDENCE drowned REEF Xisha ARCHIPELAGO
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Paleoecology of Early Ordovician Reefs in the Yichang Area,Hubei:a Correlation of Organic Reefs Between Early Ordovician and Jurassic 被引量:7
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作者 Chuantao XIAO Meng LI +2 位作者 Wei YANG Mingyi HU Chao LI 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第5期1003-1015,共13页
The Early Ordovician System is composed mainly of a series of carbonate platform deposits interbedded with shale and is especially characterized by a large number of organic reefs or buildups that occur widely in the ... The Early Ordovician System is composed mainly of a series of carbonate platform deposits interbedded with shale and is especially characterized by a large number of organic reefs or buildups that occur widely in the research area.The reefs have different thicknesses ranging from 0.5 m to 11.5 m and lengths varying from 1 m to 130 m.The reef-building organisms include Archaeoscyphia, Recepthaculitids,Batostoma,Cyanobacteria and Pulchrilamina.Through the research of characteristics of the reef-bearing strata of the Early Ordovician in the Yichang area,four sorts of biofacies are recognized,which are(1) shelly biofacies:containing Tritoechia-Pelmatozans community and Tritoechia-Pomatotrema community;(2) reef biofacies:including the Batostoma,Calathium-Archaeoscyphia, Pelmatozoa-Batostoma,Archeoscyphia and Calathium-Cyanobacteria communities; (3) standing-water biofacies:including the Acanthograptus-Dendrogptus and Yichangopora communities;and(4) allochthonous biofacies:containing Nanorthis-Psilocephlina taphocoense community.The analysis of sea-level changes indicates that there are four cycles of sea-level changes during the period when reef-bearing strata were formed in this area,and the development of reefs is obviously controlled by the velocity of sea-level changes and the growth of accommodation space.The authors hold that reefs were mostly formed in the high sea level periods.Because of the development of several subordinate cycles during the sea-level rising,the reefs are characterized by great quantity, wide distribution,thin thickness and small scale,which are similar to that of Juassic reefs in northern Tibet.The research on the evolution of communities shows that succession and replacement are the main forms.The former is favorable to the development of reefs and the latter indicates the disappearance of reefs. 展开更多
关键词 organic reef PALEOECOLOGY sea-level change Early Ordovician Yichang area
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