The Status of Coral Reefs and Its Importance for Coastal Protection: A Case Study of Northeastern Hainan Island, South China Sea

This study evaluated the status of coral communities at the fringing reefs in the northern South China Sea, and their potential role in maintaining nearby coastline stability of northeastern Hainan Island (Puqian Bay, Hainan Bay). Thirty-nine coral species were recorded with mean coral cover of 5.3%, and are dominated by massive Galaxea, Platygyra and Porites. The coral communities were clustered into two groups (Clu-HNB and Clu-PQB) corresponding to different stable coastal conditions. Coral communities at the Hainan Bay with higher diversity and greater cover corresponded to relatively stable coastline, whereas those at the southern Puqian Bay (with the lowest coral diversity and spatial coverage) corresponded to severe coastline erosion. This work provides some direct evidence that declined coral reefs would weaken their functions to maintain a stable coastline, resulting in severe coastal erosion. It is also useful to help coastal managers and local people pay more attention to the importance of coral reefs in coastal protection and encourage them to change their ways to get sustainable use of coral reef resources. It may be beneficial to inspire or initiate coastal engineering to manage coasts with natural coral reef solution.

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Observations on coral reefs of Hainan Island, South China Sea

Marine Pollution Bulletin ◽

10.1016/0025-326x(94)90430-8 ◽

1994 ◽

Vol 29 (1-3) ◽

pp. 84-89 ◽

Cited By ~ 19

Author(s):

Dieter Fiege ◽

Volker Neumann ◽

Jinhe Li

Keyword(s):

South China Sea ◽

Coral Reefs ◽

South China ◽

Hainan Island ◽

China Sea

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The coral communities of Yongle atoll: status, threats and conservation significance for coral reefs in South China Sea

Marine and Freshwater Research ◽

10.1071/mf15110 ◽

2016 ◽

Vol 67 (12) ◽

pp. 1888 ◽

Cited By ~ 17

Author(s):

Meixia Zhao ◽

Kefu Yu ◽

Qi Shi ◽

Hongqiang Yang ◽

Bernhard Riegl ◽

...

Keyword(s):

South China Sea ◽

Coral Reefs ◽

South China ◽

Reef Flat ◽

Coral Cover ◽

Reef Slope ◽

Xisha Islands ◽

China Sea ◽

Marine Habitats ◽

Coral Communities

Xisha Islands are in the central South China Sea and form one of the four large island groups in this region. They include more than 40 islands, reefs and cays, and have considerable ecological and biodiversity value, both intrinsically and as a source of larvae for coastal ecosystems throughout the South China Sea. Yongle atoll is the biggest and one of the most important atolls in the Xisha Islands. The detailed surveys of the marine habitats in the Yongle atoll were conducted from June to July 2013. This baseline survey revealed coral communities in a relatively healthy condition. Mean coral cover of different geomorphic habitats varied from 2 to 29%. Branching corals were most important, followed by encrusting and massive growth forms (48, 29 and 17% of coral cover). Pocillopora (29% of total cover in line transects), Porites (19%), Acropora (17%) and Montipora (16%) were the four dominant genera. Communities differentiated into four clusters, namely, lower reef slope, upper reef slope, outer reef flat, and inner reef flat and lagoon slope. This baseline investigation highlighted the ecological value of these reefs. Destructive fishing and overfishing are presently the most serious threats for these coral reefs. They should receive much more scientific and conservation attention.

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Coral reefs of Hainan Island, South China Sea

Marine Pollution Bulletin ◽

10.1016/0025-326x(87)90652-7 ◽

1987 ◽

Vol 18 (1) ◽

pp. 25-26 ◽

Cited By ~ 19

Author(s):

P.A. Hutchings ◽

B.L. Wu

Keyword(s):

South China Sea ◽

Coral Reefs ◽

South China ◽

Hainan Island ◽

China Sea

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Evaluation Method of Coral Reef Integrity: RMDI and Coring Rate Comparative Analysis Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.1396 ◽

2014 ◽

Vol 989-994 ◽

pp. 1396-1399

Author(s):

Jin Chao Wang ◽

Chuan Ying Wang ◽

Zeng Qiang Han

Keyword(s):

Comparative Analysis ◽

Coral Reef ◽

South China Sea ◽

Coral Reefs ◽

South China ◽

Evaluation Method ◽

Geological Data ◽

Analysis Method ◽

China Sea ◽

Borehole Camera

At present, relatively few drilling surveys have been conducted on coral reefs, and comprehensive geological info on coral reefs is difficult to obtain. However, research of coral reef is of great importance to our development and exploitation of maritime resources. The survey of South China Sea some Islands saw China’s first usage of digital borehole camera technology, which resulted in a large amount of first-hand geological data. Because the coral reef, special rock mass, integrity evaluation is very difficult, we proposed the RMDI and coring rate comparative analysis method. The evaluation method is applied to the South China Sea some Islands, and the evaluation results prove generally consistent with actual cores. The results indicate that: (1) high-resolution borehole images can provide reliable results for evaluation of coral reef integrity; (2) The RMDI and coring rate comparative analysis method is a feasible approach for the evaluation of coral reef integrity along the full or partial depth of a borehole.

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Diazotroph diversity associated with scleractinian corals and its relationships with environmental variables in the South China Sea

10.21203/rs.2.17643/v1 ◽

2019 ◽

Author(s):

Jiayuan Liang ◽

Kefu Yu ◽

Yinghui Wang ◽

Xueyong Huang ◽

Wen Huang ◽

...

Keyword(s):

Coral Reef ◽

South China Sea ◽

Coral Reefs ◽

South China ◽

Human Activities ◽

Environmental Variables ◽

The South China Sea ◽

The South ◽

Fringing Reef ◽

China Sea

Abstract Background: Coral reef ecosystems cannot operate normally without an effective nitrogen cycle. For oligotrophic coral reef areas, coral-associated diazotrophs are indispensable participants in the nitrogen cycle. How coral-associated diazotrophs will change in order to adapt to environmental changes resulting from global warming and human activities is a topic of concern for researchers. To this end, 68 colonies of scleractinian coral were collected from 6 coral reefs areas with different environmental variables in the South China Sea to investigate the composition of associated diazotrophs based on nifH gene amplification using high-throughput sequencing. The six coral reefs can be clearly divided into two types (fringing reefs and island reefs), are affected by varying degrees of human activities and are located at different latitudes from 9°20′06′′N to 22°34′55′′N with different seawater temperatures. Results: Alpha- and beta-diversity analyses showed that the distribution of diazotrophs among coral reefs exhibited greater geographical fluctuations than interspecific fluctuations. The predominant bacterial phyla included Proteobacteria, Chlorobi, Cyanobacteria, and two unclassified phyla. Chlorobi exhibited an abundance of 47–96% in coral samples from the high-latitude Daya Bay fringing reef affected by eutrophication. Unclassified bacteria II, with an abundance of 28–87%, was found in all coral samples from the midlatitude Luhuitou fringing reef affected by eutrophication. However, unclassified bacteria I and Proteobacteria dominated (> 80% abundance) in most of the coral samples from the Weizhou Island fringing reef, which is far from land, and three island reefs (Huangyan Island, Xinyi Reef, and Sanjiao Reef) at relatively low latitudes. At the genus level, some core diazotrophs were found in different coral sample groups. In addition, the correlation analysis with various environmental variables revealed that the variables correlated positively or negatively with different diazotrophic genera. Conclusions: We found that coral-associated diazotrophs were common among coral individuals. The presence of these diazotrophs was not affected by the external environment, but their population abundances were closely related to the different environmental variables. These results provide insights into the ecological characteristics of coral-associated diazotrophs and their relationships with critical environmental variables in the South China Sea.

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Evaluation of HRCLDAS and ERA5 Datasets for Near-Surface Wind over Hainan Island and South China Sea

Atmosphere ◽

10.3390/atmos12060766 ◽

2021 ◽

Vol 12 (6) ◽

pp. 766

Author(s):

Yi Jiang ◽

Shuai Han ◽

Chunxiang Shi ◽

Tao Gao ◽

Honghui Zhen ◽

...

Keyword(s):

South China Sea ◽

South China ◽

Surface Wind ◽

Hainan Island ◽

The South China Sea ◽

Wind Data ◽

The South ◽

Near Surface ◽

China Sea

Near-surface wind data are particularly important for Hainan Island and the South China Sea, and there is a wide range of wind data sources. A detailed understanding of the reliability of these datasets can help us to carry out related research. In this study, the hourly near-surface wind data from the High-Resolution China Meteorological Administration (CMA) Land Data Assimilation System (HRCLDAS) and the fifth-generation ECMWF atmospheric reanalysis data (ERA5) were evaluated by comparison with the ground automatic meteorological observation data for Hainan Island and the South China Sea. The results are as follows: (1) the HRCLDAS and ERA5 near-surface wind data trend was basically the same as the observation data trend, but there was a smaller bias, smaller root-mean-square errors, and higher correlation coefficients between the near-surface wind data from HRCLDAS and the observations; (2) the quality of HRCLDAS and ERA5 near-surface wind data was better over the islands of the South China Sea than over Hainan Island land. However, over the coastal areas of Hainan Island and island stations near Sansha, the quality of the HRCLDAS near-surface wind data was better than that of ERA5; (3) the quality of HRCLDAS near-surface wind data was better than that of ERA5 over different types of landforms. The deviation of ERA5 and HRCLDAS wind speed was the largest along the coast, and the quality of the ERA5 wind direction data was poorest over the mountains, whereas that of HRCLDAS was poorest over hilly areas; (4) the accuracy of HRCLDAS at all wind levels was higher than that of ERA5. ERA5 significantly overestimated low-grade winds and underestimated high-grade winds. The accuracy of HRCLDAS wind ratings over the islands of the South China Sea was significantly higher than that over Hainan Island land, especially for the higher wind ratings; and (5) in the typhoon process, the simulation of wind by HRCLDAS was closer to the observations, and its simulation of higher wind speeds was more accurate than the ERA5 simulations.

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