Spatial and Temporal Variability of Thermal Stress to China's Coral Reefs in South China Sea

Coral bleaching, caused by elevated sea surface temperature(SST), is occurring more frequently and seriously worldwide. Due to the lack of field observations, we understand little about the large-scale variability of thermal stress in the South China Sea(SCS) and its effect on China's coral reefs. This paper used 4-km high resolution gap-filled SST(Filled SST) data and thermal stress data related to coral bleaching derived from Coral Reef Temperature Anomaly Database(Co RTAD) to quantify the spatial and temporal characteristics of chronic thermal stress and acute thermal stress to China's coral reefs in SCS from 1982 to 2009. We analyzed the trend of SST in summer and the thermal stress frequency, intensity and duration during this period. The results indicate that, as a chronic thermal stress, summer mean SST in SCS shows an average upward trend of 0.2℃/decade and the spatial pattern is heterogeneous. Waters of Xisha Islands and Dongsha Islands of the northern SCS are warming faster through time compared to Zhongsha Islands and Nansha Islands sea areas of the southern SCS. High frequency bleaching related thermal stress events for these reefs are seen in the area to the northwest of Luzon Island. Severe anomaly thermal stress events are more likely to occur during the subsequent year of the El Nino year for these coral reefs. Besides, the duration of thermal stress varies considerably by anomaly year and by region.

Temporal stability of Symbiodinium phylotype in scleractinian coral Galaxea fascicularis from a tropical fringing reef in the South China Sea

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.

Progress on Research and Construction of Marine Ranching along the Coast of Shandong Province of China

As a new fishery mode of low-carbon economy, marine ranching has played an important role in promoting sustainable development of fishery and construction of ocean economic zone in China. Since the year of 2000, environment improvement, stock enhancement and mariculture development have been given very high degree of importance along the coast of Shandong Province of China. Studies and tests on artificial reefs and marine ranching, including effect investigation of artificial reefs set up in Jiaonan coastal areas in 1980s, hydrodynamic characteristics experiment of artificial reef, study on material and configuration of artificial reef models, algae transplantation and seaweed beds construction, stock enhancement and releasing etc., have been carried out in recent years. Furthermore, the Restoration Plan of Fishery Resources of Shandong Province has been implemented since the year of 2005, which greatly boosted the construction of artificial reefs and marine ranching along the coast of Shandong. By June of 2010, the total investment on the construction of artificial reefs and marine ranching is over $77 million USD. One hundred artificial reef districts, with total area about 33,350,000 m2 have been set up. The construction of marine ranching along the coast of Shandong Province has been in certain scale and the economic, social and ecological effects are obvious.

Running Head： Foram Assemblages from Three Substrata Comparison of Foraminiferal Assemblages from Three Kinds of Substrata, Durney Key, West-Central Florida, USA

As part of a project that assessed a proposed artificial reef site, this study compared benthic foraminiferal assemblages from three substrata： sediment, natural lime rock and recruitment tiles. The assemblage from sediment samples included 21 foraminiferal species representing 12 genera and was dominated by stress-tolerant taxa, especially Ammonia and Elphidium. Natural lime rock and recruitment tiles yielded 21 foraminiferal species representing 11 genera, which were dominated by miliolids. Intersample variability was characterized by ＂pulsating patches＂ as has been previously described for Florida estuaries. The predominance of stress-tolerant taxa in sediments was consistent with other observations from the site, which indicated that proposed artificial reef structures were not likely to recruit significant coral-reef biota.

Coral reefs in the South China Sea:Their response to and records on past environmental changes

This paper reviews both the recent and longer-term （Holocene） ecological history of coral reefs in the South China Sea （SCS）. （1） Local ecological monitoring since the 1960s shows that the coral reefs in the South China Sea have declined dramatically, reflecting the rapid decrease of living coral cover and the great loss of symbiotic zooxanthellae. Collectively, this has led to a significant decrease of annual CaCO3 production. Heavy anthropogenic activities and global warming are recognized as major triggers of the observed coral reef degradation. Observations show that the modern coral reefs in the SCS are a source of at- mospheric CO2 in summer. （2） Coral reefs of the SCS have been widely used to reveal longer-term environmental variations, including Holocene high-resolution sea surface temperature （SST） and abrupt climate events, millennial-scale E1 Nifio varia- tions, millennial- and centennial-scale sea level oscillations, strong and cyclic storm activities, East Asian monsoon intensities, variation in seawater pH, and recent seawater pollution. （3） Coral reefs of the southern SCS have experienced repeated epi- sodes of bleaching over the last 200 years due to high SST and intense E1 Nino events; coral reefs of the northern SCS suffered high levels of mortality during several abrupt winter cold-water bleaching events during the middle Holocene warm period. On average, recovery after the middle Holocene cold-bleaching took 20-30 years; recovery following other middle Holocene en- vironmental stresses took approximately 10-20 years. Such findings have significantly contributed to the understanding of the present ecological pressures faced by the coral reefs in the SCS, the histories of Holocene climate/environment changes, and the long-term models of coral reef responses to various past environmental changes.

Evolution of the Late Miocene atoll systems offshore Xisha Islands

Modern atolls have been studied systematically and thoroughly in the South China Sea.However,the knowledge of a paleo-atoll and related sedimentary system is very limited.Here we used the newly acquired high resolution 2D seismic data,and discovered three late Miocene atoll systems in the offshore Xisha Islands for the first time.We named them atoll system A,B,C,respectively.These three atoll systems,all developed on the horsts dominated by normal fault,consist mainly of atoll reefs,patch reefs,fore-reef slope deposits,and lagoons.On the basis of the interpreted sequence stratigraphic framework and the identification of fore-reef slope deposits,we suggested only the atoll system A continued to grow until Quaternary,and both of atoll system B and C had been drowned in Pliocene.In late Miocene,the atoll systems in the study area were most developed,either in magnitude or in maturity,which indicated late Miocene was the most flourishing period of reef builders,and this was in accordance with the drilling result of ODP Leg 184 in the South China Sea.Pliocene was an important reef drowning period in the study area,and both atoll systems B and C were drowned and hemipelagic deposits prevailed gradually.Quaternary was another reef drowning period in the study area,two large atoll reefs grown on the atoll system A were finally drowned,and hemipelagic deposits begun to drape and fill the palaeo-atoll systems.The growth and drowning of atolls are controlled mainly by tectonic subsidence in long term,but global eustatic can impact it in short term also.

Black band disease as a possible factor of the coral decline at the northern reef-flat of Yongxing Island,South China Sea

Black band disease （BBD）, characterized by the Cyanobacterial dominated pathogenic consortium, is thought to play a key role in the global decline of the coral reef ecosystems. The present paper originally documents a case of BBD from Yongxing Island （Xisha Islands, South China Sea）, and further probes the reasons of this abnormal phenomenon. Prior to 2007, corals at northern reef-flat of Yongxing Isand were in healthy growth. Catastrophic coral mortality occurred between 2007 and 2008. The 16S rRNA gene sequencing and PCR amplification, with universally conserved primers, were applied to detect the conta- gious bacterial community of the microbial mat. The results demonstrated that six bacterial divisions constituted the clone libraries derived from the BBD mat, and that Cyanobacteria are the most diversely represented group that inhabit BBD bacteri- al mats, despite the fact that species in five others divisions （a-Proteobacteria, y-Proteobacteria, Bacteroidetes, Verrucomi- crobia and Actinobacteria） are also consistently diverse within the BBD mats of diseased coral. Other factors such as coral bleaching, typhoons, ocean acidification and crown-of-thorns starfish outbreaks, are not primarily responsible for the coral mortality within such a short time interval. The disaster expansion of BBD associated with Cyanobacterial blooms is a more likely mechanism impacting these coral reefs. Excessive human activity enhances the eutrophication of the marine water of the reefal region and may result in occurrence of the BBD.