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We have used correlative analysis between mean December–January–February winter wind velocities, measured at the Xisha Meteorological Observatory (16°50′N, 112°20′E) in the middle of the South China Sea, and mean δ18O data for the corresponding month from Porites lutea coral, collected in Longwan waters (19°20′N, 110°39′E), to obtain a linear equation relating the two datasets. This winter wind velocity for the South China Sea (WMIIscs) can then be correlated to the coral δ18O by the equation WMIIscs = −1.213–1.351 δ18O (‰ PDB), r = −0.60, n = 40, P = 0.01. From this, the calculated WMIIscs-δ18O series from 1944 to 1997 tends to decrease during the 1940s to the 1960s; it increases slightly during the 1970s and then decreases again in the 1980s and 1990s. The calculated decadal mean WMIIscs-δ18O series had a obvious decrease from 5.92 to 4.63 m/s during the period of 1944–1997. The calculated yearly mean WMIIscs-δ18O value is 5.58 m/s from 1944 to 1976 and this decreases to 4.85 m/s from 1977 to 1998. That is the opposite trend to the observed yearly mean SST variation. The yearly mean SST anomaly is −0.27° from 1943 to 1976 and this increases to +0.16° from 1977 to 1998. Spectral analysis used on a 54-year-long calculated WMIIscs-δ18O series produces spectral peaks at 2.4–7 yr, which can be closely correlated with the quasibiennial oscillation band (QBO band, 2–2.4 yr) and the El N˜ino southern oscillation band (ENSO band, 3–8 yr). Hence most of the variability of the winter monsoon intensity in the middle of the South China Sea is mainly constrained by changes in the thermal difference between the land and the adjoining sea area, perhaps due to global warming. [Copyright &y& Elsevier]

Analyzes the oxygen isotropic composition of Porites lutea from the Nansha Islands in China. Indicators of sea surface and air temperature; Activities of El Nino events; Use of coral reefs in climate reconstruction.

Strontium to calcium (Sr/Ca) ratios in annual bands of Porites corals are commonly used as past sea surface temperature proxy in tropical oceans, whereas studies that refer to Sr/Ca–SST calibration in high-latitude corals are rather rare in general. Here we present a 50-year (1961–2010) near-fortnightly Sr/Ca record in two Porites lutea corals living near the northern limit of reef-building corals in the subtropical northern South China Sea, where winter temperatures are extreme for hermatypic corals. The Sr/Ca time series shows a clear annual cyclicity, with marked sharp/narrow winter peaks. Comparison with an instrumental SST record (since 1961) indicates that this Sr/Ca record is chiefly modulated by SST. Two different methods are discussed for calibrating Sr/Ca with SST. The correlation between interpolated Sr/Ca and SST is significant, but the coefficient is relatively low, mainly attributed to extreme cold winter SSTs (<~16°C) which cause a significant decrease or even cessation of coral skeletal extension. Another modified method using only annual low Sr/Ca values which could clearly be matched with the same features in the instrumental SST record is more reliable. The modified regression equation does not encompass SSTs below 24°C. The fidelity of the coral-based Sr/Ca–SST calibration was assessed and the precision of the method is estimated to be 0.31±0.62°C based on the calibration–verification exercise. The modified method is suggested in marginal coral areas with extreme intra-annual SST variation (e.g., from 13 to 30°C). [ABSTRACT FROM AUTHOR]

Abstract: A modern massive Porites coral was collected from the Longwan Bay (19°20′N, 110°39′E) on the east coast of the Hainan Island, China. The coral was sectioned vertical to the growth axis into discs of double density-bands representing annual growth. The samples were analyzed for the Sr/Ca ratio by inductively coupled plasma atomic emission spectrometry. The history of winter sea-surface temperature (SST) is reconstructed using the Sr/Ca ratio in winter bands of corals. The winter SST at Xisha in the middle of the South China Sea (SCS) is weakly correlated with the instrument-measured winter monsoon velocity (WMV) with a correlation coefficient of 0.19. The winter SST data from corals at Longwan Bay, Hainan, in the northern SCS are moderately correlated with the WMV (r =0.40). Interestingly we found that the difference of winter SSTs between the two sites (Xisha and Longwan Bay, Hainan) (the X–H index) is significantly negatively correlated with the WMV (r =−0.73). This negative correlation may be related to the intrusion of the warm Kuroshio Current into the SCS through the Luzon Strait promoted by the strong northeastern monsoon winds in the winter. Using the relationship between our coralline data and observed WMV, the calculated winter monsoon velocity (WMVc) was obtained for 87 years. This data set in combination with the instrument-measured data between 1993 and 1998 generate a record of WMVc for a period of 93 years from 1906 to 1998. The WMVc in the 20th century shows significant interannual and decadal variability with a trend of persistent decline in the whole 20th century at the rate of decrease of −0.02 (m/s)/a. The lowest wind velocity occurred during the last two decades of the 20th century. The WMVc has decreased significantly by about 30% from the early to the late of 20th century. The 20th century decline of winter monsoon velocity evidenced from the SCS coral records is consistent with the atmosphere–ocean general circulation models (AOGCMs) simulations for monsoon response to increasing temperatures. In addition, an obvious decline shift of WMV around 1976 can be seen in both instrumental and proxy records and it coincides with many other Pacific records. This shift is likely to correspond to a Pacific-wide change in the Pacific Decadal Oscillation occurring at the same time. [Copyright &y& Elsevier]

Analyzes the nature of Porites lutea from Nansha Islands, China. Determination on the carbon isotopic composition of Porites; Sensitivity of reef corals to environmental changes; Environmental factors influencing coral metabolism.

To date, the decadal variability of the Global Monsoon (GM) has been mainly studied using instrumental data collected over the last 50 years, and further discussion has been hampered by the limited data length. Here, we present a coral δ18O record from the northern South China Sea, where the hydrology is related to the seasonal Intertropical Convergence Zone (ITCZ) migration, and we use this record to reconstruct the decadal migration of the ITCZ since 1851 A.D. Combining our record with a synthesis of monsoon records reveals an anti‐phase inter‐hemispheric variability of the GM over the last 150 years, indicating that the decadal‐scale hydrologic variability in the tropics is modulated by the meridional migration of the ITCZ. The plausible relationship observed between the decadal variability of the GM and the Atlantic Multidecadal Oscillation suggests that the decadal variability of tropical hydrological changes is likely linked to the climate perturbations in the North Atlantic. Plain Language Summary: The prediction of monsoon variability in the coming decades will be of great importance for policy‐making and socio‐economic development. The Global Monsoon (GM) is the global‐scale seasonal atmospheric overturning associated with the migration of the Intertropical Convergence Zone (ITCZ). The variability and dynamics of the GM on decadal timescales are still unclear due to the limited length of the instrumental data (< 50 years). Here, we integrated a synthesis of the monsoon and the ITCZ records, including published records and our new coral record, and found that the GM varied in an anti‐phase inter‐hemispheric mode on decadal timescales associated with the ITCZ migration over the past 150 years, suggesting that the simultaneous intensification of the monsoons in both hemispheres since the ~1980s was unusual in a long‐term context. The linkage between the decadal variability of GM and the Atlantic Multidecadal Oscillation/Variability indicated that the North Atlantic has been driving the anti‐phase inter‐hemispheric variability of the GM on decadal timescales. Key Points: The coral δ18O record from the northern South China Sea captures the migration of the regional ITCZ on decadal timescalesThe Global Monsoon varied in an anti‐phase inter‐hemispheric mode on decadal timescales associated with the ITCZ migration since 1851 A.DThe decadal variability of the Global Monsoon was found to be linked to the Atlantic Multidecadal Oscillation [ABSTRACT FROM AUTHOR]

Compared with other ocean basins, annual resolution long-term series of sea-level records in the South China Sea (SCS) are still rare. Here we first analyzed the correlation mechanism between the oxygen stable isotopes (δ18O) of Porites coral and instrumental sea-level, sea surface salinity (SSS), sea surface temperature (SST) and rainfall of the SCS, and NINO 3.4 SST during 1980–2015 CE (Common Era); and we then quantitatively reconstructed sea-level at an annual resolution based on the coral δ18O in the SCS. The results show that the sea-level fell slightly (−0.73 ± 0.27 mm/yr) during 1850–1900 CE; then has continuously risen (1.31 ± 0.06 mm/yr) with a total increase of 152 ± 7 mm from 1900 to 2015 CE. On the inter-annual timescale, ENSO by mediating the overflow effect of seawater in the Western Pacific Warm Pool and the location of storm genesis in the western Pacific, indirectly affects sea-level, rainfall and SSS, which is finally reflected in changes in coral δ18O in the SCS. On the long-term timescale, especially since the 1900s, the gradual increase in SST and glaciers and ice sheets meltwater injected into the ocean due to the continuous warming mainly caused by human activities has not only promoted the rise of sea-level, but also caused a gradual negative bias of δ18O seawater (i.e. a gradual decrease of SSS), these processes are faithfully recorded by coral δ18O. Compared with SST, SSS or δ18O seawater may play a more important role in promoting the negative bias of coral δ18O in the SCS. Our study not only provides a better understanding of sea-level history and relationship mechanism around the SCS during 1850–2015 CE, but also may have the potential to provide a valuable proxy for the accurate quantitative reconstruction of sea-level at an annual resolution over a longer time scale for recent past periods. • On the interannual timescale, ENSO is the main driver of coral δ18O via its indirect effects on seawater δ18O in the SCS • On the long-term timescale, SST and injection of meltwater are the main driver of changes in coral δ18O and sea-level • Both SSS and SST are bridges between coral δ18O and sea-level • Coral δ18O is an ideal proxy to indicate sea-level, which has risen by 152 ± 7 mm in total from 1900 to 2015 CE in the SCS [ABSTRACT FROM AUTHOR]

The ways in which high-latitude corals respond to ongoing climate warming and the increasing incidence of extreme warm- and cold-water events remains unclear, probably due to a lack of field studies, especially in the northern South China Sea (NSCS). In this study, temporal variation in the skeletal growth rate in massive Porites lutea corals collected from the Weizhou Island, NSCS, was examined over a 27-year period (from 1984 to 2010). The coral skeletal extension rates were determined by using X-ray photography, and compared to the Degree Heating Weeks (DHWs) index (0–16.7 °C-weeks) and the Sea Surface Temperature (SST) Anomalies (0–0.6 °C for + SST_anomaly, and −3.2–0 °C for -SST_anomaly). Historical extreme high and low temperature events were calculated to estimate warm- (DHW > 6 °C-weeks, +SST_anomaly > 0.2 °C) and cold- (-SST_anomaly < −1.6 °C) water stresses on reef-building corals. The average skeletal growth rate for all coral colonies was 6.3 mm year−1, ranging from 3.1 to 9.9 mm year−1. Coral skeletal growth consistently showed a downward trajectory, especially after the year of 1997. The mean value was 7.3 mm year−1 from 1984 to 1996 and then declined by approximately 26% to 5.4 mm year−1 from 1997 to 2010. We found that an increasing frequency and intensity in warm- and cold-stresses can explain the observed decline in growth rate of Porites colonies in the Weizhou Island. [ABSTRACT FROM AUTHOR]

Abstract: Oxygen isotope (δ18O) data in winter months in living coral Porites lutea collected from the Xisha Islands, South China Sea is significantly correlated to the measured winter monsoon velocity (WMV) with a correlation coefficient of 0.63. Based on 40-year (1961–2000) instrumental data, a transfer function between the WMV and the winter δ18O is established: WMV=2.819 δ18O+19.615 (N =40, p <0.0001). Based on the calculated WMV from δ18O over the past 183years, the sequence of winter monsoon velocity (WMV) from year 1818 to 2000 in the South China Sea is re-constructed. The sequence can be divided into three stages: the first stage shows a decreasing trend of 0.009m/s·yr from 1818 to 1954, the second stage indicates an increasing trend of 0.011m/s·yr from 1955 to 1976, and the last stage shows a decreasing trend of 0.026m/s·yr from 1977 to 2000. The maximum reduction in winter monsoon velocity over the last 24years (1977–2000) is approximately 20% of the average over the last 183years (1918–2000). The variation of wind velocity shows two complete cycles over the past 183years. In particular, the strongest and weakest winter monsoon velocities in the last two centuries occurred in the 1830s and 1940s, respectively. The variation in winter monsoon velocity in the 20th century is closely linked to the surface temperature of the South China Sea, as well as air temperature over continental China. In addition, the winter monsoon was weak during two warm periods, i.e. the 1940s and 1980s. Statistical analysis of the winter monsoon velocity anomaly as well as the El Niño (warm event) and La Niña (cold event) phenomena indicates that 70% of El Niño events correspond to the weakness of the winter monsoon. [Copyright &y& Elsevier]

Abstract: Here we present interannual rare earth element (REE) records spanning the last two decades of the 20th century in two living Porites corals, collected from Longwan Bay, close to the estuarine zones off Wanquan River of Hainan Island and Hong Kong off the Pearl River Delta of Guangdong Province in the northern South China Sea. The results show that both coral REE contents (0.5–40 ng g−1 in Longwan Bay and 2–250 ng g−1 in Hong Kong for La–Lu) are characterized with a declining trend, which are significantly negative correlated with regional sea-level rise (9.4 mm a−1 from 1981 to 1996 in Longwan Bay, 13.7 mm a−1 from 1991 to 2001 in Hong Kong). The REE features are proposed to be resulted from seawater intrusion into the estuaries in response to contemporary sea-level rise. However, the tendency for the coral Er/Nd time series at Hong Kong site is absent and there is no significant relation between Er/Nd and total REEs as found for the coral at Longwan Bay site. The observations are likely attributed to changes of the water discharge and sediment load of Pearl River, which have been significantly affected by intense human activities, such as the construction of dams/reservoirs and riverbed sediment mining, in past decades. The riverine sediment load/discharge ratio of the Pearl River decreased sharply with a rate of 0.02 kg m−3 a−1, which could make significant contribution to the declining trend of coral REE. We propose that coastal corals in Longwan Bay and similar unexplored sites with little influences of river discharge and anthropogenic disruption are ideal candidates to investigate the influence of sea-level change on seawater/coral REE. [ABSTRACT FROM AUTHOR]

Coral reefs worldwide are becoming increasingly and detrimentally impacted upon by a variety of factors including significant climate changes, such as global warming and increased El Niño-Southern Oscillation activity. Generally, the persistence of coral reefs, especially at low-latitudes, is governed, in part, by sea surface temperatures not exceeding the critical limit (∼30°C) at which mass mortality can occur. Thus, it is thought that corals living at high-latitudes (i.e., currently cooler sea surface temperatures) will likely respond more favourably to hypothesized future temperature increases than corals living at low-latitudes (i.e., currently warmer sea surface temperatures). Consequently, high-latitude coral communities may have the potential to act as regions of refugia for many coral species in the face of potential future global warming. The Daya Bay (22°31'-22°50'N), northern South China Sea, contains several high-latitude non-reefal coral communities and represents one of the most northerly distributions of scleractinian corals within the region. Significantly, Daya Bay has experienced dramatic warming in both air and sea surface temperatures throughout the past 50 years. In this paper, we analyze 25 years of change in the Daya Bay coral communities, based both on historic surveys and our latest 2006-2008 regional ecological surveys. Our results suggest that, contrary to predictions, there have been significant declines in coral cover within the Daya Bay during the past 25 years (i.e., 76.6% coral cover in 1983/1984 to only 15.3% coral cover by 2008). Such changes also reflect a significant shift in the most abundant coral species, from Acropora pruinosa to Favites abdita. Most of the modern coral communities became established between 15 and 30 years ago, corresponding to a period of increased winter sea surface temperature. However, very few colonies have become established within the last 15 years, despite a more intense period of warming. By taking into account additional factors, we hypothesize that direct anthropogenic impacts, rather than climatic events, have both restricted the development, and drove the decline, of Daya Bay coral communities in the last 15 years. The Daya Bay has also been subjected to occasional extreme cold events during the past 50 years, with the most recent occurring in early 2008 (13 January-13 February). During the 2008 cold event, the lowest air temperature reaches only 6.6°C, and the mean sea surface temperature for February fall to <14°C, including six continuous days at 12.3°C. Significantly, the sea surface temperatures fall below the hypothesized critical lower temperature threshold (∼13°C) that commonly leads to mass mortality in scleractinian coral communities. Surprisingly, our coral community surveys, conducted both before (August 2007) and after (late February 2008) the extreme 2008 cold event, demonstrate that the Daya Bay coral ecosystems are barely impacted upon during the cold period. Those observations suggest that the Daya Bay scleractinian coral communities have developed adaptations to low sea surface temperatures. Overall, our data support the hypothesis that high-latitude coral communities, such as Daya Bay, have the potential to act as areas of refugia for scleractinian corals in the advent of potential future global warming. [ABSTRACT FROM AUTHOR]

The eight heavy metals Cr, Mn, Co, Ni. Cu, Zn. Cd, and Pb have been determined in samples of coral Porites lutea collected from Dafangji Island waters (21° 21'N, 111° 11'E), Dianbai County, Guangdong Province, China, by the ICP-MS method. The samples represent the growth of coral in the period of 1982-2001. The results showed that the waters were polluted by the heavy metals Cu, Ni, Zn, and Ph in certain years, but not by other metals. The contamination may have come from industrial sources, including electroplanting, metallurgy, mining, and aquatic industries in the coastal areas. The correlation coefficients among the metals and climatic and economic factors indicate that the metals Ni, Zn. and Cd behave similarly. Copper and Mn are positively correlated, and cobalt is negatively correlated with Cr. Ni, Zn, and Cd. Lead is not correlated with any other metals but is correlated with sea surface water temperature, air temperature, GDP and industrial-agricultural production in Dianbai County. Lead in corals is related to the enhanced pollution level of ocean waters as a result of increased industrial activities. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the relationship between fluorescent intensity in the Porites Lutea corals of Hainan Island, China and the rainfall recorded in the nearshore continent. Description of the coral samples; Experimental details; Results and discussion.