Correlation between Boron Isotope of Coral Acropora and pH Value of Seawater Surface

A water circulation system with the almost same element composition and socket type was adopted in coral Acropora culture under different seawater pH value conditions and the data of the relationship between boron isotopic compositions of coral and seawater pH value by thermoelectric ionization mass spectrometer were obtained. According to the correlations between α_carb-3 of coral and the pH value of cultured seawater, α_carb-3 was not a constant but related to pH value, indicating that B(OH)₃ also incorporated carbonate. Therefore, the theoretical formula could not be used to calculate the seawater pH value from the δ¹¹B_carb value of the measured marine biological carbonate. The empirical equations obtained experimentally would be an alternative method to calculate the seawater pH value. In addition, the mixed precipitation of CaCO₃ and Mg(OH)₂ was found in aquaculture tanks with high pH value, and the δ¹¹B of the solid was significantly higher than that of cultured seawater. The result indicated that the presence of Mg(OH)₂ had a significant effect on the boron isotope fractionation, which deserved our attention.     

Anthropogenic and solar forcing in δ13C time pattern of coralline sponges

We present the results of a re-analysis of a previously published carbon isotope data-set related to coralline sponges in the Caribbean Sea. The original interpretation led to the discrimination between a pre-industrial period, with a signal controlled by solar-induced climatic variations, followed by the industrial era, characterized by a progressive δ¹³C negative shift due to the massive anthropogenic carbon emissions. Our re-analysis allowed to extract from the raw isotopic data evidence of a solar forcing still visible during the industrial era, with a particular reference to the 88-year Gleissberg periods. These signals are related to slope changes in both the δ¹³C versus time and the δ¹³C versus carbon emission curves.     

单轴压缩条件下溶蚀礁灰岩细观变形破坏特征研究

礁灰岩的溶蚀对海洋工程和岛礁工程的稳定性有明显的影响.孔隙型溶蚀是礁灰岩常见的溶蚀方式.本文通过构建随机溶蚀孔洞的离散元模型,模拟孔洞型溶蚀礁灰岩的细观变形破坏特征,分析其变形破坏规律与裂隙演化特征.结果 表明,基于随机聚类算法构建的溶蚀礁灰岩离散元模型能够很好地模拟孔洞型溶蚀作用,且其变形破坏特征具有明显的规律;随着溶蚀率的增加,溶蚀礁灰岩单轴应力应变曲线由单峰型逐渐转变为双峰型或多峰型,破坏特征由脆性破坏逐渐转变为塑性破坏;随着溶蚀率的增加,礁灰岩单轴抗压强度和弹性模量都逐渐减小,抗压强度呈指数函数下降,弹性模量呈线性函数下降,而泊松比则表现为先增后降,说明试样在高溶蚀率时主要发生结构性破坏;随着溶蚀率增加,礁灰岩的宏观破裂面逐渐消失,由于溶蚀孔洞的相互作用,导致了起源于孔洞周围的裂隙开始萌生,并逐渐贯通,最终导致试样发生整体宏观破坏.本研究成果可为深入认识海洋工程和岛礁工程中溶蚀礁灰岩的变形破坏特征提供理论参考.     

Luminaolide, a novel metamorphosis-enhancing macrodiolide for scleractinian coral larvae from crustose coralline algae

A new metamorphosis-enhancing macrodiolide, luminaolide (1), was isolated from the crustose coralline algae (CCA) Hydrolithonreinboldii. Its structure was determined by spectroscopic analysis. A fraction (1.30 μg/mL) eluted with 80% aqueous MeOH by ODS gel column chromatography of the same CCA extract induced larval metamorphosis (25.9 ± 7.4%) against Leptastrea purpurea, and its metamorphosis-inducing activity was further enhanced to 92.6 ± 2.9% with the addition of 1 (25.6 ng/mL).     

三亚鹿回头海域珊瑚、石莼和碎石反射率光谱分析

以南海三亚湾鹿回头海域八种常见造礁石珊瑚优势种的反射率光谱为代表,用光谱仪测量它们和此海域常见底质石莼以及碎石的反射率光谱。通过反射率、导数光谱法研究了三亚鹿回头海域造礁石珊瑚、石莼和碎石的光谱差异。石莼于561.4 nm处出现反射率高达48%左右的显著波峰,在500～700 nm波长范围和造礁石珊瑚反射率差异较大;碎石反射率明显高于造礁石珊瑚反射率,整体差异显著。导数分析结果表明造礁石珊瑚、石莼和碎石可区分波段为：造礁石珊瑚与石莼主要为一阶导数在485～487,505～510,515～529,559～578,587～593,598～603和667～670 nm等波段。二阶导数在494.4～505.7,524～534.5,543.6～561.4和567.2～579.7 nm波段。四阶导数在515.8～430,621～627.1,628.8～635.6,639.3～645,661.8～669.8和678.4～682.4 nm等波段。造礁石珊瑚与碎石一阶导数反射光谱,主要为400～413.7,414～418,484.8～486.9,506～509.6,514.5～528.9,576.9～587.6和602.7～653.4 nm波段。二阶导数主要为,451.6～461.6,564.5～570.7和677～685 nm。四阶导数主要为,412.6～425.3,459.8～467,467.7～470.6,535.6～540.8,583.8～591.4,654.4～659.8和670.8～680 nm等波段。     

三亚鹿回头海域珊瑚、团扇藻和砂反射率光谱分析

以海南三亚湾鹿回头附近海域常见的8种优势造礁石珊瑚的反射率光谱代表该海域珊瑚的反射率光谱,用光纤光谱仪测量它们和此海域常见底质团扇藻、砂的反射率光谱。利用反射率、导数光谱法分析研究了该海域造礁石珊瑚、团扇藻和砂反射率光谱的差异。分析表明500～ 700 nm和珊瑚反射率差异相对较大;珊瑚反射率光谱明显低于砂反射率光谱,反射率谱线整体差异显著。导数分析结果显示造礁石珊瑚、团扇藻和砂的可区分波段为：石珊瑚与团扇藻的一阶导数,主要为415.1～425.6,482～487,514.5～529,577～587.6和631.9～644 nm等波段。二阶导数主要为,413～418.7,427.4～432.5,462.3～470.6,494.4～503.6,551.6～561.4,590～594和639～643 nm波段。四阶导数主要为,412.2～418.4,420.5～425.3,470.9～480.2,481.3～486.9,540.8～545.7,560～568.3和635.6～639.6 nm等波段。石珊瑚与砂的一阶导数,主要为400～413.7,514.5～529.6,576.9～587.6和602.7～667 nm波段。二阶导数主要为,420.5～430.7,446.9～458.8,467.3～472.3,537～544.3,556.8～561.4,582.8～587.2和637.6～649.4 nm。四阶导数主要为,414.4～418.7,419.5～430.3,486.9～495.8,534.2～540.1,579～583.1,622.7～627.5,640～645和665.4～672.8 nm等波段。     

珊瑚化石的红外光谱及XRD研究

通过红外吸收光谱和X射线粉晶衍射分析对不同颜色及质地且表面具放射状纹理的珊瑚化石的结构特征及组成物相进行了研究。结果表明,此类珊瑚化石主要由SiO₂组成,内部仍保留了钙质型珊瑚横断面所特有的放射状显微结构,成因属SiO₂交代作用。不同颜色和质地的珊瑚化石红外吸收光谱基本一致,均显示典型的石英质玉的红外吸收光谱特征。XRD分析表明不同颜色和质地的珊瑚化石主要组成物相一致,为SiO₂,其他矿物极微量,且不含CaCO₃。     

FABRIC-FACIES AND FABRIC-ROCK-TYPES OF REEFS

Two new concepts concerning the sedimentary petrology of reefs. fabric-facies and fabric-rock-types, are proposed in this paper. According to the author's study, 12 types of fab-ric can be recognized in recent and ancient reefs. The author suggests that reefal rocks canbe classified into 12 fabric-rock-types according to their fabric, and that reefs can be dividedinto different fabric-facies according to their fabric. The fabric-facies analysis of reefs isthe basis for understanding the sedimentary environment, porosity evolution, reservoir charac-teristics, distribution and development of reefs.     

A non-reflective spectral wave maker for SPH modeling of nonlinear wave motion

A momentum source function derived from the linear wave theory is introduced into the weakly compressible smoothed particle hydrodynamic (SPH) model for the long-time simulation of regular and irregular wave generation problems. Wave absorption is realized by adding a velocity attenuation term into the governing momentum equation. The performances of the wave maker are tested under different wave conditions. The wave maker is then applied to the study of the challenging processes, such as random wave breaking on the reef-face or the reef-crest, wave setup and spectral transfer of wave energy from the peak frequency to lower frequencies over the reef-flat. The predicted results are compared with the experimental data and a good agreement is obtained. The SPH model with a non-reflective spectral wave maker can be used as a practical tool for studying wave interaction with coastal structures.     

Computer modelling and estimation of recruitment patterns of non-branching coral colonies at three sites in the Wakatobi Marine Park, S.E. Sulawesi, Indonesia; implications for coral reef conservation

We have studied growth and estimated recruitment of massive coral colonies at three sites, Kaledupa, Hoga and Sampela, separated by about 1.5 km in the Wakatobi Marine National Park, S.E. Sulawesi, Indonesia. There was significantly higher species richness (P<0.05), coral cover (P<0.05) and rugosity (P<0.01) at Kaledupa than at Sampela. A model for coral reef growth has been developed based on a rational polynomial function:

where dx/dt is an index of coral growth with time; W is the variable (for example, coral weight, coral length or coral area), up to the power of n in the numerator and m in the denominator; a₁……a_n and b₁…b_m are constants. The values for n and m represent the degree of the polynomial, and can relate to the morphology of the coral. The model was used to simulate typical coral growth curves, and tested using published data obtained by weighing coral colonies underwater in reefs on the south-west coast of Curaçao [‘Neth. J. Sea Res. 10 (1976) 285’]. The model proved an accurate fit to the data, and parameters were obtained for a number of coral species. Surface area data was obtained on over 1200 massive corals at three different sites in the Wakatobi Marine National Park, S.E. Sulawesi, Indonesia. The year of an individual's recruitment was calculated from knowledge of the growth rate modified by application of the rational polynomial model. The estimated pattern of recruitment was variable, with little numbers of massive corals settling and growing before 1950 at the heavily used site, Sampela, relative to the reef site with little or no human use, Kaledupa, and the intermediate site, Hoga. There was a significantly greater sedimentation rate at Sampela than at either Kaledupa (P<0.0001) or Hoga (P<0.0005). The relative mean abundance of fish families present at the reef crests at the three sites, determined using digital video photography, did not correlate with sedimentation rates, underwater visibility or lack of large non-branching coral colonies. Radial growth rates of three genera of non-branching corals were significantly lower at Sampela than at Kaledupa or at Hoga, and there was a high correlation (r=0.89) between radial growth rates and underwater visibility. Porites spp. was the most abundant coral over all the sites and at all depths followed by Favites (P<0.04) and Favia spp. (P<0.03). Colony ages of Porites corals were significantly lower at the 5 m reef flat on the Sampela reef than at the same depth on both other reefs (P<0.005). At Sampela, only 2.8% of corals on the 5 m reef crest are of a size to have survived from before 1950. The Scleractinian coral community of Sampela is severely impacted by depositing sediments which can lead to the suffocation of corals, whilst also decreasing light penetration resulting in decreased growth and calcification rates. The net loss of material from Sampela, if not checked, could result in the loss of this protective barrier which would be to the detriment of the sublittoral sand flats and hence the Sampela village.