Monthly sea surface temperature records reconstructed by δ~(18)O of reef-building coral in the east of Hainan Island, South China Sea

Stable oxygen isotopic compositions of a coral colony of Porites lutea obtained on acore allowed the reconstruction of a 56-a (1943-1998) proxy record of the sea surface tempera-tures. This coral δ~(18)O data are from the east of Hainan Island water (22°20＇N, 110°39＇E), SouthChina Sea. The relationship between δ~(18)O in the skeletal aragonite carbonate and the sea surfacetemperature (SST) is SST=-5.36 δ~(18)O_(PDB)-3.51 (r=0.73, n=470), dδ~(18)O/d(SST)=-0.187‰/℃; and the thermometer was set at monthly resolution. The 56-a (1943-1998) proxy record of thesea surface temperatures reflected the same change trend in the northern part of South China Seaas the air temperature change trend in China.     

Monthly sea surface temperature records reconstructed by δ<Superscript>18</Superscript>O of reef-building coral in the east of Hainan Island,South China Sea

Stable oxygen isotopic compositions of a coral colony ofPorites lutea obtained on a core allowed the reconstruction of a 56-a (1943–1998) proxy record of the sea surface temperatures. This coral δ¹⁸O data are from the east of Hainan Island water (22°20’N, 110°39’E), South China Sea. The relationship between δ¹⁸O in the skeletal aragonite carbonate and the sea surface temperature (SST) is SST = -5.36 δ¹⁸O_PDB-3.51 (r = 0.73,n = 470), dδ¹⁸O/d(SST) = -0.187?/ °C; and the thermometer was set at monthly resolution. The 56-a (1943–1998) proxy record of the sea surface temperatures reflected the same change trend in the northern part of South China Sea as the air temperature change trend in China.     

Monthly sea surface temperature records reconstructed by δ18O of reef-building coral in the east of Hainan Island,South China Sea

Stable oxygen isotopic compositions of a coral colony ofPorites lutea obtained on a core allowed the reconstruction of a 56-a (1943–1998) proxy record of the sea surface temperatures. This coral δ¹⁸O data are from the east of Hainan Island water (22°20’N, 110°39’E), South China Sea. The relationship between δ¹⁸O in the skeletal aragonite carbonate and the sea surface temperature (SST) is SST = -5.36 δ¹⁸O_PDB-3.51 (r = 0.73,n = 470), dδ¹⁸O/d(SST) = -0.187‱/ °C; and the thermometer was set at monthly resolution. The 56-a (1943–1998) proxy record of the sea surface temperatures reflected the same change trend in the northern part of South China Sea as the air temperature change trend in China.

     

Differential impacts of solar UV radiation on photosynthetic carbon fixation from the coastal to offshore surface waters in the South China Sea

We carried out experiments during an expedition (14 August to 14 September, 2007) that covered up to 250,000 km(2) to investigate the effects of solar UV radiation (UVR, 280-400 nm) on the photosynthetic carbon fixation of tropical phytoplankton assemblages in surface seawater of the South China Sea. From coastal to pelagic surface seawaters, UV-B (280-315 nm) caused similar inhibition, while UV-A (315-400 nm) induced photosynthetic inhibition increased from coastal to offshore waters. UV-B resulted in an inhibition by up to 27% and UV-A by up to 29%. Under reduced levels of solar radiation with heavy overcast, UV-A resulted in enhanced photosynthetic carbon fixation by up to 25% in coastal waters where microplankton was abundant. However, such a positive impact was not observed in the offshore waters where piconanoplankton was more abundant. The daily integrated inhibition of UV-A reached 4.3% and 13.2%, and that of UV-B reached 16.5% and 13.5%, in the coastal and offshore waters, respectively.     

离子色谱法测定南海海水中的硝酸盐和磷酸盐及其对地球化学意义的初探

根据2010年"西太平洋海域海洋灾害对气候变化的响应"航次,从南海海域选取E断面4000m水深全层次站位,采用氧化银沉淀法,结合免化学试剂离子色谱技术分析了该站海水中的NO-3-N、PO3-4-P,NO-3、PO43-的检出限分别为4.84和17.1μg/L,回收率分别为94.5%和101.2%,相对标准偏差(RSD)分别为0.27%和0.15%,结果令人满意。并对其地球化学意义进行了初步分析探讨,为南海及周边海域海洋环境的研究提供了基础数据。     

PRELIMINARY RESEARCH ON CLAY MINERALS IN SALT LAKE SEDIMENTS OF CHINA AND ITS SIGNIFICANCE

Most of the clay minerals in salt lakes of China are characterized by illite-chlorite as-semblage, with a minor amount of montmorillonite and kaolinite and so on. There are ob-vious differences between mineral assemblages, relative contents and chemical compositionof clay minerals in salt lakes of different areas and in different sedimentary stages. Clayminerals in these salt lakes are basically allogenic, but transitional origin may also exist.The characteristics of clay minerals in salt lakes are controlled by the arid climatic zone ofChina and the different material supplies of salt lakes. With the data taken from clay miner-al study, the author discusses the relation of sedimentary environment of salt lakes, theregularities of immigration and enrichment of mineralization elements.     

南海海绵Pachychalina sp.化学成分的研究(二)

从中国南海海绵Pachychalinasp．的正丁醇可溶部分分离获得一种核苷类化合物，其结构经IR、MS、1H－NMR、13C－NMR和1H－1HCOSY等实验分析确定为尿嘧啶脱氧核苷。该化合物是首次从我国南海海洋动物中分离获得的。     

Variability of UVR effects on photosynthesis of summer phytoplankton assemblages from a tropical coastal area of the South China Sea

From June to September 2005, we carried out experiments to determine the ultraviolet radiation (UVR) -induced photoinhibition of summer phytoplankton assemblages from a coastal site of the South China Sea. Variability in taxonomic composition was determined throughout the summer, with a peak chlorophyll a (chl a approximately 20 microg chl a L(-1)) dominated by the diatom Skeletonema costatum that was detected early in the study period; the rest of the time samples were characterized by monads and flagellates, with low chl a values (1-5 chl a microg L(-1)). Surface water samples were placed in quartz tubes, inoculated with radiocarbon and exposed to solar radiation for 2-3 h to determine photosynthetic rates under three quality radiation treatments (i.e. PAB, 280-700 nm; PA, 320-700 nm and P, 400-700 nm) using different filters and under seven levels of ambient irradiance using neutral density screens (P vs E curves). UVR inhibition of samples exposed to maximum irradiance (i.e. at the surface) varied from -12.2% to 50%, while the daytime-integrated UVR-related photoinhibition in surface seawater varied from -62% to 7%. The effects of UVR on the photosynthetic parameters P(B)(max) and E(k) were also variable, but UV-B accounted for most of the observed variability. During sunny days, photosynthesis of microplankton (>20 microm) and piconanoplankton (<20 microm) were significantly inhibited by UVR (mostly by UV-B). However, during cloudy days, while piconanoplankton cells were still inhibited by UVR, microplankton cells used UVR (mostly UV-A) as the source of energy for photosynthesis, resulting in higher carbon fixation in samples exposed to UVR than the ones exposed only to photosynthetically active radiation (PAR). Our results indicate that size structure and cloudiness clearly condition the overall impact of UVR on phytoplankton photosynthesis in this tropical site of South China. In addition, model predictions for this area considering only PAR for primary production might have underestimated carbon fixation due to UVR contribution.     

南海海绵Pachychalina sp.化学成分研究(一)

从中国南海海绵Pachychalinasp．的正丁醇可溶部分分离得到一种具有特殊香味的酯类化合物，其结构经IR、MS、1HNMR、13CNMR分析确定为对羟基苯醋酸甲酯，该化合物是首次从我国南海海洋生物中分离获得。     

南海石珊瑚Acropora pulchro中的含氮化合物

从中国南海石珊瑚Acroporapulchro的正丁醇可溶部分获得四个含氮化合物．通过EIMS，IR，1HNMR，13CNMR和1H－1HCOSY等实验确定它们的结构为：胸腺嘧啶脱氧核苷（1）；尿嘧啶脱氧核苷（2），胸腺嘧啶（3）和尿嘧啶（4）。其中，化合物（2）为首次从珊瑚类动物中分离获得。     

LATE JURASSIC AND EARLY CRETACEOUS OSTRACOD ASSEMBLAGES OF NORTHEAST CHINA

Twelve outlined osrracod assemblages from Kimmeridgian of the late Jurassic to Albian of early Cretaceous in age can be recognized in Northeast China, in which three types of sedimentary facies, i. e. the marine, the marine-terrestrial transitional brackish and the inland lacustrine facies are included, while the latter is the most developed. The distribution horizons, characteristics and epochs of the ostracod assemblages are chiefly elucidated in the present paper.     

SEDIMENTARY PROPERTIES AND ENVIRONMENTAL VARIATIONS FROM CONTINENTAL SLOPE TO DEEP SEA PLAIN IN THE NORTHERN SOUTH CHINA SEA SINCE LATE PLEISTOCENE

The South China Sea is the westernmost marginal sea in the west Pacific Ocean. On thebasis of the analyses of sedimentary components, biofossils, oxygen-carbon isotopes and theirdatings in four seafloor cores which were collected from the deep sea plain to continentalslope in the northern South China Sea, the environmental variations were basically similarto other tropical ocean areas, and their cycle changes in about the ages of 40 ka and 20 kawere more apparent since the late Pleistocene. During the warm climates, the depositionrate on the continental slope was about 2.6 times as rapid as on the deep sea plain margin.The seafloor in the deep sea plain was below the CaCO_3 compensation depth. During thecold periods, however, the deposition rate on the deep sea plain margin was slightly quickerthan on the continental slope due to the sea level reduction on a larger scale and moresupply of the terrigenous clastics.     

Dysidavarones A-D, new sesquiterpene quinones from the marine sponge Dysidea avara

Dysidavarones A-D (1-4), four new sesquiterpene quinones possessing the unprecedented "dysidavarane" carbon skeleton, were isolated from the South China Sea sponge Dysidea avara. The structures were established by spectroscopic methods, and the absolute configurations were determined using quantum mechanical calculation of the electronic circular dichroic (ECD) spectrum and exciton chirality CD method. Their cytotoxic activity against four human cancer cell lines and PTP1B inhibitory activity were also evaluated.     

The impact of mineralogy in the U(VI)—Ca—PO4 system on the environmental availability of uranium

Kinetic dissolution studies were conducted on four prominent U-Ca-PO₄ minerals (metaschoepite, becquerelite, chernikovite and metaautunite). Synthetic samples were contacted with four extractants (acetic acid, deionized water, EDTA and sodium bicarbonate) at room temperature at two concentrations, 100 mM and 1 mM. Dissolution progress was monitored by periodic sampling for dissolved U, and dissolution rates were obtained from fits to a three term exponential model. Significant variations were observed in the rate and extent of dissolution among the mineralsexamined. The uranyl phosphates chernikovite and metaautunite proved resistant to dissolution in non-carbonate systems, with dissolution half-times of days to weeks in 100 mM systems and weeks to years in 1 mM systems. In contrast, the uranyl oxide hydrates schoepite and becquerelite were solubilized over much shorter time scales. While 100 mM bicarbonate was successful in dissolving U in all forms, dissolution rates varied among the four minerals. Overall, EDTA was the least sensitive to a 100 to 1 mM drop in its concentration in its solubilization of all four mineral phases, underscoring the importance of organic complexation for the environmental mobility of uranium.     

LINEAR ISOSTATIC GRAVITY ANOMALIES IN THE SOUTH CHINA SEA

In this paper a model of linear isostatic gravity has been shown in the South China Sea. By means of resolving a stochastic integral equation, a compensating density, which is corresponding to the topographic masses of unit volume, has been established. By calculation, the average depth of the mantle bottom under the South China Sea is 450 km and the depth of one of the interfaces within the layer B is 250 km. The depression areas of the South China Sea are caused by the surplus of the compensation in the depth between 450 and 560 km. The compensating and isostatic gravity anomalies have been resolved, and a geological interpretation has been made.     

南海黄蜂海绵中系列长链甲基酮成分分析

从中国南海海绵Spheciospongia Vagabunda乙酸乙酯萃取部分中分离出一组混合物,应用^13HNMR,^13CNMR,H-HCOSY和GC／MS等光谱分析技术对它们的结构进行了分析,主要为一些长链甲基酮化合物。共鉴定出二十四碳烯-2-酮异构体、二十四碳二烯-2-酮和二十四碳烯-2-酮等14种化合物,其中4种化合物的双键位置有待于进一步确定。     

南海佳丽鹿角珊瑚化学成分的研究(一)

从中国南海的一种石珊瑚一佳丽鹿角珊瑚（Acroporapuchro）的乙酸乙酯可溶部分获得两个有机化合物：正十六碳酸（Ⅰ）和（24S）－24-甲基胆甾醇（Ⅱ）。它们的结构是通过EIMS、IR、1HNMR、13CNMR和DEPT等实验分析确定的。其中纯的（24S）-24-甲基胆甾醇是首次从自然界大量获得。本文首次提供化合物（Ⅱ）的完整波谱数据。     

南海柳珊瑚Menella Spinifera Kukenthal化学成分的研究(一)

从中国南海针小月柳珊瑚(Menella Spinifera Kukenthal)中分离到一种长链甘油醚,其结构经UV、IR、MS、~1H NMR、~(13)C NMR、~1H-~1H COSY以及元素分析确定为3—十八烷氧基—1,2—丙二醇鲨肝醇(Ⅰ)。本文是第一次报导它存在于该种属柳珊瑚之中。 (Ⅰ)的化学结构     

海洋放线菌Streptomyces sp. V5产生的一个新的八元环内酯

海洋放线菌Streptomyces sp. V5分离自南中国海红树根部土壤, 从其培养液分离获得一个新的八元环内酯octalactin C (A), 以及四个已知化合物2-甲基-3-呋喃甲酸(B)、环(脯-亮)二肽(C)、环(丙-缬)二肽(D)和尿嘧啶(E). 通过完整的波谱数据解析了它们的结构.     

P-T stability conditions of methane hydrate in sediment from South China Sea

For reasonable assessment and safe exploitation of marine gas hydrate resource, it is important to determine the stability conditions of gas hydrates in marine sediment. In this paper, the seafloor water sample and sediment sample (saturated with pore water) from Shenhu Area of South China Sea were used to synthesize methane hydrates, and the stability conditions of methane hydrates were investigated by multi-step heating dissociation method. Preliminary experimental results show that the dissociation temperature of methane hydrate both in seafloor water and marine sediment, under any given pressure, is depressed by approximately -1.4 K relative to the pure water system. This phenomenon indicates that hydrate stability in marine sediment is mainly affected by pore water ions.