Institutional Repository of South China Sea Institute of Oceanology, CAS
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Strong Intraseasonal Variability of Meridional Currents near 5 degrees N in the Eastern Indian Ocean: Characteristics and Causes
No full textThis paper reports on strong, intraseasonal, upper-ocean meridional currents observed in the Indian Ocean between the Bay of Bengal (BOB) and the equator and elucidates the underlying physical processes responsible for them. In situ measurements from a subsurface mooring at 5 degrees N, 90.5 degrees E reveal strong intraseasonal variability of the meridional current with an amplitude of; similar to 0.4 m s(-1) and a typical period of 30-50 days in the upper 150 m, which by far exceeds the magnitudes of the mean flow and seasonal cycle. Such prominent intraseasonal variability is, however, not seen in zonal current at the same location. Further analysis suggests that the observed intraseasonal flows are closely associated with westward-propagating eddylike sea surface height anomalies (SSHAs) along 5 degrees N. The eddylike SSHAs are largely manifestations of symmetric Rossby waves, which result primarily from intraseasonal wind stress forcing in the equatorial waveguide and reflection of the equatorial Kelvin waves at the eastern boundary. Since the wave signals are generally symmetric about the equator, similar variability is also seen at 5 degrees S but with weaker intensity because of the inclined coastline at the eastern boundary. The Rossby waves propagate westward, causing pronounced intraseasonal SSHA and meridional current in the upper ocean across the entire southern BOB between 848 and 94 degrees E. They greatly weaken in the western Indian Basin, but zonal currents near the equator remain relatively strong
Trace metal anomalies in bleached Porites coral at Meiji Reef, tropical South China Sea
No full textCoral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium (Cr), copper (Cu), molybdenum (Mo), manganese (Mn), lead (Pb), tin (Sn), titanium (Ti), vanadium (V), and yttrium (Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea (SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events
南海白云凹陷东侧巨型麻坑中自生碳酸盐岩的特征及其地质意义
No full text探测发现南海白云凹陷东侧存在一个宽1 500m、深达75m的巨型麻坑,在麻坑内采集了大量的碳酸盐岩结核。大部分结核中存在新鲜孔洞和流体通道。本文从中选取了5块结核,进行XRD衍射、扫描电镜、碳氧同位素分析。结果表明,5个结核中碳酸盐矿物主要是含铁白云石,其中一个还有少量方解石,碎屑矿物主要是石英和长石。结核的显微结构以纤维状为主,存在裂隙和孔洞。δ~(13)C值为-24.7‰~-10.9‰V-PDB,显示孔隙流体主要以热成因甲烷为主。δ~(18)O值为5.6‰~6.9‰V-PDB,高值主要与天然气水合物分解有关。巨型麻坑海底之下最可能存在天然气水合物埋藏。含铁白云石结核在麻坑表层沉积物之下形成,随后出露海底。碳酸盐岩结核指示巨型麻坑内曾发生的甲烷渗漏活动可能与深部油气泄露有关,浅地层剖面中疑似气体羽和结核表面管状蠕虫活体都显示巨型麻坑仍在发生甲烷渗漏
南海北部晚新生代岩浆活动的地震学特征
No full text1.引言南海是西太平洋最大的边缘海之一,位于欧亚、印-澳和太平洋三大板块的交汇处,其演化过程经历了晚中生代俯冲到新生代大陆张裂、破裂及海底扩张,以及随后洋壳俯冲等一系列完整的构造演变过程,集聚了从陆到洋、从俯冲输入到岩浆输出到再俯冲输入等极具特色的构造叠加景观,是开展洋-陆构造变迁和地球深-浅循环演变的极佳场所。从世界范围来看张裂大陆边缘被划分为火山型(e.g.,Geoffroy,2005)和非火山型(e.g.,Reston,2009)两个端元,其判别的标准主要是大陆在张裂或破裂
深渊着陆器携带OBS潜次坐底位置反演定位结果
No full text海洋中深度超过6000m的海沟区域被称为海斗深渊~([1,2]),受限于其超水深、超高压、科研仪器以及技术条件的不足,人类对深渊一直知之甚少。随着科研仪器设备的发展、深渊探测技术瓶颈的突破,深渊已经成为了研究的热点区域,深渊科学正成为蕴含重大突破的最新前沿领域~([3])。深渊科学
中国南海深海真菌Exophiala sp. SCSIO 05791次级代谢产物研究
No full text对中国南海500 m深海水来源真菌Exophiala sp.SCSIO 05791进行了次级代谢产物研究;综合运用硅胶柱层析、Sephadex LH-20凝胶柱层析、中压反相柱层析以及半制备高效液相等色谱学方法对其大米发酵产物进行分离纯化,从中分离到8个单体化合物,利用核磁共振、质谱等波谱学手段并结合其理化性质及文献数据鉴定了其化学结构:stephacidin A(1)、吲哚-3-乙酸(2)、环(D)-脯氨酸-(D)-苯丙氨酸(3)、反式阿魏酸(4)、顺式阿魏酸(5)、2-(乙酰氨基)-苯酚(6)、氨基苯甲酸(7)、4-羟基苯酞(8)。化合物1~8均为首次从该属中分离得到
海洋细菌有机磷酸酐水解酶在大肠杆菌中的分泌表达研究
No full text为了考察一种海洋细菌来源的有机磷酸酐水解酶OPAA4301在大肠杆菌中胞外分泌表达生产的可能性,笔者分别从信号肽和发酵条件两方面对该酶在大肠杆菌中的产量及细胞定位情况进行观测和优化。结果发现,海洋细菌有机磷酸酐水解酶OPAA4301在大肠杆菌中可不依赖信号肽少量分泌至培养基上清中。以胞外酶产量为指标,对诱导剂和甘氨酸添加量进行优化,确定适宜的诱导剂浓度为0.8 mmol/L,适宜甘氨酸添加量为10 g/L。在优化条件下,重组酶蛋白的细胞定位主要由细胞内转变为细胞外,胞外酶活提高108.8倍,达0.28 U/m L,相当于重组蛋白胞外生产能力为0.72 g/L。本研究为重组海洋细菌有机磷酸酐酶的工程化发酵生产提供理论基础
雷州半岛东南海域污损浮标的大型藻类
No full text大型藻类是海洋污损生物群落中的常见类群,其附着会破坏浮标防护涂层,增加浮体重量,增大水流拖曳力,导致腐蚀危害风险升高,甚至可能造成浮标移位,从而缩短相关设施的工作时间。为探讨热带海区冬季浮标大型藻类附着污损状况及其与浮标布设时间的关系,于2015年2月初,对布设在雷州半岛东南海域2个近岸浮标上附着的大型海藻进行采样分析。结果表明,该海域浸海时间6个月的浮标A,浮体侧面仅附着浒苔(Enteromorpha prolifera)和石莼(Ulva lactuca)2种大型绿藻,而在浸海时间19个月的浮标B上,共采集到绿藻门的浒苔、肠浒苔(E.intestinalis)、石莼、裂片石莼(U.fasciata)和红藻门的舌状蜈蚣藻(Grateloupia livida)、柔质仙菜(Ceramium tenerrimum)6个种类。浮体侧面下部和浮底没有采集到大型污损藻类。浒苔、肠浒苔、石莼、裂片石莼为喜强光藻类,繁殖力强,配子或孢子在浮体固着形成一定生物量的种群后,不太喜光的舌状蜈蚣藻和柔质仙菜才出现,表现出先附着绿藻后附着红藻的着生规律,且浮标浸海时间越长,污损藻类的种类越多。浮体水线部位的污损主要由绿藻引发,而红藻则多出现在浮体侧面浸没区域略深的部位,这种格局应与藻类所含色素的种类和比例及光线在海水中的穿透性等因素密切相关。研究结果可为航标污损生物防治和南海大型藻类生态研究提供基础资料
深海微生物酯酶在手性羧酸酯制备中的研究
No full text酯酶作为一种工业水解酶，能够通过转酯、酯化和直接水解反应制备重要的精细化工产品和药物中间体，已被广泛应用于手性药物和手性化工产品的合成。本研究从西太平洋深海来源的微生物Pseudomonadaceae oryzihabitans HUP022的基因组中表达并鉴定了两个新颖的酯酶，分别命名为PHE14和PHE21。
对酯酶PHE14的基本酶学性质进行研究，结果表明，对硝基苯酚乙酸酯(C2)是PHE14的最适反应底物，酶活达到293.1 U/mg。Km值为0.24 mmol/L，Vmax值为200 μM/(mg· min)。PHE14水解反应的最适pH和温度分别为9.0和60°C。在多种pH缓冲溶液中，PHE14都具有非常高的稳定性。PHE14对多种有机溶剂、表面活性剂、金属离子及高浓度NaCl都具有非常好的耐受性。同时，PHE14作为一种生物催化剂，可以催化乳酸甲酯不对称水解生成一种重要的手性化工产品—D-乳酸甲酯。通过实验条件优化，可以获得对映体过量值、转化率和产率分别为99%、50.6%和88.7%的D-乳酸甲酯。本研究是第一个通过酯酶催化水解反应制备高纯度的D-乳酸甲酯的研究。
对酯酶PHE21的基本酶学性质进行研究，结果表明，PHE21的最适反应底物为对硝基苯酚丁酸酯(C4)，酶活达到333.18 U/mg，因此，PHE21被定性为酯酶。Km值为0.62 mmol/L，Vmax为4339 μM/(mg· min)。PHE21水解反应的最适pH和温度分别为8.0和65°C。PHE21同时是一个对多种金属离子、有机溶剂和表面活性剂都具有相当强的耐受性的酯酶。通过对PHE21的研究，成功地利用PHE21作为催化剂，直接催化水解反应水解外消旋的3-羟基丁酸乙酯生成一种重要的手性药物和化工产品的的中间体—光学纯的(S)-3-羟基丁酸乙酯。通过实验条件优化，最后获得了对映体过量值和产率分别为99%和87%的(S)-3-羟基丁酸乙酯。
此外，通过对酯酶PHE21的进一步研究发现，PHE21还可以通过催化不对称水解反应和转酯反应来制备另外两种重要的药物中间体—(S)-乙酸仲丁酯和(R)-乙酸仲丁酯。首先，PHE21可以通过催化外消旋的乙酸仲丁酯的不对称水解生成光学纯的(S)-乙酸仲丁酯，经过实验条件优化，最后反应产物(S)-乙酸仲丁酯的对映体过量值和产率分别为98%和83.6%。同时，PHE21还可以通过催化转酯反应生成(R)-乙酸仲丁酯，产物(R)-乙酸仲丁酯的对映体过量值和产率分别为64%和43%。
以上结果说明，本课题研究的两个新颖的海洋微生物酯酶PHE14和PHE21对多种有机溶剂、金属离子和表面活性剂都具有非常好的耐受性，同时对多种手性化合物都具有非常高的立体选择性，因此，PHE21和PHE14作为两种绿色生物催化剂，在不对称合成和其他工业领域都具有非常大的应用潜力
Aspergchromones A and B, two new polyketides from the marine sponge-associated fungus Aspergillus sp SCSIO XWS03F03
No full textTwo new polyketides, aspergchromones A (1) and B (2), together with five known compounds, secalonic acid D (3), noreugenin (4), (3S)-5-hydroxymellein (5), (4S)-6-hydroxyisosclerone (6), and (-)-regiolone (7), were isolated from the ethyl acetate extract of marine sponge-derived fungus Aspergillus sp. SCSIO XWS03F03. Their structures were elucidated by means of spectroscopic techniques (1D and 2D NMR, MS, UV, and IR). The absolute configurations of the new compounds were established by ECD calculations. Compound 3 showed moderate antimicrobial activity