Food web structure in a near-pristine mangrove area of the Australian Wet Tropics     

Ktya Abrantes  Marcus Sheaves 《Estuarine, Coastal and Shelf Science》2009,82(4):597-607

Carbon and nitrogen isotopic composition was used to identify the main sources of carbon and describe the main trophic pathways in Deluge Inlet, a near-pristine mangrove estuary in tropical north Queensland, Australia. Producers' δ¹³C varied from −28.9‰ for mangroves to −18.6‰ for seagrass. Animals were also well separated in δ¹³C (−25.4‰ to −16.3‰ for invertebrates and −25.2‰ to −17.2‰ for fish), suggesting considerable differences in ultimate sources of carbon, from a substantial reliance on mangrove carbon to an almost exclusive reliance on seagrass. In general, invertebrates had lower δ¹⁵N than fish, indicating lower trophic levels. Among fish, δ¹⁵N values reflected well the assumed trophic levels, as species from lower trophic levels had lower δ¹⁵N than species from higher trophic levels. Trophic levels and trophic length were estimated based on δ¹⁵N of invertebrate primary consumers (6.1‰), with results suggesting a food web with four trophic levels. There was also evidence of a high level of diet overlap between fish species, as indicated by similarities in δ¹³C for fish species of higher trophic levels. Stable isotope data was also useful to construct a general model for this food web, where five main trophic pathways were identified: one based on both mangrove and microphytobenthos, one on plankton, two on both microphytobenthos and seagrass, and one based mainly on seagrass. This model again suggested the presence of four trophic levels, in agreement with the value calculated based on the difference in δ¹⁵N between invertebrate primary consumers and top piscivores.  相似文献   

Larval dispersion of the estuarine crab Neohelice granulata in coastal marine waters of the Southwest Atlantic     

Claudia Bas  Toms Luppi  Eduardo Spivak  Laura Schejter 《Estuarine, Coastal and Shelf Science》2009,83(4):569-576

The estuarine brachyuran crab Neohelice granulata export their larvae from the parental intertidal population of the Mar Chiquita coastal lagoon, and probably other populations, to marine waters. The degree of larval dispersion or self-recruitment of populations is unknown. We evaluated the presence of all larval stages of N. granulata in coastal waters of Argentina between 37.9° and 35.8° S, at two different spatial scales: a broad scale of tens to hundreds of kilometers from the Río de la Plata estuary in the north, to Mar Chiquita lagoon in the south, and a small scale of hundreds of meters to some kilometers around the mouth of Mar Chiquita, during spring and summer. Additionally, we registered the larval composition and density at San Clemente creek population, in Samborombon Bay (Río de la Plata estuary), every 3 h along a 30-hour period. Evidence indicates that larval release of N. granulata is temporally synchronized with nocturnal ebb tides and all development from Zoea I to Zoea IV occur in areas close to the parental population, even with very different oceanographic characteristics. A possible mechanism based on salinity selection and wind-driven transport is proposed for such behavior, and some considerations related to the connectivity of present populations are made.  相似文献   

0#柴油水溶性成分对僧帽牡蛎DNA损伤的初步研究   总被引：7，自引：0，他引：7  

郁昂  陈荣  王重刚  郑微云 《海洋科学》2004,28(11):10-14

在实验条件下,将僧帽牡蛎(Ostrea cucullata)分别置于含有低(0．5mg/L)、中(2mg／L)和高(5mg／L)3种浓度0^#柴油水溶性成分的海水中,利用碱解旋法测定消化腺和鳃INA损伤的程度。结果表明,INA损伤的程度随污染时间的延长而增加,并存在一定的剂量-效应关系;解除污染后,DNA损伤恢复到对照水平。DNA损伤可作为监测海洋石油污染的生物标志物。  相似文献   

东海北部外陆架EY02—1孔磁性地层研究     

葛淑兰  石学法  吴永华  熊应乾  韩贻兵  唐保根 《海洋学报》2008,30(2):51-61

对长达70.20m的东海浅钻EY02-1进行了岩石磁学和古地磁分析,证明沉积物的载磁矿物主要为低矫顽力的磁铁矿,磁性地层揭示了发生于9.62~8.58m的磁极性事件,结合钻孔上部的AMS14C测年证明它为全新世初期的哥德堡磁极性漂移,线性外推的时间是距今12681~10206Ma,为全新世开始时地磁场是否发生过短期的磁极性漂移提供了新证据;与东海高分辨率的浅地层地震剖面以及典型钻孔(中法联合东海地震调查和DZQ4钻孔)对比还揭示,在中更新世地层中也出现过两次磁倾角变化。在钻孔中下部54.00~50.94m(2271—2151号样品)出现一段磁倾角变小甚至变成负值,但是由于该段沉积物以粗颗粒的砂为主并且负向样品并不连续,依据研究的标准不作为反磁极性事件。第二个比较连续的负向样品段出现在最底部70.20~64.31m。虽然研究区域内不乏揭示中更新统地层的地震剖面,但至今没有足够长的钻孔在时间上予以佐证。根据东海地震相对比和沉积物中海侵和海退旋回的不同特征以及布容期以来报道的反磁极性事件发生的时间来推测下部地层的时代归属。由于钻孔最底部的沉积主要是粗颗粒的粉砂质砂和细砂,同时钻孔也穿透了倒数第二冰期的杂乱地震相地层和其下的平行透明海相层,所以推测下部的倒转可能为发生在MIS8晚期的CR0反磁极性事件(距今265~255ka)。  相似文献   

海运船舶尾气洗涤废水中多环芳烃对海洋污染的研究现状及展望     

张丽  杨懿  顾毅康  张文婷  刘瑞杰 《海洋通报》2022,(5):491-501

分析了海运船舶尾气洗涤废水排放对多环芳烃（PAHs）类污染物的海洋富集行为的影响以及对PAHs控制的制约因素和净化技术发展现状。PAHs的海洋富集趋势与船舶的发动机尾气排放行为呈正相关性,且船舶尾气洗涤废水排放加速了PAHs向海洋中富集。国际海事组织（IMO）尚未对在PAHs中占比大且毒性强的烷基化多环芳烃进行立法限制,但单方面采取措施禁止船舶尾气洗涤废水在其所属海域排放的国家和地区日益增多,洗涤废水排放的PAHs类污染物亟须净化处理。将高级氧化光催化技术应用于洗涤废水排放的PAHs净化具有发展前景。我国应抓住机遇,大力开展针对海洋PAHs的排放限制立法以及船舶尾气洗涤废水处理先进技术的研究,这对于提升我国海事管理水平、增大国际话语权,以及保护海洋生态安全具有重要意义。  相似文献   

Natural variability in {delta}18O values of otoliths of young Pacific sardine captured in Mexican waters indicates subpopulation mixing within the first year of life     

Valle  Sonia R.; Herzka  Sharon Z. 《ICES Journal of Marine Science》2008,65(2):174-190

  相似文献   

南海软珊瑚共附生真菌Aspergillus sp.EGF15-0-3苯甲醛类化合物研究     

刘炳新  韦霞  肖细姬  张琪  张翠仙 《热带海洋学报》2021,40(4):63-69

本文研究了具有克服肿瘤耐药活性的软珊瑚共附生真菌Aspergillus sp. EGF 15-0-3苯甲醛类化学成分。采用硅胶柱层析、十八烷基硅烷键合硅胶层析、Sephadex LH-20层析、高效液相色谱(high performance liquid chromatography, HPLC)等多种方法进行分离纯化; 通过核磁共振波谱(nuclear magnetic resonance, NMR)、质谱(mass spectrometry, MS)等现代波谱分析及物理常数对照等方法进行结构鉴定; 采用MTT法对苯甲醛部位和单体化合物进行克服肿瘤耐药活性研究。从EGF15-0-3的苯甲醛部位共得到9个苯甲醛类化合物, 结构依次为flavoglaucin (1)、tetrahydroauroglaucin (2)、isoaspergin (3)、 isotetrahydroauro-glaucin (4)、dihydroauroglaucin (5)、isodihydroauroglaucin (6)、2-(1',5'-heptadienyl)-3, 6-dihydroxy-5-(3'-methyl-2'-butenyl) benzaldehyde (7)、auro-glaucin (8)和2-(2',3-epoxy-1'-heptenyl)-6-hydroxy-5- (3'methyl-2'-butenyl) benzaldehyde (9)。体外克服肿瘤耐药活性研究表明, 苯甲醛类化合物9具有较强的克服肿瘤耐药活性, 可能是由于其结构2位烷基侧链与3羟基形成吡喃环所致。  相似文献   

Secular variations ing 1 0 component of geomagnetic field and its origin     

Qingsong Liu  Rixiang Zhu  Yongxin Pan  Bin Guo 《中国科学D辑(英文版)》1999,42(2):195-201

The secular variations (SV) ing ₁ ⁰ of geomagnetic field, caused by the interaction between the geomagnetic field and the radial fluid-flow of the outer-core, are discussed with both statistical and analytic methods. When the value ofg ₁ ⁰ s ₂ ⁰ is relatively high compared with other terms, SV ing ₁ ⁰ is characterized by exponential change. When the effect of non-dipole field is notable, SV ing ₁ ⁰ shows complex features. Especially when the value of g ₁ ⁰ is close to zero, SV ing ₁ ⁰ is completely determined by the random process of non-dipole fields. Project supported by the National Natural Science Foundation of China (Grant No. 49429405) and by the Chinese Academy of Sciences.  相似文献   

西太平洋特定海域15万年以来古海洋学研究   总被引：1，自引：0，他引：1  

苍树溪  阎军 《海洋地质与第四纪地质》1993,13(3):97-101

本文是我们近年来对西太平洋特定海域进行古海洋学研究的成果概述和讨论。古海洋学是多学科、综合性边缘科学。主要是通过对海底沉积物所进行的多项分析,包括:稳定同位素地层、地球化学元素地层、古生物地层及气候地层学方法,恢复近15万年以来古海洋环境,诸如古海流、古温度、古盐度、古季风等。  相似文献   

基于STK软件的GALILEO系统仿真与分析     

郭斐  张小红  于兴旺  王明华  胡权 《测绘信息与工程》2009,34(1):3-6

介绍了卫星工具包软件STK,并利用其对GALILEO系统的星座设计、轨道生成、可见性、覆盖精度等方面进行了详细的仿真与分析。结果表明,STK逼真的图形显示使得GALILEO系统的星座仿真具有良好的可视化效果;其强大的计算与分析功能使得卫星在轨道生成、可见性及覆盖品质等方面的分析十分高效与便捷。同时,通过对系统的有效仿真与分析也为系统的建设与应用提供了一定的参考意义。  相似文献