Palynological characterization of gassy sediments in the inner part of Ría de Vigo (NW Spain). New chronological and environmental data

Palynological characterization of the pollen assemblages from core ZV-01 offers a reliable age record of shallow ‘gas seal’ and ‘gas reservoir’ sediments from the Ría de Vigo (NW Spain). Gassy sediments show a direct correspondence with the palynological assemblage zones (LPAZ) 2, 3 and 4, which range in age from 950 to 1510 a.d. for the interval 81–176 cm where gas is found. The facies acting as a seal would correspond to the sedimentation in the ria starting from 1510 a.d. These assemblages also provide significant data which make it possible to reconstruct the palaeoenvironmental changes recorded in the sedimentary infill of the Ría de Vigo. The gassy horizon corresponds to the phase when riparian and mesophilous forest were better represented. This coincides with a relative high abundance of Lingulodinium machaerophorum, which indicates that the waters of the ria had been less renewed by oceanic waters and had a plentiful supply of continental nutrients. At that time, anoxic conditions resulted from restricted vertical circulation of seawater and/or high biological productivity. The dinocyst assemblages overlying and underlying the gassy horizon in core ZV-01 are clearly different from those concomitant with the accumulation of the gassy sediments. This suggests that oceanographic conditions in the Ría de Vigo may have changed several times during the time interval covered by our record. The weaker relationship between L. machaerophorum/Spiniferites spp., and simultaneous significant increases in Impagidinium spp. and Bitectatodinium tepikiense may indicate a greater intrusion of colder, more oceanic waters into the Ría de Vigo, which may have provoked intensification in upwelling during two periods, ca. 700–850 a.d. and ca. 1500–1750 a.d.     

The importance of extratropical and tropical cyclones on the short-term evolution of barrier islands along the northern Gulf of Mexico, USA

Data are presented indicating the complexity and highly variable response of beaches to cold front passages along the northern Gulf of Mexico, in addition to the impacts of tropical cyclones and winter storms. Within the past decade, an increase in the frequency of tropical storms and hurricanes impacting the northern Gulf has dramatically altered the long-term equilibrium of a large portion of this coast. A time series of net sediment flux for subaerial and nearshore environments has been established for a section of this coast in Florida, and to a lesser extent, Mississippi. The data incorporate the morphological signature of six tropical storms/hurricanes and more than 200 frontal passages.

Data indicate that (1) barrier islands can conserve mass during catastrophic hurricanes (e.g., Hurricane Opal, a strong category 4 hurricane near landfall); (2) less severe hurricanes and tropical storms can promote rapid dune aggradation and can contribute sediment to the entire barrier system; (3) cold fronts play a critical role in the poststorm adjustment of the barrier by deflating the subaerial portion of the overwash terrace and eroding its marginal lobe along the bayside beach through locally generated, high frequency, steep waves; and (4) barrier systems along the northern Gulf do not necessarily enter an immediate poststorm recovery phase, although nested in sediment-rich nearshore environments. While high wave energy conditions associated with cold fronts play an integral role in the evolution and maintenance of barriers along the northern Gulf, these events are more effective in reworking sediment after the occurrence of extreme events such as hurricanes. This relationship is even more apparent during the clustering of tropical cyclones.

It is anticipated that these findings will have important implications for the longer term evolution of barrier systems in midlatitude, microtidal settings where the clustering of storms is apparent, and winter storms are significant in intensity and frequency along the coast.     

Geologic evolution of the Canarian Islands of Lanzarote, Fuerteventura, Gran Canaria and La Gomera and comparison of landslides at these islands with those at Tenerife, La Palma and El Hierro

In this paper we discuss the results of a swath bathymetric investigation of the Canary archipelago offshore area. These new data indicate that volcanism is pervasive throughout the seafloor in the region, much more that would be suggested by the islands. We have mapped tens of volcanic edifices between Fuerteventura and Gran Canaria and offshore Tenerife, La Gomera, El Hierro and La Palma. Volcanic flows are present between Tenerife and La Gomera and salic necks dominate the eastern insular slope of La Gomera. This bathymetry also supports land geologic studies that indicate that the oceanic archipelago has acquired its present morphology in part by mass wasting, a consequence of the collapse of the volcanic edifices. In the younger islands, Tenerife, La Palma and El Hierro, the Quaternary (1.2 to 0.15 Ma) debris avalanches are readily recognizable and can be traced offshore for distances measured in tens of km. Off the older islands, Lanzarote, Fuerteventura, Gran Canaria and La Gomera (<20 to 3.5 Ma), the avalanches have been obscured by subsequent turbidity current deposition and erosion as well as hemipelagic processes. The failure offshore western Lanzarote is in the form of a ramp at the base of the insular slope bound on the seaward side by a scarp. Its size and the lack of evidence of rotation along its landwards side precludes the possibility that it is a slump. It probably represents a slide whose outer scarp is caused by break-up of the slide. Mounds on the ramp’s surface may represent post-displacement volcanic structures or exotic blocks transported to their present locations by the slide. The failures offshore Fuerteventura are so large that, although they occurred in the Miocene-Pliocene, exotic blocks displaced from upslope are still recognizable in the insular margin morphology. The Canary Island insular margin appears to be a creation of Miocene-Pliocene mass wasting and more recent turbidity current deposition and erosion, and hemilepagic deposition. Failures offshore La Gomera are due to debris flows and/or turbidity currents. These events have obscured earlier mass wasting events. An erratum to this article is available at .     

用16S rRNA基因的内切酶图谱快速鉴别几种对虾病原菌

坎普氏弧菌是青岛海洋大学生物系微生物实验室于１９８９－１９９０年自对虾养殖场中国对虾红腿病心脏及血淋巴中分离并鉴定的菌株，副溶血菌和溶藻胶弧菌两菌株于１９９４年９月得自中国科学院微生物研究所，为建立快速、准确的中国对虾病原菌的诊断技术，根据几种细菌的１６ＳｒＲＮＡ基因的序列，设计并合成该基因的多聚酶反应的引物ＰＬ１和ＰＬ２。并用该对引物分别从坎普氏弧菌、副溶血弧菌和溶藻胶弧菌的ＤＮＡ要品中扩增出分     

中国对虾配合饵料中维生素C添加量的研究

于１９９１年７月２１日－８月１９日在河北省唐海县西林养殖场以养成期中国对虾为材料，在其配合饵料中添加维生素Ｃ进行中国对虾对维生素Ｃ需要量的试验。结果表明，当中国对虾体长为５．５－７．５ｃｍ时，若以本项研究采用的配合饵料的基本成分和配比为基础，配饵中维生素Ｃ的最佳变化添加量为０．０１８％－０．０３０％。研究发现，变动的维生素Ｃ适宜添加量对于中国对虾具有明显的促进生长，增强抗病力和抗低氧能力以及提高存     

南沙群岛海域水体漫衰减系数Kd(490)的特性研究

对南沙群岛海区水体Kd(490）的特性进行了深入分析和探讨,研究结果表明：Kd（490）的垂直分布与同步测量的海水叶绿素a浓度的垂直分布有很强的相关性;Kd（490）的垂直分布反映出该区域海水存在较强的分层现象,研究中还发现上行辐亮度漫衰减系数KL（490）与Kd（490）垂直变化趋势相当一致,但是以二者达到最大值的深度为界,上层水体的KL（490）值稍大于Kd(490）值,在这一深度以下则相反。     

Input of atmospheric lead to marine sediments in a south-east Pacific coastal area (approximately 36 degrees S)

Atmospheric input of Pb to coastal sediments in the south-east Pacific (approximately 36 degrees S) was estimated using: (1) a salt marsh (non-local emission sources) as a natural collector of atmospheric fluxes and (2) Pb concentrations in rain and air samples, both considered to be representative of the atmospheric input in the study area. A radioisotopic geochronology technique ((210)Pb) was used to estimate the total Pb atmospheric supply to the sediments. The results show that atmospheric input to Concepción Bay accounts for 13-68% of Pb in near shore sediments, evaluated through salt marsh and rain, both showing comparable results. Consequently, there are other relevant Pb sources to explain the higher concentrations in this area. Sediments in the shelf are subject to important influence of upwelling waters, estimated by Salamanca [Sources and sinks of (210)Pb in Concepción Bay, Chile (1993) PhD thesis, Marine Science Research Center, State University of New York at Stony Brook, USA] using (210)Pb. The atmospheric input, however, is mainly responsible for the total Pb input, since the salt marsh (natural atmospheric collector) shows similar Pb(xs) inventories than the shelf, corresponding to a regional-scale Pb emissions.     

海洋旅游研究初探

海洋旅游在我国发展迅猛 ,但对海洋旅游的研究明显滞后。就海洋旅游的基本概念、研究范围、特点、开发类型及开发原则等基础理论问题提出了自己粗浅的认识 ,以求引起更多的学者关注这一领域的研究 ,进行更加有益的探讨     

用陆地卫星数据描绘渤海湾海河口区不同污染等级

Okamoto (1969)指出，多变量的主成分具有变差最优性、信息损失最小性、相关最忧性和回归最优性等最优性质，因此多变量的主成分分析被广泛应用于自然科学和社会科学多种领域。由于主成分可以看作所研究的某个复杂事物的一个概括(肯德尔，1975),并可根据主成分所提供的数据，按数值大小排列顺序分级，因此主成分分析也被遥感界应用于区分不同水质(Klemas et al, 1981)。 本文以渤海湾西北部海河、永定新河河口区的陆地卫星数据作主成分分析，以显示河口区海水不同污染等级。同时以河口区各站位实测的多项有机污染数据作主成分变换，按主成分数值大小，将各站位分为不同污染等级。计算表明，遥感数据显示的不同污染等级的地理分布与实测数据是一致的。     

Hydrocarbon Potential of Pre-cenozoic Strata in the North Yellow Sea Basin

The North Yellow Sea Basin ( NYSB ), which was developed on the basement of North China (Huabei) continental block, is a typical continental Mesozoic Cenozoic sedimentary basin in the sea area. Its Mesozoic basin is a residual basin, below which there is probably a larger Paleozoic sedimentary basin. The North Yellow Sea Basin comprises four sags and three uplifts. Of them, the eastern sag is a Mesozoic Cenozoic sedimentary sag in NYSB and has the biggest sediment thickness; the current Korean drilling wells are concentrated in the eastern sag. This sag is comparatively rich in oil and gas resources and thus has a relatively good petroleum prospect in the sea. The central sag has also accommodated thick Mesozoic-Cenozoic sediments. The latest research results show that there are three series of hydrocarbon source rocks in the North Yellow Sea Basin, namely, black shales of the Paleogene, Jurassic and Cretaceous. The principal hydrocarbon source rocks in NYSB are the Mesozoic black shale. According to the drilling data of Korea, the black shales of the Paleogene, Jurassic and Cretaceous have all come up to the standards of good and mature source rocks. The NYSB owns an intact system of oil generation, reservoir and capping rocks that can help hydrocarbon to form in the basin and thus it has the great potential of oil and gas. The vertical distribution of the hydrocarbon resources is mainly considered to be in the Cretaceous and then in the Jurassic.