东海北部主要经济虾类渔业生物学的比较研究

本文根据1986—1992年东海北部拖虾调查及虾类资源动态监测调查资料,分析了10种群体数量大、经济价值高的虾类的渔业生物学特性,比较了各群体的体长、体重组成,体长与体重的关系以及繁殖、生长等特点,阐明其规律性及异同关系,为合理利用本海域的虾类资源提供科学依据。     

Antibacterial activity in the egg mass of a sea hare

Summary The eggs of a sea hare,Aplysia kurodai, contained antibacterial factors which probably play a role in the defense of eggs against bacterial infection. The active factors were composed of several heat-labile proteins, unrelated to lysozyme, and were produced in the albumen gland.     

An in situ zircon Hf isotopic,U-Pb age and trace element study of banded granulite xenolith from Hannuoba basalt： Tracking the early evolution of the lower crust in the North China craton

Backscattered electron images, in situ Hf isotopes, U-Pb ages and trace elements of zircons in a banded granulite xenolith from Hannuoba basalt have been studied. The results show that the banded granulite is a sample derived from the early lower crust of the North China craton. It is difficult to explain the petrogenesis of the xenolith with a single process. Abundant information on several processes, however, is contained in the granulite. These processes in-clude the addition of mantle material, crustal remelting, metamorphic differentiation and the delamination of early lower crust. About 80% of zircons studied yield ages of 1842 ±40 Ma, except few ages of 3097-2824 Ma and 2489-2447 Ma. The zircons with ages older than 2447 Ma have high εHf (up to +18.3) and high Hf model age (2.5-2.6 Ga), indicating that the primitive materials of the granulite were derived mainly from a depleted mantle source in late Archean. Most εhf of the zircons with early Proterozoic U-Pb age vary around zero, but two have     

Comparison of summer thermohaline field and circulation structure of the Bohai Sea between 1958 and 2000

TheBohaiSea(37°07′—41°N,117°35′—121°10′E)isashallowsemi-enclosedsea.SincetheBohaiSeaistheonlyinnerseaofChinaandalsoanimportantstra-tegicsea,itisoneofthemostinvestigatedseasinChina.Alargenumberofstudiesonthetideandthetidalcurrentaswellasnumericalsimulationofcirculationhavebeencarriedout,enhancingourunderstandingoftheBohaiSea.Long-termvariationsoftheseasurfacesalinity(SSS)andseasurfacetemperature(SST)oftheBohaiSeawereanalyzed.Linetal.[1]foundthatthepositivetrendsoftheannualmeanS…     

西北太平洋部分海域AVHRR、TMI与MODIS遥感海表层温度的初步验证

选取[10～35°N,110～165°E]的西北太平洋海域,利用2002年7月～2005年12月Argo浮标数据对AVHRR/MODIS/TMI SST的daily（升轨）数据进行验证.结果表明：AVHRR/MODIS/TMI daily SST与Argo浮标5～6 m层温度总体的均方差rms在0.6～0.9℃,平均偏差bias在-0.2～0.2℃,平均绝对偏差bias_abs在0.3～0.7℃.这与三传感器全球范围的SST反演目标相当,说明在本区域SST反演不存在显著偏差.各遥感SST与浮标温度的差异存在季节变化,夏季偏高,很可能与夏季垂直混合较弱,比对采用的实测水温与海表温度差距较大有关.在3种遥感SST中,TMISST偏离实测值的程度最高,且偏离范围较大.作者认为这与该区域黑潮经过,产生诸多涡旋和锋面,SST时空变化剧烈而TMI空间分辨率较低有关.本研究将为此西北太平洋海域的多源SST融合提供一个比较可靠的依据.     

南海北部大陆架海洋生态系统Ecopath模型的应用与分析

过度捕捞和环境恶化导致渔业资源和海洋生态系统逆向发展。采用EwE5.1软件,对南海北部大陆架建立Ecopath(生态通道模型)模型。通过各级流量、生物量、生产量、捕捞量、系统总流量以及生态位和混和营养效应等方面的分析,得出营养流通主要有2种途径,肉食鱼类间饵料竞争非常激烈,低值鱼类间具相似的捕食压力,顶级捕食者对大部分鱼类负效应不明显。系统受过度捕捞渔业影响很大,并存在营养级I利用效率低和渔业资源小型化、低值化等不稳定的幼态特征。     

^226Ra evidence for the ecosystem shift over the past 40 years in the North Pacific Subtropical Gyre

Surface seawater was collected for ~(226)Ra measurement in the North Pacific Subtropical Gyre from July to October, 1999 and October to December, 2003. Combined with the historical data reported for this sea area, a declined trend of surface ~(226)Ra concentrations was observed since 1960s, indicating the ecosystem shift in response to global warming. On one side, the enhanced stratification of the upper water column resulting from global warming reduced the ~(226)Ra input from the depth, on the other, the temporal increase of biological production resulting from the climate-related ecosystem structure change strengthened the ~(226)Ra removal from the surface ocean. Both the physical and biological processes resulted in the decrease of surface ~(226)Ra concentrations in the North Pacific Subtropical Gyre. The temporal trend of surface ~(226)Ra concentrations was consistent with the trends of chlorophyll a, silicate, phosphate and primary production previously reported. This study provided ~(226)Ra evidence for the ecosystem shift under global change.     

Benthic foraminiferal fauna turnover at 2.1 Ma in the northern South China Sea

Quantitative analysis of benthic foraminifera from ODP Site 1146 in the northern South China Sea (SCS) shows that abundance of Bulimina alazanensis, sometimes up to about 90%, decreased gradually since 3.2 Ma, especially at 2.1 Ma. Abundance of other benthic foraminiferal species, Globobulimina sub-globosa and Cibicidoides wuellerstorfi, increased after 2.1 Ma. Comparison with changes in oxygen and carbon isotopes of planktonic and benthic foraminifera shows that high abundance values of B. alazanensis corresponded with lower values of oxygen isotope, but for carbon isotope, high values of the species were consistent with heavier carbon isotope of benthic foraminifera and lighter carbon isotope of planktonic foraminifera, respectively, and vice versa. Considering factors such as uplift of Bashi Strait, expansion of the North Hemisphere Glaciation, strengthening of East Asian winter mon-soon and variations in oxygen and carbon isotope of foraminifera, changes of B. alazanensis in ODP Site 1146 suggest that the source of deep water masses of the northern South China Sea changed from the warm Pacific deep water with high oxygen content to Pacific Intermediate water with low oxygen content at 2.1 Ma. In addition, the strengthened East Asian winter monsoon resulted in increased pri-mary productivity, high nutrient and suboxic bottom water. Variations in species of B. alazanensis seemed to be unable to tolerate environmental stress induced by deep water masses and productivity changes.     

Coupling and propagating of mesoscale sea level variability between the western Pacific and the South China Sea

The coupling and propagating features of mesoscale sea level variability between the western Pacific (WP) and the South China Sea (SCS) were studied based on time series analyses of satellite altimeter measured, along-track sea surface height anomalies (SSHA) along 21°N and the slope of the northern SCS. The analyses show that mesoscale sea level fluctuations in the WP have rather limited coherent effects on the SCS, and no statistically significant propagation of mesoscale variability through the Luzon Strait was observed except in the 45-day band. Evidence suggests that the 45-day fluctuation is very much likely a character of the Kuroshio originating from its low-latitude beginning. It is also sug- gested that the westward propagating Rossby waves will deform when they encounter the dynamical barrier of the Kuroshio. The Kuroshio will then acts on the SCS in its own way. The SCS is a relatively isolated system in the sense of coupling and propagating of oceanic mesoscale waves.     

Authigenic sulfide minerals and their sulfur isotopes in sediments of the northern continental slope of the South China Sea and their implications for methane flux and gas hydrate formation

This is a report of the study of the authigenic sulfide minerals and their sulfur isotopes in a sediment core (NH-1) collected on the northern continental slope of the South China Sea, where other geo-physical and geochemical evidence seems to suggest gas hydrate formation in the sediments. The study has led to the findings: (1) the pyrite content in sediments was relatively high and its grain size relatively large compared with that in normal pelagic or hemipelagic sediments; (2) the shallowest depth of the acid volatile sulfide (AVS) content maximum was at 437.5 cm (>2 μmol/g), which was deeper than that of the authigenic pyrite content maximum (at 141.5-380.5 cm); (3) δ 34S of authigenic pyrite was positive (maximum: 15‰) at depth interval of 250-380 cm; (4) the positive δ 34S coincided with pyrite enrichment. Compared with the results obtained from the Black Sea sediments by Jorgen-sen and coworkers, these observations indicated that at the NH-1 site, the depth of the sulfate-methane interface (SMI) would be or once was at about 437.5-547.5 cm and the relatively shallow SMI depth suggested high upward methane fluxes. This was in good agreement with the results obtained from pore water sulfate gradients and core head-space methane concentrations in sediment cores collected in the area. All available evidence suggested that methane gas hydrate formation may exist or may have existed in the underlying sediments.