Variations of backscatter strength along the super slow-spreading Southwest Indian Ridge between 57°E and 70°E     

Daniel Sauter  Vronique Mendel 《Marine Geology》1997,140(3-4):237-248

Simrad EM12 backscatter strength data of the Southwest Indian Ridge (SWIR), between 57°E and 70°E, are used to reveal the along-axis segmentation of this super slow-spreading ridge. The backscatter properties of different geologic domains, like bathymetric highs and oblique basins within the rift valley, are characterized using 66 small test sites. We show that backscatter strength is higher on bathymetric swells, corresponding to segment centres, and lower in deep oblique basins corresponding to axial non-transform discontinuities and fracture zones. This contrast between segment centres and discontinuities is produced by both a thicker sediment cover and less frequent volcanic eruptions at segment ends. Using the model of Mitchell (1993), sediments have been estimated to be 2 to 5 m thicker in these areas than at segment centres. The distribution of the seamounts within the rift valley is controlling the long-wavelength variations of the mean backscatter strength calculated along the axis. Lower densities of seamounts and thicker sediments are producing lower and heterogeneous reflectivity levels in the deepest part of the axial valley floor between 61°45′E and 63°45′E. We propose that cooler mantle temperatures inducing construction of fewer volcanoes occur beneath this part of the ridge. The mean backscatter strength along the SWIR axis decreases dramatically toward the Rodrigues Triple Junction suggesting that volcanic production is reduced between 68°20′E and 69°20′E and that the transition from amagmatic tectonic deformation at the triple junction to new seafloor spreading occurs between 69°20′E and 70°E.  相似文献   

Sediment trapping and bypassing characteristics of a stable tidal inlet at Kaohsiung Harbor, Taiwan   总被引：2，自引：0，他引：2  

James T. Liu  Li-hua Hou 《Marine Geology》1997,140(3-4):367-390

Around the artificially stabilized tidal inlet that connects Kaohsiung Harbor to Taiwan Straight, 203 surficial samples of the sea floor were taken from the nearshore, in the outer harbor, and portions of the inner harbor. The bathymetry of the same area was also surveyed. The sand fraction in each sample was analyzed for the grain-size composition with a custom-built rapid sediment analyzer. A total of twenty-one size-classes were used in the analysis. Three hypothetical sediment sources were assumed to have influenced the spatial grain-size patterns in the study area: the northward and southward littoral drifts, and the sediments exported from the harbor. After reducing the influence of each hypothetical sediment source separately, the data were analyzed using empirical orthogonal (eigen) function (EOF) analysis. The results indicate that the northward long-term littoral drift is the dominant direction of sediment transport in the nearshore of the study area. A conceptual model for four different sediment trapping and bypassing patterns are proposed. (1) Excess bypass (or net outflux): this bypass pattern is characterized by the export of fine-grained sediments (mud and size classes in the very fine sand fraction) from the interior of the harbor. (2) Partial bypass (or partial trapping): this bypass pattern is represented by the size-classes in fine sand fraction. The amount of these grain sizes entering the outer harbor through the inlet is more than the amount exiting at the inlet mouth, resulting in the retention of a portion of these grain sizes. (3) Total bypass (or zero trapping): grain sizes that exhibit this bypass pattern do not come near the mouth of the inlet. These grain sizes include medium and coarse sand fractions. (4) Lag deposits: this group includes the size classes in the very coarse sand fraction, which are largely concentrated in the scour pit immediately seaward of the inlet mouth. In general, surficial sediment grain-size patterns represent a time-averaged response of the substrate to the transport processes over the time scale of at least two seasons. The differential associations of grain-size groups with various topographic features in the study area suggest morpho-textural relationships exist between the sea floor topography and grain size distribution patterns.  相似文献   

从鳕鱼碎肉中提取水解蛋白   总被引：15，自引：0，他引：15  

王长云  魏玉西 《海洋湖沼通报》1995,(4):33-39

用蛋白酶水解法从鳕鱼加工废弃物－鳕鱼碎肉中提取水解蛋白。鳕鱼碎肉经枯草杆菌ＡＳ１．３９８中性蛋白酶２４０ＩＵ／ｍｌ，ｐＨ７．０，５０℃下水解２ｈ；再经黄曲霉ＩＦＦＩ２３４２（蛋白酶活力２０００ＩＵ／ｇ）１．５％（ｗ／ｖ），５０℃，ｐＨ６．０下水解６ｈ以脱苦味。水解液经真空浓缩后喷雾干燥得水解蛋白粉。该制品易溶于水，无苦味，有海鲜味。其氨基酸组成合理，是优良的蛋白质制品。  相似文献   

The Effects of Zn, Mn, and Co Accumulation on Growth and Chemical Composition of Fucus vesiculosus L under Different Temperature and Salinity Conditions     

IVKA M. MUNDA  V. HUDNIK 《Marine Ecology》1988,9(3):213-225

Abstract. Combined effects of temperature, salinity, and metal enrichment (Zn, Mn, Co) on the growth rate and chemical composition of Fucus vesiculosus L. were studied in culture. Factorial combinations of two temperatures and three salinities were used. The results indicated that the accumulation of Zn and Mn into algal tissue was enhanced by dilution of the media, whereas Co accumulation exhibited maxima at the medium salinity. Zn accumulation was enhanced by temperature, while the opposite was true for Mn and Co.
In the presence of metals the usual dilution-induced changes in growth activity and chemical composition of Fucus plants were altered, while responses to the temperature factor remained unchanged. In diluted media, growth activity and mannitol content decreased along with a simultaneous increase of protein content. In the presence of Zn and Mn the mannitol content exhibited peaks at the medium salinity; in the presence of Co the dilution-induced pattern remained unchanged. Salinity-induced changes in growth and protein content were altered in the presence of metals. Maxima in growth rates were found at the medium salinity. Growth was higher in extremely diluted media than in scawater, indicating an inversion of responses to the salinity factor. Both the growth rate and mannitol content were lowest under the influence of Zn.  相似文献   

双向电泳的技术原理及在水产动物病害研究上的应用展望   总被引：3，自引：0，他引：3  

贾佩峤  黄倢  战文斌 《海洋湖沼通报》2003,(4):49-54

双向电泳技术作为高效、高分辨率的蛋白质分析手段，在现代生命科学研究中扮演着重要的角色。本文概述了双向电泳技术的应用现状、存在问题及未来发展方向，并对其在水产动物病害研究中的应用进行了简要介绍。  相似文献   

酶法进行海洋低值蛋白资源高值化利用初探   总被引：7，自引：2，他引：7  

师晓栋  何海伦  王运涛  张玉忠  高培基 《海洋科学》2001,25(3):4-7

首先分析了Ti鱼与四角哈两种低值海洋蛋白资源的营养成分，然后利用两株高产蛋白酶菌株通过液体发酵制备的蛋白酶制剂对两种蛋白资源进行了酶解，经过比较酶解率和肽含量，表明对于四角蛤，菌株SM98013产生的碱性蛋白酶和SM98011产生的中性蛋白酶都可高效酶解；而对Ti鱼，菌株SM98013产生的碱性蛋白酶的酶解效率较高。文中对海洋低值蛋白资源的高值化利用的途径进行了讨论。  相似文献   

Characteristics and phylogeny of light-harvesting complex gene encoded proteins from marine red alga Griffithsia japonica     

LIU Chenlin  HUANG Xiaohang  LEE Yookyung  LEE Hongkum  LI Guangyou 《海洋学报(英文版)》2005,24(2):120-130

1 Introduction T he light-harvesting com plex (LH C ) com posedofphotosynthesis pigm ents and associated proteins arelocated on the thylakoid m em brane of chloroplast inhigherplants and algae. T he capture oflightenergy isthe first step in photosynthesis and is largely accom -plished by the pigm entprotein com plexes. To m axi-m ize the capture of light energy under various envi-ronm entalconditions, the LH C s w ith differentchro-m ophore com positions have evolved in differentpho-tosynth…  相似文献   

褐藻酸降解菌的生长条件及其对海带的生理效应     

肖慧  唐学玺  王艳玲  杨震 《中国海洋大学学报(自然科学版)》2006,36(2):261-264,220

为更好地了解海带病烂的发生机制，针对褐藻酸降解菌埃氏交替单胞菌（Altermonas espejiana）菌株A1的生长及产酶条件进行了初步研究，并用不同浓度的菌液对健康海带进行了感染试验，测定了其体内可溶性蛋白质和可溶性糖含量的变化。结果表明，该菌株生长和产酶的最适条件为：20℃，0．5％～0．6％褐藻酸钠，pH=7，5，氮源为（NH4）2S04，培养时间72h。此外，感染菌株A1后，海带体内可溶性蛋白质和可溶性糖的含量均增加，且随着感染菌液浓度的升高，海带体内可溶性蛋白质含量升高，而可溶性糖含量先升高后降低。  相似文献   

重组斑马鱼Gli2蛋白N端肽段的表达及纯化     

谭训刚  张培军  杜少军 《海洋科学集刊》2006,47(47):140-148

Hedgehog(Hh)信号及其信号传递系统在生物机体发育中起着非常重要的作用。从Hhs分泌到其靶基因收到来自Hhs的信号的过程中，包括很多步骤，而每一步骤都有不同的因子参与作用。在其传递的过程中，参与受体细胞将胞外的信号传到胞内调节其目标基因的一个重要因子是果蝇分节-极性基因cubitus in terruptus(Ci)及其脊椎动物同源基 因-G li编码的蛋白。  相似文献   

Prediction of protein binding sites using physical and chemical descriptors and the support vector machine regression method     

孙重华  江凡 《海洋学报(英文版)》2010,29(11)

  相似文献