Predation by Octopus vulgaris in the Mediterranean     

Richard F.  Ambrose Bobette V.  Nelson 《Marine Ecology》1983,4(3):251-261

Abstract. Octopus vulgaris consumes at least 22 molluscan and several crab species in the Mediterranean off the coast of France. Collections of prey discards in octopus middens and in areas inhabited by octopuses revealed that molluscs comprise an estimated 80% of the O. vulguris diet. Octopus predation is probably an important source of mortality for many of these prey species, causing up to 60 % of the mortality within the size ranges sampled. O. vulgaris does not selectively consume particular sizes of its three most important prey species, the bivalves Pilaria chione and Venus verrucosa and the abalone Haliotis tuberculata. Analysis of octopus drill holes on the two bivalve species showed that their locations were nonrandom, whereas the distribution of drill holes in the abalone was not distinguishable from random.  相似文献   

山东省的淡水贝类     

马俊岭  孙鹤田 《海洋科学集刊》1997,(39):27-31

本文汇集1979-1987年山东省内陆水域渔业资源调査中有关贝类资源的部分写成。此次调査采到淡水贝类39种,分隶于9科25属;淡水贝类资源总量约为238423.5t。本文对贝类资源的利用与保护提出了建议。  相似文献   

Interannual Variation of Freshwater in the Yellow and East China Seas: Roles of the Changjiang Discharge and Wind Forcing     

Pil-Hun?ChangEmail author  Atsuhiko?Isobe 《Journal of Oceanography》2005,61(5):817-834

The interannual variation of the behavior of Changjiang freshwater has been investigated using the Princeton Ocean Model (POM). Five experiments are described in this study. Three basic experiments (Exps. B1, B2 and B3) were performed to examine the freshwater behavior in response to annual variations of the Changjiang discharge in normal, wet and dry years, respectively. Thereafter, the freshwater variation was investigated with the model forced by primary-interannual variations of river discharge with an 8-year period (Exp. I1) and a wind field with a 3.6-year period (Exp. I2). In Exp. B1, the average residence time of freshwater is roughly estimated to be 681.4 days in the Yellow Sea (YS) and 353.4 days in the combined area of the East China Sea (ECS) and the Chinese Coast (CC). This difference is attributed to the current pattern in each region and freshwater exchange among the regions. The interannual variation of freshwater volume in Exp. I1 has a large amplitude and long phase lag in the YS (38 km³ and 1.6-year against primary-interannual discharge variation), while there are relatively small amplitudes and short phase lags in the ECS (18 km³ and 0.7-year) and the CC (14 km³ and 0.5-year). It is concluded that the difference in the freshwater behavior results from the difference in the average residence time in each region.  相似文献   

黄河三角洲淡水浮游动物名录   总被引：3，自引：0，他引：3  

田家怡  高霞 《海洋湖沼通报》2001,(4):81-90

1996年对黄河三角洲9条代表性河流和3座代表性水库进行了2－6次浮游动物调查，共鉴定出浮游动物144种，隶属于47科85属。盾额隆背Sou(Bunopsscutiforons)为山东省新记录。  相似文献   

南美白对虾淡养过程中虾池水质测定与分析   总被引：5，自引：0，他引：5  

王小谷  孙浩波  杨丹  胡锡钢 《海洋学研究》2002,20(3):38-44

对 4个南美白对虾淡化养殖虾池池水的温度、盐度、p H值、溶解氧、营养盐 (硝酸盐、亚硝酸盐、铵盐、磷酸盐 )、叶绿素 a的变化进行了测定和分析 ,结果表明 :( 1 ) 4个虾池池水的温度为 2 3～ 2 9℃ ,盐度为 1 .1 0 0～ 1 .5 0 0 ,p H值为 8.1～ 8.8,溶解氧质量浓度为 4.84～ 6.95mg/L,基本适合南美白对虾生长过程中对水质的要求 ;( 2 ) 4个虾池池水中的无机氮和无机磷含量几乎全部超过富营养化阈值 ,其质量浓度的平均值分别为 0 .436mg/L和 0 .1 5 3mg/L。硝酸盐是总氮的主要存在形式 ,铵盐与亚硝酸盐在水体中的含量较高 ,但均低于南美白对虾要求的安全质量浓度 ,其质量浓度平均值分别为 82 .2 3μg/L和 5 5 .0 5μg/L。叶绿素 a含量很高 ,但在各虾池池水中的含量变化不一 ,与无机氮含量呈负相关。N/P值为 0 .5 8～ 1 1 .5 8,个别虾池达 32 .5 6,但各虾池绝大部分时间的 N/P值为 5以下。  相似文献   

Distribution of seabirds in the northern Gulf of Mexico in relation to mesoscale features: initial observations   总被引：1，自引：0，他引：1  

Ribic  Christine A.; Davis  Randall; Hess  Nancy; Peake  Dwight 《ICES Journal of Marine Science》1997,54(4):545-551

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Impact of experimental trawling on the benthic assemblage along the Tuscany coast (north Tyrrhenian Sea, Italy)     

De Biasi  Anna Maria 《ICES Journal of Marine Science》2004,61(8):1260-1266

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云南滇池无齿蚌的分布与环境     

黄宝玉  周晓丹  张迺光  陈元晓 《海洋科学集刊》1997,(39):133-135

滇池为云贵高原最大的淡水湖,湖中软体动物及介形类等水生生物非常丰富,尤其是软体动物的无齿蚌(Anodonta)更为丰富,种类多,个体数量大。本文探讨滇池无齿蚌的种类、分布,及其与水体温度、透明度、pH值等水域环境的关系。  相似文献   

Holocene evolution of the Anichab Pan on the south-west coast of Namibia     

JOHN S. COMPTON 《Sedimentology》2007,54(1):55-70

Coastal sediment-filled depressions (pans) are one of the few areas that contain Quaternary records of sea-level and palaeoenvironmental change along the western margin of southern Africa. Anichab is a 128 km² salt-encrusted pan on the hyper-arid southern coast of Namibia with an emergent, well-preserved and in-place mid-Holocene mollusc assemblage. The molluscs are typical of subtidal sands on the sheltered side of offshore islands but include several warm-water species no longer found living along this coast. The Holocene evolution of the pan was largely influenced by changes in sea level and supply of sand along the coast. Calibrated radiocarbon ages of mollusc shells indicate a maximum Holocene sea level of ca 2 m above mean sea level (msl) from 7·0 to 6·3 ka and a return to near present-day sea level by 5·3 ka. The pan surface is 2 m below msl and has been emergent since 4·9 ka from the build up of sandy beaches and coastal dunes. A thin (1–4 cm) halite crust occurs over much of the pan surface but a layer of halite-cemented sand up to 40 cm thick is restricted to the central pan. Gypsum occurs near the subsurface brine interface and is limited by calcium to the edges of the pan. Nodules of calcite-cemented sand are forming in brackish, relatively high alkalinity subsurface waters in the south-east corner of the pan and nodules of aragonite-cemented sand are forming in brines 1 m below the central pan surface. Although modern dolomite has been reported from coastal lagoons of Brazil and Australia, carbonate cements are a minor feature of Anichab Pan and dolomite was restricted to a single reworked nodule most likely of Late Pleistocene age. Therefore, Anichab Pan does not appear to be a modern analogue to extensive, mixed-water dolomite cements found in Upper Pleistocene sediment-filled depressions on the Namibian shelf.  相似文献   

淡水珍珠中球文石的XRD谱   总被引：5，自引：1，他引：5  

马红艳  崔福斋 《矿物学报》2003,23(4):371-373

球文石是CaCO3的同质多象变体，在自然界中很少出现。对不同质量淡水珍珠进行XRD物相分析，结果表明不同颜色的优质淡水珍珠中几乎全部由文石组成，方解石不发育；劣质淡水珍珠中主要含有文石、球文石；在劣质的淡水无光珠发现有球文石，可能与这些珍珠混有较多的有机物有关，文中例举了含球文石与不含球文石的淡水珍珠XRD谱。  相似文献