首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
旨在了解珠江口栖息的中华白海豚(Sousa chinensis)、宽脊江豚(Neophocaena phocaenoides)和点斑原海豚(Stenella attenuate)免疫相关基因MHC-I(Major Histocompatibility Complex)的多态性及其表达情况,以期为这3种鲸豚的保育工作提供基础资料。通过克隆测序的方法,首次证实MHC-I基因在这3种鲸豚体内表达。选择压力分析,表明MHC-I基因在这3种鲸豚中均受到强烈的正选择作用,提示其具有重要的免疫功能。3种鲸豚的MHC-I基因在系统发育树上相互混杂在一起,表明MHC-I基因存在跨物种多态性。结合选择压力分析和跨物种多态性,发现MHC-I基因受到平衡选择作用。珠江口3种鲸豚MHC-I基因多态性可能由平衡选择维持。  相似文献   

2.
宽吻海豚属(Tursiops)包括宽吻海豚(T.trunca-tus)和北太平洋宽吻海豚(T.gille)两种,现在世界各国大型水族馆均有饲养,已成为主要表演动物。为了便于简便地了解海豚的大致年龄,本文将对有关的实践经验予以小结。众所周知,要想知道海豚的确切年龄,必须是在人工繁殖饲养条件下,或者是动物死后根据牙齿上存在着的层状结构将牙齿纵剖或横切、酸蚀、染色观察切面上“年轮”而定,这就为海豚的年龄鉴定带来了难度。因此,对于捕来的海豚生前的确切年龄是不知道的。为解决这一问题,笔者根据实践经验,总结了下列方法对海豚进行年龄鉴定。刚生下来的…  相似文献   

3.
采用目标取样法,对饲养于抗风浪网箱中的4只南瓶鼻海豚(Tursiops aduncus)的行为进行了观察和记录,最终定义了南瓶鼻海豚的7种姿势和70种行为.在此基础上,根据行为发生时的姿势、动作、环境以及可能具有的功能,将这些行为划分为水面运动行为、空中行为、社群行为、索食、性行为、玩耍、休息及杂类等8个行为模式,从而初步构建了南瓶鼻海豚的行为谱.还进一步对某些行为,如社会行为的生物学和生态学意义进行了探讨.  相似文献   

4.
南海与九龙江的三种海豚   总被引:9,自引:0,他引:9  
我国南部沿海的齿鲸,已确切报道的仅太平洋驼海豚Sousa chinensis(Osbeck)、真海豚Delphinus delphis Linnaeus及江豚Neophocaena phocaenoides(G.Cuvier)等三种。本文报道南海的点斑原海豚Stenella frontalis(G.Cuvier)、热带真海豚Delphinus tropicalis van Bree与在福建九龙江采到的太平洋驼海豚Sousa chinensis(Osbeck)。  相似文献   

5.
郭红 《海洋科学》2002,26(4):24-25
海豚 ,是小型有牙齿鲸类的通称 ,人们通常把体长3m左右的齿鲸称为海豚。海豚种类很多 ,我国海域有鼠海豚Phocoenaphocoen,真海豚Delphinusdelphis,江豚Neopho caena phocaenoides,宽吻海豚Tur siopstruncatus以及中华白海豚Sousachinesis等10余种常见种海豚。有些种类已在水族馆中进行饲养 ,并已繁衍生息。1海豚搁浅救助的意义海豚搁浅救助 ,属于野生动物的保护和管理中的一个重要课题 ,特别是海豚大都栖息于公海 ,就此意义上说 ,它是国际海兽 ,…  相似文献   

6.
早在50年代, Kellogg, Scheyil1l, Evans和Norris等人分别记录和研究了海豚的声信号, Schevill和 Lawrence通过实验有力地证实了海豚具有很好的回声定位能力。60年代以来,各国对海豚动物声呐进行了广泛研究,取得了很大进展。多年来,不少国外学者在实验工作的基础上对海豚的声发射与接收机制提出了一些近似的物理模型,不同程度地解释了一些海豚声呐系统中的现象,但与仿生学的综合研究的目标还相距甚远。对海豚水下声信号进行深入的定量测量与分析,仍是海豚仿生学中一项重要的基础工作,它对进一步研究、改进水下声学探测设备和强背景噪声下弱信号的识別与检测都有着实际指导意义。目前在大约五十余种海豚中,除对胆鼻海豚(Tursiops truncates)国外有过较多的研究外,对其他海豚的研究则很少。 江豚属齿鲸亚目,是体型最小的一种海豚。它主要分布在日本海和中国及东南亚各国沿岸海域,在中国长江口分布最为集中。每年3,4月份江豚到长江口一带生殖,有时沿江深入甚远。日本学者 Kazuhiro Mizue等(1968)和英国的Purves(1983)都对江豚的水下声信号作过记录与测量,但Kazuhiro Mizue等只记录到4kHz, Purves也只记录了30Hz-35kHz的信号;遗憾的是,由于信噪比太低,他们都没有进行详细的频谱分析。本实验所记录到的江豚声信号,由于记录器频带范围的限制,频率范围仅是40Hz-70kHz,其中包括了几种不同波形的较高频和低频脉冲信号,本实验对其频谱和周期作了较为详细的分析测量。  相似文献   

7.
蓝镜头     
《海洋世界》2011,(10):2
澳大利亚莫纳什大学9月15号公布,研究人员经过DAN和头骨比对,正式确认维多利亚海豚是新物种,命名为Tursiops australis英文Burrunan dolphin。目前只发现约150只,还需更多调查来确定其种群大小。19世纪以来,仅有3种海豚被  相似文献   

8.
新西兰海域的赫克托海豚是当今世界上最小的一种海豚——雌海豚大约只有1.4米长,重48公斤;雄海豚长1.3米,重38公斤。它们主要生活在新西兰南岛沿岸海域以及北岛的西海洋。赫克托海豚这个名字来自前任新西兰国家博物馆馆长詹姆斯·赫克托爵士,以纪念这位卓著的学者。这种海豚具有圆滑的背鳍和黑白鲜明的外表,还因为它们那友善的性情而惹人喜爱。  相似文献   

9.
在新西兰北岛美丽如画的西海岸生活着一种叫茂伊海豚(也称“北岛赫克托氏海豚”)的珍稀海洋哺乳动物。它们是世界上最小的海豚,是新西兰特有的四种哺乳动物之一。然而,近几年来这种海豚的数量正受到严重的威胁。目前,全世界茂伊海豚的数量还不到150只。  相似文献   

10.
连续5年对青岛海豚表演馆中北太平洋宽吻海豚(Tursiops gille Dall)进行现场实验和行为学研究,获取了大量的生理指标数据,运用不同的分析和计算方法对所得数据进行了筛选、剔除及处理,确立了海豚各生理指标的正常闽值和范围确定的方法,从而为准确了解海豚机体的生理状况、疾病诊断及治疗奠定了基础。  相似文献   

11.
Over the Southern Ocean the dominant modes of the atmospheric field are known as the Southern Annular Mode (SAM) or Antarctic Oscillation, and the Pacific South American (PSA) pattern. Statistical analysis of sea surface wind (SSW) from satellite observation revealed two leading modes of SAM-like and PSA patterns. In the high latitudes, the SAM-like pattern of the SSW had a large amplitude over the Bellingshausen Basin and Australian-Antarctic Basin, with opposite phase between the two basins. On the intraseasonal time scale, large-scale sea surface height (SSH) also had notable variability, showing a basin-scale anti-phase mode over the two basins. To explain the response of oceanic variations to these atmospheric modes, we analyzed the relationship between the dominant modes of wind stress and large-scale SSH on the intraseasonal time scale. The SAM-like pattern of wind stress was correlated with the SSH variation over the two basins. The SSH basin mode was most simply explained by a simple barotropic response to the SAM-like mode of wind stress, with the curl of opposite phase between the two basins. We conclude that the zonal asymmetry of the wind field of the SAM plays an important role in driving the antiphase SSH basin modes.  相似文献   

12.
Poletayev  A. V. 《Oceanology》2020,60(5):682-690
Oceanology - The geological structure and bathymetry of the deepwater part of the South Caspian indicate the possible formation of significant amounts of gas hydrates. The aim of the research is to...  相似文献   

13.
This survey of the southernmost significant upwelling site in the Benguela Current showed that the oceanography is dominated by the seasonal wind cycle of predominant S-E winds in summer and N-W winds in winter. In the upwelling season, extending from September to March, a semi-permanent plume is isolated by a pronounced oceanic front whose position varies in the short-term and is related to wind direction. Surface waters change immediately and deeper waters more slowly to fluctuations in wind. The rate of upwelling was statistically related to wind data. A maximum rate of 32 m day?1 was found.In spring low temperature and salinity water flows northward on the shelf while between late summer and later winter oxygen-depleted water, rich in nutrients, flowed south at an estimated rate of 7–21 × 104 m3 s?1 in a counter current to the Good Hope Jet.Local depletion of oxygen occurs due to phytoplankton decomposition caused, in autumn, by falling light levels and, in summer in calm periods, by nitrate depletion (<1 μg-at N 1?1). Primary productions is estimated at 3.7 kg C m?2 yr?1 with a maximum growth rate (PImax) = 17.4–19.0 mg C mg chlorophyll a?1 hr?1 and half-saturation constant (KS) = 0.4–1.1 μg-at N 1?1. Nutrients were utilized and oxygen produced: ΔP:ΔN:ΔSi:ΔO=1:19.1 to 23.3:17.5 to 23.3:?227 to ?293. High N:Si ratios (maximum 4.28) were found in oxygen-depleted water produced locally while that coming from the north had low ratis, due to resolution of silica from the sediments and nitrate reduction. The mean zooplankton standing stock, 2.3 g dry weight m?2, was 12% of the phytoplankton crop. In summer stocks were maximal 40–100 km and minimal 20–50 km from the coast while in winter they were maximal inshore. Little vertical migration occurred and the waters above the thermocline contained the majority of the population.  相似文献   

14.
Using the Comprehensive Ocean-Atmosphere Data Set (COADS), wind, surface pressure and SST fields in the Equatorial Eastern Pacific and the Equatorial South Indian Ocean were analysed comprehensively.lt is pointed out that the seesaw between surface pressure in the Equatorial South Indian Ocean and the Equatorial Southeast Pacific causes the seesaw between the wind fields in the two areas, and the seesaw of wind fields results in the seesaw of SST between Indonesia and the Equatorial Eastern Pacific. El Nino is the response of ocean to the forcing of monsoon system in the Indian Ocean and the trade system in the Pacific.  相似文献   

15.
The chemical speciation of iron was determined in the Southern Ocean along a transect from 48 to 70°S at 20°E. Dissolved iron concentrations were low at 0.1–0.6 nM, with average concentrations of 0.25±0.13 nM. Organic iron complexing ligands were found to occur in excess of the dissolved iron concentration at 0.72±0.23 nM (equivalent to an excess of 0.5 nM), with a complex stability of log KFeL′=22.1±0.5 (on the basis of Fe3+ and L′). Ligand concentrations were higher in the upper water column (top 200 m) suggesting in situ production by microorganisms, and less at the surface consistent with photochemical breakdown. Our data are consistent with the presence of stable organic iron-complexing ligands in deep global ocean waters at a background level of ∼0.7 nM. It has been suggested that this might help stabilise iron at levels of ∼0.7 nM in deep ocean waters. However, much lower iron concentrations in the waters of the Southern Ocean suggest that these ligands do not prevent the removal of iron (by scavenging or biological uptake) to well below the concentration of these ligands. Scavenging reactions are probably inhibited by such ligand competition, so it is likely that biological uptake is the chief cause for the further removal of iron to these low levels in waters that suffer from very low iron inputs.  相似文献   

16.
Predictions of maximum wave height Hmax are made at Cromer, Happisburgh and Lowestoft on the East Anglian Coast using the formula Hmax = CKRKS U2/g where C is a constant, KR, KS are refraction and shoaling cofficients, U is wind speed and g is the acceleration due to gravity. Comparisonsare made with the models of Darbyshire Draper (1963) and Bretschneider (1958) Using this wave prediction formula, an estimate of the wave climate in the southern North Sea is deduced for the gales of 2–3 January 1976.  相似文献   

17.
The flux of diatom valves and radiolarian shells obtained during short-term and annual sediment trap experiments at seven localities in the Atlantic sector of the Antarctic Ocean (in the Drake Passage, Bransfield Strait, Powell Basin, NW and SE Weddell Sea and the Polar Front north of Bouvet Island) is summarized and discussed. The deployment of time-series sediment traps provided annual flux records between 1983 and 1990. The biosiliceous particle flux is characterized by significant seasonal and interannual variations. Flux pulses, accounting for 70–95% of the total annual flux, occur during austral summer, with a duration ranging between about 2 and 9 weeks. The annual values of vertical diatom and radiolarian flux range between 0.26 × 109 and more than 26 × 109 valves m−2 and between 0.21 × 104 and 70 × 104 shells m−2, respectively. Interannual differences in the particle flux range over a factor of 10. Grazers play an important role in controlling the quantity, timing and pattern of the vertical biosiliceous particle flux.The flux pattern of diatoms and radiolarians is similar at most of the sites investigated and shows a close relationship between the production of siliceous phytoplankton and proto-zooplankton. At some sites, however, the radiolarian flux pattern indicates probably phytoplankton production which is not documented by direct signals in the trap record.During their transfer through the water column to the ocean floor, the composition of the biosiliceous particles is altered mechanically (breakdown by grazing Zooplankton) and by dissolution, which significantly affects especially diatoms and phaeodarians in the upper portion of the water column and at the sediment-water interface.Significant lateral transport of suspended biosiliceous particles was observed in the bottom water layer in regions adjacent to shelf areas (Bransfield Strait), and in the vicinity of topographic elevations (Maud Rise), indicating considerable redistribution of biogenic silica in these regions.  相似文献   

18.
南黄海浮游动物群落结构研究   总被引:7,自引:2,他引:5  
根据2014年春、秋季南黄海16个站位的生物样品进行了浮游动物群落结构研究。共鉴定出99种浮游动物,其中春季68种,秋季78种。除浮游幼虫外,种类较多的类群是桡足类(34种,占总种类数的34.3%)、水螅水母(13种,13.1%)和端足类(5种,5.0%)。春季优势种为夜光虫(Y=0.259 7)、桡足幼体(Y=0.135 3)、拟长腹剑水蚤(Y=0.060 8)和伪长腹剑水蚤(Y=0.022 4),秋季时桡足幼体(Y=0.335 9)、伪长腹剑水蚤(Y=0.115 7)、强额拟哲水蚤(Y=0.053 3)、桡足类无节幼虫(Y=0.051 4)和拟长腹剑水蚤(Y=0.041 0)是优势种。春季浮游动物平均生物量为1 555.1 mg/m~3,秋季为425.8 mg/m~3。春季平均丰度为9 551.4个/m~3,秋季为2 103.7个/m~3。秋季香农-威纳指数、丰富度和均匀度结果皆比春季的高。浮游动物生物量与温度和水深相关性更高;丰度和温度相关性最高,其次和水深相关。  相似文献   

19.
20.
Izvestiya, Atmospheric and Oceanic Physics - Satellite altimetry data have been used to study water circulation in the Tatar Strait region (the northern part of the Sea of Japan) for the time...  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号