Reproductive pattern and egg development of the deep-sea crab Paromola cuvieri (Brachyura,Homolidae) around the Canary Islands (NE Atlantic)     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

This work investigated the biology of Paromola cuvieri in the Atlantic Ocean, including reproductive patterns, sex structure, depth distribution and egg development. Females were more abundant than males, mainly at depths greater than 600 m. Males were dominant in size classes larger than 110 mm carapace width (CW), especially over 120 mm, for which only males were observed. The mean length of both sexes decreased with depth. P. cuvieri appears to have continuous reproduction throughout the year. Large females tend to spawn mainly between summer and winter, but smaller females spawn during the summer. Four maturity categories were identified based on the ovary colour, and these categories were histologically validated. Three categories of testes were identified according to their colour and morphology. Sexual maturity was estimated at sizes between 71.6 and 74.0 mm CW for females and at 91.0 mm CW for males. The relative growth showed changes along the ontogeny, at 73.6 mm CW (females) and 91.3–92.2 mm CW (males). Egg development appears to not be completely synchronous, and two colour patterns can be observed simultaneously. Four stages of egg development were found: eggs undivided and fully filled with yolk in orange egg masses; eggs with a free region of yolk visible in orange or red egg masses; embryos with slightly pigmented, crescent-shaped eyes in brown egg masses; and embryos with visible pigmented structures, enlarged eyes, segmented appendages and abdomen in brown egg masses. The mean number of external eggs carried by females in stage I was estimated to be 315,753±19,267. Three species of barnacle were observed on the exoskeleton: Poecilasma aurantia, Poecilasma crassa and Heteralepas microstoma (Cirripedia, Thoracica).  相似文献   

北极斯瓦尔巴德群岛中部海域表层海水水质研究     

李海源 《中国地质调查》2019,6(3):75-80

掌握北极海水水质特征及地域分布等第一手数据对北极科考意义重大。该项研究工作是全国青少年北极科考子任务,于2017年夏季在北极斯瓦尔巴德群岛中部海域对表层海水水质特征、地域差异及相关控制因素进行了研究。选取了6个区域共40个采样点采集表层海水样本,从温度、酸碱度、电导率、溶解性总固体量、实际盐度和溶解氧饱和度等方面进行了水质特征测量分析,发现该海域6个区域在海水温度、电导率、溶解性总固体量、实际盐度及溶解氧饱和度等方面均有较大差异,而酸碱度差异不大: 北部冰区水温最低,溶解性总固体量最低,溶解氧含量较高; 西北部海湾溶解氧饱和度最高; 中部海峡溶解性总固体量最高,盐度和电导率最低; 南部海域水温最高,实际盐度和电导率最高,溶解氧饱和度最低; 东部沿海水温偏低。采样点地理位置、洋流情况、地形地貌等因素对表层海水水质均有影响。这些研究成果对补充我国在北极地区的第一手科考数据和进行深入的科考研究具有重要意义。  相似文献   

南沙他国侵占岛礁战略价值及空间格局评价     

闵开付  程亮  周晓  夏南  李宁  李满春 《热带地理》2020,40(4):684-693

从建岛潜力、岛礁辐射能力和岛礁承载能力3个方面选取26个指标，采用主客观综合赋权法确定各因子权重，利用线性加权法获得被越南、菲律宾、马来西亚、文莱等国所侵占的南沙44个岛礁的战略价值，并对结果进行空间插值，分析其空间格局特征。结果表明：1）被马来西亚侵占的弹丸礁、越南侵占的南威岛、以及菲律宾侵占的中业岛，其战略价值位列前3，评价得分分别为100、98.42和97.09。2）岛礁辐射能力空间分布格局呈现“NW—SE条带式”，“最高”和“高”等级的区域由研究区西北延伸至东南，然后向东北、西南两侧递减，辐射能力格局中有2个核心区域和2个次级核心区域。承载能力空间分布格局呈现“横向条带式”，由北向南越来越低，有1个核心区域和2个次级核心区域。建岛潜力空间分布格局有3个核心区域及2个次级核心区域。3）岛礁战略价值空间分布格局有3个核心区域，分布于研究区中部、北部及南部，与越南、菲律宾、马来西亚密切相关的核心区域各有1个。越南侵占岛礁最多且空间分布较广，有2个次级核心区域也与越南密切相关，越占岛礁若进一步建设，将形成多核心协同的战略格局，需密切关注。  相似文献   

2013年夏季南极南设得兰群岛周边海域透光层水团结构          下载免费PDF全文

周梦潇  朱国平 《极地研究》2020,32(1):90-101

南设得兰群岛位于德雷克海峡南侧, 南经布兰斯菲尔德海峡与南极半岛相望。该区域一直是南大洋海洋学研究的热点区域, 近些年已成为南极磷虾渔业的重要作业区。透光层作为海洋生物活动最为集中的区域, 也是海洋中生产力最为丰富的区域。了解透光层水团的特性及变化, 一方面可为南极半岛海洋学研究提供基础信息, 同时也可为南极磷虾等中上层海洋生物的分布及其致因提供科学支撑。通过分析2013年1月至3月南设得兰群岛周边海域5个断面的透光层温、盐数据, 本研究梳理了该区域的水团属性和分布。结果显示, 南设得兰群岛北侧较深水区水团垂向结构明显, 由上至下依次为南极夏季表层水、冬季水和绕极深层水。位于南设得兰群岛南侧的布兰斯菲尔德海峡内, 威德尔海过渡水特征几乎占据了整个布兰斯菲尔德海峡。但布兰斯菲尔德海峡西南侧水团结构较为复杂, 包括了威德尔海过渡水、别林斯高晋海过渡水和德雷克海峡水等。阐明南设得兰群岛周边复杂的水团结构对于进一步开展南大洋生物-物理相互作用研究具有重要的科学意义。  相似文献   

辽宁省14市与长山群岛旅游空间相互作用研究     

王辉  马婧  刘小宇  柯丽娜 《地理科学》2017,37(3):367-374

运用旅游空间相互作用理论,以旅游人数、旅游总收入为基础数据,利用旅游空间相互作用模型,测算辽宁省14市、长山群岛与辽宁省14市及长山诸岛3个层次的旅游空间相互作用强度、经济联系度及经济隶属度。得出结论：① 各层级间空间相互作用强度、经济联系度及经济隶属度与距离呈负相关,区域间的空间相互作用强度、经济联系度及经济隶属度随距离增大逐渐减小;② 城市间经济联系度越强,旅游空间相互作用越大,与海岛旅游空间相互作用就越频繁;③ 通过对长山群岛旅游断裂点测算,得出其主要潜在客源地为大连、沈阳、丹东市。  相似文献   

南沙群岛地名分析     

朱海天 《地理研究》2018,37(11):2344-2354

依据多种历史资料,介绍南沙群岛地名的变迁过程,对中国“更路薄”中的渔民俗称以及中国政府于1935年、1947年和1983年三次公布的南沙岛礁地名进行统计,分析渔民俗称和标准地名对维护中国领土和主权完整的重要意义,梳理了各套地名系统中的专名体系和通名体系,对地名语源进行探讨,研究各地名系统之间的演进过程,总结了各自的优点与缺憾。针对现用标准地名提出以下建议：① 有计划地公布部分资料中已有记载岛礁的标准地名;② 对大型环礁细部、新生沙洲和新建大型人工岛进行命名以利于维护主权和保障航行安全;③ 对于现用标准地名中的部分外来语源地名可恢复其渔民俗称;④ 对于存疑岛礁应尽快核实确认以去疑存真。  相似文献   

Navigating the Complex Trade-Offs of Pesticide Use on Santa Cruz Island,Galapagos     

Megan O’Connor Robinson  Paul Hirsch 《社会与自然资源》2018,31(2):232-245

Pesticide use by farmers on Santa Cruz Island, Galapagos—a perceived adaptation to changing ecological and economic dynamics—has the potential to lead to environmental degradation in an area that is known and valued worldwide for its biodiversity. We survey Santa Cruz farmers to understand motivations for and concerns about pesticide use on the island. Results from farmer surveys are supplemented with interview data to develop the case study of pesticide use on Santa Cruz Island. We then apply a “complex trade-off” framework to explore and navigate the tensions between conservation and livelihoods. We conclude by elaborating the implementation of a participatory certification system, the Participatory Guarantee System, as a possible path for reconciling trade-offs in Santa Cruz, Galapagos.  相似文献   

Characteristics of earthquake sequences in the Kuril Islands     

刁桂苓  李钦祖  陈敬伟  于利民  孙佩卿 《地震学报(英文版)》1999,12(3):292-297

IntroductionEarthquakesshowanon-homogeneousdistributionontheEarth'ssurface;inmostregions,therearenoorfeweanhquakestooccur.Mosteanhquakesconcentrateinsomenarrowandlonghugeseismicbelts,forexample,thecircum-Pacificseismicbelt,Alpine-Himalnyanseismicbeltandmid-oceanridgeseismicbelt.Themid-oceanridgeseismicbelttraversesthePacific,Indian,AtlanticandArcticOceanstoformaunifiedandinterconnectedmid-oceanridgeseismicbelt;itisalsoconnectedwiththecircum-Pacific,Alpine-Himalayanseismicbelts.Therefore,t…  相似文献   

Stratigraphy, Chronology, and Paleoenvironmental Reconstruction of the Quaternary Sedimentary Infilling of a Volcanic Tube in Fuerteventura, Canary Islands     

Juan J. Coello  Carolina Castillo  Esther Martín Gonzlez 《Quaternary Research》1999,52(3):360

La Cueva del Llano is a volcanic tube of Pleistocene age on Fuerteventura Island, in the Canary Islands. Part of it is infilled with sediments of external origin. These deposits are exceptional in stratigraphic complexity and thickness compared with other known tube infillings, and they comprise nine stratigraphic units deposited in five phases. In Phase I, which has not been dated, sedimentation of cinder from a nearby cone occurred. Phase II began ca. 16,830 ± 900 ¹⁴C yr B.P., whereas phase IV dates to 9280 ± 370 ¹⁴C yr B.P. The interpretation of sedimentary features shows that phases III and V correspond to a dry climate, similar to the present one, whereas the climate was much wetter during phases II and IV. This paleoclimatic sequence agrees with those suggested by the study of deposits formed in other sedimentary environments, not only in Fuerteventura but on other islands of the Canary group and the Sud-Maroc region.  相似文献   

Remote sensing composite information's trend surface analysis of Nansha Islands coral islets and reefs'top   总被引：1，自引：1，他引：0  

Liu Baoyin  Wang Yanfeng 《海洋学报(英文版)》1999,18(1):87-96

INTRODUCTIONIntheseaareaofNanshaIslands,therearemanyshoalpatchandrapids.Themajorareaisclassifiedas"dangerouszone".Thereforeitisverydifficulttomakeanormalinvestigationonit.Consideringtheremotesensinginformationfeaturesreflectedbythecontrolfunctionoflocalgeographicstructureandthegrowthofcoralisletsandreefs,wefindthatthemostimportantfeatureofthegeographicsystemofNanshaIslandsisthatitsdistributionisregional.Thetrendsurfaceanalysissystembasedontheremotesensingcompositeinformationistoemulatet…  相似文献