共查询到19条相似文献，搜索用时 301 毫秒
1.
为给茂名市建设文昌鱼省级自然保护区提供基础资料,根据2003年8月～2004年5月间对茂名大放鸡海域的调查结果,对文昌鱼和蛇尾的分布特性进行了研究.结果表明:文昌鱼和蛇尾均呈集群分布,在空间分布上表现为正相关关系,不存在强烈的竞争关系.文昌鱼主要分布在中值粒径MdΦ为0.4～2.2之间砂质中.在0.5≤MdΦ＜1.5范围内,文昌鱼分布密度相对地高,而在MdΦ＜0.5或MdΦ≥1.5范围内,文昌鱼分布密度相对较低.粒径0.36～0.78 mm组分＜50%时,文昌鱼分布密度≤50 ind/m2;粒径0.36～0.78 mm组分≥50%时,文昌鱼分布密度＞100 ind/m2.蛇尾分布在中值粒径MdΦ为0.2～0.8之间砂质中.粒径 0.36～0.78 mm组分占10%～50%时,蛇尾分布密度较低,而粒径0.36～0.78 mm组分占60%～80%时,蛇尾分布密度较高. 相似文献
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为研究清楚南海硇洲岛海域文昌鱼分布的底质环境条件,利用2006年7月～12月3个季度采集的硇洲岛海域沉积物样品,进行8种孔径的套筛分选,取得不同粒径颗粒的百分比数据.运用沉积物的各种参数,结合文昌鱼的分布数据进行分析,发现硇洲岛海域文昌鱼适宜栖息底质类型为细中砂、中砂和粗中砂.中值粒径MDΦ0.547～2.745φ;四分位离差QDΦ0.536～0.980;四分位偏态SKΦ-0.147～0.101;众值粒径MoΦ0.731～3.152.φ0.2～0.85mm粒级颗粒所占比例≥58%时,文昌鱼密度显著地高.聚类分析和回归分析发现0.2～0.85mm粒级含量和文昌鱼分布密度具有明显的相关性.对比各地文昌鱼栖息底质发现,砂质结构基本一致,但具体类型存在地域差异. 相似文献
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利用2009-2010年四个季度月用底栖生物抓斗式采样器捕获的文昌鱼样品,从其资源分布、年龄结构、生物学和生态学特征等方面对厦门国家级珍稀海洋物种自然保护区文昌鱼的种群健康状况进行评价研究.结果表明:(1)文昌鱼种群资源分布衰减趋势明显,只在黄厝—前埔海区、小嶝岛—角屿海区和南线—十八线海区3个核心区还有分布,但资源密度低,分布范围狭小,而在鳄鱼屿实验区未能发现.(2)文昌鱼体重与体长之间关系:W=6.6895×10-4L3.1818;体长与体质量生长方程分别为:厶=65.63[1-e-0.68(t+032)],Wt=404.62[1-e-0.68(t+032)]3.1818;夏季、冬季航次的优势体长组分别为25-35mm和35-45mm,优势体重组分别为25-50mg和50-100mg;秋季低龄鱼较多,而冬季高龄鱼比例较高.(3)采用ELEFAN Ⅰ技术分析了厦门文昌鱼的Von Bertalanffy生长参数K、L∞、总死亡系数Z、自然死亡系数M和开发率E,发现其生长参数K值较大,自然死亡系数较高,开发率较大(0.69).综之,厦门自然保护区内的文昌鱼种群健康状况整体不佳,应注意资源保护,加强保护文昌鱼栖息地的底质和水质以及防止过度捕捞以实现其资源可持续利用. 相似文献
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厦门海域文昌鱼及其他大型底栖动物资源现状研究 总被引：1，自引：0，他引：1
根据 2014年 8月在厦门黄厝和十八线潮下带海区,以及 2014年 1月-6月在厦门玩月坡潮间带获得的文昌鱼及其
他大型底栖动物数据,对厦门海域文昌鱼及其他大型底栖动物资源现状进行了分析。黄厝潮下带大型底栖动物物种数、栖息
密度和生物量分别为 25种、80. 7 i nd/ m 2 和 13. 46 g/ m 2 ,十八线潮下带大型底栖动物物种数、栖息密度和生物量分别为 25种、
76. 2 i nd/ m 2 和 6. 53 g/ m 2 。黄厝潮下带大型底栖动物丰度指数 （ d ） 平均值略低于十八线潮下带,而均匀度指数 （J ） 和物种
多样性指数 （ H' ） 平均值略高于十八线潮下带。黄厝潮下带、十八线潮下带的文昌鱼栖息密度分别为 51. 1i nd/ m 2 和 39. 8 i nd/ m 2
文昌鱼生物量分别为 4. 63 g/ m 2 和 3. 68 g/ m 2 。单因素方差分析表明,除了黄厝海区和十八线海区之间的文昌鱼体长呈显著差
异,其余文昌鱼种群参数和大型底栖动物群落参数均无显著差异。文昌鱼栖息密度和生物量与底质粒径分选系数呈显著负相
关。玩月坡潮间带低潮区文昌鱼及其他大型底栖动物资源贫乏。厦门海域文昌鱼的资源量与文昌鱼放流、海岸工程和采砂作
业有关。 相似文献
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采用滦河口外昌黎海域2005年、2008年及2011年三期文昌鱼分布及底质调查数据,对该海域的底质结构及文昌鱼分布时空变化进行了研究。结果表明:滦河口外昌黎海域文昌鱼主要分布在细砂、中细砂、细中砂及中粗砂类型的底质中,中值粒径范围为1.38~2.98φ,分选性好,四分位偏态近似对称,呈正偏;影响文昌鱼分布的主要粒组为0.125~1.000mm,文昌鱼主要分布在该粒组体积分数90%的海域;与其他海域适宜文昌鱼栖息的底质对比,发现昌黎海域适宜文昌鱼栖息的底质颗粒较细;在监测期内,文昌鱼种群呈现退化的趋势。研究区内的主要河流滦河入海悬沙量减少,沙源补充不足是该海域文昌鱼种群退化的主要原因,同时昌黎海域海洋养殖产业的迅猛发展及环境污染的加剧也对文昌鱼的生存和繁衍构成一定的威胁。 相似文献
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根据1981年和2004年胶州湾口青岛文昌鱼(Branchiostoma belcheri tsingtauense Tchang et Koo)采集资料,分析了23年来青岛文昌鱼体质量、体长、生物量和栖息密度的变化,发现1981年文昌鱼个体最大体长为55 mm,平均体长为37.63 mm,而2004年个体最大体长仅42 mm,平均体长只有29.82 mm;1981年各月平均体质量范围为0.06～0.14 g,2004年为0.03～0.04 g;1981年平均栖息密度为753个/m2,2004年为1 220个/m2。采用成对数据平均数比较的假设双尾检验法进行数据统计分析结果也表明,文昌鱼的平均体长和体质量在1981年和2004年均有显著的差异,平均分布密度在显著水平a为0.01时,差异不显著,而在a为0.05时,差异显著;说明2004年采集的青岛文昌鱼个体长度和质量都明显变小而分布密度有所增加;而平均生物量,1981年和2004年没有显著性差异。不同体长个体数比例表明,1981年和2004年文昌鱼种群的年龄组成以及各年龄组的生长情况等方面也不相同。引起这些变化的原因初步分析为底质的改变、栖息地萎缩、饵料丰度和组成改变以及人类活动的干扰。 相似文献
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本文根据2014年至2017年在厦门文昌鱼保护区黄厝、南线十八线、鳄鱼屿和小嶝岛四处潮下带以及参照点白城潮下带获得的大型底栖动物和沉积物粒径数据,探讨底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响。聚类分析表明个别黏土含量较高的取样站没有发现文昌鱼且大型底栖动物种数少。单因素方差分析表明,厦门潮下带部分大型底栖动物群落参数和优势种数量存在显著差异。底质粒径分析表明, 2017年9月,鳄鱼屿和白城潮下带黏土和粉砂含量高于黄厝、南线十八线和小嶝岛潮下带的黏土和粉砂含量。2016年夏季黄厝、南线十八线潮下带黏土和粉砂含量明显高于2014年夏季的黏土和粉砂含量。相关分析表明,5个大型底栖动物群落参数如物种数、栖息密度、生物量、多样性指数(H′)和丰度指数(d), 7个常见种的栖息密度和生物量与粉砂和黏土含量呈显著正相关,均匀度指数(J)和4种常见种的数量与粉砂和黏土含量无显著相关,白氏文昌鱼(Branchiostoma belcheri)的栖息密度和生物量与粉砂和黏土含量呈显著负相关。上述结果证实,黏土含量增加到15%和粉砂含量增加到60%有利于多数大型底栖动物栖息密度和生物量的增加,但导致白氏文昌鱼栖息密度和生物量的减少,而红角沙蚕(Ceratonereiserythraeenis)、滑指矶沙蚕(Eunice indica)、光滑倍棘蛇尾(Amphioplus laevis)受底质细化的影响较小。 相似文献
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采用现场采样方法对福建沿海文昌鱼(Branchiostoma balcheri)的分布和资源状况进行了调查,为文昌鱼的保护提供依据。全省19个海区潮间带均未捕获文昌鱼;12个海区的潮下带浅海定量调查中,仅5个海区采集到文昌鱼。东山湾海区文昌鱼密度最高,为41.67尾/m2,其次是厦门十八线海区,为14.5尾/m2,厦门南线海区和黄厝海区分别为5.39尾/m2和4.71尾/m2,泉州大港海区仅捕到1尾,闽江口3个海区均未捕获。所获文昌鱼年龄大多为1龄,占39.2%,2龄占23.5%,3龄占25.5%,其他(1龄以下、4龄、5龄及以上)占11.8%。与20多年前的历史资料相比,文昌鱼的分布区大为缩小,资源量大为降低,资源已濒临枯竭。必须加大对文昌鱼资源的保护力度,有必要增设文昌鱼自然保护区,并加强对文昌鱼保护区的管理。 相似文献
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厦门文昌鱼遗传多样性研究 总被引：6，自引：1，他引：6
运用分子标记技术，对厦门现有文昌鱼(Branchiostoma balcheri Gray)海域(蟹口海域、南线海域、黄厝海域)文昌鱼种群进行遗传多样性研究。通过10个有效引物的RAPD反应，共扩增出238条带，其中多态性条带为121，占总扩增条带的50．84％。Nei指数法分析和UP(小俄统计分析表明：厦门3个海域文昌鱼可分为2个组。平均遗传距离为0．11。南线海域文昌鱼和黄厝海域文昌鱼的遗传距离为0．07，亲缘关系较近，聚类于同一组；蟹口海域文昌鱼与南线海域文昌鱼和黄厝海域文昌鱼的遗传距离分别为0．12和0．14，亲缘关系较远，单独为一组，结论 与3个海域的文昌鱼形态比较结果一致，出现遗传分化。Shannon遗传多样性指数统计结果表明：蟹口海域种群为0．616，南线海域种群为0．497，黄厝海域种群为0．391。厦门文昌鱼种群遗传多样性是各种群的遗传特性与该海域各种环境生态因子长期作用的结果，三元线性相关分析发现目前主要生态因素是底质和海水深度，3个海域中以蟹口海域的自然环境最为优越(其底质为中粗沙或粗中沙、水深8—15m)。根据以上研究结果，本文提出了厦门海域文昌鱼资源的保护建议。 相似文献
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In order to realize the spatiotemporal variations of benthic macrofaunal communities at the "Amphioxus Sand"habitat, six surveys including four seasons and three consecutive summers(i.e., 2014, 2015 and 2016) were conducted in two core sites, i.e., Huangcuo(HC) and Nanxian-Shibaxian(NX), in the Xiamen Amphioxus Nature Reserve in China. A total of 155 species of macrofauna were recorded, therein, polychaetes were dominant in terms of species number and density. Significant spatiotemporal variations of macrofaunal communities were observed. The density of polychaetes and the biomass of molluscs in the HC site were higher than those in the NX site. Macrofauna were more diverse and abundant in the cold seasons(winter and spring) than that in the warm seasons(summer and autumn). The annual variations of macrofaunal communities may be attributed to the changes in sediment texture among the three years of the survey. The variations in macrofaunal communities were mainly related to the proportion of polychaetes within the community. In addition, the density of amphioxus(include Branchiostoma japonicum and B. belcheri) was negatively correlated to that of polychaetes, bivalves, and crustaceans. Amphioxus was less likely to be found in the sediments with higher silt and clay content. Five biotic indices including Margaref's richness index(d), Peilou's evenness index(J′), Shannon-Wiener diversity index(H′),AMBI and M-AMBI were calculated in the present study. AMBI seems suitable in assessing benthic health at the"Amphioxus Sand" habitat, and a potential risk of ecological health in Xiamen Amphioxus Nature Reserve should be aware. 相似文献
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The vertical distribution of microphytobenthos (MPB) was investigated in intertidal flats of the Nakdong River estuary over different temporal periods. The MPB biomass were measured as chlorophyll a concentration in the sediment, and monitored at two different depth scales. From August 2006 to August 2007, monthly sampling was carried out at four sites to a depth of 10 cm. The vertical distribution exhibited an exponential decline with depth and the slope was closely related to sediment composition and MPB biomass in the surface sediment. The two slightly muddy sand (5–25% mud, <63 μm) sites presented similar trends of seasonal variation to a sediment depth of 10 cm, and no statistical difference was observed in their initial values and the slope of the exponential curves applied to each data set. The site with higher mud content also had higher surface biomass, and the fitted exponential curve had a larger slope than sites with more sand content. The seasonal variations of phaeo-pigments compared to chlorophyll a revealed higher grazing stress on the MPB in summer at the three slightly muddy sand sites, and low grazing stress all year around at the sand (<5% mud) site. In January, April and October 2007, and January 2008, diurnal sampling was conducted at hourly intervals at one slightly muddy sand site. The investigation in January 2007 which was conducted at 1 cm intervals to a depth of 10 cm sediment showed the migration mainly existed in the upper 1 cm. The other diurnal sampling was undertaken to a 1 cm depth at 0.5 mm intervals. An evident migratory rhythm was present, with migration up to the surface during daytime emersion and down into deeper sediment during night and high tide submersion. Migrating cells could reach sediments as deep as 6 or even 10 mm. When the visible thick biofilms formed, the migratory rhythm changed by keeping higher biomass at the surface even at night and during high tide submersion. Generally, the MPB surface biomass was an important factor in structuring the MPB vertical distribution. The vertical distribution to depths of 10 cm was closely related to the sediment composition over the long term, while the MPB migration influenced the vertical distribution over the short term in the top 1 cm of the sediment. 相似文献
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文章依据山东省近岸海域表层沉积物调查资料,分析了沉积物粒度的时空变化特征及其影响因素。结果显示:2020年,山东省近岸海域表层沉积物粒径总体呈由近岸向远海逐渐变小的趋势,其中,粉砂含量最高,平均66.45%;砂次之,平均26.78%;黏土含量较低,平均6.77%。沉积物不同粒级组分具有明显的空间分布差异性,类型包含粉砂、砂质粉砂、粉砂质砂和砂,以粉砂为主,占调查站位的61.9%。2016—2020年,山东省近岸海域表层沉积物整体呈现粗化的趋势,其中,日照、青岛、潍坊和滨州近岸海域粗化趋势较为明显,东营次之,烟台和威海粗化程度最低。沉积物粒度时空特征的主要影响因素包含物源、区域水动力条件(如,渤海和黄海海流、山东省沿岸流等)及沿海海岸工程建设情况,具体的影响机制仍需进一步调查研究。本研究成果可以为山东省近岸海域底质类型变化分析和海岸带保护与利用提供参考。 相似文献
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The interplay of sediment characteristics,depth, water temperature,and ocean currents shaping the biogeography of lancelets (Subphylum Cephalochordata) in the NW Pacific waters 
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下载免费PDF全文 Lancelets (or amphioxus) are often found within the soft bottom of shallow tropical and temperate seas. The present study is the first to provide a fine‐scale biogeography of five species of lancelets (Asymmetron lucayanum, Branchiostoma belcheri, Branchiostoma japonicum, Epigonichthys cultellus, and Epigonichthys maldivensis) in the NW Pacific and examine the effects of multiple environmental parameters. From multivariate analyses, the distribution and abundance patterns of lancelets were explained by a combination of factors comprising depth, temperature of the collecting month, mean temperature of the coldest month in the year, medium particle size and silt/clay ratio of the sediments. In addition, ocean currents also affect their distribution range. The major occurrence of A. lucayanum and E. maldivensis was associated with the warm Kuroshio current, but E. maldivensis exhibited higher tolerance to low salinity and low temperature, and preferred substrata of slightly larger grain size, a lower ratio of suspended sediments, and deeper water. The closely related B. belcheri and B. japonicum exhibited fine‐scale habitat differentiation, and B. japonicum was abundant along the southern coast of China, where the salinity is lower in winter because of the China Coastal Current and the substratum is composed of very coarse sand with suspended sediments. Branchiostoma belcheri occurred in low abundance and was only recorded in Northern Taiwan and the Taiwan Banks. Epigonichthys cultellus was found only at the Taiwan Banks, which had deep water, coarse sand, and a negligible amount of suspended sediments. 相似文献
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Melanie Beck Olaf Dellwig Gerd Liebezeit Bernhard Schnetger Hans-Jürgen Brumsack 《Estuarine, Coastal and Shelf Science》2008
Spatial and seasonal variations of sulphate, dissolved organic carbon (DOC), nutrients and metabolic products were determined down to 5 m sediment depth in pore waters of intertidal flats located in NW Germany. The impact of sediment permeability, pore water flow, and organic matter supply on deep pore water biogeochemistry was evaluated. Low sediment permeability leads to an enrichment of remineralisation products in pore waters of clay-rich sediments. In permeable sandy sediments pore water biogeochemistry differs depending on whether tidal flat margins or central parts of the tidal flat are studied. Pore water flow in tidal flat margins increases organic matter input. Substrate availability and enhanced temperatures in summer stimulate sulphate reducers down to 3.5 m sediment depth. Sulphate, DOC, and nutrient concentrations exhibit seasonal variations in deep permeable sediments of the tidal flat margin. In contrast, seasonal variations are small in deep pore waters of central parts of the sand flat. This study shows for the first time that seasonal variations in pore water chemistry are not limited to surface sediments, but may be observed down to some metres depth in permeable tidal flat margin sediments. In such systems more organic matter seems to be remineralised than deduced from surface sediment studies. 相似文献
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《Marine Geology》2007,236(1-2):61-77
Cabo Pulmo, Mexico, is often cited as the eastern Pacific's northernmost coral reef. We investigated sedimentary dynamics to verify whether the system functions sedimentologically as a reef, which would mean that it retained internal sediment in a framework and exported peri-reefal sediment creating clearly identifiable facies dominated by reefal fauna. We mapped distribution of sediments using grab samples, the acoustic ground-discrimination systems QTC View and Echoplus at 50 kHz signal frequency and an IKONOS satellite image. Morphologically, the bay of Cabo Pulmo can be divided into intrusive dikes and rocky hardgrounds in less than 10 m depth and a sandy interior with rocky outcrops sloping to over 40 m. Reefal fauna without lasting framework-building but with production of typically reef-associated carbonate sediments, as well as a patch-reef facies were found on the dikes and hardgrounds. Sediments in the bay were a mixture of carbonates and siliciclastics and were influenced by a seasonal river near the bay's center that imported siliciclastic material. To the north and south sediments had a higher carbonate content, although overall the bay was characterized by > 50% siliciclastics. The shallower subtidal sands were dominated by mollusk fragments, whereas in depths > 30 m planktonic foraminiferal sand was found. Acoustically and optically remote-sensed maps were used to differentiate between the rocky and sandy areas and to identify the presumed off-shelf transport pathway of reef-derived carbonates. Overall, the sedimentary system is characterized by carbonate production, but the coarser reef derived carbonates (coral and reef-dwelling mollusks) are transported off-shelf along a steep depth gradient and little typical peri-reef sediment remains. This transport is likely aided by storms. Since no sediment retaining frameworks are formed, the dikes cannot retain internal sediment, and the reefal fauna was not dominant in sediments throughout the bay, we conclude that Cabo Pulmo sedimentologically functions only in a limited way like a coral reef. 相似文献
19.
A sediment trap was deployed 3 m from the bottom at a water depth of 62 m on the southern flank of Georges Bank (41°02·2′N, 67°33·5′W) from 30 September 1978 to 10 March 1979 to qualitatively determine the size of sediments resuspended from the bottom by winter storms and to determine if seasonal changes in the phytoplankton could be observed in the trapped sediment.Bulk X-ray analyses of the trapped sediment showed layers of distinctly different textures preserved in the collection vessel. The median grain size of sampled layers ranged from 2·7 to 6·5 φ (fine sand to silt), but all layers contained a pronounced mode in the 3 φ (fine sand) range. Nine layers containing relatively large amounts of sand were present. The sand content was 75% in the coarest layers and about 32% in the fine layers. The median grain size of bottom sediments at the deployment site was considerably coarser than the trap samples, although the dominant grain size was also 3 φ.Average bottom-current speeds during the deployment period were about 30 cm s?1 with a range of 10 to 50 cm s?1. Bottom stress, computed from the observed currents and waves, suggest that 11 storms caused sufficient stress to resuspend 3 φ-sized sediments, in good agreement with the nine layers of relatively coarse sediments collected in the trap. Surface waves had to be included in the calculation of bottom stress because the bottom currents alone were insufficient to cause the resuspension of 3 φ-sized sediment.The trapped sediments contain numerous diatoms and coccoliths that are typical of late fall and winter assemblages. No clear seasonal difference in the flora was noted among sampled layers, probably due to the large influx of resuspended material and a reduced primary flux during this period. An undescribed species of Thalassiosira (G. Fryxell, personal communication), and siliceous scales of unknown systematic position were observed at all levels. 相似文献