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1.
The key to the nine species:M. nitidulum Garman,M. aurolaternatum Garman,M. spinosum (Steindachner),M. asperum Richardson,M. obtusirostrum Tåning,M. orientale (Gilbert),M. phengodes (Lütken),M. selenoides Wisner andM. brachygnathum (Bleeker), was prepared for the genusMyctophum, typical surface migrating myctophid fishes, from the Pacific and Indian Oceans. The three species ofM. cuvieri (Castelnau),M. indicus (Day),M. novaeseelandidae (Steindachner) were excluded from the present key, since they have not been reported since they were originally described.M. lychnobium Bolin formsM. spinosumlychnobium complex and was also excluded. The systematic accounts were given for seven species. 相似文献
2.
通过比较贻贝属5个物种包括中国的两种贻贝的线粒体16S rRNA基因部分序列,来初步确定它们的系统发育关系和了解中国沿海两种贻贝的遗传多样性情况.以Perna viridis为外群,采用NJ法和MP法构建分子系统树.系统发育分析表明,5种贻贝(Mytilus californianus, M. corcuscus, M. galloprovincialis, M. edulis, M. trossulus)在系统树上依次进行分叉,呈放射状.M. californianus最为原始,M. corcuscus次之.每一个贻贝物种都形成单系.其中,M. edulis和M. trossulus是非常相似的,M. corcuscus和M. californianus的亲缘关系近.同时发现,我国沿海分布的紫贻贝(M. galloprovincialis)和厚壳贻贝(M. corcuscus)的遗传多样性都较高,但厚壳贻贝的遗传多样性要低于紫贻贝,可能是由于厚壳贻贝过度被渔民开采等导致厚壳贻贝群体大小降低的缘故.这里系统发育分析为将来进行物种进化、迁移和育种方面的比较研究提供理论基础. 相似文献
3.
《African Journal of Marine Science》2013,35(1):347-356
In this study demersal survey data for the period 1990–1999 are used to investigate the average distribution of the Cape hake Merluccius capensis and M. paradoxus off Namibia in terms of density and mean length. Further, biomass estimates are compared on the basis of depth and density stratification. The main distribution of M. capensis was north of 27°S and that of M. paradoxus south of 24°S. M. paradoxus was deeper than M. capensis. For both species, average length increased with depth. M. paradoxus expanded its range to the north through the 1990s as its population size (off South Africa and Namibia) increased. In Namibian waters, small M. paradoxus were found only south of 25°S. Mean length of M. capensis increased north of 21°S, largely as a result of decreased numbers of small fish in shallower water. Abundance estimates stratified by depth were no different from those post-stratified on similar densities. 相似文献
4.
Effects of the North American polychaete Marenzelleria cf. viridis on a simple shallow-water benthic community of the northern Baltic Sea were studied in a field experiment combining natural densities of dominating macrofaunal species. The presence of M. cf. viridis increased benthic production (chlorophyll a) and reduced the survival of the native polychaete Nereis diversicolor. Adult Macoma balthica caused a significant mortality on M. cf. viridis whereas adult Cerastoderma glaucum had no effect on M. cf. viridis. We suggest that the competitive interactions between M. cf. viridis and M. balthica are a possible key factor determining the distribution pattern of M. cf. viridis in the Baltic Sea. 相似文献
5.
研究了滇池螺蛳(Margarya melanioides)分布和底泥营养成分之间的关系。2013年在滇池87个采样点采集螺蛳和底泥样本,图示分析所有采样点的活的螺蛳数量,确定活螺在滇池中的分布位点及分布密度;选择8个采样点的底泥样本,进行16项营养元素(有机质、磷、氮、锌、铁、锰、镁、钙、铜、钠、钾、砷、汞、铅、镉、铬)含量测定,分析这些样本营养元素的差异。根据这8个采样点中有无螺蛳生长,将8个底泥样本分为两组,采用完全随机设计两样本比较的t检验,结果两组样本间仅铜的含量有统计学差异(P0.05),这可能是由于滇池螺蛳的生长有效富集了重金属铜元素,使有螺区域比无螺区域底泥中铜的含量明显减少。这在一定程度上说明了螺蛳生长与底泥的关系,可为滇池污染防治及螺蛳种群保护提供相关的科学依据。 相似文献
6.
7.
嵊泗列岛海域三种贻贝贝体框架特征的差异 总被引：1，自引：1，他引：0
以壳长SL、壳宽SW、壳高SH(BD)、OA(壳顶至韧带末端的直线距离)、OB(壳顶至壳背面最高点的直线距离)、OC(壳顶至壳后端最远点的直线距离)、OD(壳顶至壳高性状在腹缘的落点的直线距离)、AB(韧带末端至壳背缘最高点的直线距离)、BC(壳背缘最高点至壳后端最远点的直线距离)、CD(壳后端最远点至壳高性状在腹缘的落点的直线距离)为贝体框架变量,采用多元分析方法系统比较了嵊泗列岛海域厚壳贻贝、紫贻贝和"杂交贻贝"贝体框架特征的差异,结果表明:(1)在所涉9项贝体框架特征指标中,紫贻贝与厚壳贻贝间无显著差异的指标仅为L5(OC/SL)和L7(AB/SL)(P0.05),而"杂交贻贝"各项指标则均与厚壳贻贝和紫贻贝具显著差异(P0.05),厚壳贻贝和紫贻贝变异系数大于10%的指标均仅为L7(AB/SL),而"杂交贻贝"则仅为L3(OA/SL);(2)厚壳贻贝与紫贻贝间的欧氏距离最短(P0.05),仅为0.160;厚壳贻贝与"杂交贻贝"间和紫贻贝与"杂交贻贝"间的欧氏距离相近(P0.05),分别为0.452和0.418;(3)经主成分分析,提取到的3个特征值均大于1的主成分,累计贡献率达82.928%,其中第一主成分、第二主成分、第三主成分可依次归为与滤食功能区水平剖面占比相关的贝体框架因子,与消化功能区水平剖面占比相关的贝体框架因子,和与消化功能区垂直剖面占比相关的贝体框架因子,通过第一主成分仅能较清晰地区分厚壳贻贝和"杂交贻贝";(4)采用逐步判别法,以判别贡献率较大的L1(SW/SL)、L3(OA/SL)、L4(OB/SL)、L5(OC/SL)、L6(OD/SL)和L7(AB/SL)为自变量,所建Fisher分类函数方程组可较清晰区分厚壳贻贝、紫贻贝和"杂交贻贝",三者的判别准确率依次为94.6%、94.6%和100%,综合判别准确率为96.4%。 相似文献
8.
研究了海洋链霉菌分离株M095的基因转移系统。利用属间接合转移将具有oriT的大肠杆菌-链霉菌穿梭质粒pIJ8600转入EscherichiacoliET12567(pUZ8002)中,获得供体菌。将供体菌与预萌发的菌株M095的孢子进行接合转移,将质粒pIJ8600转入菌株M095中,其转化率为1.99×10-4个接合转化子/受体。Southern杂交证明质粒pIJ8600已经整合到菌株M095的染色体上。同时,将来自Spirulinamaxima(Cyanophyta)的别藻蓝蛋白基因(apc)克隆在质粒pIJ8600的XbaI和BglII位点,产生质粒pAPIJ。用接合转移法将质粒pAPIJ转入菌株M095。通过SDS-PAGE分析,得到2个大小为22ku和17ku的蛋白,分别相对应于别藻蓝蛋白的α和β亚基。这些结果进一步证明菌株M095的遗传转化体系已经成功建立起来,这将为其他海洋放线菌遗传转化工作的研究奠定基础。 相似文献
9.
Chris Lalas 《新西兰海洋与淡水研究杂志》2013,47(2):635-642
Macroctopus maorum, also known as Octopus maorum and Pinnoctopus cordiformis, grows to 12 kg and is the largest octopod in Australasia. In New Zealand, this species features in the diets of seals and albatrosses. Beaks of depredated octopus resist digestion and accumulate in the stomach until regurgitated or defecated. Beaks of M. maorum were differentiated reliably from those of other octopods in prey remains for octopus > c.100 g. Previous studies estimated the size of depredated M. maorum from measures of lower beaks using equations derived either from a small sample of M. maorum or from related species. Here, allometric equations to estimate ventral mantle length (4.6–27.5 cm), dorsal mantle length (5.1–29.0 cm), total length (20–198 cm), and body mass (36–12 000 g) were derived from measures of both upper and lower beaks of 90 specimens of M. maorum. These regressions were imprecise and reflected innate variability in octopus morphometrics, a characteristic reflected in the results of analyses of published data for M. maorum from northern New Zealand and for two other large octopods, Octopus vulgaris and Enteroctopus magnificus. 相似文献
10.
采用生物急性和慢性毒性实验的方法,研究了赤潮异弯藻对蒙古裸腹溞和日本新糠虾的毒性影响,并初步探讨了赤潮异弯藻导致二者较快死亡的机制。结果发现,赤潮异弯藻不仅对蒙古裸腹溞和日本新糠虾的存活有显著影响,而且使其个体变小、产幼前发育时间延长、总生殖量降低、平均存活时间缩短,种群数量增长受抑制。显微观察发现,蒙古裸腹溞能摄食赤潮异弯藻,但摄食后,其粪便紧紧地粘在蒙古裸腹溞的肠道末端;日本新糠虾不摄食赤潮异弯藻,但该藻粘附在其触须、附肢以及腹部、尾部的刚毛上,以及作为食物的卤虫幼体也被大量粘附在一起,聚集成团,或通过赤潮异弯藻粘附在日本新糠虾的附肢上。因此赤潮异弯藻很可能通过干扰蒙古裸腹溞和日本新糠虾正常的生理活动,而导致其快速死亡。 相似文献
11.
《African Journal of Marine Science》2013,35(2):195-204
Seasonal and short-term variability of environmental parameters influence the spawning strategies of fish species. In this study, the spawning strategies and the transport of early stages of the two Cape hake species off South Africa were investigated. Distribution of eggs and larvae of Merluccius paradoxus and M. capensis was analysed in order to derive more detailed and species-specific information on spawning season, spawning location, and transport of early stages. Samples were collected during three pilot surveys between January and October 2007 and during an extensive survey in September/October 2008 in the southern Benguela upwelling system off South Africa. Eggs and larvae of M. paradoxus were found in greater numbers than those of M. capensis during all surveys. Highest abundances were found from September to October, indicating one spawning peak for M. paradoxus during late austral winter to spring. The western Agulhas Bank was identified as the primary spawning ground, and smaller spawning events occurred on the West Coast. Larvae of both species were mainly distributed in subsurface waters between 25 and 100 m. More than 50% of all larvae caught had a total length between 3 and 4 mm and size increased significantly with decreasing latitude. Merluccius capensis were found closer inshore than M. paradoxus, indicating that early stages of the two species followed separate drift routes. We assume that this distribution pattern most likely evolved from differences in spawning location and phenology. The spawning strategies of M. paradoxus and M. capensis are well adapted to a time-frame of optimal transport conditions favourable for larval survival in the highly variable environment of the southern Benguela upwelling system, but the peak spawning of the two species is separated in time and space. 相似文献
12.
《African Journal of Marine Science》2013,35(3):261-268
Prevalence of infection with the myxozoan parasite Kudoa thyrsites is not well documented in sardine Sardinops sagax, the Cape hakes Merluccius capensis and M. paradoxus, and kingklip Genypterus capensis. Quantitative polymerase chain reaction assays were used to determine the prevalence of K. thyrsites in wild-caught S. sagax (n?=?296), Merluccius spp. (n?=?162) and G. capensis (n?=?70), harvested in 2015. Sardinops sagax were harvested from the east, south and west coasts of South Africa, whereas M. capensis, M. paradoxus and G. capensis were taken from the west coast only. Relationships between K. thyrsites infection prevalence and fish capture locality, season, sex and size were determined with Chi-square tests. Prevalence was highest in S. sagax (91%), followed by M. capensis and M. paradoxus (87%) and G. capensis (40%). Prevalence was independent of sex of the host for all fish species. In the case of S. sagax only, the prevalence of infection was independent of locality of capture but depended on season, with prevalence lowest during spring and highest during autumn. No significant relationship (p?>?0.05) was found between infection prevalence and host size for any of the fish species. 相似文献
13.
本研究通过转录组技术对不同氮源培养下的多形微眼藻(Minutocellus polymorphus)固碳途径进行分析。通过对转录本进行NR、NT、Swiss-Prot和KOG富集分类及GO、KEGG相关代谢途径和基因差异表达分析,构建了多形微眼藻固碳途径。研究发现该藻除具有C_3固碳途径外,还具有较完整的C_4固碳通路。在注释到的164个固碳相关编码基因中,有33个出现明显表达差异。根据基因的差异表达情况可以发现,在有机氮源中多形微眼藻C_3固碳途径的核酮糖-1,5-二磷酸再生阶段和C_4固碳途径的磷酸烯醇式丙酮酸再生阶段相关编码基因均有上调表达, C_4固碳羧化阶段相关编码基因均有下调表达。研究对比了多形微眼藻与假微型海链藻(Thalassiosira pseudonana)、三角褐脂藻(Phaeodactylum tricornutum)和抑食金球藻(Aureococcus anophagefferens)固碳途径的异同点,发现多形微眼藻与抑食金球藻有相似的C_4固碳途径,与三角褐脂藻有相似的C_3固碳途径。进一步分析多形微眼藻碳氮代谢途径基因表达情况,发现两种代谢途径相互支撑,存在协同效应。研究结果可丰富微藻的固碳通路研究,也可为深入分析褐潮暴发原因提供依据。 相似文献
14.
Mariano J. Albano Carlos Rumbold Ignacio L. Chiesa Guadalupe Vazquez Eduardo D. Spivak Sandra M. Obenat 《新西兰海洋与淡水研究杂志》2019,53(1):15-32
We report the occurrence of the invasive amphipod Monocorophium acherusicum in Mar del Plata port, Argentina, using morphological and molecular analysis and estimated mean abundance to detect monthly variations of this population. We compared M. acherusicum morphology with that of M. insidiosum and Crassicorophium bonelli, the two most similar locally occurring species, to establish the diagnostic characteristics for the correct identification of them; moreover, we provide some taxonomic notes about others corophiids regionally distributed. M. acherusicum were collected in a subtidal biofouling community and its mean abundance was maximum in summer. In the molecular analysis, the maximum-likelihood tree showed that specimens from Mar del Plata were clustered with M. acherusicum specimens from GenBank and Boldsystems. We support and confirm the species identity in Mar del Plata port using DNA barcoding and with taxonomic methods. 相似文献
15.
《African Journal of Marine Science》2013,35(3):455-458
Flathead mullet Mugil cephalus and freshwater mullet Myxus capensis are important components in South African estuarine fish communities and fisheries, but there is little information on their age and growth or age validation. This study validated the periodicity of growth zone formation in sectioned sagittal otoliths and scales of fish of known age that had been at liberty for 10 years. For both M. cephalus and M. capensis, the number of growth zones counted on otolith sections did not differ significantly from the known age of the fish. There were significantly fewer growth zones on scales than the known age of both M. cephalus and M. capensis. Growth zone deposition rate could therefore be validated as annual for otoliths but not for scales of the two species. It is recommended that future ageing studies focus on otoliths rather than scales. 相似文献
16.
海洋链霉菌M506 的鉴定及代谢产物抑菌活性初步研究 总被引：1，自引：0，他引：1
自胶州湾沉积物中分离出海洋链霉菌M506,根据其形态特征观察、生理生化特征试验及基于16S rDNA序列系统进化分析,初步鉴定该菌为灰略红链霉菌.采用不同培养条件对其进行小规模发酵,利用金黄色葡萄球菌(Staphylococcus aureus),大肠杆菌(Escherichia coli),枯草芽孢杆菌(Bacillus subtilis)和苏云金芽孢杆菌(Bacillus thuringiensis)四株细菌作为指示菌,检测其抑菌活性.结果表明,该菌株代谢产物粗提物对于金黄色葡萄球菌、枯草芽孢杆菌和大肠杆菌等具有显著抑制活性. 相似文献
17.
Effect of native and invasive cordgrass on Macoma petalum density, growth, and isotopic signatures 总被引：1，自引：0，他引：1
Ecosystem engineers can influence community and ecosystem dynamics by controlling resources, modifying the flow of energy or biomass, or changing physical characteristics of the habitat. Invasive hybrid cordgrass (Spartina alterniflora × Spartina foliosa) is an ecosystem engineer in salt marshes in San Francisco Bay, California, U.S.A. that raises intertidal elevations and may be either increasing C4 plant carbon input into food webs or tying up carbon in a form that is not usable by consumers. A manipulative experiment compared abundance, growth, and stable isotope (δ13C and δ15N) composition of the clam Macoma petalum (=M. balthica) among native marsh, hybrid Spartina, and mudflats in central San Francisco Bay. We found higher densities (individuals m−2) of M. petalum on mudflats compared to either native or hybrid Spartina (p < 0.001). Macoma petalum shell growth was significantly greater in mudflats than in either vegetation type in 2002 (p = 0.005) but not 2003. Differences in shell growth between native and hybrid Spartina were not significant. Stable isotope results showed differences between habitats in δ13C but not δ15N. Carbon signatures of M. petalum placed in Spartina were much more depleted than the isotopic signature of Spartina. Neither native nor hybrid Spartina appears to be a significant carbon source for M. petalum in San Francisco Bay, and we found no evidence that hybrid Spartina contributes carbon to M. petalum beyond what is provided by S. foliosa, despite the hybrid's much greater biomass. Our results show that loss of mudflat habitat, rather than increased input of C4 carbon, is the greatest effect of the invasion of hybrid Spartina on M. petalum. 相似文献
18.
Stable C and N isotopic composition of sinking particles and zooplankton over the southeastern Bering Sea shelf 总被引：1，自引：0，他引：1
Stacy L. Smith Susan M. Henrichs Taekeun Rho 《Deep Sea Research Part II: Topical Studies in Oceanography》2002,49(26):6031-6050
Stable carbon and nitrogen isotopic composition of zooplankton, suspended particulate organic matter (SPOM), and sinking particles collected using sediment traps were measured for samples obtained from the southeastern Bering Sea middle and outer shelf during 1997–1999. The quantity of material collected by the middle shelf sediment trap was greater in both spring and late summer and fall than in early and mid-summer. The δ15N of SPOM, sinking material and zooplankton showed greater inter-annual variability at the middle shelf site (M2) than at the outer shelf site (M3). Zooplankton and sinking organic matter collected by M2 sediment traps became more depleted in 15N from 1997 through 1999, associated with a change from unusually warm to unusually cold conditions. Suspended and sinking organic matter and zooplankton collected from M3 decreased only slightly in δ15N from 1998 to 1999. SPOM, zooplankton, and sediment trap samples collected at M2 were usually enriched in δ15N and δ13C over those from M3. However, in 1999 sediment trap samples from the middle shelf were enriched in 13C over M3 material, but the δ15N of samples from the two sites was similar. The geographic pattern could be explained greater productivity over the middle shelf, associated with either isotopically heavy nitrogen being regenerated from sediments, or with utilization of a greater fraction of the available inorganic nitrogen pool during most years. 相似文献
19.
Diel patterns in survey trawl catches for the Cape hakes Merluccius capensis and M. paradoxus off Namibia were studied in order to examine the effect of diel bias on catchability, and its implication for survey abundance estimation and the consistency of the survey time-series. Catch rates (numbers per haul) by species and length from summer demersal biomass surveys conducted during the period 2002–2013 were used, together with a computation of the corresponding light-level data from which the solar zenith angles were obtained. Generalised additive models were fitted to assess the relationship between the catches and a number of explanatory variables. Significant covariates were zenith angle, depth and geographical position. The final models explained 78% and 59% of the variability in catch rates of M. capensis and M. paradoxus, respectively. For M. capensis, the response to zenith angle increased sharply for values above 100°, which represents the time between sunset and sunrise. For M. paradoxus there was a moderate increase in the response to zenith angle during the night. In cases where some fishing took place at night in shallow water, the survey results for M. capensis were more greatly affected than was the case for M. paradoxus, which is related to the different depth preference of the two species. Fishing in depths shallower than 400?m outside daylight hours should therefore be avoided in order to reduce bias and ensure consistency in abundance estimates from surveys. 相似文献
20.
肠道细菌对厚壳贻贝稚贝附着的作用研究 总被引：1，自引：0，他引：1
为探讨肠道细菌形成的微生物被膜对贝类附着的作用,从厚壳贻贝(Mytilus coruscus)成体肠道中分离10株肠道细菌,调查厚壳贻贝肠道细菌形成微生物被膜特性,分析微生物被膜密度、细菌种属与厚壳贻贝稚贝附着之间的相互关系。所有肠道细菌均可有效促进稚贝附着。其中,Paracoccus sp.1微生物被膜诱导的稚贝附着率最高(61%),且微生物被膜膜厚较厚,细菌分布较密集;仅5株肠道细菌Roseovarius sp.1、Winogradskyella sp.1、Tenacibaculum sp.4、Bacillus sp.5和Nonlabens sp.1的被膜密度与附着显著相关(P0.05)。系统发育分析发现肠道细菌诱导附着率与其种属无关。本研究表明源于厚壳贻贝成贝肠道细菌可以促进其稚贝的附着,说明肠道细菌对厚壳贻贝的生长发育具有一定的作用。本研究结果为深入探讨肠道细菌与厚壳贻贝相互作用和推动该种规模化养殖提供理论依据。 相似文献