Scale dependence of accumulation-dispersal coefficient of marine organisms

An attempt is made to find a relation betweenK, the absolute value of accumulation-dispersal coefficient of marine organisms referred to a region or a group (Kawai, 1986a), andL, the square root of the area of the region or the group over which the distribution density of organisms is averaged.K is estimated as shown below. For appropriate sampling time-intervals,K becomes greater than other coefficients such as population growth coefficient. Using this result, an order of magnitude ofK dependent onL is estimated from various data of temporal change in density. With the aid of a dependenceQL ^–2/3 (Kawai, 1985b), a relationKL ^–2/3 is predicted for 30 cmL 30 km, whereQ andK are the root-mean-square values of area-averaged horizontal divergence of near-surface flows and of the accumulation-dispersal coefficient, respectively. The reason whyK tends to have the order of magnitude of weak or mediumQ is discussed. The doubling-halving time of the distribution density due to accumulation-dispersal,T, is related toK byT=(log_e2)/¦K¦L ^2/3. Finally, sampling time-intervals to estimate accumulation-dispersal coefficients are referred to.     

Diversity and distribution of seagrasses in the Union of the Comoros

This study represents the first in situ assessment of seagrasses in the Union of the Comoros. The presence of the following 10 species (ranked in order of abundance) was confirmed: Thalassia hemprichii, Thalassodendron ciliatum, Syringodium isoetifolium, Halodule wrightii, Cymodocea rotundata, Cymodocea serrulata, Halodule uninervis, Halophila ovalis, Zostera capensis and Enhalus acoroides. Seagrasses occurred in large, continuous beds in the shallow waters at the northern and southern tips of Grande Comore Island and around the Bimbini Peninsula on western Anjouan Island, but were sparsely distributed throughout the shallow waters surrounding Mohéli Island.     

短蛸对不同生物饵料利用的比较

为比较短蛸（Octopus ocellatus）对不同生物饵料的利用效果,以南美白对虾、肉球近方蟹、菲律宾蛤仔和玉筋鱼四种饵料进行了饲喂实验。结果表明：1）肉球近方蟹组短蛸增重率显著高于其他各组（P<0.05）,南美白对虾组脏体比显著高于玉筋鱼组（P<0.05）,各饵料组肝体比无显著差异;2）南美白对虾组和肉球近方蟹组短蛸肌肉的蛋白质含量显著高于菲律宾蛤仔组和玉筋鱼组（P<0.05）,肉球近方蟹组脂肪含量显著高于其余各组（P<0.05）,玉筋鱼组灰分含量显著低于其他各组（P<0.05）;3）南美白对虾组短蛸肝胰腺谷丙转氨酶活性显著高于其余各组（P<0.05）,肉球近方蟹组谷草转氨酶活性显著高于其余各组（P<0.05）,玉筋鱼组谷氨酸脱氢酶活性显著低于其余各组（P<0.05）,菲律宾蛤仔组酸性磷酸酶活性显著高于其余各组（P<0.05）,玉筋鱼组胃蛋白酶活性显著高于其他各组（P<0.05）。综上,投喂肉球近方蟹可以显著提高短蛸的增重率;不同饵料对短蛸肌肉的蛋白质、脂肪和灰分含量有影响,对其肝胰腺功能和胃蛋白酶活性也有显著影响。     

Distribution of helminths in the digestive tracts of New Zealand freshwater eels

The distributions of the nematode parasites Paraquimperia sp., Spirocamallanus sp., and Cucullanus sp. in the intestines and recta of Anguilla dieffenbachii and A. australis from Lake Ellesmere and the South Branch of the Waimakariri River were studied over two years. Peak occurrence of Paraquimperia was in the anterior intestine of A. australis and mid intestine of A. dieffenbachii. Male and female Spirocamallanus sp. established in the mid intestine, but as female worms grew they attached more anteriorly and thus maintained the mid body in the mid intestine, prevented the tail end entering the rectum, and maintained the vulvae close to male worms. Cucullanus sp. was most often found in the mid intestine, but occurred throughout the intestine, possibly because of migration with food. Paraquimperia and Spirocamallanus extended their range with crowding; Cucullanus increased in density in the mid intestine. Posteriad movement, with or without subsequent evacuation, was a general feature of all species in both hosts, held live or examined after death. Chilling and freezing slowed or arrested loss from dead hosts. Larger worms (Spirocamallanus sp.) moved and were lost more rapidly than small worms (Paraquimperia sp.); worm loss was more rapid from A. dieffenbachii than from A. australis.     

Bathymetric segregation of sea urchins on reefs of the Canarian Archipelago: Role of flow-induced forces

We examined whether adults of three species of sea urchins species (Diadema antillarum, Arbacia lixula, and Paracentrotus lividus) exhibit a consistent depth-dependent partitioning pattern on rocky reefs of the Canarian Archipelago (eastern Atlantic). Hydrodynamic experiments were carried out to quantify the resistance to flow-induced dislodgement in these three species. We tested the model that different morphology can result in habitat partitioning among these sea urchins. Abundances of D. antillarum increased with depth. In contrast, A. lixula and P. lividus showed the opposite zonation pattern, coexisting in high abundances in the shallowest depths (<5 m), and occurring in low densities in the deepest part of reefs (>7 m). Both A. lixula and P. lividus had greater adhesion-surface to body-height ratios than D. antillarum. Similarly, A. lixula and P. lividus showed a greater ability to resist flow-induced dislodgement compared with D. antillarum. The mean “velocity of dislodgement” was 300% and 50% greater for A. lixula and P. lividus, respectively, relative to D. antillarum, for any particular size. As a result, A. lixula and P. lividus are better fitted to life in high-flow environments than D. antillarum. We conclude that the risk of dislodgement by water motion likely play a relevant role in the vertical distribution patterns of these sea urchins in the eastern Atlantic.     

A refinement of the previous hypothesis of turbulent energy spectrum

To refine the previous hypothesis of turbulent energy spectrum (Nan-niti, 1970), further theoretical consideration and a simple experiment using electric fans was carried out. From the hypothesis ofq=δε/δk andεq=const., the following relations are derived for the spectrumF, and the autocorrelation functionR:F(k)∼k _{−(5−2α)/3} andR(t)∼1−(t/τ)_2(1−α)/3, whereq is the local energy supply,ε the energy dissipation rate, andk the wavenumber,t the time,τ the lifetime of the largest eddy. The following further relations are also obtained:ε∼l _−α,v∼l _β,v∼τ _γ andγ=(1−α)/(2+α)=β/(1−β), wherel is the length scale of the phenomenon,v turbulent velocity,α=1/2,β=1/6, andγ=1/5. The experimental results support these relations.     

Optical properties of the red tide in Isahaya Bay,southwestern Japan: Influence of chlorophyll a concentration

Remote sensing reflectance [R _rs(λ)] and absorption coefficients of red tides were measured in Isahaya Bay, southwestern Japan, to investigate differences in the optical properties of red tide and non-red tide waters. We defined colored areas of the sea surface, visualized from shipboard, as “red tides”. Peaks of the R _rs(λ) spectra of non-red tide waters were at 565 nm, while those of red tides shifted to longer wavelengths (589 nm). The spectral shape of R _rs(λ) was close to that of the reciprocal of the total absorption coefficient [1/a(λ)], implying that the R _rs(λ) peak is determined by absorption. Absorption coefficients of phytoplankton [a _ph(λ)], non-pigment particles and colored dissolved organic matter increased with increasing chlorophyll a concentration (Chl a), and those coefficients were correlated with Chl a for both red tide and non-red tide waters. Using these relationships between absorption coefficients and Chl a, variation in the spectrum of 1/a(λ) as a function of Chl a was calculated. The peak of 1/a(λ) shifted to longer wavelengths with increasing Chl a. Furthermore, the relative contribution of a _ph(λ) to the total absorption in red tide water was significantly higher than in non-red tide water in the wavelength range 550–600 nm, including the peak. Our results show that the variation of a _ph(λ) with Chl a dominates the behavior of the R _rs(λ) peak, and utilization of R _rs(λ) peaks at 589 and 565 nm may be useful to discriminate between red tide and non-red tide waters by remote sensing.     

文蛤亮氨酸氨肽酶LAP3的基因克隆及其在幼体不同发育时期、成体不同组织的表达分析

为探索贝类LAP3基因的结构和功能特征以及在生长发育过程中的作用,利用cDNA末端快速扩增（RACE）法获得文蛤LAP3（Mm-LAP3）基因的cDNA全长序列,并对其生物信息学、组织及发育时期表达特征进行了分析。结果显示,Mm-LAP3基因cDNA全长2 037 bp,ORF区1 254 bp,编码417个氨基酸;Mm-LAP3蛋白由Peptidase_M17超家族序列的N-端结构域和Peptidase_M17催化结构域组成。荧光实时定量PCR结果表明,Mm-LAP3基因在文蛤成体6个组织和幼体10个发育时期中均有表达,其中在斧足中的表达量显著高于其他组织（P<0.05）,这与斧足蛋白含量丰富、代谢旺盛相关;在幼体10个发育时期中的表达量呈现逐渐升高的趋势,在D形幼虫时期达到最高,随后又有所降低,推测Mm-LAP3基因在早期发育时期参与了某些组织器官的形成。     

4种石磺科贝类的胆甾醇含量测定

将瘤背石磺(Onchidium struma)、里氏拟石磺(Paraoncidium reevesii)、平疣桑椹石磺(Platevindex mortoni)和紫色疣石磺(Peronia verruculata)样品,经活体解剖取四种石磺肌肉组织,运用高效液相色谱法对其可食部分进行了胆甾醇含量测定。结果表明:瘤背石磺胆甾醇平均浓度最高,达5 870.00 mg/kg;平疣桑椹石磺、紫色疣石磺、里氏拟石磺的胆甾醇平均质量分别为3 480.00、388.00、316.00 mg/kg,统计分析显示四种石磺可食部分的胆甾醇含量差异显著。     

一株海洋金藻的18S rRNA 基因序列分析及分类

Isochrysis sp.strain HG是一株分离自福建长乐自然海区的金藻,是一种良好的西施舌育苗饵料藻。显微形态观察表明,Isochrysis sp.strain HG的形态特性与等鞭金藻属的球等鞭金藻(I.galbana)和湛江等鞭金藻(I.zhanjiangensis)比较接近。进一步克隆Isochrysis sp.strain HG的核糖体小亚基(small subunit,SSU)18S rRNA基因,获得了长度为1780bp的基因序列。同源性分析表明,该序列与在NCBI数据库中登录的等鞭金藻属的18S rRNA基因序列同源性最高,说明结果与形态鉴定的结果相一致。基于18S rRNA基因序列的系统发育分析表明,Isochrysis sp.strain HG与等鞭金藻属的I.zhangjiangensis、Isochrysis sp.strain CCAP927/14、I.galbana和Isochrysis sp.strain Santou聚在一个分支类群上,其中I.zhangjiangensis与Isochrysis sp.strain CCAP927/14聚为一个独立的子类群,和I.galbana、Isochrysis sp.strain Santou以及目标菌株Isochrysis sp.strain HG形成4个并列独立的分支。根据形态及分子系统分析结果,Isochrysis sp.strain HG可能是不同于I.zhangjiangensis、I.galbana的等鞭金藻种类。     

短角异剑水蚤对克氏双锯鱼稚鱼成活、生长和脂肪酸组成的影响

为评估短角异剑水蚤(Apocyclops royi)作为海水鱼类仔稚鱼的饵料价值和投喂效果,比较分析了其与卤虫无节幼体(Artemia nauplii)的脂肪酸组成及2种生物饵料对克氏双锯鱼(Amphiprion clarkii)稚鱼存活、生长和脂肪酸组成的影响。结果显示,短角异剑水蚤DHA、EPA和ARA含量分别达21.185%、11.088%和3.250%,海水仔稚鱼必需脂肪酸(EFA)总含量高达37.417%,均显著高于卤虫无节幼体。投喂短角异剑水蚤的克氏双锯鱼稚鱼(5~20 d)成活率(80.71%±8.23%)与投喂卤虫无节幼体组(76.30%±7.00%)差异不显著;稚鱼体长(7.75 mm±1.18 mm)、体重(0.0163 g±0.0080 g)和体长特定生长率(3.46%±0.75%)均显著高于卤虫无节幼体投喂组;稚鱼体内DHA(21.843%)、EPA(6.914%)和ARA(2.725%)含量也均显著高于后者。研究表明,短角异剑水蚤适于作为海水鱼类仔稚鱼的生物饵料,在水产养殖中具有广阔的应用前景。     

基于16S rRNA与COI基因40种石斑鱼亚科鱼类分子系统进化关系

本研究采集了分布在西太平洋的石斑鱼亚科10属共40种鱼类,采用PCR扩增及测序技术获得所有样品16S rRNA、COI基因部分序列,利用最大似然法构建系统进化树并分析。结果表明:40种鱼类COI基因为651 bp,编码227个氨基酸,16S rRNA基因同源序列566 bp,序列存在一定的碱基插入与缺失,各物种16S rRNA基因序列变异比COI要少,序列较为保守。构建的系统进化树上,在本研究的石斑鱼亚科10个属中,鳃棘鲈属分类地位最原始,位于进化树基部,6种鳃棘鲈能聚成一个单系;烟鲈属与九棘鲈属关系较近,两者聚为一支,侧牙鲈属的进化地位介于鳃棘鲈属与九棘鲈属之间;石斑鱼属的进化地位最高,位于进化树顶部,形成两个平行分支,但是石斑鱼属种类未能聚成一个单系;驼背鲈属、鸢鮨属、下美鮨属、光腭鲈属及宽额鲈属均未能形成独立分支,而是与石斑鱼属种类聚在一起,显示其与石斑鱼属有很近的亲缘关系,部分可能是石斑鱼属的特化类群。     

Ecological consequence of the introduction of the polychaete Marenzelleria cf. viridis into a shallow-water biotope of the northern Baltic Sea

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.     

Numerical prediction of performance of submerged breakwaters

The results of a numerical model study on the transmission characteristics of a submerged breakwater are presented. Study aimed to determine the effect of depth of submergence, crest width, initial wave conditions and material properties on the transmission characteristics of the submerged breakwater. The results highlight the optimum crest width of the breakwater and optimum clear spacing between two breakwaters. A submerged permeable breakwater with d_s/d=0.5, p=0.3 and f=1.0, reduces the transmission coefficient by about 10% than the impermeable breakwater. The results indicates an optimum width ratio of B/d=0.75 for achieving minimum transmission. By restricting the effective width ratio of the series of breakwaters to 0.75, studies were conducted to determine the effect of clear spacing between breakwaters on transmission coefficient, suggesting an optimum clear spacing of w/b=2.00 to obtain K_t below 0.6.     

Response of Acartia populations to environmental variability and effects of invasive congenerics in the estuary of Bilbao, Bay of Biscay

The effect of environmental factors (river discharge, water temperature and dissolved oxygen saturation) on the abundance and distribution of Acartia populations and the interactions between their congenerics was evaluated by means of transfer function (TF) models in the estuary of Bilbao during the period 1998–2005. The recorded species were Acartia clausi, Acartia tonsa, Acartia margalefi and Acartia discaudata. Acartia clausi dominated in the entire euhaline region of this estuary until 2003 when it was displaced from the inner part by A. tonsa. This invasive species (A. tonsa) was found for the first time in 2001 and colonized successfully the inner (salinity 30) and intermediate (salinity 33) waters of this estuary since 2003. The TF models revealed an immediate and negative effect of A. tonsa on A. clausi in the intermediate salinity (33) waters, where these species showed the highest spatial overlap. The results indicate that environmental changes from 2003 influenced the abundance of Acartia species, being unfavourable for A. clausi. The decrease of A. clausi abundance in low salinity waters was related to a significant decrease of dissolved oxygen saturation levels, whereas the increase of temperature was linked to a significant increase of A. tonsa. Acartia margalefi and A. discaudata were scarce over the entire period, but they were found to be valuable indicators of hydrological changes, which were associated to climate factors. These two latter species increased in abundance and expanded their seasonal distribution, and in the case of A. margalefi also its spatial distribution, in 2002, coinciding with the period in the time-series when autumn–winter rainfall and summer temperatures were lowest, and dissolved oxygen saturation levels were highest.     

Length-weight relationships of important zooplankton from the Inland Sea of Japan

Measurements of dry weight, carbon- and nitrogen contents together with the body length of important zooplankton from the Inland Sea of Japan were made using freshly caught specimens. The values of the former three parameters were found to be highly correlated to length, and species specific regression equations were calculated for 10 species of Copepoda (Calanus sinicus, Euchaeta plana, E. concinna, Centropages abdominalis, Sinocalanus tenellus, Acartia clausi, A. tsuensis, Tortanus forcipatus, Oithona brevicornis andO. similis), 3 species of Cladocera (Podon leuckarti, P. polyphemoides andPenilia avirostris), 1 species of each of Mysidacea (Neomysis japonica), and Natantia (Acetes japonicus), and two forms of Chaetognatha (Sagitta crassa andS. crassa f.naikaiensis).     

文昌鱼线粒体基因组特征分析及分子标记探讨

线粒体基因组已被广泛应用于后生动物分子系统发育和群体遗传的研究。文昌鱼（Amphioxus）作为研究脊椎动物起源和进化的模式动物,在脊椎动物起源和进化研究中占据极为重要的位置。作者综合分析文昌鱼2科7个种的51条线粒体基因组全序列,全面揭示了文昌鱼线粒体基因组的基本特征。文昌鱼线粒体基因组均编码后生动物标准的37个基因...     

Pumping rates of the mud shrimpCallianassa japonica

Pumping rate of a mud shrimp,Callianassa japonica, in its burrow was measured by continuous monitoring of dye concentration in the burrow water. Measurement of dilution in two directions from stained overlying seawater to normal burrow water andvice versa, gave no significant difference in results. The rate of exchange (v) of burrow water was estimated from,v=(u _t−u ₀)V/(m−u _t−1)t, whereV is volume of burrow water,u ₀,u _t−1 andu _tis dye concentration of burrow water at time 0,t−1 andt, respectively, andm is dye concentration of overlying water. The pumping rate ranged from 0.63 to 5.46 ml min⁻¹, which corresponded to a turnover time for the burrow water of 7–51 min. Short term changes in the pumping rate were correlated to intermittent behaviour of the shrimp in the burrow.     

几何形态学对8种扇贝的形态分类的应用

几何形态学(morphometrics)是基于笛卡尔地标点的统计分析方法,主要运用广义普鲁克分析(GPA)、薄板样条分析(TPS)、主成分分析(PCA)、典型变量分析(CVA)等方法,定量的对形态变化进行识别,结果更为客观。本研究运用几何形态学方法对8种常见扇贝(栉孔扇贝Azumapecten farreri、虾夷盘扇贝Mizuhopecten yessoensis、海湾扇贝Argopecten irradians、平濑掌扇贝Volachlamys hirasei、北海道扇贝Swiftopecten swiftii、荣套扇贝Gloripallium pallium、华贵类栉孔扇贝Mimachlamys nobilis、美丽环扇贝Annachlamys striatula)间形态关系进行研究,运用界标点和半界标点对扇贝的壳盘和壳耳进行数字化标点,利用PCA、CVA、TPS方法,获得8种扇贝的形态差异并进一步分析,建立系统发育树。PCA和CVA分析结果表明可以通过几何形态测量学分析方法将8种扇贝基于形态差异进行有效区分。此外,结合TPS的分析结果,发现壳耳和壳盘在扇贝中具有种间规律性差异。...     

A simple method of taking a subsample of zooplankton

Between May 1968 and April 1970 a survey was made of the distribution, vertical range, and seasonal occurrence of euphausiids in Cook Strait.

The euphausiid fauna reflects the predominantly subtropical origin of the coastal currents and, of the 11 species present, only Euphausia vallentini has pronounced subantarctic affinities. Nyctiphanes australis is the dominant species, with Euphausia lucens and Thysanoessa gregaria present in lesser numbers. New records included E. recurva, E. spinifera, and Stylocheiron elongatum, and the identity of Southland Current Nematoscelis euphausiids as N. megalops was confirmed. This assemblage of species, lacking a dominant subantarctic or subtropical element, may best be considered as representing a transitional fauna inhabiting a broad Subtropical Convergence Region.