Distribution of sea cucumbers in relation to sediment characteristics in coral reef lagoons and adjacent waters around Ishigaki Island,southern Japan

To elucidate which environmental factors affect lagoonal‐scale sea cucumber distributions in Ishigaki Island, Okinawa, Japan, intertidal and subtidal areas of three coral reef lagoons were classified into several ground divisions by bottom characteristics, and sea cucumber densities therein were compared with the composition of sediment cover, grain size and organic content, and coverage of macroalgae, seagrass, and massive corals. Holothuria atra, Holothuria leucospilota, Stichopus chloronotus, and Synapta maculata had highest densities in the nearshore areas but were rare in reef flats, probably because of wave disturbance and low areal cover of sand sediment as potential feeding environments. No relationship was observed between sea cucumber densities and sediment organic content or grain size. Thus, even if these sea cucumbers have selectivity for habitats with a high sediment organic content, the effect of such selectivity on the distribution seems to be limited to relatively small areas. The sea cucumber distributions can be classified by bottom sediment/biota composition into bedrock (H. leucospilota), sand (H. atra), and lagoonal types (St. chloronotus and Sy. maculata). These habitat selections were possibly related to various aspects of sea cucumber ecology such as refuge from predators or turbulence, or settlement and nursery place, which have implications for importance of the complexity of lagoonal‐scale topography and sediment/biota conditions for the coexistence of various holothurian species.     

Spatial partitioning between species of the phytoplankton-feeding guild on an estuarine intertidal sand flat and its implication on habitat carrying capacity

The fishery yield of Manila clams, Ruditapes philippinarum, increased considerably in the 1970s but has decreased rapidly since the middle 1980s on extensive intertidal sand flats in Ariake Sound (Kyushu, Japan). A survey conducted in 2004 on a 3.4-km² sand flat located in the central part of the Sound (Shirakawa sand flat) revealed four dominant species: two thalassinidean shrimps (Upogebia major and Nihonotrypaea japonica), which are deep-reaching burrow dwellers with strong bioturbation activities, and two bivalves (Mactra veneriformis and R. philippinarum). All four species belong to a phytoplankton (diatom)-feeding guild. In the late 1970s, the Manila clam population prevailed in high densities over the entire sand flat, whereas its distribution was restricted to the lowest quarter of the shore in 2004. In contrast, the population sizes and zones of occurrence of the other phytoplankton feeders have expanded in the absence of R. philippinarum, perhaps an indication of competitive release. After establishment, effects of the thalassinidean shrimps on sediment stability appear to have further reduced clam abundances. Across the sand flat in 2004, wet weight population biomass estimates for N. japonica, U. major, M. veneriformis, and R. philippinarum (whole body for shrimps and soft tissue for bivalves) were 304, 111, 378, and 234 tonnes, respectively. Based on Manila clam fishery yield records from Shirakawa, the carrying capacity of the Shirakawa sand flat in the late 1970s was estimated to be two times greater than the sum value for the whole phytoplankton-feeding guild in 2004. It is hypothesized that (1) the amount of phytoplankton determines the carrying capacity for the benthic community on the Shirakawa sand flat, with both phytoplankton and benthic biomass at maxima in the late 1970s, and (2) the subsequent increases in competition for space have caused further declines in the Manila clam population biomass to approximately one-eighth of its past value.     

渤海湾南部滩涂贝类群落结构特征及其环境因子相关性研究

本研究以渤海湾南部(滨州)滩涂为研究区域,设置6个断面共36个采样站位,覆盖潮间带(高潮带-中潮带-低潮带)和潮下带,研究该区域贝类资源群落结构特征及其环境因子相关性。结果表明:整个调查区域常见贝类总共有30种。潮间带共有23种常见贝类,优势种为光滑篮蛤(Potamocorbula laevis Hinds 1843)、四角蛤蜊(Mactra quadrangularis Reeve 1854)、短文蛤(Meretrix petechialis Lamarck 1799);潮下带共有26种常见贝类,优势种为中国蛤蜊(Mactra chinensisi Philippi 1846)、等边浅蛤(Gomphina aequilatera Sowerby 1825)、朝鲜笋螺(Terebra koreana Yoo 1976)、红带织纹螺(Nassarius succinctus A.Adams 1852)、纵肋织纹螺(Nassarius variciferus A.Adams 1851);潮间带贝类多样性指数(H'')和均匀度指数(J'')显著高于潮下带,而丰富度指数(D)则相反;潮间带贝类生物量(710.16 g/m²)和栖息密度(4 523个/m²)远高于潮下带(17.10 g/m²,35个/m²)。群落结构多元统计分析将贝类按照站位划分为5个组群,包括东侧潮下带、西侧潮下带、西侧潮间带、东侧潮间带以及D4站位。冗余分析(RDA)结果表明,对潮间带贝类影响较大的环境因子主要为沉积物的粒径以及砂、粉砂含量,而对潮下带贝类影响较大的主要为浮游植物密度、沉积物的粒径以及砂、粉砂和黏土含量。渤海湾南部(滨州)滩涂贝类资源较为丰富,但应从不同滩涂区域生态特性的角度出发,加强贝类的保护和资源修复,本研究可为该区域贝类的资源养护和可持续利用提供数据基础。     

New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam <Emphasis Type="Italic">Ruditapes philippinarum</Emphasis> challenged by the protozoan parasite <Emphasis Type="Italic">Perkinsus olseni</Emphasis>

Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.     

养殖迁移对菲律宾蛤仔挥发性有机物质组成变化的影响

环境条件变化是造成贝类挥发性有机物质(VOCs)组成变化的主要原因。菲律宾蛤仔养殖生产中,常进行从开放式自然滩涂迁移至人工围塘养殖的活动。本文研究了这一过程前后菲律宾蛤仔(Ruditapes philippinarum)肌肉组织的VOCs组成特征、变化及其与环境因子相关性。结果显示:基于固相微萃取和气质联用技术,共鉴定出52种VOCs,分别属于醛、醇、酯、烃、呋喃、烷烃、烯、芳香烃、含硫和含氮化合物等。迁移前样本中,检出41种化合物,迁移至人工围塘养殖20 d后,检出32种。迁移造成了化合物种类数量降低、种类发生变化。醛、醇类的相对含量最高、迁移前后的变化尤为显著,呈现由醛高醇低的组成逆转为醇高醛低的特点。溶氧是影响VOCs组成变化及其醇、醛类差别的重要因子。饵料生物量、相对丰度和多样性与VOCs的组成具有显著相关性:自然滩涂微型真核生物多样性高但生物量和丰度相对低,人工围塘多样性低但生物量和丰度高,是VOCs组成差异的关键影响因子。本研究建立了贝类VOCs与关键环境因子的直接联系,为进一步解析贝类品质的环境关系、优化和调控养殖环境等研究提供了参考。     

Population biology and secondary production of the harvested clam Tivela mactroides (Born, 1778) (Bivalvia,Veneridae) in Southeastern Brazil

The population structure, growth and production of the trigonal clam Tivela mactroides were investigated by monthly sampling between January 2003 and October 2004 in two areas (southern and northern) of the intertidal and subtidal zones of Caraguatatuba Bay, Southeastern Brazil. Intertidal sampling was carried out in each area along eight transects perpendicular to the shoreline. In the subtidal zone of both areas, one 50‐m dredging was performed along five sampling stations arranged on three transects perpendicular to the coast. The intertidal abundance of T. mactroides was higher in the southern (more dissipative conditions) than in the northern area. High abundances occurred in February–March 2004 in the south and in September 2004 in the north. The size structure showed that younger individuals dominated in the sublittoral, indicating that recruitment occurs in this zone, followed by the migration of these individuals to the intertidal, where they complete their life cycle. Tivela mactroides showed continuous reproduction, with 26 cohorts detected in the study period. The lower estimates for the growth index (?′ = 3.22), mortality rate (Z = 2.10 year^?1) and turnover rate (P/B = 1.21 year^?1), and conversely the longer life span (2.5 years) of T. mactroides in Caraguatatuba Bay (24°S) compared with Venezuelan populations (10°N) suggests a latitudinal pattern of these life‐history traits. The high production of T. mactroides in Caraguatatuba Bay was due to continuous recruitment and rapid and continuous growth, and demonstrates the importance of T. mactroides as a biological resource for many marine species and for the local residents.     

低氧胁迫对菲律宾蛤仔抗氧化酶的影响

为了研究不同低氧水平对菲律宾蛤仔(Ruditapes philippinarum)的影响,在实验室条件下设置溶解氧为0.5 mg/L和2.0 mg/L的低氧海水环境,以溶氧水平为7.0 mg/L的天然海水为对照组,研究了低氧胁迫对菲律宾蛤仔抗氧化酶的影响。结果表明:在低氧胁迫的时间越长的条件下,乳酸脱氢LDH和琥珀酸脱氢酶SDH的活力逐渐降低,而碱性磷酸酶AKP活力逐渐增大;对于相同的酶,对照组的酶活力高于处理组的酶活力;在溶氧DO越低的情况下,菲律宾蛤仔的死亡率越高。     

An examination of the trout population of five lakes near Rotorua,New Zealand

Five lakes, varying from 10 to 100 hectares in area and each containing an existing population of Salmo gairdneri, were gill‐netted and stocked with tagged fish each year from 1960 to 1965 to determine the effect of regular stocking on the size and numbers of fish present. There was little natural spawning of trout in most of the lakes. Growth in length and weight of tagged fish was computed and an annual estimate of population calculated from the netting returns. Appendices give details of the statistical analyses of the data.

Fish production has been correlated with the trophic status of the lakes as indicated by their temperature and oxygen content. There was no clear relationship between lake size and trout production but trout production decreased as the environment became more eutrophic. Results also showed a close inverse relationship between numbers supported and average weight achieved by the trout. It is concluded that the angling potential of local lakes can be maintained despite the eutrophication resulting from intensive agricultural development of the catchments. These lakes will produce large‐sized fish if the trout population is kept relatively small.

Loss in weight in brown and rainbow trout as a result of spawning activities in local lakes and streams was found to be similar. Both male and female fish lost between 22 and 40 percent of their weight over a spawning period. This probably accounted for the observed low‐condition factor among older fish in the lake populations.     

LPS胁迫下五个群体菲律宾蛤仔TYR基因在鳃和肝胰腺中表达特性研究

为了解TYR基因与蛤仔免疫的关系,本实验利用荧光定量PCR技术研究了菲律宾蛤仔五个群体(白蛤、白斑马蛤、斑马蛤、养殖和野生群体)的鳃组织和肝胰腺组织在LPS胁迫下TYR基因在不同时间(0 h、3 h、12 h、24 h、48 h)的表达特性。结果表明,在LPS注射后鳃组织中TYR6基因表达水平在白蛤和白斑马蛤3 h、6 h、12 h,野生蛤仔3 h,斑马蛤3 h、6 h,养殖群体6 h、12 h显著上调(P0.05),3h野生蛤仔和斑马蛤达到峰值, 6 h白蛤、白斑马蛤、养殖群体达到峰值(P0.05);在肝胰腺中,养殖群体和白斑马蛤6 h,白蛤6 h、24 h,野生群体24 h,斑马蛤3 h显著上调, 3 h野生蛤仔和斑马蛤达到峰值,6h养殖群体、白蛤、白斑马达到峰值(P0.05);鳃组织中TYR10基因表达水平在白蛤、野生群体和白斑马蛤3 h,养殖群体3 h、6 h,斑马蛤3 h、12 h显著上调(P0.05),肝胰腺组织中TYR10基因表达水平在白蛤3 h,野生群体3 h、6 h、12 h,斑马蛤、养殖群体6 h显著上调(P0.05),推测TYR基因在五个菲律宾蛤仔群体的鳃和肝胰腺中参与了免疫应答。通过对TYR基因的氨基酸序列进行二级结构分析和系统发育树分析,找到两个铜离子结合位点和6个组氨酸残基,并发现TYR6基因和长牡蛎同源性最高,为39.43%, TYR10基因和大珠母贝同源性最高,为51.04%。本文首次探讨在LPS胁迫下菲律宾蛤仔TYR基因的表达特性,为进一步探究TYR基因与菲律宾蛤仔免疫应答机制提供参考。     

菲律宾蛤仔垦区三联人工育苗技术

2017年9月至2018年1月,在福清东壁岛三联垦区(A、B、C)开展了菲律宾蛤仔垦区人工育苗技术研究,其中A、B垦区用于育苗,C垦区用于饵料培育,并于2017年9月开始分两批次共向A、B垦区投放菲律宾蛤仔亲贝1670 t。结果显示,育苗期间菲律宾蛤仔亲贝共出现4次大规模产卵。亲贝精卵排放率为32.0%~84.0%,孵化率为45.00%~68.54%;浮游幼虫生长速度为4.73~7.14μm/d,变态率为28.37%~59.67%;稚贝壳长生长速度为7.08~25.10μm/d,共培育砂粒苗7580亿粒,育苗成活率为50.23%。因此,采用垦区三联方法可保障菲律宾蛤仔苗种的生物饵料供给,从而提高砂粒苗的生长速度和成活率。     

Microsatellites reveal fine‐scale genetic structure of the Chinese surf clam Mactra chinensis (Mollusca,Bivalvia, Mactridae) in Northern China

As a commercially important fisheries resource in East Asia, the Chinese surf clam Mactra chinensis has experienced severe population declines in the past decades, probably due to over‐exploitation. To provide scientific bases for fisheries management and artificial breeding, we investigated genetic variation and population structure of Mactra chinensis in Northern China using microsatellites. Samples collected from eight localities throughout natural habitats of the species in Northern China were genotyped. Nine microsatellites revealed high allelic diversity with 14–36 alleles per locus. Observed and expected heterozygosity varied from 0.593 to 0.945 and from 0.638 to 0.958, respectively. Pairwise F_ST values indicated that all population pairs had small but significant genetic differentiation. A Mantel test showed statistically significant correlations between genetic distance and geographical distance, indicating that genetic differentiation of the Chinese surf clam conformed to a pattern of isolation‐by‐distance. Cluster analysis using neighbor‐joining separated the eight populations into three groups. The three areas of low gene flow identified by barrier analysis corresponded with local oceanographic features, suggesting that marine currents and peninsulas play an important role in population structuring of this species.     

菲律宾蛤仔(Ruditapes philippinarum)“斑马蛤2号”筏式和底播养殖模式比较研究

为探究菲律宾蛤仔（Ruditapes philippinarum）筏式养殖模式可行性，在我国黄海北部首次开展了菲律宾蛤仔"斑马蛤2号"新品种的筏式与底播养殖模式对比试验。采用平均壳长为2.37 cm，平均全湿重为2.99 g规格的"斑马蛤2号"苗种为试验材料，对两种养殖方式的"斑马蛤2号"生长、存活、营养成分进行比较分析，结果表明，筏式养殖"斑马蛤2号"夏季（4-7月）壳长、壳宽、壳高、全湿重、软体重的相对生长速率分别比底播养殖"斑马蛤2号"快149.54%、100.61%、116.30%、152.25%、132.58%（P<0.05）。筏式养殖"斑马蛤2号"存活率为90%以上，显著高于底播养殖（P<0.05）。两种养殖方式的"斑马蛤2号"水分、灰分、粗蛋白、糖原、脂肪酸等营养成分季节变化规律基本一致。筏式养殖"斑马蛤2号"冬季糖原、单不饱和脂肪酸含量明显高于底播养殖"斑马蛤2号"（P<0.05）。研究表明，当年10月采用多层聚乙烯网笼按密度为150-200粒/层放养菲律宾蛤仔"斑马蛤2号"大规格苗种（平均壳长为2.37 cm，平均全湿重为2.99 g），可于翌年的4月、7月、10月收获平均壳长为3.03、3.36、3.51 cm的市场规格产品。筏式养殖模式具有存活率高的优点。"斑马蛤2号"筏式养殖模式试验的成功为蛤仔健康养殖提供了新途径。     

基于GLM模型Logistic回归的菲律宾蛤仔地理群体判别

菲律宾蛤仔(Ruditapesphilippinarum)是重要的海洋经济贝类和海水养殖品种,具有较强的表型可塑性特点,不同地理群体之间存在表型差异。本研究根据实测数据建立了胶州湾与天鹅湖菲律宾蛤仔壳长(SL)与壳高(SH)、壳宽(SW)和活体重(W)的回归方程,定量分析了两个地理群体的形态学差异。由于其近似圆形的形态使得所能测量的外部指标较少,限制了传统形态测量学在其地理群体判别中的应用。本研究提出了将传统形态测量学和广义线性模型(GLM)相结合的方法,建立了判别菲律宾蛤仔地理群体的逻辑斯蒂(Logistic)回归方程。结果表明:菲律宾蛤仔的天鹅湖群体比胶州湾群体具有更高的SH/SL和SW/SL比值,壳形椭圆较圆且隆起程度高,"凸"形明显;基于GLM模型的Logistic回归能够快速准确地判别菲律宾蛤仔的地理群体归属,判别正确率高达94.23%。本研究为双壳类物种地理群体判别提供了新的分析方法和技术手段。     

基于淤涨速率的潮滩围垦适宜性评价

潮滩既具有重要的生态服务功能,亦是潜在的土地资源。过去几十年来,中国沿海潮间带的开发以围垦为主要驱动力,表现为海岸线主体向海推进。随着围垦规模和速度加快加大,出现了一系列生态、环境及土地利用问题,因此对于围垦适宜性的研究具有现实意义。本文以浙江省为例,利用遥感技术首先获取了大陆海岸线阶段性变化特征。接着从地貌均衡的角度,依据潮滩垂向淤涨速率和垂直岸线的潮滩剖面形态估算适宜的潮滩围垦速率。最后,比较海岸线实际推进速率与估算所得的围垦适宜速率,进行围垦适宜性分级评价。研究表明,1985-2015年间,围垦活动是浙江省大陆海岸线向海推进的主要原因。从时间进程来看,1985-1995年浙江省大陆海岸线向海推进缓慢,受围垦活动影响较小;1995-2015年间围垦活动频繁,人工岸线比例增加较多。围垦适宜速率的估算显示,杭州湾南岸围垦1 km后所需恢复时间最短,围垦适宜速率为12.5～64.3 m/a,其次为象山港和台州湾,围垦适宜速率分别为2.0～38.3 m/a和6.0～22.2 m/a;三门湾和温州湾围垦后所需恢复时间最长,围垦适宜速率分别为1.2～18.5 m/a和1.7～3.8 m/a。基于潮滩淤涨速率的围垦适宜性评价表明,1985-2015年间,浙江省主要围垦区域中围垦速率过快的是三门湾的下洋涂、蛇蟠岛和温州湾岸段,围垦速率较快区域为杭州湾南岸庵东浅滩部分岸段和象山港的莼湖镇、涂茨镇岸段以及台州湾的南洋涂,围垦速率略快的是庵东浅滩以及台州湾的北洋涂,围垦速率适宜的岸段仅有象山港的高湖塘和蒲门村岸段。浙江省过去30年的围垦进程和岸线变化启示,围垦活动应充分考虑潮滩环境的地貌动力均衡和自然恢复潜力。     

AFLP analysis revealed differences in genetic diversity of four natural populations of Manila clam(Ruditapes philippinarum) in China

1 IntroductionManila clam (Ruditapes philippinarum) is aworldwide distributed species. In China, it is foundfrom the northern to southern seashores (Wang etal., 1993; Zhuang, 2001). This species is eura-line with the salinity tolerance ranging from 20 to4…     

Community structure and functional traits of mollusks associated with coastal reef macroalgae in Northeastern Brazil

This study investigated the community structure and functional traits of the mollusk fauna associated with macroalgae with different thallus morphologies in a reef environment in Northeastern Brazil. A total of 15 individuals of each species of macroalgae adhered to natural substrate and 15 individuals of Padina gymnospora detached from the substrate were collected. The structural complexity of algal habitats was measured and the associated malacofauna screened and identified. All three macroalgae differed significantly in the complexity of their habitat, with Sargassum polyceratium being the most complex. A total of 823 specimens of mollusks belonging to 22 species and 11 families were recorded, of which Columbellidae was the most represented with six species. The functional trait “size” revealed that micromollusks smaller than 10 millimeters were predominant in the community; however, individuals of larger sizes (up to 24.54 millimeters) belonging to young stages of other species were also present. Eight functional trophic groups were identified, of which “carnivorous” stood out with seven species. Six functional groups of microhabitats were identified, with intra‐specific variation in habitats, while habitat expansion was documented for species not yet recorded in association with macroalgae. The structure of the molluskan community differed among the three algae species with the greatest richness, abundance, and diversity of mollusks and functional traits occurring with S. polyceratium. Community structure differed between algae adhered to natural substrate and detached algae, with the latter having lower mollusk richness and diversity, but with greater abundance of some species that remained on algal fronds after release from the reef environment. This study reinforces the importance of algal habitat for marine invertebrate fauna, especially for micromollusks that spend their entire life cycle, or part of it, in association with macroalgae.     

A theoretical individual-based model of Brown Ring Disease in Manila clams,Venerupis philippinarum

An individual-based mathematical model was developed to investigate the biological and environmental interactions that influence the prevalence and intensity of Brown Ring Disease (BRD), a disease, caused by the bacterial pathogen, Vibrio tapetis, in the Manila clam (Venerupis (= Tapes, = Ruditapes) philippinarum). V. tapetis acts as an external microparasite, adhering at the surface of the mantle edge and its secretion, the periostracal lamina, causing the symptomatic brown deposit. Brown Ring Disease is atypical in that it leaves a shell scar that provides a unique tool for diagnosis of either live or dead clams. The model was formulated using laboratory and field measurements of BRD development in Manila clams, physiological responses of the clam to the pathogen, and the physiology of V. tapetis, as well as theoretical understanding of bacterial disease progression in marine shellfish. The simulation results obtained for an individual Manila clam were expanded to cohorts and populations using a probability distribution that prescribed a range of variability for parameters in a three dimensional framework; assimilation rate, clam hemocyte activity rate (the number of bacteria ingested per hemocyte per day), and clam calcification rate (a measure of the ability to recover by covering over the symptomatic brown ring deposit), which sensitivity studies indicated to be processes important in determining BRD prevalence and intensity. This approach allows concurrent simulation of individuals with a variety of different physiological capabilities (phenotypes) and hence by implication differing genotypic composition. Different combinations of the three variables provide robust estimates for the fate of individuals with particular characteristics in a population that consists of mixtures of all possible combinations.The BRD model was implemented using environmental observations from sites in Brittany, France, where Manila clams routinely exhibit BRD signs. The simulated annual cycle of BRD prevalence and intensity agrees with observed disease cycles in cultured clam populations from this region, with maximum disease prevalence and intensity occurring from December to April. Sensitivity analyses of modeled physiological processes showed that the level of hemocyte activity is the primary intrinsic determinant of recovery of infected clams. Simulations designed to investigate environmental effects on BRD suggested that the outcome of the host–parasite interaction is dependent on food supply (high values being favorable for the host) and temperature. Results of simulations illustrate the complex interaction of temperature effects on propagation and viability of the bacterium, on the phagocytic activity of the hemocytes, and on other physiological processes of the host clam. Simulations using 1 °C and 2 °C increases in temperature generally favored disease development, indicating that climate warming might favor the spread of BRD.     

4种壳色蛤仔TYR基因的表达特性研究

为了解色素控制基因与壳色的关系,本实验用荧光定量聚合酶链式反应(Polymerase Chain Reaction,PCR)技术分析了酪氨酸酶基因(Tyrosinase,TYR)在菲律宾蛤仔(Ruditapes philippinarum)4种壳色蛤仔和7种组织中的表达特性。结果表明,酪氨酸酶基因在鳃、外套膜、闭壳肌、性腺、内脏团、水管和唇瓣中均有表达,其中外套膜中表达量较高,其次为鳃,在闭壳肌中表达量最少。不同的酪氨酸酶基因在4种壳色的表达量不同,酪氨酸酶基因TYR2、TYR3、TYR6和TYR9在白斑马蛤中表达量居高,且与斑马蛤和白蛤差异显著(P0.05)。TYR2、TYR6和TYR10在橙蛤中表达量最高,推测与橙色形成有关。TYR11在斑马蛤中表达量最高,且与白蛤和白斑马蛤差异显著(P0.05),推测与背景色形成有关。系统发育分析结果表明,TYR3与马氏珠母贝(Pinctada martensii)同源性最高为64%。TYR10与加州双斑蛸(Octopus bimaculoides)同源性最高,为53%。与长牡蛎进化关系最近。     

Phytoplankton subsidies to the inter‐tidal zone are strongly affected by surf‐zone hydrodynamics

The size of bottom‐up subsidies, food and larvae, from the ocean has a profound impact on inter‐tidal communities and populations. Alongshore variations in subsidies are attributed to variation in coastal conditions, but also might be due to variations in surf‐zone hydrodynamics. We tested this hypothesis by comparing surf‐zone phytoplankton concentrations to surf‐zone hydrodynamics as indicated by the width of the surf zones. To minimize the potential effects of alongshore variation in phytoplankton abundance in the coastal ocean, we sampled closely spaced sites (median separation 1 km) over short periods (3 days). Surf‐zone concentrations of coastal phytoplankton taxa (e.g. Chaetoceros spp., Pseudo‐nitzschia spp. and dinoflagellates) varied with surf‐zone width; 65% to 94% of the variability in their concentration is explained by surf‐zone width. Where surf zones were narrow and more reflective, phytoplankton concentrations were one to several orders of magnitude lower than in wider, more dissipative surf zones. The most closely spaced stations were 30 m apart, but represented distinct habitats – a reflective and a more dissipative surf zone. Phytoplankton concentrations in the reflective surf zone were an order of magnitude or more lower than in the adjacent more dissipative surf zone. A reanalysis of a published study on phytoplankton subsidies found similar results. Alongshore variation in surf‐zone hydrodynamics appears to be an important driver of phytoplankton subsidies to the inter‐tidal zone.