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1.
砗磲是软体动物门瓣鳃纲砗磲科生物的统称,广泛分布于热带珊瑚礁海域。20世纪八九十年代,澳大利亚、美国以及菲律宾等太平洋岛屿国家集中开展了砗磲增养殖及与之相关的生理、生态和经济学等基础研究。砗磲通过与其共生的虫黄藻获得营养,这一特性使得砗磲生长速度极快。砗磲的单位面积保有量可达400t·hm-2,使得它们在热带珊瑚礁海域中具有重要的生态学和养殖意义。不仅如此,砗磲在其生长过程中所体现出来的珊瑚礁修复价值以及碳汇渔业价值对于海洋开发和保护都有着极其重要的意义。同时,我国南海拥有环境优越的广阔热带海域,可开展砗磲养殖的面积达3000km2以上。结合以上认识,作者认为砗磲养殖具有形成热带海洋贝类养殖重大产业的潜力,可以为我国南海珊瑚礁保护和生态文明建设工程提供支撑。 相似文献
2.
海南岛沿岸海域砗磲资源调查及保护前景展望 总被引：1，自引：0，他引：1
砗磲是珊瑚礁海域的重要贝类之一,对维护珊瑚礁生态系统平衡起着重要作用。然而,近年来海洋的大力开发和利用给我国沿海砗磲资源造成严重威胁。本研究通过截线样带法对海南岛沿岸海域砗磲的种类和分布进行实地调查,结果表明,海南岛沿岸海域砗磲覆盖度呈现南北差异,东南沿岸海域砗磲覆盖度明显高于西北沿岸海域,这种差异可能是由自然因素和人为因素共同造成。调查海域共发现3种砗磲:诺亚砗磲(Tridacna noae)最多,占砗磲样品总数的58.6%;其次是番红砗磲(T. crocea),占34.3%;鳞砗磲(T. squamosa)最少,仅占7.1%。海洋管理部门应该加强对砗磲多样性的保护力度,合理开发和可持续利用并重,从而有效保护砗磲、珊瑚礁乃至海洋生态系统。 相似文献
3.
采用室内实验生态学方法,以水体中氨氮、活性磷酸盐和溶氧变化为指标研究了光照强度和光色对番红砗磲代谢的影响。结果表明:(1)在0—10000lx光照时,番红砗磲排氨量逐渐减少,在光照12000lx时转为吸收海水中氨氮,并在16000lx时达到最高[1.89μg/(ind·h)];在2000lx光照条件下,番红砗磲可吸收海水中活性磷酸盐并释放氧气。其活性磷酸盐吸收量随光照强度增强而增加,在16000lx时达到最高峰。在实验光照范围内,番红砗磲产氧率随光照强度的增强逐渐增加。上述结果显示番红砗磲最佳光照强度约为16000lx。(2)当番红砗磲自黑暗转移至各光照组后,其氨氮、活性磷酸盐吸收率均随时间逐渐降低,而产氧率则逐渐升高。(3)光色显著影响番红砗磲合成代谢,蓝光最佳,红光次之,白光最差。 相似文献
4.
为了解海南近岸砗磲资源动态变化,于蜈支洲岛周边海域选取5个代表性站位,自2017-2020年采用断面调查的方法,开展了砗磲资源评估、种群数量变化以及其环境相关性分析等,结果显示：（1）各站位砗磲密度为0-30.00×10-2 ind./m2,且主要分布于3 m水深,在该水深区域,站位3和站位11砗磲密度最高,站位4次之,站位9和站位13最低,统计学分析表明砗磲密度与站位呈显著相关性（P<0.05）。（2）2017年,蜈支洲岛海域四种规格砗磲（壳长<5 cm、5-10 cm、10-15 cm和≥ 15 cm）均有分布,2018-2020年,未发现壳长≥ 15 cm的大规格个体。（3）尽管温度及各水质因子均与砗磲密度相关性不显著（P>0.05）,水体硝酸盐NO3-浓度与砗磲密度相关系数最高（0.29）。（4）砗磲主要分布于活珊瑚底质（66.67%）,其次为礁石（24.24%）,砂石底质最低（9.09%）。（5）砗磲外套膜RGB颜色参数值与周边底质颜色存在相关性,空间上,站位3的砗磲外套膜RGB颜色参数值与周边底质颜色相关性高于站位11;时间上,2020年砗磲外套膜颜色与周边底质B值相关系数R高于2017年（0.899 vs.0.712）。研究首次开展了海南岛近岸海域砗磲资源时空动态变化及影响因素研究,其结果可为砗磲资源保护提供数据支持。 相似文献
5.
本研究对中国南海3种小型砗磲(Tridacnaspp.)[番红砗磲(Tridacnacrocea,包括2种外壳形态)、长砗磲(Tridacna maxima)和诺亚砗磲(Tridacna noae)]的外壳形态性状进行生物统计学差异分析。研究表明,4组砗磲外壳存在显著形态学差异。单因素方差分析发现9个外壳比例性状能够较好区分3种砗磲,且2种不同外壳形态的番红砗磲在壳宽/壳长、足丝孔宽/壳长、壳质量/壳长和左右壳厚比壳长存在显著性差异(P<0.05);在基于欧氏距离Ward法且指定聚类数k=4的条件下,4组砗磲层次聚类效果较好;主成分分析提取3个主成分建立散点图,累计主成分贡献率73.85%,各主成分贡献率依次为50.47%,13.78%和9.60%;线性判别分析得出3个判别函数,方差解释率依次为70.13%、20.97%和8.90%。3种多元统计方法从不同角度解释各组砗磲的外壳形态差异,结果均显示两组番红砗磲的外壳形态更为接近,同时长砗磲与诺亚砗磲的外壳形态较为接近。 相似文献
6.
以番红砗磲(Tridacna crocea)为实验对象,通过单因素对比实验对其外套膜色素的提取条件进行了优化,并利用薄层层析色谱法对色素组成进行了初步分析。结果表明:丙酮和乙醇为适宜的番红砗磲外套膜色素提取剂;使用丙酮为提取剂时,浸提时间为4 h,提取温度为25℃,料液比为1︰40。使用乙醇为提取剂时,浸提时间为4 h,提取温度为30℃,料液比为1︰200;利用薄层色谱法分离外套膜颜色为蓝色和红棕色的番红砗磲外套膜色素后发现,蓝色番红砗磲外套膜色素由9种色素组分构成,红棕色个体番红砗磲外套膜色素由10种色素组分构成。 相似文献
7.
以蓝色、棕黄色和绿色三种不同外套膜颜色的番红砗磲(Tridacna crocea)为实验对象,设置5000 lx、10000 lx和15000 lx三组光照强度,探究了番红砗磲外套膜颜色变化与光照强度的相关性。结果表明:(1)在不同光照强度下,蓝色个体外套膜颜色加深,棕黄色个体颜色变化不大,而绿色个体外套膜颜色变浅。(2)蓝色个体在光照刺激2周后外套膜颜色即出现显著变化,0~2周色差为13.81~21.59;在不同光照强度刺激下,棕黄色和绿色个体的外套膜颜色的色差随时间延长而逐渐增强,4~6周外套膜颜色色差最大。(3)番红砗磲原外套膜颜色类别对其外套膜颜色红绿特征数值(a)和黄蓝特征数值(b)影响显著(P<0.05);光照强度对番红砗磲外套膜颜色黄蓝特征数值(b)影响显著(P<0.05);光照强度和番红砗磲原外套膜颜色类别的交互作用对红绿特征数值(a)的影响显著。上述结果可为定向培育外套膜颜色鲜艳的番红砗磲以及解析砗磲环境适应机制提供参考。 相似文献
8.
砗蚝(Hippopus hippopus)的人工繁育 总被引：1，自引：0，他引：1
于2016年4—9月开展了砗蚝(Hippopus hippopus)人工繁育技术研究。采用五羟色胺进行催产、促使配子排放;精卵分别收集,进行异体间受精以避免自交;受精卵经过30h孵化,选出600万D形幼虫进行培育。砗蚝的早期生活史与砗磲(Tridacna spp.)相似,经历前期面盘幼虫、中期面盘幼虫、后期面盘幼虫、足面盘幼虫、单水管稚贝、双水管稚贝、外套膜触手稚贝、幼贝等阶段。与砗磲不同的是,砗蚝怀卵量较少,但卵径较大,D型幼虫也较大,幼虫趋光性更强,壳长2.0mm以后外套膜不伸出壳缘外,幼贝贝壳形态也不同于砗磲。同砗磲幼虫一样,砗蚝幼虫需要构建虫黄藻系统之后,才能出现鳃、次生壳等,从而完成变态成为稚贝。砗蚝幼虫变态率较低,仅为1.4%。中间育成期间,丝状藻和锥形螺是稚贝培育的主要敌害,需及时清理才能确保稚幼贝正常生长发育。经过120d的精心饲育,培养出平均壳长6.3mm幼贝500余个。本研究为进一步开展砗蚝人工繁育、中间育成、增殖放流、资源修复及移植保育提供了参考。 相似文献
9.
现代砗磲壳体锶同位素与其生活环境的关系 总被引：1，自引：0，他引：1
对来自西沙群岛的双壳类磷砗壳体沿着其生长纹取样并系统地作了锶同位素的分析,得出了该生物壳体的锶同位素生长变化曲线。我们发现鳞砗磲壳体的锶同位素生长曲线显示出周期性的变化,与生物体的生长周期相一致,产生这种现象的因素主要是沿岸大陆河流排放量年同期性的变化。 相似文献
10.
碳酸盐生物壳体的周期性生长纹层是记录气候环境变化的天然材料。随着原位微区测试技术的快速发展,高分辨率的同位素和化学元素组成的快速分析显著推动了古气候环境变化及生物地球化学研究。应用激光剥蚀等离子体质谱仪(LAICP-MS)对南黄海现代牡蛎Crassostrea gigas壳体韧带部的元素组成进行原位微区测试,利用内标元素43Ca进行元素比值的校正,探讨了牡蛎壳中化学元素特征及其环境意义。研究的长牡蛎壳体中Mg/Ca、Sr/Ca、Na/Ca比值具有显著的季节性周期变化。环境水体物理化学性质的变化对壳体生长速率影响较大,壳中白垩质方解石和叶片方解石生长层分别对应较高和较低的环境温度,白垩方解石层具有较高的Mg/Ca、Sr/Ca和较低的Na/Ca比值。Mg/Ca比值可指示牡蛎壳体生长环境水体温度,利用前人Mg/Ca比值公式计算可以恢复与器测资料相符的近岸海水温度结果。本研究对应用LA-ICP-MS分析技术开展高分辨率的生物壳体元素组成和环境示踪研究具有借鉴意义。 相似文献
11.
Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a 14 C dated(AD 990±40) fossil giant clam, Tridacna gigas, from Shidao Island, South China Sea. The δ18O profile of the T. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with the δ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of the Tridacna specimen was stable after the onset of sexual maturity. Spectral analysis of the δ18O and blue color intensity time series suggested that the El Nio–Southern Oscillation(ENSO) period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations. 相似文献
12.
The climate of the South China Sea is dominated by the East Asian monsoon (EAM) system. Existing paleoclimate reconstructions offered an excellent insight into longer-term EAM variations. However, due to a lack of appropriate high-resolution paleoclimate data, relatively little is known about the frequency and strength of EAM extremes during the Holocene. To evaluate and establish a potential proxy archive for past variations of the EAM on shorter time-scales, we have carried out a calibration study on shells of the bivalve mollusk, Paphia undulata (Born 1778) from Daya Bay, China. This species has a short lifespan (3 years). Shells grow uninterruptedly between February/March and mid-November and are formed near oxygen isotopic (δ18O) equilibrium with the ambient environment. Shell growth patterns, δ18Oshell and δ13Cshell values, can be used to estimate the relative amount of precipitation and terrestrial runoff. Therefore, shells of this species can provide reliable, sub-seasonally resolved data on past East Asian summer monsoon strengths. The feasibility of this method has been tested with two Holocene shells from sediment cores taken from the nearby Beibu Gulf. A rather peculiar finding is that shell growth of P. undulata seems to be largely uncoupled to measured local environmental variables. Growth rates are negatively correlated to seawater temperature and chlorophyll a levels and positively to salinity. It is hypothesized here that extraordinary fast shell growth in early spring (February/March; low temperature and primary productivity) are facilitated by preserved energy resources, ensuring that the bivalve quickly reaches the predation window and the required size for reproduction. 相似文献
13.
东北印度洋赤道90°E海岭和孟加拉扇MD81349,MD77181岩心记录了30万a来气候变化的历史.分析发现浮游有孔虫壳体(方解石晶体)的天然热释光变化与δ18O反映的冰川旋回存在着良好的一致性:天然热释光强度的增大与间冰期对应,降低与冰期对应.对MD81349岩心天然热释光时间序列的频谱分析结果显示热释光的显著周期为99,46,23,20和11ka,其中99,46,23,20ka分别与天文学周期中的地球轨道偏心率周期100ka,地轴倾斜度(黄赤交角)周期54,41ka,太阳辐射年度差异的岁差周期23,19ka接近,这表明地球冷暖交替与太阳辐射强度周期性变化密切相关,在不同海水温度条件下结晶形成的方解石晶体的热释光强度差异显著,因而有孔虫壳体积存的热释光能够反映地球气候的变化. 相似文献
14.
本文以中国太平洋牡蛎二倍体自交作为对照,比较了诱导三倍体群体及其杂交三倍体的早期表型性状。通过对各试验组卵径、卵裂率、D幼率、D形幼虫大小、生长、存活率和倍性等指标进行测定,进一步评估了2种诱导方法的有效性。结果表明:与诱导三倍体群体相比,杂交三倍体表现出明显优势,D幼率、D形幼虫大小均大于诱导三倍体群体,且差异显著(P<0.05);稚贝期壳长和壳高生长也显著快于诱导三倍体群体(P<0.05)。至附着,杂交三倍体的存活率很高,显著优于诱导三倍体群体。就三倍体率而言,杂交三倍体达到100%,而诱导三倍体群体仅为51.00%±11.79%。由上得知,杂交三倍体更适合应用于大规模生产。 相似文献
15.
Rangia cuneata is an upper estuarine clam common in the coastal regions of the Gulf of Mexico. Limited data exist regarding oxygen isotope fractionation and microstructural increment periodicity in this species. As these clams were recently identified as an invasive species in other regions, such data may be useful for environmental management purposes. Additionally, the shell of this clam is common in archeological middens, and thus may serve as a paleoenvironmental proxy. In order to assess these aspects of the species’ natural history, samples were collected from the upper Mobile Bay, Alabama, USA. A stable oxygen isotope profile was generated from one of these valves, and compared to growth increments seen in thin section. Time-series water temperature data from near the collection site were used to construct idealized models of oxygen isotope variation, assuming equilibrium fractionation, constant shell growth, and stable water δ18O values. Comparison of the modeled and measured data suggest the shell was precipitated in, or near oxygen isotope equilibrium with ambient water, and that the microstructural increments in the shell were precipitated in response to tidal cycles. 相似文献
16.
We present high-resolution isotopic records and cathodoluminescence studies of recently dead and live bivalve specimens from
cold seeps, in an attempt to reconstruct environmental conditions during organism growth, and thereby the possible variability
of fluid-venting activity at the seafloor. Shells of the burrowing lucinid Myrtea aff. amorpha were collected at three localities near actively venting methane seeps in the Eastern Mediterranean deep sea, using the Nautile
submersible during two French oceanographic cruises: from the Kazan mud volcano, in the vicinity of the Anaximander mounts
(MEDINAUT cruise, 1998), and from the central pockmark province and the Amon mud volcano of the Nile deep-sea fan (NAUTINIL
cruise, 2003). The oxygen and carbon isotope compositions of 18 shells from the various localities, and also from different
sites at the same locality show a rather strong scatter (1.8 < δ
18O‰ < 3.4; −10.2 < δ
13C‰ < 2.2), and values lower than those expected for carbonate precipitated at equilibrium with present-day bottom waters.
This means that warm methane-rich fluids were mixed with bottom seawater during precipitation of shell carbonates. We have
tried to determine ontogenetic age of two shells by using cathodoluminescence as a sclerochronological proxy, because the
direct counting of carbonate increments was not possible in these specimens. There is a relatively good correspondence between
cathodoluminescence trends and oxygen isotope profiles that might support the link between manganese incorporation during
growth and temperature. Eight specimens of lucinid shells were selected for high-resolution isotopic profiling. A few shells
exhibit decreasing δ
18O and δ
13C values from the umbo to the actively growing ventral shell margin, which can be attributed to the commonly observed physiologically
controlled deceleration of growth with increasing organism age, this metabolic effect corresponding to the increase of incorporation
of respiratory CO2. A few shells exhibit high-frequency δ
18O variations with an amplitude of about 1.5‰ that might be related to temperature variations controlled by fluid-venting activity.
One shell from the pockmark province of the Nile deep-sea fan records a strong, sharp δ
13C decrease of about 9‰, and extending over a 5-mm interval in the shell that can be related to a major methane release event.
Another shell from the Kazan mud volcano exhibits a progressive increase of δ
13C values from −10‰ to 0‰ with age, which might indicate decreasing methane flow throughout the organism’s life. This study
has demonstrated that bivalve shells from deep-sea cold seeps represent good indicators of variability in seepage activity
of methane-rich fluids, at various scales in both space and time. Although the precise chronology of the observed events was
not established, because shell growth rate is not known in this case, this remains a priority for future studies in such environments. 相似文献
17.
An assemblage of geoduck clam shells from the marine environment of coastal British Columbia was studied. Shells were cut
and the widths of internal shell growth increments, annuli, were measured from the hinge plate. The largest shells showed
more than one hundred annual increments. Shell growth exhibited juvenile maxima at ontogenetic ages 3–6 years. The growth
maximum was followed by a distinct decline that continued until the death of each individual. Further, this ontogenetic growth
trend was mathematically removed from the data in order to examine growth variations other than ageing. The longest growth
records from the oldest shells were compared to monthly indices of the Pacific Decadal Oscillation (PDO). It was found that
the PDO exerts the strongest influence on the shell growth during the very start of the growing season, in February and March.
We also detected increased magnitude of growth variations towards the end of the 20th century. Similar trends were apparent
in the PDO record. Moreover, the shell specimen displaying the strongest trend of increasing variance had the strongest PDO-linked
regional growth signal. Our results support the view that PDO exerts a governing influence on the biological and ecological
system along Northeast Pacific coastal areas. Incorporation of geoduck shell growth increment analyses into multi-disciplinary
studies dealing with palaeoceanography and archaeology is suggested as a promising future approach. 相似文献
18.
Marcello A. Mannino Kenneth D. Thomas Melanie J. Leng Hilary J. Sloane 《Geo-Marine Letters》2008,28(5-6):309-325
Shells of the rocky shore intertidal gastropod Osilinus turbinatus (von Born), often abundant in archaeological deposits in the Mediterranean region, are a potential source of data on palaeotemperature, palaeoseasonality and archaeological seasonality. To evaluate this species as a climate archive, investigations of annual patterns of shell growth and of monthly variations in oxygen isotopes in shell carbonates were made on different populations in NW Sicily. Mark-recapture experiments at San Vito lo Capo and Mazzaforno show that O. turbinatus grows almost continuously throughout the year but at different rates in different seasons. Around 75% of the yearly shell growth occurs in the autumn and winter. On average, larger/older shells produce narrower annual growth increments than smaller/younger ones. Conspicuous growth lines in larger/older shells show that growth stops during the hottest part of the summer. Oxygen isotope analyses on monthly collected shells of O. turbinatus from three shores (Cala Grande, Monte Cofano and Mazzaforno) show that the isotope values record temperature variations through the year. In all the datasets, surface seawater temperatures (SSTs) calculated from δ18OSHELL mostly underestimate measured SSTs, offsets being generally greater in summer. Minimum annual offsets range from 0.0°C to 0.7°C and maximum annual offsets from 3.1°C to 8.7°C. δ18OSHELL values fail to record temperatures higher than 25°C. Careful selection of shells to be analysed can reduce offsets between δ18OSHELL temperature estimates and measured SSTs for many parts of the year, except the hottest. Allowing for this, shells of O. turbinatus offer good potential as climate archives and for archaeological studies of seasonal patterns of human foraging for shellfish. 相似文献
19.
Bernd R. Schöne 《Geo-Marine Letters》2008,28(5-6):269-285
Physiology corrupts geochemical records of mollusk shells in many ways, e.g., by actively controlling the incorporation of trace elements in the skeleton. However, the effects of variable biomineralization rates and growth cessation have largely remained unconsidered. Mediated by endogenous timekeeping mechanisms, mollusks stop growing skeletal material on a regular basis ranging from ultradian to annual timescales. During growth cessation, the shells do not record environmental conditions. Shell growth also stops when environmental conditions are beyond the physiological tolerance of the organism, e.g., above and below genetically determined, species-specific thermal extremes where shell growth slows and eventually ceases. Such growth disruptions can occur at non-periodic time intervals. Due to growth retardations and halts, proxy records of mollusk shells are thus incomplete, and reconstructed environmental amplitudes prone to truncation. Furthermore, environmental records are biased toward the physiological optimum of the animal. Favorable environmental conditions increase shell growth, whereas adverse environmental conditions result in reduced shell production and lowered overall metabolism. Not least, the duration of the growing season and overall growth rate decrease as the mollusk grows older. Mathematical modeling approaches can significantly improve proxy records obtained from mollusk shells. For example, if the duration of growth cessation is known, it may be possible to model the missing environmental record. It is also fairly easy to account for age-related growth trends, or variable time-averaging in different portions of the shell. However, a major premise for a reliable interpretation of proxy records from a mollusk shell or other organisms secreting biogenic hard parts is a proper understanding of the physiology, and of course, a high-resolution record of the many different environmental factors that may influence physiology and shell growth. The present paper reviews examples from the literature, and unpublished data on how physiology influences geochemical proxy records from mollusk shells, and presents methods how to eliminate such adverse effects. 相似文献