基于椭圆傅里叶分析的次南极电灯鱼矢耳石形态多样性

次南极电灯鱼矢耳石形态特征具有多样性.为了深入研究其形态特征,利用南设得兰群岛外侧水域采集的456尾次南极电灯鱼(体长范围6.0～8.8 cm)样本,对其矢耳石形态进行分析和判别.根据形态特征将次南极电灯鱼耳石分为4种类型,并采用椭圆傅里叶分析法选取表征耳石类型的77个傅里叶特征系数进行了分析.结果表明: 对4种耳石类型两两比较后发现,具有显著性差异的傅里叶特征系数最多及最少分别占总体的61%和28.6%;对77个傅里叶系数进行主成分分析,前22个主成分解释了总变异的76.6%;选取了17个傅里叶特征系数进行判别分析,建立判别函数,总体判别率为87.2%;根据椭圆傅里叶分析重建的耳石轮廓反映了4种耳石类型间的差异.4种耳石类型在不同体长及体质量的次南极电灯鱼中皆有出现,表明耳石类型具有随机性,且左右耳石类型不一致,表明其左右耳石外形具有差异性.4种耳石类型中,Ⅰ型和Ⅱ型占总体的72.6%,为次南极电灯鱼耳石的主要形态;Ⅲ型和Ⅳ型占总体的27.4%,为次要形态.     

用荧光物质浸泡标记重口裂腹鱼仔鱼耳石

用荧光物质对重口裂腹鱼仔鱼浸泡标记表明,200～300 mg/L的茜素络合物溶液浸泡12 h对重口裂腹鱼仔鱼耳石有很好的标记效果,荧光和可见光下均能检测到明显的标记环;100～150 mg/L的标记能检测到荧光标记环,但可见光下标记环较微弱.相同浸泡时间,随着浸泡浓度的增加,耳石上标记环强度增加;相同浸泡浓度,随着浸泡时间的增加,耳石上标记环强度增加.3对耳石中,微耳石和矢耳石对茜素络合物较敏感,星耳石敏感性较低.盐酸四环素的标记效果很差,浸泡浓度为50～160 mg/L时,3对耳石上均不能检测到标记环,同时110～160 mg/L的盐酸四环素浸泡液对仔鱼有较高的致昏或致死作用.因此,茜素络合物是对重口裂腹鱼鱼苗进行化学标记比较合适的荧光物质,而盐酸四环素不适合于标记该鱼的耳石.     

黑龙江秋大麻哈鱼耳石形态发育研究

对进入中国黑龙江的秋大麻哈鱼生殖群体进行人工繁育, 观察不同发育阶段和回归成体的耳石形态及其结构变化。结果表明:秋大麻哈鱼胚胎、胚后仔稚鱼、幼鱼和二龄鱼的矢耳石随个体生长发育,其大小在不断增长, 轮廓和表面形态结构也在发生演变, 逐渐趋似于回归成体的耳石形态。秋大麻哈鱼回归生殖群体的不同年龄和雌雄个体间矢耳石、微耳石形态基本一致。矢耳石形似梨形, 大小约为3 mm×5 mm×1 mm, 重量约为9 mg, 光镜下可见耳石日轮和年轮结构。日轮形成在胚胎发眼后约5日, 采用人工标记方法证实了生长轮的日周期特性。二龄鱼耳石已出现边缘生长区, 形成年轮。矢耳石增长与鱼体叉长生长显著相关(SL=21.574 OL-7.005,R2=0.9926)。       

西南大西洋拉式南美南极鱼耳石外型特征

基于2009年12月至2010年1月西南大西洋阿根廷外公海海域采集的拉式南美南极鱼(Patagonotothen ramsayi)145对耳石样本,对其形态特征进行了分析。结果表明,拉式南美南极鱼耳石长(OL)和宽(OW)分别为4.50—7.99 mm和1.99—3.69 mm之间。耳石外型呈狭长有缺刻,基叶长,翼叶短,具明显的主间沟,后端闭合呈钝圆形,整体结构凸凹不平。左右矢耳石形态无显著性差异。耳石绝对尺寸随体长增加而增加,但相对尺寸减少,耳石的形态结构比例基本不变。耳石长、宽、面积(S)及周长(P)与体重呈对数关系,耳石背长(DL)和基叶长(RL)与体重(W)呈指数关系,耳石背宽(DW)与体重呈乘幂关系,而耳石翼叶长(ARL)与体重则呈线性关系。耳石宽、面积、背长、背宽、周长、翼叶长及基叶长与体长(L)拟合符合对数关系,仅耳石长与体长呈线性关系。本研究可为鱼类耳石形态研究提供参考,并为南美南极鱼渔业生物学研究提供基础资料。     

南极冰鱼年龄与生长的研究进展

南极冰鱼在南极海洋生态系统物质与能量循环中起着至关重要的作用。作为"白血鱼",其科学研究意义和商业价值也为全球所关注,但其年龄与生长研究仍存在较多的不确定性。为此,本文综述了国内外近50年来南极冰鱼年龄与生长的研究进展,概述了南极冰鱼基本分类及其在南极海域的地理分布。在总结南极冰鱼年龄与生长研究的基本方法(包括渔获物体长频度法及钙化组织分析法等)的基础上,着重对南极冰鱼耳石处理及研究进行了归纳,通过耳石前处理(直接观察、燃烧和切割打磨)和轮纹鉴定等,对耳石研究中的耳石鉴龄方法、耳石形态学及耳石日轮等做了总结。通过总结南极冰鱼年龄与生长研究方面的困难和不足,如幼鱼耳石的处理方式及首轮形成的时间等,对今后中国开展南极冰鱼年龄与生长研究提出了展望。     

基于形态分析探究鳞头犬牙南极鱼各生活史阶段耳石形态变化

鳞头犬牙南极鱼为南极最为重要的底层鱼类,具有重要的生态作用和极高的商业价值,鱼类耳石形态随着生活史过程的推移有所差异,故耳石形态分析可用于推断鳞头犬牙南极鱼的生活史过程。本研究利用采集自南极罗斯海、阿蒙森海、威德尔海及拉扎列夫海120尾分属4个生活史阶段的鳞头犬牙南极鱼耳石,结合传统测量分析与椭圆傅里叶分析两种形态学研究方法,对其各生活史阶段耳石形态的差异进行研究。结果表明: 鳞头犬牙南极鱼各生活史阶段耳石形态存在差异,随着生活史过程的推移,耳石的变化趋势为整体上由轮廓平滑、复杂度较低向轮廓曲折、高度复杂化转变,且纵轴方向增长速度低于横轴方向,翼叶等特征部位变化显著。针对耳石形态的线性判别分析结果显示,椭圆傅里叶分析判别值较高,为85.4%,而传统测量分析判别值较低,为71.9%,表明相较于传统测量分析,椭圆傅里叶分析更具优势。     

六种鲤科鱼类耳石形态以及在种类和群体识别中的应用

描述了6种鲤科鱼类的耳石形态特征,并利用耳石形态的测量性状,对其种类特征进行了判别分析。其中,对张氏(卜夕又鱼)、长鳍吻鮈、圆口铜鱼、宜昌鳅（鱼它）和鲫的判别正确率为100％,异鳔鳅（鱼它）的判别正确率为90.91％,6种鱼类的平均判别正确率达到了99.1％,说明了鱼类的耳石形态特征可以用于鉴别种类。三个区域鲫群体的平均判别正确率为68.9％,显示三个区域鲫群体的耳石形态存在一定的差别。     

西沙群岛鹦嘴鱼科耳石形态学物种鉴定的可行性研究

研究于2018—2021年在西沙群岛海域采集鹦嘴鱼样本,通过传统形态测量法选取的19个耳石形态指标和椭圆傅里叶分析法选取的77个椭圆傅里叶系数对其进行鉴别分析,探究耳石形态在鹦嘴鱼科物种鉴别中的可行性。结果表明,仅使用耳石形态指标鉴别鹦嘴鱼时综合判别率为56.8%,低于仅使用椭圆傅里叶系数的63.1%和两种参数结合的75.7%;而结合两种参数对其4个属的综合判别率为88.6%,其中绚鹦嘴鱼属的判别率达到100%; 15种鹦嘴鱼的耳石形态聚类结果与已有研究的进化树结果基本一致,特别是属层面的聚类,呈现高度一致,证实了耳石形态具有遗传的属性,也说明了耳石形态学用于鱼类物种鉴定的可行性。研究结果将为西沙群岛鹦嘴鱼的基础研究提供科学资料,为鹦嘴鱼资源的保护与开发提供理论依据。     

软刺裸裂尻鱼耳石日轮及年轮沉积规律研究

研究利用软刺裸裂尻鱼(Schizopygopsis malacanthus)确证了耳石生长轮沉积规律,并在此基础上,探究了其生长轮与年轮关系,推算了第一年轮形成时间。研究结果表明:仔鱼微耳石第一轮纹在出膜后第二天形成,在实验条件下,轮纹沉积具有日周期性,生长轮为日轮;成鱼轮纹沉积具有年周期性,生长轮每年增加1轮。基于耳石日轮技术推算养殖和野生软刺裸裂尻鱼第一年轮形成时间分别为2021年1月28日至3月13日(n=40)和2017年3月8日至5月10日(n=75)。养殖和野生样本耳石轮纹数年际间的分析结果发现,软刺裸裂尻鱼耳石轮纹数和耳石年生长宽度随着年龄增加逐渐降低,耳石年生长面积随着年龄增加逐渐增加。这些结果揭示了软刺裸裂尻鱼耳石轮纹沉积规律,有助于增加年龄鉴定的准确性,进而为种群动态研究和渔业管理政策制定等提供参考。     

南极鱼类耳石微化学研究进展

南大洋生态系统的特异性极为显著,栖息在该海域的鱼类资源也存在着较为明显的本地特征以及对极端环境的适应能力。耳石微化学记录了鱼类完整生活史过程,可以揭示鱼类生活史过程中经历的时空变化。利用耳石中微化学元素,可以解决鱼类生态学中,如产卵场和洄游路径推测、生活史过程重建、种群划分等一系列实际问题。随着耳石微化学技术的不断完善,耳石微化学研究在海洋鱼类中的应用越来越广泛。相对于其他海区,目前南大洋鱼类耳石微量元素研究相对较少,仅涉及3科11种鱼类,约占南极鱼类总数的5%,且主要研究集中于商业性价值较高的鱼类,包括小鳞犬牙南极鱼(Dissostichus eleginoides)、鳞头犬齿南极鱼(D.mawsoni)、次南极电灯鱼(Electrona carlsbergi)、南极电灯鱼(E.antarctica)、裘氏鳄头冰鱼(Champsocephalus gunnari)和侧纹南极鱼(Pleuragramma antarcticum)等11种南极鱼类。耳石微化学研究主要集中在鱼类栖息环境重塑、种群划分以及生活史过程重建等三个方面。今后,更为先进的技术,如微计算断层扫描技术以及人工智能等,将为南极鱼类耳石微化学研究提供重要的支撑。考虑到南大洋鱼类多数具有典型的环南极分布特征,可通过耳石微化学技术进一步探究鱼类产卵场推定以及环极连通性等,并进一步阐释南极鱼类的生物-环境相互作用,相关工作也将为南大洋鱼类资源的开发利用及有效管理提供支撑信息。     

几种生物CaCO_3霰石结晶的取向性

ＣａＣＯ３结晶广泛分布于生物界,其主要结晶形式为方解石、霰石及球霰石。用Ｘ－射线衍射法对三角帆蚌及合浦珍珠母贝的珍珠层、墨鱼骨和大黄鱼耳石的ＣａＣＯ３结晶进行测定,发现各样品均有一定取向性,以三角帆蚌和合浦珍珠母贝珍珠层的取向性为最强,墨鱼骨的取向性次之,大黄鱼耳石的取向性最小,以上材料粉末样的衍射分析表明,各样品对应ｄ值间差异极小,均为Ｘ射线衍射卡（５—０４５３）所表征的ＣａＣＯ３霰石结构。     

几种生物CaCO3霰石结晶的取向性

CaCO3结晶广泛分布于生物界,其主要结晶形式为方解石、霰石及球霰石。用X－射线衍射法对三角帆蚌及合浦珍珠母贝的珍珠层、墨鱼骨和大黄鱼耳石的CaCO3结晶进行测定,发现各样品均有一定取向性,以三角帆蚌和合浦珍珠母贝珍珠层的取向性为最强,墨鱼骨的取向性次之,大黄鱼耳石的取向性最小,以上材料粉末样的衍射分析表明,各样品对应d值间差异极小,均为X射线衍射卡（5－0453）所表征的CaCO3霰石结构。     

CO(2)-Driven Ocean Acidification Alters and Weakens Integrity of the Calcareous Tubes Produced by the Serpulid Tubeworm, Hydroides elegans

As a consequence of anthropogenic CO(2-)driven ocean acidification (OA), coastal waters are becoming increasingly challenging for calcifiers due to reductions in saturation states of calcium carbonate (CaCO(3)) minerals. The response of calcification rate is one of the most frequently investigated symptoms of OA. However, OA may also result in poor quality calcareous products through impaired calcification processes despite there being no observed change in calcification rate. The mineralogy and ultrastructure of the calcareous products under OA conditions may be altered, resulting in changes to the mechanical properties of calcified structures. Here, the warm water biofouling tubeworm, Hydroides elegans, was reared from larva to early juvenile stage at the aragonite saturation state (Ω(A)) for the current pCO(2) level (ambient) and those predicted for the years 2050, 2100 and 2300. Composition, ultrastructure and mechanical strength of the calcareous tubes produced by those early juvenile tubeworms were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and nanoindentation. Juvenile tubes were composed primarily of the highly soluble CaCO(3) mineral form, aragonite. Tubes produced in seawater with aragonite saturation states near or below one had significantly higher proportions of the crystalline precursor, amorphous calcium carbonate (ACC) and the calcite/aragonite ratio dramatically increased. These alterations in tube mineralogy resulted in a holistic deterioration of the tube hardness and elasticity. Thus, in conditions where Ω(A) is near or below one, the aragonite-producing juvenile tubeworms may no longer be able to maintain the integrity of their calcification products, and may result in reduced survivorship due to the weakened tube protection.     

Impact of aragonite saturation state changes on migratory pteropods

Thecosome pteropods play a key role in the food web of various marine ecosystems and they calcify, secreting the unstable CaCO(3) mineral aragonite to form their shell material. Here, we have estimated the effect of ocean acidification on pteropod calcification by exploiting empirical relationships between their gross calcification rates (CaCO(3) precipitation) and aragonite saturation state Ω(a), combined with model projections of future Ω(a). These were corrected for modern model-data bias and taken over the depth range where pteropods are observed to migrate vertically. Results indicate large reductions in gross calcification at temperate and high latitudes. Over much of the Arctic, the pteropod Limacina helicina will become unable to precipitate CaCO(3) by the end of the century under the IPCC SRES A2 scenario. These results emphasize concerns over the future of shelled pteropods, particularly L. helicina in high latitudes. Shell-less L. helicina are not known to have ever existed nor would we expect them to survive. Declines of pteropod populations could drive dramatic ecological changes in the various pelagic ecosystems in which they play a critical role.     

Modelling calcium carbonate biomineralisation processes

The structure-directing influence of the organic dicarboxylates malonate, succinate, glutarate and adipate as templating species on the hydrothermal formation of CaCO(3) was investigated at different temperatures (60, 80, 90, 120, 150 and 190 degrees C) and with a range of molar ratios of [Ca(2+)]/[templating species] (20, 14.3, 10, 7.7, 5, 1, 0.5 and 0.33). In the presence of the dicarboxylates, one, two or three polymorphs of CaCO(3) - calcite, aragonite and vaterite - could be formed, depending on the reaction conditions. In addition changes in crystal morphology were observed for the CaCO(3) polymorphs depending on the concentration of the template. In contrast, synthesis under ambient conditions of temperature and pressure resulted only in calcite formation, although template-dependent morphological changes were again observed. Crystalline products were all characterized by powder X-ray patterns and SEM (Scanning Electron Microscopy) micrographs. The ambient reactions with the chelating, dinucleating carboxylato ligands H(3)heidi and H(5)hpdta produce more profound changes in calcite morphology. With H(3)heidi rounded calcite crystals with shapes similar to that of otoliths are formed and with H(5)hpdta the formation of microtrumpets of constructed from bundles of nanocrystals of calcite is observed. The possible mode of action of these ligands on calcite formation is discussed in the context of known coordination chemistry with other metal ions.     

CaCO3 biomineralization: acidic 8-kDa proteins isolated from aragonitic abalone shell nacre can specifically modify calcite crystal morphology

Acidic proteins from many biogenic minerals are implicated in directing the formation of crystal polymorphs and morphologies. We characterize the first extremely acidic proteins purified from biomineralized aragonite. These abalone nacre proteins are two variants of 8.7 and 7.8 kDa designated AP8 (for aragonite proteins of approximately 8 kDa). The AP8 proteins have compositions dominated by Asx ( approximately 35 mol %) and Gly ( approximately 40 mol %) residues, suggesting that their structures have high Ca(2+)-binding capacity and backbone flexibility. The growth of asymmetrically rounded CaCO(3) crystals in the presence of AP8 reveals that both proteins preferentially interact with specific locations on the crystal surface. In contrast, CaCO(3) crystals grown with nacre proteins depleted of AP8 retain the morphology of unmodified calcite rhombohedra. Our observations thus identify sites of protein-mineral interaction and provide evidence to support the long-standing theory that acidic proteins are more effective crystal-modulators than other proteins from the same biomineralized material.     

Seawater Mg/Ca controls polymorph mineralogy of microbial CaCO3: a potential proxy for calcite-aragonite seas in Precambrian time

A previously published hydrothermal brine-river water mixing model driven by ocean crust production suggests that the molar Mg/Ca ratio of seawater (mMg/Ca(sw)) has varied significantly (approximately 1.0-5.2) over Precambrian time, resulting in six intervals of aragonite-favouring seas (mMg/Ca(sw) > 2) and five intervals of calcite-favouring seas (mMg/Ca(sw) < 2) since the Late Archaean. To evaluate the viability of microbial carbonates as mineralogical proxy for Precambrian calcite-aragonite seas, calcifying microbial marine biofilms were cultured in experimental seawaters formulated over the range of Mg/Ca ratios believed to have characterized Precambrian seawater. Biofilms cultured in experimental aragonite seawater (mMg/Ca(sw) = 5.2) precipitated primarily aragonite with lesser amounts of high-Mg calcite (mMg/Ca(calcite) = 0.16), while biofilms cultured in experimental calcite seawater (mMg/Ca(sw) = 1.5) precipitated exclusively lower magnesian calcite (mMg/Ca(calcite) = 0.06). Furthermore, Mg/Ca(calcite )varied proportionally with Mg/Ca(sw). This nearly abiotic mineralogical response of the biofilm CaCO3 to altered Mg/Ca(sw) is consistent with the assertion that biofilm calcification proceeds more through the elevation of , via metabolic removal of CO2 and/or H+, than through the elevation of Ca2+, which would alter the Mg/Ca ratio of the biofilm's calcifying fluid causing its pattern of CaCO3 polymorph precipitation (aragonite vs. calcite; Mg-incorporation in calcite) to deviate from that of abiotic calcification. If previous assertions are correct that the physicochemical properties of Precambrian seawater were such that Mg/Ca(sw) was the primary variable influencing CaCO3 polymorph mineralogy, then the observed response of the biofilms' CaCO3 polymorph mineralogy to variations in Mg/Ca(sw), combined with the ubiquity of such microbial carbonates in Precambrian strata, suggests that the original polymorph mineralogy and Mg/Ca(calcite )of well-preserved microbial carbonates may be an archive of calcite-aragonite seas throughout Precambrian time. These results invite a systematic evaluation of microbial carbonate primary mineralogy to empirically constrain Precambrian seawater Mg/Ca.     

Abalone nacre insoluble matrix induces growth of flat and oriented aragonite crystals

Mollusc shell formation takes place in a preformed extracellular matrix, composed of insoluble chitin, coated with proteins and dissolved macromolecules. The water-soluble matrix is known to have a strong influence on the growth of CaCO(3), whereas the role of the insoluble matrix on mineralization is unclear. Therefore, we mineralized the EDTA (ethylenediaminetetraacetic acid) insoluble organic matrix of abalone nacre with a modified double-diffusion set-up, where the diffusing solutions were constantly renewed. Control experiments were performed with cellulose and chitosan foils. The mineralized matrices/foils were analyzed with SEM. We show that the insoluble matrix of abalone nacre induces the growth of flat and roughly polygonal CaCO(3) crystals. In some of the experiments with the insoluble matrix, the growth of three-dimensional parallel sheets of densely packed platelets inside the insoluble matrix was observed. XRD on these samples revealed that they consist of oriented aragonite.     

In vitro regulation of CaCO(3) crystal polymorphism by the highly acidic molluscan shell protein Aspein

Biominerals, especially molluscan shells, generally contain unusually acidic proteins. These proteins are believed to function in crystal nucleation and inhibition. We previously identified an unusually acidic protein Aspein from the pearl oyster Pinctada fucata. Here we show that Aspein can control the CaCO(3) polymorph (calcite/aragonite) in vitro. While aragonite is preferentially formed in Mg(2+) -rich solutions imitating the extrapallial fluids of marine molluscs, Aspein exclusively induced calcite precipitation. Our results suggest that Aspein is involved in the specific calcite formation in the prismatic layer. Experiments using truncated Aspein demonstrated that the aspartic acid rich domain is crucial for the calcite precipitation.     

小黄鱼内耳淋巴液液晶与耳石结晶关系的初步研究

作者以扫描电镜观察了小黄鱼耳尘的“透镜样”结构;Ｘ衍射分析表明小黄鱼耳石由ＣａＣＯ３霰石构成;以偏光显著镜发现内耳淋巴液中有液晶态存在。最后,以液晶理论对耳尘、耳石的形成进行了讨论。