大型藻类规模化养殖水域海-气界面CO2交换通量估算

选择山东俚岛湾大型藻类养殖水域作为研究区域,根据2011年4、8、10月和2012年1月4个航次的大面调查获得的pH、总碱度(TA)、叶绿素a等基础数据,分析了该区域表层海水溶解无机碳(DIC)体系各分量的浓度、组成比例及时空变化特征,估算了海-气界面CO2的交换通量。结果表明,该区域表层海水DIC、HCO-3、CO2-3及CO2的年平均浓度分别为2024.8±147.0、1842.4±132.1、170.0±42.8和12.4±2.5μmol/L。养殖区与非养殖区之间DIC、HCO-3浓度差异不显著(P>0.05),而CO2浓度差异极显著(P<0.01)。表层海水pCO2和海-气界面CO2的交换通量的年平均值分别为287.8±37.9μatm和-32.7±17.2mmol/m2.d,养殖区与非养殖区之间、不同季节之间均差异极显著(P<0.01)。大型藻类的养殖活动有利于海洋对大气CO2的吸收。     

桑沟湾春季海–气界面CO2交换通量及其与养殖活动的关系分析

为研究不同养殖活动对海–气界面CO2交换通量(F)的影响,于2014年5月采用走航式CO2分压仪对中国北方典型的多营养层次混合养殖海域—桑沟湾养殖区的表层水CO2分压(pCO2)进行了大面调查,并通过数据计算桑沟湾海区的F值。在调查过程中,选择在网箱养殖区、贝类养殖区、藻类养殖区等区域内进行24 h定点连续观测。探讨了春季桑沟湾海–气界面CO2的交换通量及其主要影响因素。大面调查结果显示,桑沟湾内海水中pCO2总体变化趋势是由湾内向湾外递减,网箱养殖区海水中pCO2远远高于其他区域。在大面调查中,贝类、藻类、贝藻混养、网箱养殖区的F值分别为(–1.02±0.83)、(–15.40±1.28)、(–4.32±1.41)、8.14 mmol/(m2·d)。定点连续监测显示,藻类、贝类、网箱养殖区的pCO2 24 h平均值分别为(320±14)、(330±10)、(413±37) μatm。研究表明,光合作用是海–气界面CO2交换通量的主要影响因素之一,不同养殖区之间的海–气界面CO2交换通量差异显著。影响各养殖区海–气界面CO2交换通量日变化规律的影响因子与走航调查结果一致。养殖活动是影响海–气界面CO2交换通量的主导因素。     

下三横山岛养殖海域海-气界面CO2交换通量的空间分布特征及影响因素

为研究下三横山岛养殖海域海-气界面CO₂交换通量及影响因素,从2020年7月开始,在该海域开展为期一年(4次)的监测和分析,主要剖析其温度、盐度、pH、总碱度(TA)及水体中溶解无机碳(DIC)、溶解有机碳(DOC)、颗粒有机碳(POC)分布差异,估算下三横山岛养殖海域表层海水CO₂分压(pCO₂)及海-气界面CO₂通量(FCO₂)值,并分析pCO₂的影响因素,探讨下三横山岛该养殖海域海-气界面CO₂交换通量。结果表明,下三横山岛海域表层海水4个季节的温度、盐度、pH、TA、DIC、DOC、POC的分布在季节上差异极显著(P<0.01)。下三横山岛海域pCO₂全年的变化范围为29.93～836.80μatm, FCO₂值的变化范围为-45.67～216.50 mmol·(m²·d)^-1。pCO₂与FCO₂     

贝类养殖区CO2释放量化新模型的应用研究

海水贝类钙化过程将产生 CO₂, 但由于不同养殖海区碳酸盐体系组成差异大, 需要在考虑海区碳酸盐体系变化特征的基础上更精确地量化该过程导致的 CO₂ 释放量。本研究将各种生物地球化学过程中产生的 CO₂ 源/汇效应强度定义为 Φ, 在钙化作用过程中, Φ_cal 值可表示特定海区水文条件下, 贝壳钙化作用实际释放到大气中的 CO₂ 与该过程产生的 CO₂ 的比率。应用新碳酸盐化学模型计算结果显示: Φ_cal 值呈现季节变化特点, 胶州湾、桑沟湾和深澳湾的 Φ_cal 值均为夏季最低; 养殖海区内碳酸盐系统的区域性差异可改变 Φ_cal 值, 胶州湾、桑沟湾和深澳湾的平均 Φ_cal 值分别为 0.79, 0.72 和 0.72; 在贝类主要生长季节(3―7 月), 养殖海区的 Φ_cal 值呈现下降趋势, 此外, 多项式拟合结果表明胶州湾海区该阶段 Φ_cal 值随温度的上升而降低。在温度高于 18 ℃后, Φ_cal 值下降的速度逐渐加快。 Pearson 相关分析表明, 胶州湾内 Φ_cal 值与表层海水的 CO₂ 分压相关性极显著(P＜0.01)。最后, 基于模型计算的胶州湾内 Φ_cal 值水平, 按胶州湾菲律宾蛤仔年产量 3.2×10⁵ t 计, 胶州湾养殖菲律宾蛤仔贝壳生长部分预计每年向大气中排放约 1.084×10⁵ t CO₂。本研究初步证实 Φ_cal 可在考虑海区碳酸盐体系特征的基础上, 更精确地量化贝类钙化作用导致的 CO₂ 释放量, 为后续的贝类的碳源/碳汇过程研究提供一定的参考。     

三倍体长牡蛎浮筏养殖技术的研究

本文报道了两个相邻海区近５００ｈｍ＾２三倍体长牡蛎Ｃｒａｓｓｏｔｒｅａ ｇｉｇａｓ（Ｔｈｕｎｂｅｒｇ）浮筏养殖的研究结果。三倍体牡蛎的采苗器为栉孔扇贝壳,每片采苗器采苗１０￣１２个,以１５￣２０ｃｍ间距夹于３股聚乙（丙）烯蝇间并吊养在浮筏上。三倍体牡蛎在个体重、出肉率和条件指数等养殖经济性状方面比二部体分别增加４２．１％、１６．２％、５６．７％,成活率也有一定的提高。三部体在生长等方面性状优势的生     

基于微卫星标记整合长牡蛎遗传图谱

为了提高长牡蛎遗传图谱上的微卫星标记密度,实验采用6个家系图谱间的共有微卫星标记作为锚定标记,构建了长牡蛎的整合图谱.该整合图谱共有161个微卫星标记,覆盖10个连锁群,图谱长度和平均间距分别为615.4和3.8 cM.各连锁群的标记数介于10 ～ 24个之间,连锁群长度为47.3～73.3 cM,是目前密度最高的长牡蛎微卫星图谱.不同作图家系连锁群上的标记分组保持一致,但标记顺序出现差异,可能与长牡蛎自然群体中存在大量的染色体重排现象有关.结果表明,该图谱可以为今后长牡蛎的遗传育种研究提供新的遗传工具.     

Genetic differentiation between Zhe oyster Crassostrea plicatula and pacific oyster Crassostrea gigas populations in China assessed by microsatellite analysis

ABSTRACT:   Genetic differentiation and relationships between Crassostrea plicatula and Crassostrea gigas populations from China were studied by means of the microsatellite technique. Seven loci were used to screen five populations each collected from C. plicatula and C. gigas . All loci showed high polymorphism for all populations, as observed in average number of alleles per locus (19.1–28.1), and average expected heterozygosity (0.891–0.954). Significant departures from Hardy–Weinberg equilibrium due to heterozygote deficiency were observed over most populations at each locus and were best explained by null alleles. F _ST values showed significant genetic differentiation between C. plicatula and C. gigas populations. According to the neighbor-joining tree constructed on the basis of the genetic distance ( D _A), the ten populations fell into two distinct groups ( C. plicatula and C. gigas groups), and the results of principal coordinate analysis and assignment tests also supported the neighbor-joining clustering. The outcomes presented here suggested that the microsatellite markers have great potential for differentiating C. plicatula from C. gigas populations. The information obtained in this study has important implications for the suitable management and conservation of these genetic resources in China.     

Sex-specific growth and condition of the Pacific oyster (Crassostrea gigas Thunberg)

In order to study the possibility of gaining commercial benefit from culturing an excess of one sex of the Pacific oyster (Crassostrea gigas), comparative data on the growth rate and condition of male and female oysters are reported. Historically, measurement of sex‐specific growth rate in oysters has been overlooked or confounded by protandric sex. The recent conclusion that the sex ratio of Pacific oysters is predominantly under genetic rather than environmental control introduces the possibility of manipulating sex ratio for commercial gain if they exhibit asynchronous sex‐specific growth rates. Pacific oysters were cultured intertidally in Smoky Bay, south Australia. The observations, made over the 7‐month gametogenic cycle from August to February to ensure no sex reversal, were of growth rates of male and female oysters and ambient chlorophyll a concentrations. Mean shell growth of female oysters was significantly faster than that of males (4.5 ± 3.3 compared with 3.8 ± 3.2 μm day^?1 mm^?1 total length). Sex‐specific asymmetries in length and weight were generally significant and increased in magnitude during the 7‐month study period, suggesting potential commercial benefits from increasing the proportion of cultured female oysters. The fastest increase in the sex‐specific disparity in growth and condition came after the October chlorophyll a peak, suggesting that females utilize blooms more efficiently than males. Our results compare favourably with methods currently used to increase oyster growth (e.g. triploidy can provide growth gains of 13–51%).     

低渗诱导太平洋牡蛎三倍体以及与其他诱导方法的比较

通过低渗方法抑制受精卵第二极体(PB2)的释放,诱导太平洋牡蛎(Crassostrea gigas)三倍体.在水温为23～25℃的条件下,分别采用不同低渗海水(盐度分别为4、6、8、10、12、14、16),在不同处理时机,即第1个第一极体(PB1)出现、30%的PB1出现、40%的PB1出现、50%的PB1出现以及第1个第二极体(PB2)出现时,对太平洋牡蛎受精卵进行10 min、15 min、20 min、25 min持续处理.处理后,于正常盐度海水中孵化,收集D形幼虫,通过流式细胞仪进行倍性测定,确定最佳诱导条件.结果表明,当太平洋牡蛎受精卵PB1出现40%时,在盐度为8的低渗海水中,持续处理15 min,得到最高三倍体诱导率为(89.16±1.39)%.与对照组相比,低渗诱导获得的三倍体幼虫表现出明显的生长优势.将低渗方法同高温(32℃)、低温(2℃)和6-DMAP(450μmo1/L)处理等多倍体诱导方法进行比较,结果显示,低渗组的卵裂率和孵化率显著高于高温、低温和6-DMAP诱导的太平洋牡蛎三倍体(P＜0.05).6-DMAP诱导的三倍体率虽略高于低渗诱导,但差异不显著(P＞0.05).通过综合评价指数(Ie)比较,认为低渗诱导多倍体的方法比高温、低温和6-DMAP诱导具有明显的优势.     

福建漳浦太平洋牡蛎微卫星等位基因比较

本文采用Ucdcg153、157、202微卫星分子标记对福建漳浦从广东饶平引人的太平洋牡蛎育苗亲贝进行等位基因比较.两组样品(Cg♀和cg♂)携带的等位基因在微卫星重复区间及其附近存在高度相似的变异特征.这些特征区间分别是:Ucdcg153 23～40位碱基区间,Ucdcg157 73～100位碱基区间,Ucd-cg2...     

长牡蛎非整倍体的制备、胚胎发育及存活能力

通过二倍体、三倍体杂交的方法制备长牡蛎(Crassostreagigas)非整倍体。实验组设为2n♀×3n♂组、3n♀×2n♂组和3n×3n组,对照组为2n×2n组。与对照组相比,实验组畸形率高,担轮虫孵化率及D形幼虫生成率等参数均降低,幼虫死亡率高。在担轮幼虫向D形幼虫转化期,实验组发育滞后。培育过程中染色体数为25左右的非整倍体不能存活,整倍体和染色体数与整倍体接近的非整倍体能够存活。实验证实该方法是进行贝类非整倍体制备的有效手段。     

长牡蛎出肉率与壳形性状的 QTL 定位分析

本研究以长牡蛎(Crassostrea gigas)F1全同胞家系为作图群体,在已构建的基于120个微卫星和66个SNP标记的长牡蛎性别平均连锁图谱上,利用PROC QTL 2.0软件对出肉率和壳形(壳宽和壳深)性状进行QTL定位分析。结果表明,共检测到13个相关的QTL,分布在3个连锁群上;其中,与出肉率相关的4个QTL定位在1号和3号连锁群上(LG1和LG3),表型解释率为0.25%~47.53%;与壳宽相关的3个QTL定位在10号连锁群上(LG10),表型解释率为0.71%~45.39%;与壳深相关的6个QTL也定位在LG10,表型解释率为3.37%~24.78%。根据QTL连锁群分析和性状相关性分析结果可以推测,出肉率与糖原含量性状以及壳宽与壳深性状分别具有相近的遗传特征,利用与相关性状共同关联的分子标记可以同时对出肉率与糖原含量性状、壳宽与壳深性状进行遗传改良。本研究结果为今后长牡蛎相关性状候选基因克隆和分子标记辅助育种提供了参考。     

Reproduction, condition and mortality of the Pacific oyster Crassostrea gigas (Thunberg) in Sonora, México

Starting in 1997, mortality outbreaks in cultured oysters Crassostrea gigas have been reported in northwestern México. Previous studies have shown that massive die‐offs result from multi‐factor processes related to reproduction of the species. We studied the reproductive cycle and the condition index of cultured oysters in the coastal lagoon of El Soldado, Sonora, as well as the relationship of the life cycle with environmental parameters. We used oocyte diameter to determine reproductive stages and the condition index to describe the physiological state of oysters. Additionally, the temperature, salinity, seston and chlorophyll a were recorded at the study site. The results showed that C. gigas began accelerated reproductive activity in March under the influence of high temperature and increased concentrations of food. No spawning events were recorded and gametes were reabsorbed within the gonad in September and October. The results showed a period of nutrient storage during autumn–winter and another period of gamete production in spring–summer. A mortality event occurred at the end of winter, tied to significant increases in temperature and availability of food and in accelerated reproductive activity and high condition index. These conditions were very similar to those reported in other countries during summer die‐offs of C. gigas.     

干露胁迫对长牡蛎基因组DNA甲基化的影响

为探讨干露胁迫对海产贝类基因组DNA甲基化的影响,应用荧光标记甲基化敏感扩增多态性(fluorescencelabeled methylation sensitive amplified polymorphism,F-MSAP)技术,比较了不同干露条件下(0 d、0.5 d、1 d、3 d、5 d、7 d、9 d和11 d)长牡蛎(Crassostrea gigas)基因组DNA甲基化的变化。结果表明,对照组(干露处理0 d)闭壳肌与鳃组织的总体甲基化水平分别为29.76%和29.82%;干露处理0.5 d、1 d、3 d、5 d、7 d、9 d和11 d的长牡蛎全基因组甲基化水平呈现先增高后降低的趋势,其中,闭壳肌组织的总体甲基化水平分别为36.59%、38.86%、43.02%、39.30%、51.13%、46.79%和35.06%,鳃组织总体甲基化水平分别为39.39%、42.13%、39.36%、43.54%、56.19%、38.57%和28.99%;干露处理7 d的长牡蛎甲基化水平明显高于其他时期(P0.05),11 d时甲基化水平基本恢复至初始状态。甲基化变异模式分析发现,闭壳肌与鳃组织DNA甲基化变异位点存在差异,甲基化升高位点变化程度较大(P0.05)。以上结果表明,长牡蛎通过改变DNA甲基化模式来应答干露胁迫,发生了不同程度的甲基化与去甲基化反应,DNA甲基化与长牡蛎的抗逆性状密切相关。