Reconstructing estuarine conditions: oyster shells as recorders of environmental change, Southwest Florida   总被引：1，自引：0，他引：1  

Donna M. Surge  Kyger C Lohmann  Glenn A. Goodfriend   《Estuarine, Coastal and Shelf Science》2003,57(5-6):737-756

Live-collected shells of the oyster, Crassostrea virginica, contain geochemical records of modern temperature and salinity, so records of prehistoric conditions may be obtained from subfossil shells. Restoration of channelized watersheds in Florida is receiving much attention, and plans for targeted watersheds require information about estuarine conditions before channelization. Lack of historical records necessitates alternative methods to understand pre-disturbance conditions. A ¹⁴C-calibrated, amino-acid geochronology based on racemization of glutamic acid yielded ages ranging from 190–1220 AD and from 1270–1860 AD for subfossil oysters from Blackwater River (near-natural watershed) and for Faka-Union Bay (channelized watershed), respectively. δ¹⁸O and δ¹³C values of subfossil shells from Blackwater River indicate salinity and summer temperatures similar to present. Winter temperatures recorded in shells from 190, 590, 720, and 1050 AD appear 1–5 °C colder than present winter temperatures, whereas the shell from 1220 AD records winter temperatures similar to modern winter temperatures. These temperature shifts may indicate change in climate or natural seasonal variation of winter temperature from year to year. Subfossils from Faka-Union Bay may reflect a complicated hydrology, which cannot be evaluated by isotopic compositions alone and demonstrates the need for development of independent elemental proxies for temperature and salinity. Decreases in δ¹³C from subfossil to modern shells may in part result from CO₂ added to the atmosphere from fossil fuel burning (the Suess effect). Subfossil δ¹³C that is >1‰ more positive than modern shells suggest a change in the dominant carbon sources from terrestrial C₄ or aquatic plants to C₃ plants (mangroves).  相似文献   

太平洋牡蛎高产育苗技术的研究     

于瑞海  姜春丽  孙志刚  房德芝  王长竹  工喜连  邢秀忠 《海洋科学进展》1996,(4)

本文主要从强化亲贝蓄养，加强洗卵和分池孵化工作入手，提高其孵化率，及时选幼；幼虫培养及时筛选不同规格幼虫，投附着基后严格管理等措施来提高其变态率，达到稳产、高产，取得单位水体出苗量平均为３８万多个／ｍ３的好效果和明显的经济效益。  相似文献   

太平洋牡蛎精子形成的研究   总被引：1，自引：0，他引：1  

任素莲  王德秀  绳秀珍  王如才  姜明  刘晓云 《中国海洋大学学报(自然科学版)》2001,31(4):501-505

透射电镜下研究了太平洋牡蛎 (Crassostrea gigas Thunberg)的精子形成过程。精子细胞中含有前顶体颗粒、线粒体、高尔基体、中心粒等多种细胞结构 ,线粒体、前顶体颗粒的数量较多。在精子形成过程中 ,前顶体颗粒逐渐汇集、愈合成顶体泡 ,顶体泡覆盖在细胞核的一端逐渐发育为顶体 ;线粒体则向顶体相反的方向移动 ,最后移到核后端形成 4个较大的线粒体球 ;中心粒移到核后端由远端中心粒形成轴丝 ;细胞核发生致密 ,形态发生变化 ,最后形成杯状的精子核 ;多余的细胞质被抛弃。  相似文献   

TRIPLOIDY INDUCTION IN PACIFIC OYSTER CRASSOSTREA GIGAS BY CAFFEINE WITH THERMAL SHOCK     

张国范  常亚青  宋坚  丁君  沈金开  王永平 《中国海洋湖沼学报》1998,(3)

INrnODUCTIONPacificOyster,Crassostreafor,isoneofthemostimPOrtantcommeroialmolluscsintheworld.Itsbiologica.lcharatersaremostsuitableforInariculture.Inmeentyears,thedeve1opmentofploiddripulationtecboqUesinoystershassiedcanlycontributedtotheimprovementofbwhstockintennsofgrowth,viabilityandmeatqUality(Allen,etal.l986).ThesuccessfulinductionoftriploidmolluscswasfirstachievedbyStanleyeta.l.(l98l,l984)intheAmericanoyster.Dedngetal-(l987),Quilletetal.(l986),CooPeretal.(l989)andGuoetal-(1992)…  相似文献   

太平洋牡蛎配子和精子人卵的扫描电镜观察及胚胎发育的初步研究     

田传远  梁英  王如才  任素莲  于瑞海  赵厚均 《海洋科学进展》2000,18(2):51-55

通过扫描电镜观察,太平洋牡蛎精子由头部、中段和尾段组成.精子全长约21.6μm,尾段长约18.2μm,末端观察到"针眼"样结构;头部最大处的直径约2.6μm;中段直径约1.1μm;未成熟精子尾段中部出现膨大,该处直径约0.3μm.卵呈梨形;卵的直径约为41.9μm.卵表面有微绒毛组成的皱折结构,可见卵黄膜孔.卵质收回时,在卵表面卵柄处可见明显的树枝状结构.受精后,受精卵表面的卵黄膜剥离处可见较多数量的皮质小泡.在水温21.2～23.5℃,精卵混合34min时,释时出第1极体;1h22min时,放出第2极体;21h55min时,胚胎发育至初期D形幼虫.  相似文献   

长牡蛎中天然牛磺酸的提取   总被引：6，自引：0，他引：6  

张辉  管华诗  赵志强 《海洋科学》2005,29(4):1-4

以长牡蛎(Crassostrea gigas)为研究对象,探讨并优化了从牡蛎中提取和制备牛磺酸的工艺。牛磺酸纯度采用TLC进行分析,其结构进一步用红外光谱(IR)和核磁共振波谱(NMR)进行了确证。结果表明,长牡蛎富含牛磺酸,在60℃水溶液中提取率(0．8％,湿质量)较高,为天然牛磺酸开发提供了参考数据。  相似文献   

The effect of PCBs on glycogen reserves in the eastern oyster Crassostrea virginica     

V. Encomio  Fu-Lin E. Chu   《Marine environmental research》2000,50(1-5)

Recent declines in Chesapeake Bay oyster populations have been attributed to disease, and reduced water quality from pollution. The stress associated with pollutant exposure may reduce energy available for growth and reproduction. Polychlorinated biphenyls (PCBs) are lipophilic contaminants that may potentially affect mobilization of lipid reserves, increasing reliance on glycogen stores, which could otherwise be utilized to supply energy for gametogenesis. Thus, PCBs may indirectly affect glycogen stores in oysters in a deleterious manner. To test for this effect, reproductively inactive oysters were exposed to PCBs by feeding individuals 0.7 g of algal paste containing 0, 0.35, or 3.5 μg PCBs daily for 8 weeks. Additionally, a group of oysters was exposed to PCBs (0, 0.35, and 3.5 μg) plus 0.3 g of non-toxic artificial sediment to examine interactive effects of sediment particles and PCBs. Adductor muscle, mantle, and gonadal tissues were analyzed for glycogen content. Results suggest that glycogen content is reduced in the adductor muscle with increasing PCB exposure, but there are no effects of PCBs in the mantle and gonadal tissues.  相似文献   

长牡蛎三倍体的诱导和培育   总被引：3，自引：0，他引：3  

林琪  吴建绍  曾志南  陈朴贤  陈木 《台湾海峡》2000,19(4):478-483

本文报道了采用高温结合咖啡因、CB、6 DMAP等方法诱导长牡蛎三倍体的研究结果。结果表明 :CB、6 DMAP的三倍体诱导率高 ,分别达 85 .39%和81 .2 6 % ,适用于大规模生产。高温结合咖啡因处理三倍体诱导率低 ,且存活率也很低。采用CB抑制受精卵第二极体排放诱导培育出三倍体种苗 7.2× 1 0 7粒。  相似文献   

湛江港区底泥悬浮物对近江牡蛎的毒害效应     

叶健欣  杨锋  李兰涛  叶宁  林尤通 《广东海洋大学学报》2010,30(6)

模拟湛江港涉海工程施工产生的悬浮物,探讨底泥悬浮物对工程附近海区近江牡蛎养殖的影响,研究不同浓度悬浮物对大、小规格近江牡蛎(Crassostrea rivularis)的毒害效应。结果表明,悬浮物对大规格近江牡蛎(8.12±1.76 cm)的毒害影响不明显;对小规格近江牡蛎(2.33±0.78 cm),悬浮物浓度≤270 mg/L时死亡率低于30%,悬浮物浓度≥810 mg/L时死亡明显增加,死亡率达60%。通过概率单位法计算,小规格近江牡蛎的96 h半致死浓度为627.17 mg/L。  相似文献   

Variations in retention efficiency of bivalves to different concentrations and organic content of suspended particles     

张继红  方建光  梁兴明 《中国海洋湖沼学报》2010,(1)

Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations.By comparing the RE of C.farreri with that of C.gigas and M.edulis,we gained further knowledge on the feeding physiological characteristics of C.farreri and ascertained the possible cause of high summer mortalities of this species.The experimental feeding conditions in...  相似文献