乐清湾泥蚶血细胞周期和DNA含量   总被引：9，自引：1，他引：9  

吴洪喜  柴雪良  吴建波  沈志坚 《海洋科学》2002,26(3):47-49

用流式细胞仪测定乐清湾泥蚶血细胞DNA含量，得出组方图中只有一个峰（G0/G1），表明了乐清湾泥蚶血液不存在合成期（S）、合成后期（G2）和分裂期（M）细胞，血细胞已失去分裂功能，不存在周期现象，以小鸡血细胞做标准对照物（DNA含量以2.3pg/N)，测得乐清湾泥蚶血细胞DNA含量为3.08pg/N。  相似文献   

莱州湾围隔浮游生态系统氮、磷营养盐迁移-转化模型研究     

李克强  王修林  韩秀荣  石晓勇  祝陈坚  李瑞香 《中国海洋大学学报(自然科学版)》2007,37(6):987-994

通过对目前生态动力学模型的总结和综合，以生态系统中氮、磷营养盐循环为主线，建立了适用于海洋围隔浮游生态系统的多变量的营养盐迁移-转化动力学模型。该模型包括浮游植物、浮游动物、溶解无机态营养盐、溶解有机态营养盐和生物碎屑5个模块，涉及溶解无机氮、磷酸盐、溶解有机氮、溶解有机磷、浮游植物、浮游动物和生物碎屑7个状态变量。利用2002年8月末莱州湾围隔生态实验数据进行了模型的验证工作，成功地模拟了富加营养盐条件下围隔浮游生态系统中氮、磷营养盐生物化学迁移-转化过程，并通过灵敏度分析探讨了模型主要状态变量对参数改变的灵敏程度。  相似文献   

胶州湾近岸海域水质状况调查与评价     

孙优善  孙鹤鲲  王学昌  魏志强 《海洋湖沼通报》2007,(4):93-97

根据2005年5月、8月和10月对胶州湾近岸海域的水质调查结果,应用单因子污染指数和富营养化指数进行了该海域的水质评价和分析.结果表明:PO43--P在局部海域有超标现象,DIN则超标严重;E值在0.24~64.92范围,该海域水体呈富营养化。与往年相比,湾内部分水域COD、DIN及PO43--P含量有所提高,应根据海域纳污能力,实施陆源污染物排海总量控制。  相似文献   

大亚湾海域沉积物中的硝化与反硝化作用   总被引：3，自引：0，他引：3       下载免费PDF全文

徐继荣  王友绍  殷建平  孙翠慈  张凤琴  王清吉  何磊  董俊德 《海洋与湖沼》2007,38(3):206-211

2004年1、4、8、10月在大亚湾海域的4个站点采用自行设计和制作的无扰动沉积物采样器采集沉积物样品,通过使用AIT技术(乙炔同时抑制硝化与反硝化作用),进行实验室同步恒温受控模拟培养实验,并同时测定沉积物上覆水的温度、盐度、DO和pH值,沉积物的Eh值和有机质含量,间隙水的NO3-、NO2-和NH4 浓度,研究沉积物中的硝化与反硝化速率及其影响因素。结果显示大亚湾沉积物的硝化速率范围为[(0.00—4.68)±0.87]μmol/(m2·h);反硝化速率范围[(0.00—2.88)±0.41]μmol/(m2·h);硝化与反硝化作用之间存在耦合,比例范围为0%—100%。沉积物的硝化、反硝化速率和耦合比例与上覆水的温度、DO含量,及沉积物中的有机质含量和Eh值密切相关,人类活动对沉积物的硝化与反硝化作用有明显的影响。  相似文献   

Diachronous Palaeoproterozoic deformation and metamorphism in the Committee Bay belt,Rae Province,Nunavut: insights from 40Ar–39Ar cooling ages and thermal modelling     

R. G. BERMAN  H. A. SANDEMAN  A. CAMACHO 《Journal of Metamorphic Geology》2010,28(5):439-457

Regional‐scale ⁴⁰Ar–³⁹Ar data presented in this paper reveal significant across‐strike and along‐strike age differences in the Committee Bay belt (CBb), Rae Province, Nunavut, Canada, that complement variations in observed monazite ages. ⁴⁰Ar–³⁹Ar hornblende ages are c. 1795, 1775, and 1750 Ma in the western, eastern and central parts of the Prince Albert Group (PAG) domain respectively. The migmatite domain and Walker Lake intrusive complex are characterized by c. 1750–1730 ⁴⁰Ar–³⁹Ar hornblende ages without significant along‐strike variation. The ⁴⁰Ar–³⁹Ar data provide important constraints on the cooling history and on thermal modelling that elucidates the controls on diachroneity and metamorphic patterns within the belt. In the western CBb, prograde monazite growth occurred 26 ± 10 Myr earlier in the migmatite domain (1864 ± 9 Ma; peak P–T = 5 kbar?700 °C) than in the PAG domain (1838 ± 5 Ma; peak P–T = 5 kbar?580 °C). Calculations indicate that this earlier monazite growth results from tectonic thickening of higher heat productivity Archean lithologies in the migmatite domain, which undergoes more rapid prograde heating than the less radiogenetic and lower grade rocks of the PAG domain. Granite generation via biotite dehydration melting at 800 °C and 20 km depth is predicted to occur c. 1835 Ma, in agreement with geochronological constraints. The tectonic burial of crustal domains with contrasting radiogenic properties also explains the general congruence of lower to upper amphibolite facies metamorphic zones generated during the two main orogenic cycles (i.e. M₂–D₁ and M₃–D₂). The modelled timing of prograde monazite growth in the migmatite domain suggests that D₂ tectonic thickening began at 1872 ± 9 Ma, some 8 ± 3 Myr before monzazite growth, coeval with the inferred time of collision of the Meta Incognita terrane with the southern Rae Province. Along‐strike diachroneity, reflected in 25 Myr younger monazite and ⁴⁰Ar–³⁹Ar hornblende ages in the eastern relative to the western PAG domain, cannot be accounted for by heat productivity contrasts along the belt. Instead the younger deformation and metamorphism in the eastern CBb was driven by its proximity to the eastern promontory of the Superior Province which collided with the Rae Province at c. 1820 Ma. The ⁴⁰Ar–³⁹Ar data presented here support the interpretation that the youngest monazite in the CBb crystallized at c. 1790 Ma in the central CBb when this part of the belt was downfolded into a gentle synformal structure while the western part of the belt cooled through ⁴⁰Ar–³⁹Ar hornblende closure. The results of this study illustrate the important influence of contrasting rock properties on the thermal evolution of orogenic belts and on the temporal record of this evolution.  相似文献   

Effects of subsurface soil characteristics on wetland–groundwater interaction in the coastal plain of the Chesapeake Bay watershed     

Sanghcul Lee  Gregory W. McCarty  Glenn E. Moglen  Megan W. Lang  Ali M. Sadeghi  Timothy R. Green  In‐Young Yeo  Martin C. Rabenhorst 《水文研究》2019,33(2):305-315

Ecosystem services provided by depressional wetlands on the coastal plain of the Chesapeake Bay watershed (CBW) have been widely recognized and studied. However, wetland–groundwater interactions remain largely unknown in the CBW. The objective of this study was to examine the vertical interactions of depressional wetlands and groundwater with respect to different subsurface soil characteristics. This study examined two depressional wetlands with a low‐permeability and high‐permeability soil layer on the coastal plain of the CBW. The surface water level (SWL) and groundwater level (GWL) were monitored over 1 year from a well and piezometer at each site, respectively, and those data were used to examine the impacts of subsurface soil characteristics on wetland–groundwater interactions. A large difference between the SWL and GWL was observed at the wetland with a low‐permeability soil layer, although there was strong similarity between the SWL and GWL at the wetland with a high‐permeability soil layer. Our observations also identified a strong vertical hydraulic gradient between the SWL and GWL at the wetland with a high‐permeability soil layer relative to one with a low‐permeability soil layer. The hydroperiod (i.e., the total time of surface water inundation or saturation) of the wetland with a low‐permeability soil layer appeared to rely on groundwater less than the wetland with a high‐permeability soil layer. The findings showed that vertical wetland–groundwater interactions varied with subsurface soil characteristics on the coastal plain of the CBW. Therefore, subsurface soil characteristics should be carefully considered to anticipate the hydrologic behavior of wetlands in this region.  相似文献   

Characterization of tidally influenced seasonal nutrient flux to the Bay of Bengal and its implications on the coastal ecosystem          下载免费PDF全文

Palash Debnath  Abhijit Mukherjee  Kousik Das 《水文研究》2018,32(9):1282-1300

Submarine groundwater discharge (SGD) introduces solute and nutrients to the global oceans, resulting in considerable nutrient cycling and dynamics in the coastal areas. We have conducted high‐resolution, spatio‐temporal, lunar tidal cycle patterns and variability of discharged solute/nutrient assessment to get an overview of seasonal nutrient flux to the Bay of Bengal in eastern parts of the Indian subcontinent. Whereas the premonsoon season SGD was found to be dominant in the marine influence (M‐SGD), the postmonsoon season was found to be predominated by the terrestrial component of SGD (T‐SGD), extending from coast to near offshore. The solute fluxes and redox transformation were found to be extensively influenced by tidal and diurnal cycles, overlapping on seasonal patterns. We have assessed the possible role of SGD‐associated solute/nutrient fluxes and their discharge mechanisms, and their associated temporal distributions have severe implications on the biological productivity of the Bay of Bengal. The estimated annual solute fluxes, using the average end‐member concentration of the SGD‐associated nutrients, were found to be 240 and 224 mM·m^?2·day^?1 for NO₃^? and Fe_tot, respectively. Together with huge freshwater flux from the Himalayan and Peninsular Indian rivers, the SGD has considerable influence on the bay water circulation, stratification, and solute cycling. Thus, the observation from this study implies that SGD‐associated nutrient flux to the Bay of Bengal may function as a nutrient sink, which might influence the long‐term solute/nutrient flux along the eastern coast of India.  相似文献   

Florida Bay: Modern analogue for Lofer cyclothems?     

Paul Enos  Elias Samankassou 《Sedimentology》2022,69(1):254-281

Lofer cyclothems of the Alpine Upper Triassic have many features in common with Holocene sediments of Florida Bay. The modal ‘complete’ Lofer cycle is essentially symmetrical, having a deepening and shoaling phase, as does the cycle-in-progress in Florida Bay. Lateral discontinuity and thickness variations within members of the Lofer cyclothems indicate syn-depositional relief, possibly in the form of mud banks, the signature feature of Florida Bay sedimentation. Spatial and temporal dimensions, although poorly constrained, appear comparable. Analogous depositional textures, biota and sedimentary structures, while not unique to either environment, strengthen the inferences that can be made about the Triassic depositional environment and regarding future evolution of the modern environment. The striking similarities between the Holocene icehouse sediments and the Late Triassic greenhouse deposits suggest that sedimentation patterns at the scale of individual cycles or parasequences may be largely independent of the global climate regime.  相似文献   

渤海湾北部滦河三角洲晚更新世以来沉积环境划分及碳埋藏速率的评价          下载免费PDF全文

陈皓  何磊  叶思源  韩宗珠  袁红明  Edward A. Laws 《中国地质》2022,49(5):1555-1570

【研究目的】 开展渤海湾北部滦河三角洲晚更新世以来不同沉积环境的划分,计算分析碳埋藏速率的大小和控制因素,进一步评价区域碳储能力。【研究方法】 本文对BXZK03孔岩芯开展晚更新世以来的古沉积环境恢复,并取样分析了包括粒度、年代(AMS14C 和OSL)、含水量、有机碳、总碳和其他营养成分等在内的测试指标。【研究结果】 该孔晚更新世以来地层自下而上划分为泛滥平原、海滩沙脊、浅海、障壁沙坝(三角洲前缘)和潟湖的沉积环境单元,各沉积单元平均有机碳埋藏速率大小依次为：障壁沙坝51.47 g/(m²·a)>海滩沙脊32.59 g/(m²·a)>浅海7.82 g/(m²·a)>潟湖4.66 g/(m²·a)。总碳、有机碳与各营养元素具有显著(P< 0.01)线性相关关系,方差分析显示沉积速率和碳浓度分别是滦河三角洲碳埋藏速率的主要控制因素。【结论】 滦河三角洲沉积物中有机碳浓度相对较低,但是在全新世三角洲沉积速率较高,使得有机碳埋藏速率也相对较高,因此具有一定的碳储能力。  相似文献   

渤海湾中部中、新生代构造演化与潜山的形成     

周琦杰  刘永江  王德英  关庆彬  王光增  王宇  李遵亭  李三忠 《地学前缘》2022,29(5):147-160

渤海湾盆地是华北克拉通东部的晚中—新生代断陷盆地,其东部为西太平洋活动大陆边缘,经历了多期不同性质的构造运动叠加。目前对渤海湾地区中—新生代的构造期次划分及各期次构造运动的应力状态的认识仍存在较大的争议。潜山是盆地沉积之前就已形成的基岩古地貌山,后被新地层覆盖而成,潜山内幕所保留的先存断裂及潜山与上覆盖层之间的接触关系为研究盆地构造运动提供了依据。本文以渤中19-6潜山构造为例,基于三维地震资料的精细解释、结合相干剖面及钻井资料进行系统构造解析,建立渤中19-6潜山构造演化新模型,并探讨了华北克拉通东缘的区域构造演化。研究结果表明:(1)渤中19-6潜山构造西部以一系列S-N向雁列式正断层为界,断层东侧为隆起的渤中19-6潜山构造,西侧为低洼的沙南凹陷。古潜山最早形成于晚三叠世,早白垩世形成如今以S-N向正断层为界的东隆西降的潜山构造格局;(2)渤中19-6潜山构造西部边界S-N向断裂以及上覆地层中存在的E-W向断裂为两侧大型走滑带间雁列式断裂构造,是该潜山构造储层形成的重要控制因素;(3)该潜山受华北板块与扬子板块剪刀式闭合碰撞和古太平洋板块NNW向俯冲的多重影响,中生代以来,共经历了印支早期挤压隆起、印支晚期伸展改造、燕山早期左行压扭改造、燕山中期左行伸展改造、燕山晚期左行压扭改造、喜山期右行伸展埋藏6个阶段的发育演化。  相似文献