漂白粉消毒后对虾养殖源水细菌群落的响应特征研究          下载免费PDF全文

王庚申  颜懿  李彤  董鹏生  谢建军  许文军  张德民  张化俊 《海洋与湖沼》2024,55(1):202-212

漂白粉消毒是凡纳滨对虾养殖源水常见的管控措施, 可有效控制病原菌传播; 然而,消毒会强烈扰动水体微生物群落,但源水细菌群落对漂白粉消毒的响应特征尚未阐明。在室内条件下, 设置高浓度(60 mg/L)和低浓度(20 mg/L)漂白粉消毒源水, 通过高通量测序及荧光定量PCR技术探究消毒后源水细菌群落、病原菌及抗生素抗性基因(ARGs)的动态响应规律。结果显示, 消毒后, 拟杆菌门(Bacteroidota)丰度上升, 高浓度组变形菌门(Proteobacteria)的丰度显著降低; 至第3天, 两组源水的细菌群落组成趋于一致。此外, 漂白粉消毒显著改变了源水的细菌群落结构及共现网络的复杂性。在控制水体病原菌方面, 消毒后病原菌的总丰度降低, 但种类增加, 高浓度漂白粉消毒对病原菌的抑制作用更加显著。漂白粉消毒对ARGs的去除具有选择性, 仅对sul1、floR、cfr、tetQ有一定的去除作用, 且高、低浓度对ARGs的去除无差异。综上, 60 mg/L可以作为漂白粉消毒养殖源水的更好浓度选择。研究结果从微生物生态视角评价了不同浓度漂白粉的消毒作用, 可为对虾养殖生产中的源水管控提供理论支撑。  相似文献   

在细胞水平上对高温珊瑚白化的初步研究     

李淑  余克服  陈天然  施祺 《热带海洋学报》2011,30(2)

全球变暖背景下的异常高温能够导致珊瑚及其虫黄藻组成的共生体系崩溃,虫黄藻大量损失,出现珊瑚白化,并可能进一步导致珊瑚礁生态系统退化.文章通过对6种造礁石珊瑚的急性高温胁迫实验,分析不同种属的石珊瑚虫黄藻共生体系对高温的耐受性差异,为全球变暖背景下珊瑚群落演替趋势提供理论依据.结果显示:1)在急性高温胁迫下,石珊瑚耐受的差异性与其形态有关,枝状珊瑚耐受性最低,在高温胁迫下最先白化、死亡,而叶片状和块状珊瑚对高温的耐受性较强,这与野外珊瑚礁白化的现场观测结果一致.2)在高温胁迫下,不同种属珊瑚共生虫黄藻损失的方式不同:珊瑚持续排出虫黄藻,如鹿角杯形珊瑚 Pocillopora damicornis;珊瑚先排出一定的共生藻,之后珊瑚组织携带大量虫黄藻与珊瑚骨骼分离,如风信子鹿角珊瑚 Acropora hyacinthus 和松枝鹿角珊瑚 Acropora brueggemanni;先排出部分虫黄藻后,虫黄藻以有丝分裂增殖的方式迅速补充其数量,如十字牡丹珊瑚 Pavona decussata;虫黄藻细胞直接坏死而损失虫黄藻,如澄黄滨珊瑚 Porites lutea.研究强调,预测珊瑚对全球变化的响应问题时,应当同时考虑珊瑚宿主和共生藻的作用.  相似文献   

南沙群岛现代滨珊瑚骨骼Sr/Ca、δ18O和δ13C对极端高温事件响应     

徐潇峰  余克服  陈天然  陶士臣  严宏强  陈特固 《热带地理》2022,42(11):1771-1782

以南沙群岛永暑礁的现代滨珊瑚YSL24（生长时间为1985—1999年）与YSL2A（生长时间为1971—1999年）为材料,通过对其骨骼开展高分辨率的Sr/Ca、δ¹⁸O和δ¹³C分析,探讨其对极端高温事件的响应特征。有记录表明,1971—1999年,南海南部在1973、1983和1998年发生了极端高温事件,滨珊瑚骨骼Sr/Ca序列清楚地记录了这3次高温事件,其相应条带Sr/Ca周期数值显著低于序列其他年份。而δ¹⁸O对高温事件的响应不太明显,其原因可能与δ¹⁸O序列同时受温度和盐度变化的影响有关。δ¹³C在这3个高温年份均在夏季发生了异常负偏,应该是由高温胁迫下共生藻光合作用强度下降所致。因此,珊瑚骨骼的Sr/Ca和δ¹³C对南沙群岛高温胁迫具有明显的响应,可作为记录过去白化事件的可靠指标。  相似文献   

Relationship between historical sea-surface temperature variability and climate change-induced coral mortality in the western Indian Ocean     

M. Ateweberhan  Tim R. McClanahan 《Marine pollution bulletin》2010,60(7):964-970

Many of the world’s coral reefs suffered high coral mortality during the 1998 ENSO, with the highest mortality in the western Indian Ocean (WIO). A meta-analysis of field data on change in coral cover across the 1998 ENSO event was conducted for 36 major reef areas in the WIO, and relationship of the change with the historical sea-surface temperature (SST) variability investigated. WIO reefs were categorized into three major SST groups of differing coral cover change. Cover change was negatively associated with standard deviation (SD) SST until about SD 2.3, with increasing flatness of the SST frequency distributions. It increased with further increase in SD as the SST distributions became strongly bimodal in the Arabian/Persian Gulf area. The study indicates that environmental resistance/tolerance to extreme anomalous events could be predicted and management priorities directed accordingly for a warmer and more variable future climate.  相似文献   

近45年涠洲岛5次珊瑚热白化的海洋站SST指标变化趋势分析   总被引：2，自引：1，他引：1  

汤超莲  李鸣  郑兆勇  周雄  时小军 《热带地理》2010,30(6)

根据涠洲岛珊瑚礁普查(Reef Check)历史资料和涠洲岛海洋站实测海表温度(SST)历史资料,采用对比分析与相关分析方法,分析1966―2010年该岛珊瑚热白化的SST指标变化特征,结果显示:1)涠洲岛珊瑚热白化的最热周平均SST值为31.6℃或最热日平均SST值为32℃;2)1966―2010年涠洲岛的逐年最热月月均SST、最热日日均SST、年极端最高SST及最热周平均SST呈准同步变化,彼此间的相关系数为0.71~0.89,4种珊瑚热白化SST指标没有显著上升趋势;3)最热月月均SST和最热周平均SST的变化趋势与全球变暖在统计上存在显著相关关系。  相似文献   

Coral reef bleaching at Agatti Island of Lakshadweep atolls, India     

Ramar Vinoth  Mohan Gopi  Thipramalai Thankappanpillai Ajith Kumar  Thirunavukarassu Thangaradjou  Thangavel Balasubramanian 《中国海洋大学学报(英文版)》2012,11(1):105-110

A survey on coral bleaching was carried out at Agatti Island of Lakshadweep from May to June 2010.Elevated sea surface temperatures(SSTs)of the region exceeded the seasonal average and delayed the onset of monsoon,which triggered widespread bleaching of corals.The Agatti reefs showed an average of 73%bleached corals with apparent bleaching-related mortality of sea anemones(87%)and giant clams(83%).The SST increased up to 34℃with an average maximum SST of 32.5℃ during the study period between May and June 2010.Coral reefs on the southern side of the island are fully or partially exposed to sun light during low tide in contrast to the other side.This suggests that the mortality is more likely due to the low tide exposure than exclusively due to the elevated SST.Observations indicated a clear increase in coral bleaching during April 2010,at levels higher than that in normal summer.  相似文献   

天山乌鲁木齐河源末次冰期冰川沉积光释光测年   总被引：6，自引：5，他引：1  

曾兰华  欧先交  陈嵘  赖忠平 《冰川冻土》2019,41(4):761-769

乌鲁木齐河源地区是中国冰川遗迹保存最丰富、地貌最典型的区域之一,是根据冰川遗迹重建第四纪冰川历史的理想地区。大量的研究工作以及技术测年结果也使其成为试验冰川沉积光释光（optically stimulated luminescence,OSL）测年可行性的理想地点。共采集了6个冰碛及上覆黄土样品用于光释光测年。提取38~63 μm的石英颗粒,运用SAR-SGC法测试等效剂量。各种检验表明测试程序是适用的。通过地貌地层关系、重复样品、已有年代的对比等方法,检验该地冰川沉积OSL测年的可行性。结果表明,OSL年代结果与地貌地层新老关系非常吻合,与已有的其他测年技术的年代结果也具可比性,表明这些样品的OSL信号在沉积之前晒退较好,OSL年代是可信的。冰川观测站侧碛垄的OSL年代为14.8±1.2 ka;9号冰川支谷口附近冰碛的OSL年代为13.5±1.1 ka和17.2±1.3 ka;上望峰冰碛的OSL年代为20.1±1.6 ka。综合OSL年代结果与此前其他测年结果,这几套冰碛垄形成于深海氧同位素MIS 2阶段应该是比较统一的认识。上望峰冰碛上覆黄土的OSL年代（10.5±0.8 ka）也印证了该结论。OSL年代指示上望峰冰碛对应于末次冰期最盛期,冰川观测站和9号冰川支谷谷口冰碛对应于晚冰期。下望峰冰碛的OSL年代为36.3±2.8 ka,对应于MIS 3阶段。下望峰冰碛的形成时代,仍有待更多沉积学以及测年工作进一步确定。  相似文献   

瓷石酸浸除铁漂白的试验研究     

孙彦彬  王安平  马丽艳 《吉林大学学报(地球科学版)》2003,33(3):390-392

分别采用盐酸和草酸为浸出酸，对吉林省长白地区的瓷石进行了酸浸除铁漂白试验。对比了盐酸和草酸的酸浸除铁漂白的效果，结果发现用草酸比用盐酸除铁漂白效果好。草酸的浓度、矿浆浓度、浸出时间、浸出温度等因素对除铁漂白效果有一定影响。矿浆质量分数以15％为宜，随着草酸浓度的增加、浸出时间的延长、浸出温度的升高，瓷石的除铁漂白效果明显提高。最佳的除铁漂白方案为：草酸水溶液质量分数为l.00％，矿浆质量分数为15％，浸出反应时间为150min，浸出反应温度为60℃。经除铁漂白处理，使瓷石中铁的质量分数由原来的O．64％降为O．20％，瓷石白度由原来的68．2％提高到了83．7％，最高可达84％。  相似文献   

Chronostratigraphy of a sediment record from the Hajar mountain range in north Oman: Implications for optical dating of insufficiently bleached sediments     

M. Fuchs  C. Woda  A. Bürkert 《Quaternary Geochronology》2007,2(1-4):202-207

In this study we report on optical stimulated luminescence (OSL) ages of quartz extracted from a sedimentary record in the N-Oman mountain range. Equivalent dose (D_E) distributions derived from single aliquot measurements (SAR) of small aliquots (ca. 200 grains) were investigated to test whether the skewness and broadness of the dose distribution can be used as criteria for the identification of insufficient bleaching. Furthermore, the methods proposed by Lepper and McKeever [2002 An objective methodology for dose distribution analysis. Radiation Protection Dosimetry 101 (1–4), 349-352]. Singhvi [Juyal, N., Chamyal, L.S., Bhandari, S., Bushan, R., Singhvi, A.K., in press. Continental record of the southwest monsoon during the last 130 ka: evidence from the southern margin of the Thar Desert, India. Quaternary Science Review] and Fuchs and Lang [2001 Fuchs, M., Lang, A., 2001. OSL dating of coarse-grain fluvial quartz using single-aliquot protocols on sediments from NE Peloponnese, Greece. Quaternary Science Review 20, 783–787.] to derive D_E's from insufficiently bleached sediments were compared. At first, the investigations were carried out on artificially bleached, irradiated and mixed quartz material from the Oman study area to simulate insufficiently bleached sediments. Then, the various statistical methods for identifying insufficient bleaching and D_E derivation were applied to the natural samples from the study area, where 18 samples were measured. For the identification of insufficient bleaching the preferential parameter is the broadness of a distribution. For D_E calculation, both the Singhvi method and the Fuchs and Lang method produce similar results, which are consistent with the stratigraphic order. A drawback of both methods is their sensitivity to low outliers. The Lepper and McKeever method was not applied to the natural samples, due to limitations in its application to a small number of aliquots and due to the ambiguous identification of the rising limb of the dose distributions.  相似文献   

Rapid in situ assessment of luminescence-bleaching depths for deriving burial and exposure chronologies of rock surfaces     

《Quaternary Geochronology》2022

Recent developments in luminescence dating offer new ways to date exposure and burial durations of rocks. The new rock surface dating methods ideally require high-resolution data, faster sample preparation and measurement times, and field screening methods to select samples with appropriate luminescence characteristics and bleaching histories. Presented here is a demonstration of an EMCCD (electron multiplying charge coupled device) based system capable of imaging high-resolution infrared stimulated luminescence (IRSL) and infrared-photoluminescence (IRPL) from rock samples. The IRPL can be detected at both 880 nm and 955 nm. Using this instrument, the entire luminescence-depth profile can be reconstructed by imaging a single surface cut perpendicular to the exposed rock face. We demonstrate the possibility of reconstructing luminescence-depth profiles suitable for rock surface dating from large (cm-scale) rock samples, without using a regeneration dose for normalisation of the natural luminescence signals. Based on the different bleaching characteristics of the IRSL and IRPL emissions at 880 nm and 955 nm, we show that it is possible to gain reliable estimates of bleaching depths from measurement of as few as two images of the IRPL signal (one for each emission), or from measurement of the IRSL decay curve. We thus by-pass laborious sample preparations and the need for a gamma source to estimate the bleaching depth, thereby extending the 2D luminescence-depth profile imaging technique to other laboratories that lack access to ionising radiation facilities. This study also makes a significant progression towards development of a field instrument for in situ relative exposure dating, and sample screening for rock surface burial dating.  相似文献