浅谈区域划分与环境调查对沉船考古工作的重要性

沉船考古是一项极为复杂的系统性工作,水下环境复杂、文物打捞操作困难、海洋人文资料缺失等因素制约我国水下文化遗产保护工作。沉船考古工作不仅要对沉船本身及所载器物进行考古发掘,还要结合陆域考古学、海洋学划分重点沉船区域进行系统性发掘研究,对沉船本身及所载器物所处的海底环境和受腐蚀状况进行详细调查和研究,为文物修复和保护工作提供支撑。     

雨滴对水-气界面溶解氧与pH扩散影响的平面光极观测方法

水-气界面是一个重要的物质交换过程界面,对生态系统及生物地球化学循环过程有着重要影响。自然界的降雨可以改变水体表面平衡状态,提高气体在界面的通量交换速率,使得水体界面溶解氧和pH的水平、垂直方向浓度分布发生变化。本文利用平面传感膜具有高时空分辨率、可提供两维浓度分布信息的特点,开展了雨滴对水-气微界面层中的氧气扩散和pH值分布变化模拟实验,采用双参数平面光极同步测量获取低溶解气体在水-气界面的两维分布浓度变化。实验结果证明在受风速、温度影响较小区域,降雨过程对调节表层水体的溶解氧含量和pH值变化具有重要作用,雨滴可以打破水-气界面的微表层平衡机制,促进大气中氧气在表层水体的溶解,使得水面垂直方向23 mm内的溶解氧平均升高2.3 mg/L;降雨对水面12 mm之内表层水体pH值产生的影响较为明显,pH值平均降低了0.2~0.4个单位,表明降雨雨滴促进大气在水-气界面的迁移进程,溶解的CO₂使得表层水体向酸性方向转化。本文提出的基于平面光极两维观测方法为评估低风速、高降雨或低降雨区域的海岸带溶解氧和pH值的变化提供高空间分辨率的水-气界面实时观测新的技术支撑。     

Modeling the biodegradation of phenolic compounds by microalgae

Phenols represent a group of organic pollutants frequently found in many near-shore marine systems. The microbial degradation of phenols, mainly by bacteria and fungi, has been extensively studied both experimentally and theoretically, but only relatively recently the capabilities of some algae for phenols biodegradation gained interest. The biodegradation of phenols by microalgae occurs only under aerobic conditions. In this paper, a dynamic energy budget model is proposed for describing aerobic biodegradation of phenolic compounds by microalgae and qualitatively validated against experimental data. A microalgal cell has the ability to produce biomass via the autotrophic assimilation (uptake of light and dissolved inorganic carbon), the heterotrophic assimilation (uptake of dissolved organic carbon) and, to a lesser extend, via the biodegradation of phenols. The rules of synthesizing units are used for the uptake and interactions of substrates and for the merging of assimilates. The model is capable of making predictions under oxygen and carbon (inorganic and organic) limiting conditions. Model predictions cover a wide range of experimental evidence, but also give a possible explanation for the inhibition of bioremoval of phenols in the presence of glucose. The dissolved oxygen profiles numerically observed show low oxygen concentration during the intermediate phase of the biodegradation process and a rapid increase after the consumption of the phenolic compound, indicating that lack of oxygen could be a limiting factor for the biodegradation of phenols. The presence of glucose increases the specific growth rate but decreases the specific biodegradation rate of the phenolic compound. Model analysis suggests that this inhibition may be due to the competition for oxygen between glucose and phenol assimilation. In general, the balance between the benefits and costs of the different types of assimilation determines the microalgal growth rates as well as the phenol biodegradation rates. Being based on general assumptions, the model can be applied to the biodegradation of a wide variety of aromatic compounds.     

The boundary between stable and unstable shelf in Iraq as inferred from using ideal gravity to elevation ratio

The line of complete compensation, the ideal value for the ratio of gravity to elevation (?0.11 mGal/m) in Iraq, is obtained using gravity data derived from 477 stations. This line is found to separate the stable shelf from unstable shelf. It is also confirmed with the western limit of the basin as shown on the structural map that is constructed at the base of Al-Fath (L-Fars) formation (M. Miocene). The obtained line coincides with the thinnest crustal line shown on the crustal thickness map of Iraq. It is believed that this line may also define the thinnest sedimentary cover in Iraq. The obtained result can be a useful template for a tectonic view of Iraq.     

环雷州半岛海域表层沉积物与鲬鱼汞污染研究

对2018年1月在广东环雷州半岛近海海域采集的海底表层沉积物、鲬鱼(Platycephalus indicus)进行汞含量的测定,分析比较了鲬鱼不同部位汞含量的差异,并采用单因子污染指数法对沉积物和鲬鱼的汞污染状况进行了风险评价。结果表明,环雷州半岛海域表层沉积物中汞含量范围为0.005×10^-6～0.359×10^-6,平均值为0.081×10^-6,雷州半岛东部海域表层沉积物汞含量高于南部和西部海域。鲬鱼的鳃中汞含量范围为0.032×10^-6～0.034×10^-6,平均值为0.033×10^-6;肌肉中的汞含量范围为0.065×10^-6～0.080×10^-6,平均值为0.073×10^-6;肝脏中的汞含量范围为0.228×10^-6～0.270×10^-6,平均值为0.249×10^-6。鲬鱼样品的汞含量都呈现出肝脏＞肌肉＞鳃。单因子污染指数评价结果显示,雷州半岛海域鲬鱼受到汞的轻微污染,雷州半岛东部海域表层沉积物存在汞污染生态风险,而其南部、西部海域尚未受到汞污染的威胁。     

平面光极的研制及浒苔对沉积物-海水界面溶解氧影响的模拟观测

利用油酸修饰合成了具有良好光化学稳定性,对氧不敏感, 可发射520 nm荧光的量子点(QDs),以八乙基卟啉铂(PtOEP)作为荧光指示剂,聚苯乙烯(PS)为包埋基质,掺杂QDs为参比光染料制备了溶解氧比率法传感膜。针对短时间内大量繁殖的浒苔造成的生态灾害现象,利用制备的平面光极在实验室内对浒苔影响下的海水—沉积物周围的溶解氧的动态变化进行了模拟观测研究,实验结果表明,高CO2浓度下的浒苔藻体的呼吸作用要高于正常CO2水平,而两者在光合作用带来的氧浓度的升高方面并没有显著性差异,均可升高至7 mg/L以上。高温下的浒苔很快进入衰退消亡,不利于光合作用,氧最高值仅达2.3 mg/L,沉降后可在沉积物—海水界面附近形成大范围无氧,局部贫氧区,改变了海底区域的溶解氧分布体系,将会对海底的生态结构和生活环境产生较大影响。     

湛江湾和平水母属2新种(软水母亚纲,锥螅水母目,和平水母科)

采自广东湛江湾海域软水母亚纲(Leptomedusae Claus,1877)、锥螅水母目(Conica Broch,1916)、和平水母科(Eirenidae Haeckel, 1879)、和平水母属(Eirene Eschscholtz,1829) 2新种,即大腺和平水母新种(E. macrogonia Huang, Sun et Liu,sp. nov.)和湛江和平水母新种(E. zhanjiangensis Huang, Zhang et Zao, sp. nov.)。其鉴别特征如下:(1)大腺和平水母,新种;伞扁于半球形,胶质中等厚;胃柄基部塔状,胃柄较长,伸出伞腔口外;垂管长度短于口唇,4个发达口唇边缘呈齿状皱褶;生殖腺发达波状弯曲,着生于辐管下伞部,从胃柄基部延伸到伞缘外;19～24条缘触手,5～8个缘疣,触手基部呈球状,无排泄乳突;每2条触手间或触手和缘疣间有1个平衡囊,每个平衡囊有1～2个平衡石;4条辐管,1条环管。(2)湛江和平水母,新种;伞半球形,胶质厚;胃柄基部呈塔形,末端变窄;垂管较长,约等于口唇长度,口唇边缘有齿状皱褶;生殖腺带状,从胃柄基部延伸至近伞缘;缘触手多,70～125条,触手基球有排泄乳突;平衡囊数目约为触手数的1/2;4条辐管,1条环管。     

博贺湾海域海水和生物重金属污染特征和评价

为减少重金属污染和保护海洋生态环境,文章基于2014年10月博贺湾海域的调查数据,分析海水和生物的重金属污染情况,并采用内梅罗指数和目标危险系数评价海水质量和人类食用海产品而摄入重金属的潜在健康风险。研究结果表明:博贺湾海域海水重金属含量总体较低,大部分符合一类海水水质标准;Pb的空间分布不均匀,高值区主要分布于莲头岭附近站位,很有可能是受港口区和产业园区排污的影响;水质等级为较清洁和清洁,海水重金属污染的整体程度较低;生物重金属含量大部分符合一类海洋生物质量标准,生物质量总体较高,其中软体类的重金属含量整体较高且Pb和Cd含量较高,鱼类的重金属含量整体较低但Hg含量较高,所有生物的Cu和Zn含量均较高;各生物重金属污染的目标危险系数均小于1,人类食用生物样品的海产品而摄入重金属没有潜在健康风险。     

汞异常与地震活动关系及预报效能研究进展

汞主要来源于地球深部地幔岩石和岩浆,具有溶解度小、蒸气压低、穿透能力强等特点.地震前,汞在高温和强压力梯度下穿过不同的介质到达地表,导致汞震前异常.汞的前兆异常特征通常被用作地震前预测的重要指标.本文综合国内应用汞的地震观测案例,得出以下结论:(1)与气态汞相比,水溶性汞具有收集方便、不易受传输介质干扰、前兆异常幅度大等特征,易震前观测;(2)水溶性汞观测异常结束到发震时间间隔较长,而气态汞异常一般持续到地震发生;(3)震前汞的异常幅度通常是本底值的数倍至几十倍,这往往与震中距离、震级大小及地质构造有关;(4)对于5级及以下地震,水溶性汞异常范围通常在200 km以内,5~6级地震映震范围在500 km以内.此外,汞震前观测异常与孕震应力场作用下的地下流体活动有关,汞的同位素分馏技术提供了一种新的手段来解决断裂带汞的来源以及汞与地壳深部流体活动的关系.