2010年5月与2013年6月黄、渤海大型底栖动物群落组成和结构的比较研究

基于2010年5月和2013年6月采集的黄、渤海海域的大型底栖动物数据,对该海域大型底栖动物的种类组成和群落结构等进行了研究,对该海域大型底栖动物群落结构的时间和空间差异进行了分析,并利用AMBI和m-AMBI生物指数对各站位的生态质量状况进行了评估。研究结果表明:在2010年5月和2013年6月所采站位的大型底栖动物共有131种,其中软体动物和甲壳动物占据了较大比例的物种数量,分别为51种和42种;其次为鱼类、多毛类和棘皮动物。该海域的优势物种为日本鼓虾 Alpheus japonicus、日本褐虾 Crangon hakodatei、司氏盖蛇尾Stegophiura sladeni和奇异指纹蛤Acila mirabilis,其中司氏盖蛇尾具有最大的丰度和优势度。生物指数(AMBI和m-AMBI)的结果显示黄、渤海区域底栖生态环境仍相对稳定,但与历史资料比较得知,该海域大型底栖动物生存环境整体趋于恶化。     

海底边界层溶解氧通量原位观测技术方法研究

海底边界层是溶质和悬浮颗粒物在海床与水体间交换的重要场所,也是沉积物质的主要成岩作用区,对海洋、湖泊有着重要的生物、化学、地质学意义。底栖溶解氧消耗速率是评估早期碳矿化作用的重要指示剂,也是研究元素循环周转的重要指标。溶解氧通量原位监测技术是获取底栖溶解氧消耗速率、了解化学物质输运机制,进而研究底栖生态系统、环境污染影响、生物地球化学进程的重要手段。针对传统溶解氧观测方法在效率和准确度上的局限性,介绍了目前底边界层原位氧通量测量技术的发展现状,对包括底栖培养室、微电极剖面、涡动相关技术和平面光极系统在内的观测特点进行了对比分析,讨论了各自的不足与局限,提出了今后需要关注的改进方向。     

Parameterization of Wave Breaking Probability and Whitecap Coverage

1 .Introduction Wave breaking and associated whitecapping have long beeninteresting due totheir close relationto many fields of ocean study,including air-sea interaction,remote sensing,ocean engineering,aswell as wave dynamics .The breaking probabilityBan…     

基于破碎临界区的新型拍岸浪统计计算模型研究

When waves propagate from deep water to shallow water, wave heights and steepness increase and then waves roll back and break. This phenomenon is called surf. Currently, the present statistical calcula...     

A Bingham-plastic model for fluid mud transport under waves and currents

Simplified equations of fluid mud motion, which is described as Bingham-Plastic model under waves and currents, are presented by order analysis. The simplified equations are non-linear ordinary differential equations which are solved by hybrid numerical-analytical technique. As the computational cost is very low, the effects of wave current parameters and fluid mud properties on the transportation velocity of the fluid mud are studied systematically. It is found that the fluid mud can move toward one direction even if the shear stress acting on the fluid mud bed is much smaller than the fluid mud yield stress under the condition of wave and current coexistence. Experiments of the fluid mud motion under current with fluctuation water surface are carried out. The fluid mud transportation velocity predicted by the presented mathematical model can roughly match that measured in experiments.     

Numerical simulation and experimental research on hydrodynamic performance of propeller with varying shaft depths

In order to study hydrodynamic performance of a propeller in the free surface, the numerical simulation and open-water experiments are carried out with varying shaft depths of propeller. The influences of shaft depths of a propeller on thrust and torque coefficient in calm water are mainly studied. Meanwhile, this paper also studies the propeller air-ingestion under special working conditions by experiment and theoretical calculation method, and compares the calculation results and experimental results. The results prove that the theoretical calculation model used in this paper can imitate the propeller air-ingestion successfully. The successful phenomenon simulation provides an essential theoretical basis to understand the physical essence of the propeller air-ingestion.     

莱州湾夏季大型底栖动物群落结构特征及其与历史资料的比较

2009年6月在莱州湾9个站位采集的大型底栖动物样品的研究结果,并与历史资料进行了对比。共鉴定出大型底栖动物96种,总平均丰度为1 902.21 ind./m2,总平均生物量为8.30 g/m2,其中软体动物占据绝对优势。基于丰度进行的CLUSTER聚类分析和MDS标序图将研究海域划分为3个组,与沉积物底质类型显著相关。研究海域底质类型包括粘土质粉砂、砂、砂质粉砂、粉砂质砂4种。通过BIOENV分析,影响其群落结构的主要环境因子有水深、底温、沉积物偏态、中值粒径、有机质、叶绿素含量。多样性指数反映各站位生物多样性差异较大。ABC曲线显示大部分站位群落结构受到中等程度扰动,只有2个站位显示未受扰动。通过与历史数据的对比发现,平均丰度较1980年代和1990年代有所增加,但物种数目明显减少。以上结果表明莱州湾近年来受人类活动影响较大,出现了不同程度的污染,导致大型底栖动物的群落结构发生变化及生物多样性下降。     

铜离子对单环刺螠的毒性及对体壁抗氧化酶活性的影响

本文研究了重金属Cu2+对单环刺螠毒性效应。通过急性毒性试验,确定了Cu2+对单环刺螠24h、48h、72h及96h的半致死浓度,并计算得到其安全浓度为0.0675mg/L,高于渔业水质。通过酶活测定,发现Cu2+对单环刺螠抗氧化酶活性有影响。实验结果表明当暴露于0.25mg/L及0.50mg/L浓度的Cu2+中,24h时,单环刺螠体壁SOD、GPx活性显著提高(P<0.05);之后,随着暴露时间的增长,SOD、GPx、CAT三种酶活性均有所下降,除SOD外,其余两种酶活性均低于对照组,其中0.50mg/L组96h时CAT的活性显著低于对照组(P<0.05),说明Cu2+抑制了GPx及CAT的活性,并导致了虫体的死亡。     

基于几何非线性的Pall型摩擦阻尼器滞回特性分析与试验验证

本文从Palll摩擦阻尼器四连杆机构的几伺非线性变形特征出发,分析一种改进的Pall摩擦阻尼器--T形芯板摩擦阻尼器的滞回特性以及支撑的受力特点.本文与不考虑几何非线性的简化计算方法得到完全不同的结论:支撑的拉力在阻尼器起滑后并不保持为一常数,而是呈显著增加趋势,支撑最大拉力可达起滑时的2～3倍.试验结果也充分验证了这一结论.这一结论意味着按传统简化计算方法设计的Pall阻尼结构可能存在较大安全隐患.