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1.
一种池塘陆基实验围隔 总被引：4，自引：4，他引：0
该陆基围隔适用于池塘养殖学与生态学研究。围隔面积为２５ｍ２（５ｍ×５ｍ）,水面以上超高０．３～０．５ｍ,水深１．５～１．８ｍ,容积３７．５～４５ｍ３。以木桩及青竹构成支架;以涂塑高密度聚乙烯编织布为隔水材料（围隔幔）,将其包围并固定在支架上。因围隔内受风力影响较小,为了模拟池塘水的混合状况,围隔中设１台９０Ｗ的微型电动搅水机。４年（１９９４～１９９７）的使用结果表明围隔效果良好,其中的生态系发育与运行正常,放养的养殖生物生长良好。专门的观测证明空白围隔与设置围隔的空白池塘理化条件的数值和变动都基本一致。研究结果证明,此种围隔完全可以替代池塘用于养殖学与生态学方面的实验研究,不失为一种有效、经济而方便的科学研究设施。 相似文献
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海水池塘混合施肥养殖台湾红罗非鱼的鱼产力和负荷力 总被引：2，自引：0，他引：2
于１９９５年７—９月,在烟台市黄海水产集团公司第二养虾场,采用围隔实验法研究了海水池塘混合施肥养殖台湾红罗非鱼的鱼产力、负荷力和最适放养量。实验中每个围隔面积为 ５ｍ×５ｍ,各设 １台 ９０Ｗ的搅水机（４ ８００ｒ／ ｈ）。每日施肥基准为：鸡粪干物质, ２５ｋｇ／ｈａ：氮肥, Ｎ０．１５× １０－６;磷肥,Ｐ０．０１５× １０－６。结果表明,静水海水池塘混合施肥的鱼产力为０．７９ｇ／（ｍ２·ｄ）,池塘对台湾红罗非鱼的负荷力为１７９６．０ｋｇ／ｈａ,鱼（体重７０ｇ／ｉｎｄ）的最适放养量约为８０００ｉｎｄ／ｈａ。 相似文献
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为了考察１９８０ 年国际标准海水状态方程在盐度小于０ ．５ 条件下的适用性,测定了０ ．０３９～２ ．０００ 盐度范围内的稀释大洋水的密度,并与状态方程的计算值作了比较。测定值与计算值之间的平均偏差为±０．６×１０－ ３ｋｇ／ｍ３ ,小于状态方程的标准偏差３．６ ×１０－ ３ｋｇ／ｍ３ 。结果认为１９８０ 年国际标准海水状态方程的低盐范围可以从现在的０．５ 继续扩展到０．０３９ 。 相似文献
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海水池塘施肥混养滤食性鱼贝的初步研究 总被引：1，自引：1，他引：0
实验于１９９５年７月１０日至９月１６日,在烟台市黄海水产集团公司第二养虾场进行。采用围隔生态系实验法,利用４个海水池塘陆基围隔（５ｍ×５ｍ）初步研究了台湾红罗非鱼（Ｏｒｅ－ｏｃｈｒｏｍｉｓｍｏｓｓａｍｂｉｃｕｓ×Ｏ．ｎｉｌｏｔｉｃｕｓ）与菲律宾蛤仔（Ｒｕｄｉｔａｐｅｓｐｈｉｌｉｐｐｉｎａｒｕｍ）施肥混养的效果。结果表明：菲律宾蛤仔的生产力为１．２４ｇ／ｍ２·ｄ,负荷力为３８３０．０ｋｇ／ｈｍ２;罗非鱼的生产力为１．８６ｇ·（ｍ２·ｄ）－１,负荷力为１５８０．８ｋｇ／ｈｍ２。鱼贝对施入氮、磷的利用率分别为１５．０６％和６．８０％,比单养罗非鱼要高;总生产力和总负荷力都明显高于单养罗非鱼。 相似文献
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长江口水航道治理工程,是我国建国以来最大的水上基础设施项目,也是世界上罕见的河口航道治理工程,它采用双导堤、丁坝结合疏浚的工程措施,分期将原依靠疏浚维护的７ｍ航首对１２．５ｍ。全工程各类堤坝总长约１３３ｋｍ,航槽疏浚土方近２．５亿ｍ＾３,计划总工期８年左右,工程总投资约主１５５亿人民币,其中一期工程工期为３年,约３２．５亿元开工以来工程顺利。 相似文献
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虾夷扇贝人工苗种高产技术研究 总被引：1，自引：0，他引：1
在虾夷扇贝苗种生产中，改进了亲贝升温促熟、产卵、孵化、幼虫培育等技术措施。在海上保苗中，选择适宜保苗袋和培养水深，使成活率明显提高，生长速度加快。在４４５ｍ＾３水体中，培育出商品苗（壳高１．５ｃｍ以上）１．５亿粒，取得较好的经济效益。 相似文献
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１材料和方法１．１试验海区环境因子 本试验在乐清湾漩门水域进行。网箱泊置海区为泥沙底质，水深１５ｍ，５～１０月份水温１７～３１℃，比重１．００８～１．０１７，海水透明度３００～５００ｃｍ。试验期间海区曾遭受热带风暴潮袭击。１．２网箱结构和规格试验在规格为３ｍ×３ｍ×４ｍ的板框式浮动网箱内进行。箱体为单层聚乙烯网衣结构，用铁锚和沉石固定。网衣网目大小分别是２０目，０．６ｃｍ和１．０ｃｍ网径。１．３养殖措施１．３．１苗种及放苗数第一茬养殖于５月４日将体长０．８～１．２ｃｍ的中国对虾苗２００００尾直放… 相似文献
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主要根据台湾海峡的实测海流资料，以夏、冬为代表季节，分析了台湾海峡２—３个纬向断面的海流结构，计算出各断面的海水通量。结果表明：夏季，台湾海峡中、北部海域各层的海流一般偏Ｎ向流动，Ｎ向的海水净通量为３．３２×１０６ｍ３·ｓ－１；冬季，高温高盐的黑潮水和南海水由南向北经南部断面进入台湾海峡，其海水通量分别为１．６９×１０６ｍ３·ｓ－１和０．５９×１０６ｍ３·ｓ－１；而东海水由北向南通过北部断面进入台湾海峡，其海水通量为１．０２×１０６ｍ３·ｓ－１，其中，有０．４０×１０６ｍ３·ｓ－１的海水沿着福建和广东近岸流进南海，其余０．６２×１０６ｍ３·ｓ－１的海水在台湾海峡北部混合后随同黑潮水和南海水流入东海。总之，流经台湾海峡的Ｎ向海水净通量为１．７４×１０６ｍ３·ｓ－１。 相似文献
11.
用高效液相色谱法(HPLC)研究了围隔实验过程中水柱颗粒物主要色素的组成及动态变化,并就滤食性鱼类鲢对水体主要色素代谢的影响进行了讨论。结果表明:水柱中的主要色素有叶绿素a、异黄素、岩藻黄素、黄体素、玉米黄素和蓝藻叶黄素等,未放鱼的围隔中实验后期各种色素含量均降低到最低水平,有鱼的围隔中鱼类密度越高则色素含量降低越多。未放鱼的围隔中叶绿素a代谢产物———脱植基叶绿素a、脱镁叶绿素a、脱镁叶绿酸a与叶绿素a的比值均大于其它围隔,有鱼的围隔中鱼类密度大的这几个比值也比较大。 相似文献
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《Deep Sea Research Part II: Topical Studies in Oceanography》1999,46(11-12):2433-2446
Measurements of Lagrangian trajectories acquired with neutrally buoyant floats in an upper ocean mixing layer during a five-day period of nearly cloudless and calm conditions, provide an opportunity for investigating the implications of photo-adaptation of phytoplankton exposed to varying light intensities as they traverse the water column in convective plumes. The predominant convective motions develop over night and persist through the morning until giving way to thermal restratification. Despite the paucity of observed trajectories, their essential characteristics are extracted and used to generate a large number of pseudo-tracks having characteristics similar to those measured at any given depth and time of day. A Monte Carlo simulation is run for a sample set of biological variables to identify predominant features of the production. For each pseudo-trajectory the production is calculated from a photo-adaptive model in order to identify primary features of the instantaneous and accumulated production. The simulation illustrates the way in which photo-inhibition can reduce production near the surface during the morning, developing a subsurface layer of increased production that progressively deepens to approximately 12 m at noon. The surface production is suppressed during the afternoon, but subsequently recovers as light levels drop below the photo-inhibition threshold. 相似文献
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基于2018年8月福建三沙湾湾内外共两个定点站位的船基和座底三脚架观测数据,研究了三沙湾底边界动力过程及悬沙输运特征。结果表明,三沙湾湾内湾外两个站位均表现出涨落潮历时相近但涨落潮流速明显不对称的现象,即湾内涨潮流速大于落潮流速,湾外则相反。湾内水体受淡水输入影响较大,表现出落潮期间显著的温盐层化,而涨潮期间水体混合良好;湾外水体受淡水影响不明显,表现为水体温度主导的层化。通过对底边界层动力过程的分析表明,湾内（距底0.75 m）、湾外（距底0.50 m）站位底边界层的平均摩阻流速分别是0.016 m/s、0.013 m/s,且两个站位拖曳系数基本相等（2.03×10-3）,表明在相同流速下湾内站位的底部切应力更大,近底沉积物再悬浮和搬运相对湾外站位更为显著。因此观测期间悬沙浓度最大值出现在湾内站位,为109 mg/L,且悬沙在垂向上的分布可达上层水体;湾外站位悬沙浓度更低,并且底部悬浮泥沙仅能影响至距底5 m的水体。悬沙通量机制分解结果表明,三沙湾夏季的潮周期单宽悬沙从湾外向湾内方向净输运,湾内站位向湾内方向净输运74.88 g/(m·s),平流输沙占主导作用,贡献率41.7%;湾外站位向湾内方向净输运10.57 g/(m·s),主要受平流输沙和垂向净环流的控制,贡献率94.9% 相似文献
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海水实验围隔中放养罗非鱼的生态学效应 总被引：4，自引：0，他引：4
围隔实验和在围隔内进行的其他实验结果表明,台湾红罗非鱼(简称罗非鱼)对食物的选择性及其生态学效应与食物资源状况有关。放养罗非鱼的围隔中浮游植物生物量和生产力往往较高,但罗非鱼密度超过8000尾/hm2后可明显压制海洋原甲藻等大型鞭毛藻类。当罗非鱼食物丰富时其对围隔中桡足类的压制作用相对较弱,当其他食物资源缺乏时往往选择捕食个体较大的桡足类。放养罗非鱼对围隔水中氮浓度和COD的影响较小,但加快了磷的循环,罗非鱼密度超过8000尾/hm2的围隔中PO4-P浓度明显高于对照围隔。 相似文献
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《Deep Sea Research Part II: Topical Studies in Oceanography》1999,46(1-2):305-333
Fourteen neutrally buoyant SOFAR floats at a nominal depth of 1800 m were tracked acoustically for 3.7 yr in the vicinity of the western boundary and the equator of the Atlantic Ocean. The trajectories revealed a swift, narrow, southward-flowing deep western boundary current (DWBC) extending from 7N across the equator. Two floats crossed the equator in the DWBC and went to 10S. Two other floats left the DWBC and drifted eastward in the equatorial band (3S–3N). Three floats entered the DWBC from the equatorial current system and drifted southward. These results suggest that at times the DWBC flows directly southward across the equator with a mean velocity of 8–9 cm/s averaged over long distances (∼2800 km). At other times DWBC water is diverted eastward near the equator for long periods (2–3 yr), which can reduce the mean along-boundary velocity to 1–2 cm/s. This is much less than the instantaneous along-boundary velocities in the DWBC, which are often above 25 cm/s and occasionally exceed 50 cm/s. Mean eastward-flowing jets were observed near 2N and 2S bounding a mean westward jet centered on the equator (1S–1N). The southern jet at 2S coincides with a CFC-rich plume centered south of the equator. The CFC plume is inferred to have been advected by the southern jet across the Atlantic and into the Gulf of Guinea. 相似文献
16.
Some features of jump in water temperature in aSargassum forest 总被引：1，自引：0，他引：1
To clarify the influence of aSargassum forest on water temperature distributions observations were made inside and outside aSargassum forest off the Nagata Shore on the northern Saiki Bay open to the Bungo Channel on the Pacific side of Kyushu, Japan. About sixty thermistor probes were deployed at 0.5 m depth intervals from the bottom to the sea surface at seven stations spaced at 50–80 m distances along two transects: one inside the forest and the other outside. Water temperature was measured at five minutes intervals from 6 to 9 August 1987 with thermistor probes. The spatial standing crop distribution of theSargassum forest along the transects was investigated. A water temperature jump of about 2°C, recorded during the observation, is probably caused by an intrusion of a warm water mass from the central Bungo Channel to Saiki Bay. The water temperature jump under theSargassum forest on the rough bottom with stones occurred one to two hours behind that outside the forest (sandy bed) although the distance between the transects inside and outside the forest was only 50–80 m. It is suggested that theSargassum forest and the rough bottom would prevent intruding warm water from smoothly replacing cold water due to resistance of theSargassum species and the bottom to a current. 相似文献
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In this work, the problem of optimizing the shape of a thin floating plate (sometimes called a dock) to maximize radiation damping is investigated. The plate is modeled with zero draft and floats on the surface of an irrotational, incompressible ocean of infinite extent. For simplicity, only rigid heave motions are considered. The flow problem is analyzed using the Chen and Mei variational principle wherein the potential field inside a hemisphere surrounding the plate is represented using a spherical harmonic expansion and matched on the hemisphere to an outer field described by distributing sources on the hemisphere. The plate shape is parameterized using a Fourier series which is suitable for use with the variational principle. Gradients of the damping coefficient with respect to the shape parameters are developed by solving an adjoint flow problem whose potential is shown to be a scalar multiple of the original flow potential. Optimal plate shapes are determined using the well-known optimization code NPSOL which makes use of the damping coefficient calculation and gradients. 相似文献
18.
Daisuke Takahashi Hikaru Endo Yuki Minegishi Yasushi Gomi Kenji Kaneko 《Journal of Oceanography》2018,74(1):81-100
Flow fields in Shizugawa Bay on the Sanriku ria coast, which faces the Pacific Ocean, were investigated using hydrographic observations for the purpose of understanding oceanographic conditions and the process of water exchanges in the bay after the 2011 earthquake off the Pacific coast of Tohoku. In spring to summer, density-driven surface outflow is part of estuarine circulation and is induced by a pressure gradient force under larger longitudinal gradients in density along with lower salinity water in the innermost part of the bay, regardless of wind forcing. In winter to summer, another density-driven current with a thermal structure is induced by a pressure gradient force under the smaller longitudinal density gradients in calm wind conditions. Particularly in winter, Tsugaru Warm Current water can be transported in the surface layer inside the bay. Wind-driven bay-scale circulation with downwind and upwind currents in the surface and deeper layers, respectively, is induced by strong longitudinal wind forcing under the smaller longitudinal density gradients, irrespective of season. Particularly in fall to spring, this circulation can cause the intrusions of oceanic water associated with Oyashio water and Tsugaru Warm Current water in the deeper layer. These results suggest that wind- and density-driven currents can produce the active exchange of water from inside and outside the bay throughout the year. 相似文献
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Based on the scales transformation of electromagnetic theory, the analytical expressions of electric fields inside and outside a magnetised cold plasma sphere are presented by reforming the spherical electromagnetic parameter. The obtained results are in good agreement with that in the literature. The angle between the direction of inside field and that of outside field is derived. In S wave band, calculations for the effects induced by parameters of the inner field are established. Simulations show that the angle between incident field and the outside magnetic field influences the inner field remarkably. The inner field will increase as the electron density increases. The inner field varies with frequency nonlinearly. There is an angle between the inner field and the incident field, it changes nonlinearly with the frequency. 相似文献
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Spring blooms of phytoplankton composed of centric diatoms developed in late February, March, and April in Otsuchi Bay on Sanriku ria coast, Japan. During this period, associated with prolonged seasonal west wind (>1 day), intense exchange of waters occurred between inside and outside the bay: outflow of nearsurface brackish water over inflow of oceanic water at depth. This circulation interrupted formation of the blooms, and transported phytoplankton populations seaward. By such water movements, a significant amount of nutrients in the bay was carried out, otherwise replenished into the bay, depending on water masses located outside the bay. Owing to irregular features of wind events, a bloom lasted from several days to a week. From February to April, supply of nutrients seemed to be replete except for the latter half of the bloom period, and estimates of the critical depth exceeded the depth of the bottom consistently. Thus, net growth of phytoplankton was expected throughout the observation period, and potentially blooms could be formed. However, the blooms were only formed under calm weather. We hypothesize that the exchange of waters dilutes populations in the bay, and that formation of the bloom, that is, accumulation of biomass depends on a balance between the growth of phytoplankton and the dilution of bay water. 相似文献