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1.
左涛  王俊  王秀霞 《海洋学报》2016,38(10):94-104
拟哲水蚤是莱州湾桡足类中周年出现的优势种;是上层鱼类幼鱼早期开口饵料的重要贡献者;掌握其种群动态分布特点;有利于了解湾内生物环境状况、次级生产力生产水平。基于2011年5月至20 12年4月采集的浮游生物资料的分析结果显示;莱州湾拟哲水蚤的发育期丰度组成和个体大小均表现了明显的季节变化。调查季节中;4-6月以成体居多;其他季节以桡足幼体CⅢ-CⅤ较多;其中10-11月和3月主要由后期桡足幼体CⅣ和CⅤ期构成。成体中以雌体为主导;雌/雄比介于1.46~9.62;该比值在3-4月最低;10-11月最高。拟哲水蚤各期桡足幼体和成体个体大小以4-5月最大、8月最小;并与水温表现出明显的负相关。拟哲水蚤桡足幼体和成体的总生物量月变化与丰度变化相同;即以8月值最高;3-5月值最低;月均值为2.69 mg/m3(以碳计);日生产力估算值为0.74 mg/(m3·d)(以碳计)。由上述结果;推测莱州湾拟哲水蚤的种群结构周年变化主要可分3个阶段;4-6月是莱州湾拟哲水蚤开始繁殖期;7-8月为种群数量快速增长期;9月之后为种群增长相对停滞期。  相似文献   

2.
孟加拉湾上层地转环流周年变化的遥感研究   总被引:2,自引:1,他引:1       下载免费PDF全文
邱云  李立 《海洋学报》2007,29(3):39-46
应用1993~2003年TOPEX/Poseidon卫星测高数据结合历史水文资料,反演了孟加拉湾海面动力地形的平均周年变化,探讨了孟加拉湾上层环流季节特征和演变规律.结果显示,虽然孟加拉湾的大气环流受季风支配年周期波动显著,但表层环流形态的周年演变却呈3个不同的阶段.1~4月间(东北季风后期)湾内受一个海盆尺度的强大反气旋式环流的支配,湾口为西向流;5月西南季风骤起,印度季风漂流越过印度半岛南端出现在湾口,湾内反气旋环流弱化,在其南北两侧各出现一气旋式涡,构成5~9月间南北相间的三涡结构;10月东北季风再起,湾口漂流再次转向,10~12月间湾内则为海盆尺度的弱气旋式环流.受上述环流格局影响,位于西边界的印度沿岸流亦呈相应的3个阶段变化.分析表明,孟加拉湾风应力旋度的变化是造成湾内环流3个阶段演变的主要原因.本地风场和来自赤道海域的外强迫的共同驱动形成了孟加拉湾环流周年演变的独特规律.  相似文献   

3.
利用1998―2007年Seaflux资料结合太阳短波辐射及海面风场数据,分析了孟加拉湾海表日增温(Diurnal Warming of Sea Surface Temperature, dSST)的季节变化特征及其形成机制。结果显示,在赤道海域(5.0°N以南),dSST以年周期变化为主并呈现12月至次年5月高、6—11月低的单峰结构,在湾内(5.0°N以北),dSST则表现出显著的半年周期变化而呈现独特的春、秋季高,夏、冬季低的双峰结构。dSST空间分布形态春季呈湾中部高、四周低的态势;秋季湾口较低、湾内及赤道海域较高;夏、冬季形态基本一致均呈赤道高、湾内低的格局,但夏、冬季湾内高值中心略有不同,分别位于斯里兰卡岛东北部近海及湾西边界区。进一步分析表明,海面风速对整个研究海域的影响均较为重要,因此决定了dSST空间分布形态的季节变化。太阳短波辐射对湾内dSST季节变化的影响也较为重要,但在湾口以南至赤道大部分海域的影响较弱。  相似文献   

4.
In April 1996, a massive algal bloom of the coccolithophorid Gephyrocapsa oceanica developed in both Chita Bay and Atsumi Bay which comprise the bay known as Mikawa Bay of Japan. It was the first record of such a bloom in this area. In Chita Bay, the bloom persisted until the middle of May, however in Atsumi Bay, it remained until early June. From the analysis of salinity, water temperature, and current velocity and direction data, it is considered that the following mechanism accounts for the occurrence and maintenance of the bloom: Before the bloom, the standing crop of phytoplankton was poor, resulting in relatively rich nutrients throughout the bay. Thereafter, with the influx of oceanic water into Mikawa Bay, high salinity occurred firstly in Chita Bay. Under these hydrographic conditions, the bloom occurred first in Chita Bay, and extended throughout the bay with the clockwise circulation of water into Atsumi Bay. In Chita Bay, the bloom was influenced by rainfall and G. oceanica flowed out from this area. Whereas, in Atsumi Bay, the bloom persisted for longer due to the clockwise circulation and another influx of oceanic water.  相似文献   

5.
The spatial distribution of the larval abundance of the clam Ruditapes philippinarum has been investigated at 65 stations throughout Tokyo Bay on August 2, 2001. The large number of small D-shaped larvae that were found shortly after hatching in the waters around the Banzu, Futtu, and Sanmaizu-Haneda areas indicates that spawning populations in these areas probably contribute greatly to the larval supply in the bay. Small larvae also occurred abundantly around the Yokohama and Ichihara port areas, suggesting that these port regions play a role in the transport of larvae into Tokyo Bay. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

6.
On the basis of data collected in the Jiaozhou Bay in June and July 2003, the DIC distribution in seawater is studied,and an average air-sea flux of CO2 is estimated. The results show that the content of DIC inside the bay is markedly higher than outside the bay in June, but the contem of DIC outside the bay is markedly higher than inside the bay in July. The trend of DIC distribution inside the bay is similar, viz. the content is the maximum in the northeast, then decreases gradually toward the west, and the content is the minimum in the west. The total trend of vertical distribution is to increase gradually from surface to bottom. This characteristic of DIC distribution is determined by Jiaozhou Bay hydrology and there is a close relation between DIC and particulate N.P. Average CO2 flux across the air-sea interface is 0.55 mol/(m^2.a) in June and 0.72 mol/(m^2.a) in July. Jiaozhou Bay is considered as a net annual source for atmospheric CO2 in June and July, and the total CO2 flux from seawater into atmosphere is about 740 t in June and 969 t in July.  相似文献   

7.
采用MPN计数法对胶州湾大肠菌群丰度进行7年(84个月)连续监测,结果表明,大肠菌群丰度的周年变化明显,全年最高丰度与最低丰度相差约2.2倍。胶州湾大肠菌群丰度自2005—2009年明显下降,降幅达67%,说明胶州湾环境质量有所好转。研究还发现大肠菌群丰度变化具有明显的区域特征,河口区最高,湾内区最低,差异近11倍。大...  相似文献   

8.
From August 2006 to August 2007, the concentrations of dissolved silica (Si(OH)4) were monitored in the surface water of Urasoko Bay and the mouth of the stream that runs into the bay. Urasoko Bay is located on the northern coast of Ishigaki Island, Okinawa, Japan, which is in a subtropical area of the North Pacific Ocean and is surrounded by a relatively poorly developed fringing reef. Added to these samples were freshwater from the upstream area and brackish water that exudes at the beach site, which were collected from April to June 2007. Rainwater samples were also collected during the study period. The concentration of Si(OH)4 generally decreased from upstream to the bay site, and, on clear days, Si(OH)4 data from all study sites (the bay, beach, stream mouth, and upstream) plotted against salinity fell on a single straight line. When the influence of rainwater was, the results were scattered below the straight line, which suggests dilution by rainwater with a much lower Si(OH)4 concentration. These findings show that offshore seawater, rainwater, and upstream freshwater regulate the concentration of Si(OH)4 in the surface water of Urasoko Bay.  相似文献   

9.
Seasonal variations in freshwater, salt, phosphorus and nitrogen budgets of Hakata Bay, Japan were investigated from April 1993 until March 1994. The internal sink of dissolved inorganic phosphorus (DIP) and nitrogen (DIN), and the internal source of dissolved organic phosphorus (DOP) and nitrogen (DON) predominate in the bay. This means that the production of organic matter is larger than respiration, and atmospheric CO2 is absorbed in the water column of Hakata Bay. Denitrification is more dominant than nitrogen fixation in the bay. Compared to Tokyo and Mikawa Bays, Hakata Bay is harder to eutrophicate, mainly due to the shorter residence time of freshwater.  相似文献   

10.
We present the results of joint analysis of (1) predominant modes of the low-frequency variability of the atmosphere, (2) mechanisms of formation of annual-cycle anomalies, and (3) sudden extreme anomalies on a planetary scale. NCEP/NCAR reanalysis data over 1958–1998 and operational objective analysis of the RF Service for Hydrometeorology and Environmental Monitoring (Rosgidromet) over 2002–2007 with monthly averaging are used. We have attempted to study the cases of extreme monthly mean anomalies in the atmospheric general circulation and their consequences. The role of interannual winter negative anomalies of the air temperature over continents in stabilizing the annual cycle of the present-day climate (which was observed in the 1950s–1960s) is shown, as well as the role of the deformation of the North Atlantic dipole into the planetary wave oriented from west to east (the deformation was observed in April 1997 and again in 2007) in the weakening of the annual climatic cycle.  相似文献   

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