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131.
Abstract. The major problem in coastal areas of developing countries is disturbance caused by anthropogenic influence. This disturbance can be quantified by analysing the distribution and composition of marine communities using uni- and multivariate techniques and the biotic index. A study of benthic macrofauna was carried out along the São Sebastião Channel, northern coast of São Paulo State, Brazil, in an area with a submarine outfall, a petroleum terminal and a commercial harbour. Sampling was undertaken seasonally, by means of a van Veen grab (0.1 m2 ) at 15 oceanographic stations, from November 1993 to August 1994. A total of 392 species were identified (129 Polychaeta, 127 Mollusca, 98 Crustacea, 28 Echinodermata and 10 other phyla). The sedimentary pattern recorded for the São Sebastião Channel is very heterogeneous, influenced mainly by strong wind-driven currents, and differs from nearby shelf areas. The study area could be divided into three regions based on sediment texture and fauna: one region dominated by medium and coarse sand with low values of organic carbon; a second area where pelitic fractions were dominant with high values of organic carbon and nitrogen; and a third region characterised by fine and very fine sand, presenting intermediate organic carbon values. No temporal significant variation in abundance and species composition was found, except in autumn. The use of the 'marine Biotic Coefficient' showed the same ecological trend as the faunal abundance and demonstrated that the central continental region of the channel is affected by human activities. 相似文献
132.
133.
State Estimation of the North Pacific Ocean by a Four-Dimensional Variational Data Assimilation Experiment 总被引:1,自引:0,他引:1
Toshiyuki Awaji Shuhei Masuda Yoichi Ishikawa Nozomi Sugiura Takahiro Toyoda Tomohiro Nakamura 《Journal of Oceanography》2003,59(6):931-943
A four-dimensional variational data assimilation system has been applied to an experiment to describe the dynamic state of
the North Pacific Ocean. A synthesis of available observational records and a sophisticated ocean general circulation model
produces a dynamically consistent dataset, which, in contrast to the nudging approach, provides realistic features of the
seasonally-varying ocean circulation with no artificial sources/sinks for temperature and salinity fields. This new dataset
enables us to estimate heat and water mass transports in addition to the qualification of water mass formation and movement
processes. A sensitivity experiment on our assimilation system reveals that the origin of the North Pacific Intermediate Water
can be traced back to the Sea of Okhotsk and the Bering Sea in the subarctic region and to the subtropical Kuroshio region
further south. These results demonstrate that our data assimilation system is a very powerful tool for the identification
and characterization of ocean variabilities and for our understanding of the dynamic state of ocean circulation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
134.
135.
用小麦岛和团岛观测站提供的青岛近海气象和水温资料,以适于SO2气体和硫酸盐(SO42-)气溶胶的干沉降模型研究了模型中的输送阻尼对两种污染物质干沉降速率的贡献,并计算了2003年青岛近海地区两种污染物质干沉降速率的季节变化。结果表明:对SO2而言,粘性副层传输系数对沉降速率的贡献大于空气动力学传输系数;对于SO42-,空气动力学传输系数对沉降速率的贡献要大于表面传输系数。SO2和SO42-的干沉降速率变化范围分别为0.187~0.868cm/s和0.188~0.532cm/s。两种污染物质干沉降速率的四季变化有相似的规律,即冬季>秋季>春季>夏季。 相似文献
136.
In recent years, the red tide erupted frequently, and caused a great economic loss. At present, most literatures emphasize the academic research on the growth mechanism of red tide alga. In order to find out the characters of red tide in detail and improve the precision of forecast, this paper gives some new approaches to dealing with the red tide. By the extreme values, we deal with the red tide frequency analysis and get the estimation of T-times red tide level U (T) , which is the level once the consistence of red tide alga exceeds on the average in a period of T times. 相似文献
137.
探讨了用复合酶法制备鱼是鱼活性寡肽及其氨基酸组成和相对分子质量分布情况。应用正交试验法研究了酶量、酶解温度、酶解时间对鱼是鱼蛋白质水解度和酶解液苦味的影响。结果表明,最佳酶解作用条件是:酶量为100u/mL;酶解温度为50℃;酶解时间为4h。此时的酶解液苦味较低,水解度可达62.81%。应用氨基酸分析仪和凝胶排阻高效液相色谱分析了该寡肽的氨基酸组成和相对分子质量的分布范围,其十肽以下的小肽占67.77%,氨基酸组成平衡,必需氨基酸含量丰富。鱼是鱼活性寡肽有望成为保健食品、医药等领域的新型高品质原料。 相似文献
138.
There is the natural habitat of polyps of the common jellyfish Aurelia aurita in the Taniyama area, Kagoshima Bay. We examined the attachment substrata, density, colony structure and strobilation of
the polyps. The polyps were observed only on the horizontal undersurface of floating piers. They attached specifically to
Mytilus shells, solitary ascidians, calcareous polychaete tubes, muddy amphipod tubes and the gap space that fouling animals peeled
off the substrata. The polyp colonies were distributed in patches. Spatial distribution patterns of the polyps within their
colonies were uniform. Strobilation occurred during late December to March, when water temperatures were 16–17°C, and a large
number of ephyrae were released. An increase in man-made structures such as floating piers in coastal areas may lead to bloomings
of Aurelia aurita medusae.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
139.
140.
The distribution and geochemical composition of suspended-particulate matter (SPM) in the East China Sea (ECS) were investigated
during the summer period of high continental runoff to elucidate SPM sources, distribution and cross-shelf transport. The
spatial variability of SPM distribution (0.3–6.5 mg l−1) and geochemical composition (POC, Al, Si, Fe, Mn, Ca, Mg and K) in the ECS was pronounced during summer when the continental
fluxes of freshwater and terrestrial materials were highest during the year. Under the influences of Changjiang runoff, Kuroshio
intrusion, surface production and bottom resuspension, the distribution generally showed strong gradients decreasing seaward
for both biogenic and lithogenic materials. Particulate organic carbon was enriched in surface water (mean ∼18%) due to the
influence of biological productivity, and was diluted by resuspended and/or laterally-transported materials in bottom water
(mean 9.4%). The abundance of lithogenic elements (Al, Si, Fe, Mn) increased toward the bottom, and the distribution correlations
were highly significant. Particulate CaCO3 distribution provided evidence that the SPM of the bottom water in the northern part of the study area was likely mixed with
sediments originally derived from Huanghe. A distinct benthic nepheloid layer (BNL) was present in all seaward transects of
the ECS shelf. Sediment resuspension may be caused by tidal fluctuation and other forcing and be regarded as the principal
agent in the formation of BNL. This BNL was likely responsible for the transport of biogenic and lithogenic particles across
or along the ECS shelf. Total inventories of SPM, POC and PN are 46, 2.8 and 0.4 Tg, respectively, measured over the total
area of 0.45 × 106 km2 of the ECS shelf. Their mean residence times are about 27, 13 and 11 days, respectively. The inventory of SPM in the water
column was higher in the northernmost and southernmost transects and lower in the middle transects, reflecting the influences
of terrestrial inputs from Changjiang and/or resuspended materials from Huanghe deposits in the north and perhaps from Minjiang
and/or Taiwan’s rivers in the south. The distribution and transport patterns of SPM and geochemical elements strongly indicate
that continental sources and cross-shelf transport modulate ECS particulate matter in summer. 相似文献