南洋珠生产及国际市场趋势

●南洋珠历史及养殖场分布南洋珠养殖的历史不超过五十年,而真正有南洋珠供应世界各地市场不过是近二十年间的事。很多人士都是只闻其名,在外国有些小市镇的珠宝业者,可能并未见过南洋珠。目前南洋珠场的分布计澳洲北部约二十家,产量占全球约百分之六十,而价值更高至占全球百分之七十。印尼分布各岛屿约有七十家,两年前产量曾直追澳洲,后因遭逢地震,使水质受污染而大受打击;目前产量仅占全球约百分之三十。

Influence of climatic warming in the Southern and Northern Hemi-sphere on the tropical cyclone over the western North Pacific Ocean

Based on analyzing the surface air temperature series in the Southern and Northern Hemisphere and the tropical cyclone (TC) over the western North Pacific Ocean, the relationships between climatic warming and the frequency and intensity of tropical cyclone are investigated. The results showed that with the climatic warming in both hemispheres, the frequency of the tropical cyclone over the western North Pacific Ocean reduces and its intensity weakens simultaneously. A possible explanation might be that the cold air invasion from the Southern Hemisphere weakens due to global warming.

Statistical Characteristics of Austral Summer Cyclones in Southern Ocean

Characteristics of cyclones and explosively developing cyclones (or 'bombs') over the Southern Ocean in austral summer (December, January and February) from 2004 to 2008 are analyzed by using the Final Analysis (FNL) data produced by the National Centers for Environmental Prediction (NCEP) of the United States. Statistical results show that both cyclones and explosively developing cyclones frequently develop in January, and most of them occur within the latitudinal zone between 55°S and 70°S. These cyclones gradually approach the Antarctic Continent from December to February. Generally cyclones and bombs move east-southeastward with some exceptions of northeastward movement. The lifetime of cyclones is around 2-6 d, and the horizontal scale is about 1000 km. Explosive cyclones have the lifetime of about 1 week with the horizontal scale reaching up to 3000 km. Compared with cyclones developed in the Northern Hemisphere, cyclones over the southern ocean have much higher occurrence frequency, lower central pressure and larger horizontal scale, which may be caused by the unique geographical features of the Southern Hemisphere.

Distribution of Organic Matter,Iron,Mangenese in Surface Sediments in the Nansha Islands Sea Area,South China Sea

Concentrations of organic matter, iron and manganese in the deep sea surface sediments in the Nansha Islands sea area, South China Sea are measured. Horizontal and vertical distributions of iron and manganese are discussed. The vertical distribution of iron and manganese in the sediments results from reduction, diffusion, and redeposition of manganese (or iron) oxide and hydroxide in the sediment. There are the maxima of iron and manganese in solid phase in the top of the sediment, which is caused by the penetration of O2 and the upward flux of Mn2+ ( or Fe2+ ). Manganese bacteria play a very important role in the cycle of solid-phase iron and manganese in the ocean environment. Manganese bacteria oxidize Mn2+ ( or Fe2+ ) in dissolved state to Mn4+ ( or Fe3+ ) in oxidized state under the aerobic condition, whereas they reduce iron and manganese in anaerobic conditions.

THE SOUTH CHINA SEA SUMMER MONSOON AND THE SEASONAL MODALITY AND WEST EXTENDING OF THE NORTHERN HEMISPHERE PACIFIC SUBTROPICAL HIGH

Based on the 4-layer dbl wavelet packet and shannon entropy decomposition /reconstruction method and the NCEP/NCAR daily reanalysis data set, the correlation between the South China Sea summer monsoon and the Northern Hemisphere Pacific subtropical high seasonal modality/shift xvas studied and discussed, and a corresponding summer monsoon frequency-band energy criterion was defined and introduced for diagnosing the Pacific subtropical high’s modality/shift. A few new phenomena and correlation between the South China Sea summer monsoon and the Northern Hemisphere Pacific subtropical high were also revealed and presented.

Will harmful dinoflagellate Karenia mikimotoi grow phagotrophically?

We studied the phagotrophic ability of dinoflagellate strain Karenia mikimotoi KM-Lu （isolated from the South China Sea）, using fluorescent microspheres, bacteria isolated from the culture of K. mikimotoi and a marine microalgae lsochrysis galbana. We found that K. mikimotoi cultured under conditions of high light intensity could ingest fluorescent microspheres （diameters 0.5 and 2.0 lain） and fluorescence-labeled bacteria and microalgae. Under a low light intensity, however, only fluorescent microspheres （diameter 0.5 μm） and fluorescence-labeled microalgae were ingested. K. mikimotoi showed better growth by ingesting living marine bacteria or microalgae I. galbana than the controls, either in nutrient-depleted or nutrient-replete conditions. In nutrient-depleted conditions, the growth ofK. mikirnotoi was more significant with L galbana as the prey item. In conclusion, the harmful dinoflagellate K. mikimotoi from the South China Sea has apparent phagotrophic ability, and some marine bacteria and microalgae may promote the growth of K. mikimotoi.

Effect of opening the Drake Passage on the oceanic general circulation:A box model study

The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat exchange between mid-and high latitudes in the Southern Ocean.After the opening of the DP,the Antarctic Circumpolar Current(ACC) forms and its associated strong temperature front blocks the heat transport from mid-latitudes to high latitudes.A simple box model is formulated,in which the effects of the wind stress(for the case of DP closed) and the thermal front(for the case of DP open) on the variability of Antarctic Bottom Water(AABW) and North Atlantic Deep Water(NADW) are explored.The sensitivity experiments demonstrate that:(1) When the DP is closed,the enhancement of the wind-driven gyre leads to the decline of AABW formation in the Southern Ocean and the increase of NADW formation in the North Atlantic.As a result,water in high latitudes of the Southern Ocean becomes warmer,so does the bottom water of global ocean.(2) When the DP is open,there is no formation of AABW until the intensity of thermal front along ACC exceeds a threshold value(it is 4.03℃ in our model).Before the formation of AABW,temperature in most of the oceans is higher than that after the formation of AABW,which usually leads to the cooling of high latitudes of the Southern Hemisphere and the bottom water in global ocean.When the strength of the thermal front is lower than the critical value,there is no AABW formation,and temperature in most of the oceans is slightly higher.These results demonstrate that during the opening of the DP,changes in wind stress and the formation of the thermal front in the Southern Ocean can substantially affect the formation of AABW and NADW,thus changing the state of meridional overturning circulation in the global ocean.

Provenance of a prominent sediment drift on the northern slope of the South China Sea

The sedimentation rate of the sediment drift in the southeast of Dongsha Islands is as high as 49 cm/ka in the last 1.05 Ma. Although the sedimentation rate changes with time, the con tents of rare elements of the sediments remain almost the same, indicating that the source area of the sediments has been constant with time. On the triangular diagrams of La-Th-Sc and Th-Sc-Zr/10, the samples from the southeast of Dongsha Islands fall within the continental island arc field, overlapping the samples from Taiwan, while the samples from the Pearl River, those from the west of the Philippines that contain volcanic material, are separated from them. This indicates that the sediments from the southeast of Dongsha Islands have a close relationship to those from Taiwan in terms of provenance. In fact, the sediments on the northern slope of the South China Sea were derived from northeast direction, as well as from Taiwan, most probably transported from Taiwan through Penghu channel into the South China Sea. The terrigenous part of the deep-sea sediments in the north of the South China Sea was provided by different sources.