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21.
A preliminary study of carbon system in the East China Sea 总被引:1,自引:0,他引:1
Shizuo Tsunogai Shuichi Watanabe Junya Nakamura Tsuneo Ono Tetsuro Sato 《Journal of Oceanography》1997,53(1):9-17
In the central part of the East China Sea, the activity of CO2 in the surface water and total carbonate, pH and alkalinity in the water column were determined in winter and autumn of 1993.
The activity of CO2 in the continental shelf water was about 50 ppm lower than that of surface air. This decrease corresponds to the absorption
of about 40 gC/m2/yr of atmospheric CO2 in the coastal zone or 1 GtC/yr in the global continental shelf, if this rate is applicable to entire coastal seas. The normalized
total carbonate contents were higher in the water near the coast and near the bottom. This increase toward the bottom may
be due to the organic matter deposited on the bottom. This conclusion is supported by the distribution of pH. The normalized
alkalinity distribution also showed higher values in the near-coast water, but in the surface water, indicating the supply
of bicarbonate from river water. The residence time of the East China Sea water, including the Yellow Sea water, has been
calculated to be about 0.8 yr from the excess alkalinity and the alkalinity input. Using this residence time and the excess
carbonate, we can estimate that the amount of dissolved carbonate transported from the coastal zone to the oceanic basin is
about 70 gC/m2/yr or 2 GtC/yr/area-of-global-continental-shelf. This also means that the rivers transport carbon to the oceans at a rate
of 30 gC/m2/yr of the coastal sea or 0.8 GtC/yr/ area-of-global shelf, the carbon consisting of dissolved inorganic carbonate and terrestrial
organic carbon decomposed on the continental shelf. 相似文献
22.
光照强度对海洋微藻脂肪含量及脂肪酸组成影响的研究 总被引:1,自引:0,他引:1
近年来,海洋微藻脂肪酸组成的研究及其应用越来越受到国内外科学家的重视。高度不饱和脂肪酸(PUFA),特别是长链的n-3 PUFA,如二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)对海洋动物和人类都具有营养学和医学上的价值。在海洋微藻的培养过程中,光照强度是海洋微藻生长的条件之一,光线的明与暗,光度的强与弱,不仅对微藻的生长速率、产量有影响,而且对其脂肪含量和脂肪酸的组成也有影响(Teshima et al.,1983;Thompson et al.,1990; Renaud et al., 1991)。
作者在以往研究的基础上,选择了3种有代表性的海洋微藻:(1)小球藻Chlorella sp-2(李荷芳等,1999),此藻脂肪酸中EPA含量高、且不含DHA;(2)球等鞭金藻(Isochrysis galbana),该藻DHA含量较高,但几乎不含EPA;(3)前沟藻(Amphidinium sp.)的EPA、DHA含量均高。将以上3种微藻作为原料,在不同的光照强度下进行培养,测定并分析藻体中的脂肪含量和脂肪酸组成的变化,从而了解光强对海洋微藻脂肪含量及其脂肪酸组成的影响。 相似文献
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25.
Ulla Botelho Machado 《Applied Ocean Research》2002,24(6):321-330
In this article a method to estimate the mean upcrossing intensity, μ(u), of a stochastic process is proposed. It is assumed that the stochastic process is a sum of a Gaussian process and a second-order correction term. The method is based on the two-dimensional Saddlepoint approximation. The accuracy of the method is tested on processes having analytical solutions for μ(u). Numerical examples are given where the stochastic process represents (i) the horizontal response of a floating offshore structure in a Gaussian sea, and (ii) the response of a structure subjected to a Gaussian wind velocity process. In addition, the estimates are compared to empirical upcrossing intensities of simulated responses. For case (ii), the obtained μ(u) estimates are compared to estimates obtained by numerical integration. 相似文献
26.
Lawrence W. Harding Jr Blanche W. Meeson Thomas R. Fisher Jr 《Estuarine, Coastal and Shelf Science》1986,23(6)
Chesapeake Bay is a large and productive estuary that has received close scrutiny in recent years because of indications that its water quality and biota have been damaged by man's activities. Data on primary production for the estuary as a whole, however, are surprisingly sparse. We describe here the distribution of photosynthetic carbon assimilation by phytoplankton in Chesapeake Bay, and relate productivity patterns to hydrographic characteristics of the estuary. Between March 1982 and April 1983, a series of four cruises was conducted on Chesapeake Bay, and two cruises on the urbanized Delaware Bay for comparison. The upper Chesapeake and Delaware were highly turbid with high concentrations of suspended particulate matter and dissolved inorganic nutrients. Low chlorophyll concentrations were usually found in these areas of high turbidity, despite the abundance of nutrients, suggesting light limitation. Application of Wofsy's (1983) model of phytoplanton growth confirmed this suggestion. Chlorophyll and productivity maxima usually occurred seaward of the turbidity maxima where light penetration increased and suffient nutrients were present to support active phytoplankton growth. Further seaward of the chlorophyll maxima in the Chesapeake, the photic zone depth increased, concentrations of nutrients decreased, and phytoplankton biomass decreased, suggesting that nutrient availability, rather than light, controlled phytoplankton growth in the lower portion of the estuary. In contrast to the Chesapeake, Delaware Bay was more turbid, had generally higher nutrient concentrations, and was lower in phytoplankton productivity. The chlorophyll maxima and region of rapid phytoplankton growth occurred further toward the lower estuary and shelf regions in Delaware Bay because the high turbidity extended further seaward. Nutrients were never depleted at the shelf end of the estuary sufficiently to retard phytoplankton growth. Photosynthesis-irradiance (P-I) curves from simulated in situ and constant intensity incubations showed a strong correlation of the light-limited slope (aB) with the light-saturated rate (
) on each cruise. Spatial variations in
corresponded to patterns of phytoplankton abundance, as did integral production (PP) and carbon-based growth rates (μC, μm), and photosynthetic parameters varied significantly with temperature. 相似文献
27.
礁膜配子放散条件的研究 总被引:2,自引:0,他引:2
本文报道了礁膜配子的放散与温度、光照、比重的关系。结果表明,自然海区的礁膜在白天大量放散配子。配子放散的适宜温度为19-21℃;光照为2000-5000lx时能促进配子大量放散出来;配子放散的适宜比重为1.05-1.025;这些研究结果将为礁膜人工育苗提供一些科学依据。 相似文献
28.
渤海湾、黄河口和长江口海域海水中颗粒氨基酸含量的分布 总被引:2,自引:0,他引:2
海水中除含有大量无机物质外,还含有种类繁多,但含量很低的有机物质,其含量约为C 0.5-2.0mg/L。海水有机物质可分为溶解有机物质(DOM)和颗粒有机物质(POM)。前者为主要组分,后者所含比例很小。在大洋中POM的主要来源有:①浮游生物,尤其是浮游植物活体、死骸及其分解碎屑;②海水中进行的DOM-POM的动力平衡产物。近岸海水还受河流流入的陆地POM和大气带入的陆源尘埃的影响。POM主要由蛋白质、碳水化合物、脂类等组成。POM是食碎屑动物的良好食物,它构成海洋食物链的一环,与水域生物生产力有直接的联系。POM中蛋白质含量以颗粒氨基酸(PAA)表示。Daumas(1976)曾报道过沿岸海水中PAA含量的季节变异,纪明侯等(1992年)于1980-1981年首次对青岛胶州湾内PAA含量在不同站位和不同季节中的变化特征进行调査研究。作者等继而于1982年7月、1983年10月和1984年5、7、8月乘“金星二号”考察船前后首次研究了渤海湾、黄河口和长江口附近水域中颗粒氨基酸的组成与含量在不同站位中的分布。所得结果如下。 相似文献
29.
哀牢山-红河断裂带中段应变分析 总被引:1,自引:0,他引:1
对哀牢山—红河断裂带中段和平—水塘剖面、墨江—元江剖面和其它地段的岩石应变及磁组构进行了分析,表明应变强度的校正磁各向异性度PJ从断裂带向西至三叠系明显降低,变形强度向西迅速减弱。磁化率椭球体主轴展布反映出剪切带内、外变形方式的改变。剪切带内,以水平走滑运动为主;向西则以水平缩短为主。在应变分析中,对断裂带内的S—C组构两组面理夹角、杏仁体和石榴石应变标志体进行了测量,结果显示,剪切带内的磁组构和岩石组构间关系较差。此外,还对这两条剖面中的三叠系进行了应变和磁组构分析,找出了它们与磁化率椭球体对应轴率间的相关性。 相似文献
30.
十四株海洋微藻脂肪酸组成的研究 总被引:5,自引:0,他引:5
对 4个门的 14株 (红藻门 8株 ,甲藻门 1株 ,隐藻门 2株 ,绿藻门 3株 )海洋微藻进行了脂肪酸含量测定 ,微藻在确定的条件下生长 ,指数生长末期收获。结果表明 ,各门的微藻都有其独特的脂肪酸特征 :红藻中含有大量的 2 0 :4 n- 6和 2 0 :5n- 3,其中紫球藻 R2 5含量最高 ,占总脂肪酸的4 9.8% (AA占总脂肪酸的 2 0 .5% ,EPA占总脂肪酸的 2 9.3% )。隐藻的主要脂肪酸是 16 :0、18:1n- 9、18:3n- 3、18:4 n- 3、2 0 :5n- 3、2 2 :5n- 3。与其它甲藻有别的虫黄藻 ,18:4 n- 3含量很少并且不含EPA,其主要合成的是 16 :0、18:1n- 9和 2 2 :6 n- 3。 C16和 C18的不饱和脂肪酸是本实验研究的 3株绿藻的主要脂肪酸 相似文献