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981.
Distributions and seasonal variations of dissolved carbohydrates in the Jiaozhou Bay,China 总被引:1,自引:0,他引:1
Surface seawater samples were collected in the Jiaozhou Bay, a typical semi-closed basin located at the western part of the Shandong Peninsula, China, during four cruises. Concentrations of monosaccharides (MCHO), polysaccharides (PCHO) and total dissolved carbohydrates (TCHO) were measured with the 2,4,6-tripyridyl-s-triazine spectroscopic method. Concentrations of TCHO varied from 10.8 to 276.1 μM C for all samples and the ratios of TCHO to dissolved organic carbon (DOC) ranged from 1.1 to 67.9% with an average of 10.1%. This result indicated that dissolved carbohydrates were an important constituent of DOC in the surface seawater of the Jiaozhou Bay. In all samples, the concentrations of MCHO ranged from 2.9 to 65.9 μM C, comprising 46.1 ± 16.6% of TCHO on average, while PCHO ranged from 0.3 to 210.2 μM C, comprising 53.9 ± 16.6% of TCHO on average. As a major part of dissolved carbohydrates, the concentrations of PCHO were higher than those of MCHO. MCHO and PCHO accumulated in January and July, with minimum average concentration in April. The seasonal variation in the ratios of TCHO to DOC was related to water temperature, with high values in January and low values in July and October. The concentrations of dissolved carbohydrates displayed a decreasing trend from the coastal to the central areas. Negative correlations between concentrations of TCHO and salinity in July suggested that riverine input around the Jiaozhou Bay had an important effect on the concentrations of dissolved carbohydrates in surface seawater. The pattern of distributions of MCHO and PCHO reported in this study added to the global picture of dissolved carbohydrates distribution. 相似文献
982.
Juan Chen Fei-Hua Wu Qiang Xiao Zhang-Hua Yang Sheng-Kai Huang Jian Wang Yu-Guang Wu Xue-Jun Dong Zhen-Ming Pei Hai-Lei Zheng 《Estuarine, Coastal and Shelf Science》2010
The diurnal variation of nitric oxide (NO) emission fluxes from a Kandelia obovata and Avicennia marina mangrove wetland were studied in the Zhangjiang River Estuary Mangrove National Nature Reserve using a dynamic chamber-based technique and a chemiluminescent analyzer. Results from field experiments show that NO emission from K. obovata and A. marina sampling sites reached maximal values of 1.07 ng N m−2 s−1 and 1.23 ng N m−2 s−1, respectively after the night tide. Meanwhile NO emission maintained at a steady lower level in daytime for both wetland sites. In laboratory experiments, NO emission from the mangrove wetland soil samples treated with simulated tides in the darkness exhibited higher values than those in the light, therefore it seems that tides and darkness could increase NO emission from mangrove wetlands, while intensive light, high temperature, and dryness in the daytime decreased NO emission. Compared with K. obovata soil samples, the diurnal average NO emission rate of the A. marina site was significantly higher, which was closely related to relatively higher diurnal average CO2 emission rate, soil available nitrogen content and soil net nitrification rate of the A. marina site. Moreover, soil samples of the A. marina site were more responsive to simulated tides and the addition of nitrogen than those of the K. obovata site. 相似文献
983.
深圳湾位于珠江口东岸,属半封闭海湾,2006年12月至2007年11月,在湾内进行污损生物周年挂板试验,共记录污损生物24种,隶属于7个动物门。月板平均附着生物量表层2780.72g/m2,底层4110.10g/m2,最高峰出现在7月份;四季板平均湿重表层2521.13g/m2,底层4382.10g/m2,最高峰出现在秋季;半年板平均湿重表层4065.10g/m2,底层4298.30g/m2;年板平均湿重表层6212.20g/m2,底层20009.10g/m2。四季优势种显著不同,华美盘管虫、总合草苔虫和藤壶在春、冬季附着量较大,夏季没有附着。沙筛贝和总状真枝螅在夏、秋季的附着量较大,冬季没有附着。 相似文献
984.
985.
986.
987.
收集了中国黄渤海区域(112°~125°E,35°~45°N)2000—2009年10 a内MODIS气溶胶光学厚度AOD月均标准数据,按陆地和海洋(陆海)像元及海洋像元两类分别进行经验模态分解(EMD),结合南方涛动指数(SOI)和我国年度化石燃料消耗总量讨论黄渤海海区气溶胶时间变化特征及成因。研究表明该陆海区域大气气溶胶光学厚度6月份多为全年最高,海洋区域最高值出现在4—7月之间;秋冬季(10—次年2月)气溶胶光学厚度达到最低;EMD分解获得气溶胶具有4 a变化周期特性,与南方涛动指数的相关性均达到0.7,说明大气气溶胶同样受到全球气候变化的影响;与我国煤炭化石年消耗量相关系数达到0.98,该研究区气溶胶受陆源影响明显,人类活动对海洋环境的作用不容忽视。 相似文献
988.
Pathologic condition of Manila clam, Ruditapes philippinarum collected from Haeju off the west coast of North Korea in February and March 2007 was investigated in this study. The diagnostics included a protozoan parasite, Perkinsus olseni, the brown ring disease (BRD) caused by bacteria Vibrio tapetis and metazoan parasites Trematod and Cestod. P. olseni infection was examined using histology and Ray’s fluid thioglycollate medium (RFTM) assay along with Choi’s NaOH digestion technique. Trematode and cestode infection was also examined from the histology. A total of 140 clams with 35–45 mm in shell length (2–3 years old) were analyzed. Condition factor (CF), a ratio of the wet tissue weight to the shell dry weight, ranged from 0.445±0.074 (February) to 0.544±0.132 (March). Total body burden of P. olseni (i.e. infection intensity) ranged from 18,644±37,755 (February) to 26,933±80,611 cells/g wet tissue (March) with the prevalence of 76.7–43.3% (March) respectively. Prevalence of trematode and cestode infection in February and March varied 22.5–25.0 and 15.0–22.5% respectively. Infection intensity of V. tapetis ranged 1–2 and the prevalence was 1.4 (February) and 5.7% (March). Prevalence and infection intensity of P. olseni in clams from Haeju was comparatively lower than those of clams reported on the west coast of Korea. BRD and the other metazoan parasite infection were also relatively lower or similar to the condition of the clams reported previously. CF of Haeju clams was also relatively higher than the clams in Gyeonggi Bay and Taean, suggesting that Haeju clams had relatively better pathologic and health condition. 相似文献
989.
中国东北地区地缘关系演化过程及区域效应 总被引:2,自引:0,他引:2
梳理相关文献,深入分析探讨20世纪以来东北地区地缘关系的演化过程,刻画地缘关系变化对区域发展的影响。研究发现:20世纪10~40年代,东北地区地缘关系呈现“半畸形”开放的状态,整个地区长期处于军阀战乱与日本侵略阶段;这一时期,东北地区迎来移民高峰,农业经济、民族工业快速发展,但同时境内日本经济肆意扩张,大量资源与财富被掠夺。新中国成立以来,地缘关系由50、60年代的依赖型转向80年代以后的多元和平发展;受其及政策等其他因素影响,地区内工业由蓬勃发展到缓慢波动前行。如今,东北地区地缘政治关系仍十分复杂,但地缘经济合作前景开阔;未来应大力推动东北亚国家及次区域间安全与经济合作,同时提高东北地区内生发展动力及对外开放水平。 相似文献
990.
人海关系地域系统视角下海洋本体的解构与研究重点 总被引:2,自引:1,他引:1
在揭示人海辩证关系与海洋社会属性的基础上,从人海关系地域系统的视角,解析了海洋的构成。第一海洋(自然海洋)是人海关系地域系统中自然存在而非人为构筑的海洋部分,其核心要素是地理位置、物质构成和空间形态。第二海洋(人工海洋)是人类海洋实践中所建造的设施及相应的物质、能量及信息流动,包括基地设施、人类主体之间的物质信息交流和人类与海洋之间的采集排放活动。第三海洋(关系海洋)是不同人类主体在海洋实践中形成的互动关系,核心内容是主体构成、内容组成以及表现形式。第四海洋(观念海洋)是人类对海洋及海洋实践活动的认知,核心是在处理人类与海洋、陆地与海洋和人类主体之间关系时所秉持的理念。现实中,自然海洋、实践性的人工海洋和关系海洋与构想性的观念海洋相互作用,形成了丰富多样的海洋世界。随着人类海洋实践的深化,关系海洋和观念海洋与自然海洋和人工海洋一并成为了研究与实践的重点。 相似文献