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21.
Sedimentary Phosphorus Form Distribution and Cycling in the Littoral Subzones of a Eutrophic Lake 总被引:2,自引:0,他引:2
Algae which bloom in open water and accumulate in the littoral zones may affect the biogeochemical cycle of phosphorus in eutrophic lakes. To determine such effects, a part of the lakeshore with little allochthonous nutrient input in Taihu Lake, China was selected for this field study. Distinct differences in sedimentary P forms were found among the different littoral subzones. The surface sedimentary total phosphorus (TP) content was 655 mg/kg in the eulittoral subzone and 631 to 641 mg/kg in the infralittoral subzone. Both were much higher than that in the profundal zone (410 mg/kg). Calcium‐bound P (Ca‐P) was significantly correlated to exchangeable P (Ex‐P), and they both had the highest contents in the infralittoral subzone and the lowest in the profundal zone. The aluminum‐ and iron‐bound P (Al‐P, Fe‐P) contents decreased from land to water along the ecotone section. Lower Fe/P ratios and higher Al‐P/Fe‐P ratios appeared in the infralittoral subzone, as compared with the profundal zone. This suggested that the accumulated algae could lead to a great deposit of P in the littoral zones. However, the active sedimentary P form transformation in the littoral zones would also result in a partial release of the accumulated P to the overlying water. 相似文献
22.
Chlorophyll blooms consistently develop in the oligotrophic NE Pacific in late summer, isolated from land masses and sources of higher chlorophyll waters. These blooms are potentially driven by nitrogen fixation, or by vertically migrating phytoplankton, and a better understanding of their ubiquity could improve our estimate of the global nitrogen fixation rate. Here, global SeaWiFS chlorophyll data from 1997 to 2007 are examined to determine if similar blooms occur in other oligotrophic gyres. Our analysis revealed blooms in five other areas. Two of these are regions where blooms have been previously identified: the SW Pacific and off the southern tip of Madagascar. Previously, unnoticed summer blooms were also identified in the NE and SW Atlantic and in a band along 10°S in the Indian Ocean. There is considerable variation in the intensity and frequency of blooms in the different regions, occurring the least frequently in the Atlantic Ocean. The blooms that develop along 10°S in the Indian Ocean are unique in that they are clearly associated with a hydrographic feature, the 10°S thermocline ridge, which explains the bloom within a conventional upwelling scenario. The environment and timing of the blooms, developing in oligotrophic waters in late summer, are conducive to both nitrogen fixers and vertically migrating phytoplankton, which require a relatively stable water column. However, the specific locations of the chlorophyll blooms generally do not coincide with areas of maximum levels of nitrogen fixation or Trichodesmium. The NE Pacific chlorophyll blooms develop in a region with a very high SiO4/NO3 ratio, where silicate will not be a limiting nutrient for diatoms. The blooms often develop between eddies, wrapping around the periphery of anti-cyclonic features. However, none of the areas where the blooms develop have particularly high eddy kinetic energy, from either a basin-scale or a mesoscale perspective, suggesting that other factors, such as interactions with a front or dynamics associated with the critical latitude, operate in conjunction with the eddy field to produce the observed blooms. 相似文献
23.
太湖蓝藻水华遥感动态监测预警信息系统 总被引:1,自引:0,他引:1
太湖蓝藻水华暴发对其周边地区的生态、经济和社会造成了严重影响,对蓝藻水华进行监测预警对于改善太湖水环境具有重要意义。本文在分析蓝藻水华遥感监测预警研究动态基础上,从信息系统构建角度,结合太湖蓝藻水华监测情况,对太湖蓝藻水华遥感监测预警流程进行系统性分析,提出建立太湖蓝藻水华遥感监测预警系统的总体框架,利用C#语言和IDL语言实现了该框架的软件架构,并且论述了实现该系统框架所采用的系统集成技术和软件模式技术。 相似文献
24.
唐森铭 《中国海洋湖沼学报》2002,(1)
INTRODUCTIONThemainpurposeofthisstudywastodeterminethemagnitudeandfrequencyofharmfuldiatomanddinoflagellateoutbreaksinHongKong’swesternandeasternwaters (e .g.LammaStraitsandPortShelterrespectively)fortheperiodJanuary 1 997toDecember1 999.Thiswasdoneinordertod… 相似文献
25.
中国北方盐田和盐湖高盐水域藻类的初步研究 总被引:3,自引:0,他引:3
于1986年3月-1990年9月,对中国北方一些盐田和盐湖的高盐水域(盐度61.0-320.0)中的藻类(主要是浮游藻)进行调查。在青岛东风盐场和天津汉沽盐场每月2次定点采集藻类标本水样72份以及随机在山西解地、青海尕海,新疆达板城盐湖和巴里坤湖采集水样5份。鉴定出蓝藻5种,绿藻8种,硅藻8种。结果表明,均是典型的耐盐或喜盐种类,但其种的多样与水体的盐度呈负相关,藻类种群生物量以春季和秋季最为丰富 相似文献
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27.
Diel fluctuations in dissolved free amino acids and monosaccharides in Chesapeake Bay dinoflagellate blooms 总被引:1,自引:0,他引:1
The accumulation of phytoplankton biomass in recurring summer dinoflagellate blooms of Chesapeake Bay is accompanied by large pools of dissolved organic matter (DOM). Two fractions of the DOM, free amino acids (DFAA) and monosaccharides (MONO), were measured at 3 h intervals in mixed species dinoflagellate blooms (Katodinium rotundatum, Gymnodinium spp.) and related to productivity, biomass and photoperiod. Peak chlorophyll levels for the three blooms were 28, 65 and 938 μg1−1. In general, DFAA and MONO concentrations increased with increasing biomass of bloom-forming species, reaching 203 and 844 μg1−1. MONO appeared to accumulate during the day while there was no consistent pattern for DFAA. The accumulations of DFAA and MONO in blooms indicate that bloom production might stimulate microheterotrophy, thereby enhancing carbon and nutrient cycling in bloom-impacted regions. 相似文献
28.
29.
根据1992年8月30日-9月4日在日本名古层如开的第九届国际光合作用大会上交流的以藻类为材料的研究论文,综述了分子遗传学方面的研究成果。认为这些成果体现了光合作用研究的最新进展,蕴含有一定的应用前景;表明类分子遗传学不仅是藻类学研究领域的带头学科,而且已经活跃在光合作用等重大生物学问题研究的前沿;反映了藻类分子遗传学向解决生物学重大问题和推动藻类资料开发方向发展的趋势。 相似文献
30.