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1.
The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River. 相似文献
2.
In this paper,the aquatic chemical characteristics in the Hangzhou Bay,Xiangshan Bay and Leqing Bay along the coastal region of Zhejiang Province are discussed . Results show that the seasonal variations of chemical elements are obvious. The distribution of silicate in Hangzhou Bay and contents of dissolved oxygen and nutrient in the Xiangshan Bay are found to be unusual in winter. Correlations among the elements are complex. The content of nutrient in the Hangzhou Bay is higher than that in Xiangshan Bay and the content of nutrient in the Xiangshan Bay is higher than that in the Leqing Bay . The variation of the ratio of N/P is obvious. This reflects the aquatic chemical characteristics in the bay. Finally, this paper also discusses the reason why the aquatic chemical characteristics in the bays are unusual. 相似文献
3.
Understanding the ocean's role in the global carbon cycle and its response to environmental change requires a high spatio-temporal resolution of observation.Merging ocean color data from multiple sources is an effective way to alleviate the limitation of individual ocean color sensors(e.g.,swath width and gaps,cloudy or rainy weather,and sun glint) and to improve the temporal and spatial coverage.Since the missions of Sea-Viewing Wide Field-of-View Sensor(Sea Wi FS) and Medium-spectral Resolution Imaging Spectrometer(MERIS) ended on December 11,2010 and May 9,2012,respectively,the number of available ocean color sensors has declined,reducing the benefits of the merged ocean color data with respect to the spatial and temporal coverage.In present work,Medium Resolution Spectral Imager(MERSI)/FY-3 of China is added in merged processing and a new dataset of global ocean chlorophyll a(Chl a) concentration(2000–2015) is generated from the remote sensing reflectance(Rrs(λ)) observations of MERIS,Moderate-resolution imaging spectra-radiometer(MODIS)-AQUA,Visible infrared Imaging Radiometer(VIIRS) and MERSI.These data resources are first merged into unified remote sensing reflectance data,and then Chl a concentration data are inversed using the combined Chl a algorithm of color index-based algorithm(CIA) and OC3.The merged data products show major improvements in spatial and temporal coverage from the addition of MERSI.The average daily coverage of merged products is approximately 24% of the global ocean and increases by approximately 9% when MERSI data are added in the merging process.Sampling frequency(temporal coverage) is greatly improved by combining MERSI data,with the median sampling frequency increasing from 15.6%(57 d/a) to 29.9%(109 d/a).The merged Chl a products herein were validated by in situ measurements and comparing them with the merged products using the same approach except for omitting MERSI and Glob Colour and MEa SUREs merged data.Correlation and relative error between the new merged Chl a products and in situ observation are stable relative to the results of the merged products without the addition of MERSI.Time series of the Chl a concentration anomalies are similar to the merged products without adding MERSI and single sensors.The new merged products agree within approximately 10% of the merged Chl a product from Glob Colour and MEa SUREs. 相似文献
4.
Community succession of zooplankton in marine derived saline lakes in antarctic continental margin 总被引：2，自引：0，他引：2
Ecological research has been made for quite a long period in some marine-derived saline lakes in the Vest-fold Hills, Antarctica. The results show distinct succession of zooplankton community in those lakes. The change in community structure of zooplankton is related directly to environmental evolution in nature and the variation of lake conditions, such as physical and chemical factors as well. In the Burton Lake, there is a rather stable annual fluctuation in both temperature and salinity, and the community has probably been in the stage of climax succession. The Fletcher Lake is still undergoing a process by unregular tide flood from nearby bay, so that zooplankton community has been changing due to variance in temperature and salinity. 相似文献
5.
Resulting from the rising levels of atmospheric carbon, ocean acidification has become a global problem. It has significant impacts on the development, survival, growth and physiology of marine organisms. Therefore, a highprecision sensor is urgently needed to measure the pH of sea-water. Iridium wire with a diameter of 0.25 mm is used as the substrate, and an Ir/Ir(OH)_x pH electrode is prepared by a one-step electrochemical method in a Li OH solution at the room temperature. A scanning electron microscope(SEM) observation reveals that it is coated with nanoscale particles. In laboratory tests, the electrode exhibits a very promising pH response, with an ideal Nernst slope(56.14–59.52), fast response, good stability and long life-span in tested pH buffer solutions. For a sea trial,four pH electrodes and one Ag/Ag Cl reference electrode are integrated with a self-made chemical sensor, and a profile detection of nearly 70 m is implemented near Newport Harbor, California on August 3, 2015. The results reflect that the pH value measured by the sensor is very close to the data given by Sea-Bird 911 plus CTD, with a difference value ranging from 0.000 075 to 0.064 719. And the sensor shows a better data matching degree in 0–40m water depth. In addition, the high precision and accuracy of the sensor make it possible to use in the ocean observation field. 相似文献
6.
沈华悌 《海洋学报(英文版)》1986,5(3):437-446
On the basis of the 14C dating data, lithological characters biological and chemical compositions and so on, the relict sediment of the East China Sea shelf is divided into two types of genesis -regression and transgression, with four sedimention periodes in this paper.The upper relict sediment layer is the sandy sediment of the transgressive bottom layer in Postglacial period. Its sediment age becomes younger and younger from east to west. The direction of its age variation is in accord with the transgressive direction, showing that the sandy sediment is the product of transgression in Post-glacial period. The age of the lower relict sediment layer is over 15,000 a. BP. The main variation trend appears older in the west but younger in the east, agreeing with the regressive direction of glacial epoch at the end of Epipleistocene. 相似文献
7.
Five manganese nodules collected from the Northern Mid - Pacific have been analysed for their U and Th isotopes.lt is found that the enrichment of thorium compared to uranium is universal in deep- sea manganese, nodules and in the top sides of the nodules there are large excesses of Th and Pa decreasing exponentially with depth. For each of the nodules, the concordant growth rates are obtained from three different methods: 230Thex 230Thex/232Th and 231Paex.The growth rates of manganese nodules are closely related to the chemical compositions of the nodules and the types of the underlying sediments. The growth rates of five nodules are determined to be in the range of 0.79-7.4 mm/106a, in agreement with those predicted from the chemical compositions of the nodules. By the comparison of the extrapolated 230Thex,230Thex/232 Th and 231PaeX data from the top and bottom surfaces of the nodule from Site M21 yields, the nodule turnover time is (9.83-13.7)×104a. 相似文献
8.
-The present paper reports a new type of coating possessing with excellent anticorrosive properties for marine application. The coatings are urushiol-titanium chelate polymer. The present authors list the anticorrosive spectra of the new coating in various chemicals. The chemical structure of the new coating was studied using IR, GPC, DTA and TG techniques. The relationship between chemical structure and anticorrosive properties is also discussed. 相似文献
9.
The species of iodine in the water samples collected from the west Pacific Ocean and its adjacent seas were analysed. Results show that the concentration of total inorganic iodine appears higher in the south than that in the north of the Equator. The iodide concentration is distributed symmetrically on both sides of the Equator in tropic and subtropic zones and it decreases away from the Equator. Around the Antarctic Divergence iodide concentration approaches its minimum in the surface waters .which only accounts for 10% of the total iodine. The dissolved organic iodine concentration keeps constant generally either in horizontal or in vertical. Discussions on the relationships of iodine with chemical, biological and hydrological factors reveal that iodine has a transitional behavior between conservative and biodepleting elements; I/S ratio is of a certain stability on a vast scale, however, it may be largely affected by organism activity in some zones. Besides, evidence shows that iodine is adsorbed by 相似文献
10.
Lee Minji Kim Jin Ho Kim Yun-Bae Park Chan Hong Shin Kyoungsoon Baek Seung Ho 《海洋学报(英文版)》2020,39(2):107-122
The East Sea(Sea of Japan)is a marginal,semi-closed sea in the northwestern Pacific.The Ulleung Basin area,which is located near the subpolar front of the East Sea,is known to have high primary production and good fisheries in spring season.After episodic wind-driven events during the spring of 2017,horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin area.In addition,growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton biomass.Because of strong northwestern wind,phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this season.The phytoplankton abundances in the coastal stations were significantly higher than offshore and island stations.In contrast,the nutrient and chlorophyll a(Chl a)concentrations and the phytoplankton biomass were quite low in all locations.Bacillariophyceae was dominated group(>75.1%for coastal,40.0%for offshore and 43.6%for island stations).In the algal bioassays,the phytoplankton production was stimulated by N availability.The in vivo Chl a values in the+N and+NP treatments were significantly higher than the values in the control and the+P treatments.Based on the field survey,the higher nutrients in coastal waters affected the growth of diatom assemblages,however,little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay experiments.The growth of phytoplankton depended on the initial cell density.All of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers,and the low level of biomass supply from the coasts resulted in low primary production.Both supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea. 相似文献
11.
热液喷口附近的羽状流中存在明显的化学及浊度异常，通过探测这些异常可判断是否存在热液喷口及确定喷口的具体位置。本文研制了一款可用于探测热液喷口的多通道化学传感器，该传感器具有体积小、精度高的特点，且可在4000米深海中进行工作。该化学传感器共配备五个全固态电极，一个为参比电极，其余四个为离子选择性电极，并且可根据所测量的化学离子进行更换。本文基于该化学传感器共进行了两组实验。在第一组浅海试验中，化学传感器集成了pH，Eh，CO32-和SO42-电极，在浅海海域中测量对应化学量，结果表明该化学传感器可在实际应用中获得高精度、稳定的测量数据。第二组实验为深海热液探测，装配了pH，Eh，CO32-和H2S电极的化学传感器在西南印度洋中脊区域的29次测线中投入使用，共获得有效数据27组。通过对测量所得到的化学量进行分析，本文提出了一种确定热液喷口的化学异常探测方法，若某时间段内Eh和H2S的电势降低，而pH和CO32-的电势上升则可判定存在化学异常。利用该方法对27组有效数据进行分析，共发现5个潜在的热液喷口。实验结果表明，该化学传感器可有效地探测由热液引起的化学异常，适用于实际热液探测中。 相似文献
12.
海洋化学传感器研制的动态评述 总被引：5，自引：0，他引：5
化学海洋学研究数据的获得要方便、经济、高效的分析测试手段,化学传感器则是海洋调查和监测ＤＯ、ｐＨ、ＣＯ２、ＮＨ３－Ｎ和Ｓ（－ＩＩ）等的理想手段和工具。本文评述了６０年代末以来用于天然水体中ＣＯ２、ＮＨ３－Ｎ和Ｓ（－ＩＩ）检测的化学传感器的研制情况,进一步讨论了海洋化学传感器研制所需解决的问题和发展方面,并分析了海洋化学传感器研制进展缓慢的原因。 相似文献
13.
Electric potential due to a ring electrode 总被引：2，自引：0，他引：2
Electrical sensors utilizing ring electrodes mounted on cylindrical rods have been used by several workers to measure the resistivity of marine sediments. As the resistivity of sediment is dependent upon the water content of the sediment, such measurements are extremely valuable for determining the density of sediments. Recently, ring electrodes have also been used in instrumentation to determine fluctuations in the marine sediment-seawater interface due to erosion or deposition. In the past, approximate formulas have been used to evaluate the response of the sensors. In this work, an exact formula is derived, and it is shown that the previous formulas are in error by up to 5%. Although this is not serious for most borehole logging applications, it is essential to use the exact formulas to interpret data from electromagnetic sediment level sensors 相似文献
14.
基于多参数化学传感器的海底热液探测方法研究 总被引：1，自引：0，他引：1
基于热液及其羽状流的化学异常提出了一种海底热液的化学式探测方法。根据自行开发的Eh.Ag/Ag2S和pH三种化学电极,设计了多参数化学传感器系统。通过海试证明多参数化学传感器可灵敏地检测出由热液异常引起的化学量变化,并在长达半年的多次使用中表现出其稳定性好、寿命长的特点。在东太平洋中脊(EPR)赤道区域和西南印度洋中脊(SWIR)的60条测线中,获得有效测线55条,其中在29条测线上发现明显或可能的热液异常。研究表明,应用多参数化学传感器探测进行海底热液化学异常,是一种有效的方法。 相似文献
15.
A microprocessor-based CTD (conductivity-temperature-depth) sensor unit is described in which the microprocessor is used to vary the analog-to-digital conversion process to achieve 16-bit resolution at a measurement rate of 500 measurements per second, or 18-bit resolution at 30 measurements per second. Software control of resolution, sampling rate, and sampling sequence permit the sensor unit to be software-configured for a wide variety of missions. Pressure and conductivity sensors are expected to substantially improve the system accuracy. The conductivity cell design has six electrodes which are all relatively remote from the external measurement volume (approximated by a 2-cm diameter sphere). This so called recessed-electrode concept is expected to eliminate calibration drift due to contamination of the electrodes and the insulating surfaces of the cell, thus ensuring excellent long-term stability 相似文献
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《Deep Sea Research Part I: Oceanographic Research Papers》2006,53(3):561-573
We report on a direct and autonomous measure of new production based on time series observations with ISUS nitrate sensors deployed for several years on oceanographic moorings offshore of Monterey Bay, California. The amplitude of diel cycles of surface nitrate is correlated with rates of primary production measured by 14C uptake. The drawdown of nitrate averaged over a year is about 70% of the fixed nitrogen needed for biomass production. Phytoplankton biomass predicted from the diel nitrate uptake and a fixed rate constant for nitrate loss (grazing and export) matched observations over the annual cycle. New production rates determined with the moored sensors are highly correlated with nitrate concentration and the intensity of upwelling. The implication is that arrays of moorings with chemical sensors can now be used to estimate new production of biomass and ecosystem processes over multiple temporal and spatial scales. 相似文献
19.
A flexible configuration for an array of sensors has been developed for measurements in energetic regions of the ocean where the flow has high spatial and temporal variability. Central to the system is a two-axis electromagnetic current meter that measures the flow through a ducted volume containing a uniform magnetic field and nonprotruding electrodes flush with the duct surfaces. This geometry minimizes the electrode boundary-layer effect on the output, thus improving calibration and reducing fouling and damage potential. An inexpensive amplifier designed for low signal-to-noise ratios is employed to produce very low zero drift during operation 相似文献
20.
光纤化学/生物传感技术在海洋环境监测中的应用 总被引：3，自引：0，他引：3
本文通过光纤溶解氧、 p H、湿度等化学传感探头及发光菌水质毒性监测生物传感探头的研制 ,开发出了一类能用于环境监测的新型传感器。本文的创新之处在于传感探头的设计与包装 ,以及数种可逆性、选择性、稳定性、使用寿命、响应时间、灵敏度等响应特性具佳的化学及生物传感膜的配方和制作技术。利用这些技术 ,通过对光纤探头的设计与包装 ,可以实现在现场及实验室模拟条件下对样品的选择性检测。研制的传感器能广泛应用于海洋污染调查、内河水质评价、水产养殖、工矿企业水气排污自检等诸多方面。 相似文献