Effects of light quality on growth rates and pigments of Chaetoceros gracilis(Bacillariophyceae)     

LI Yongfu  LI Ruiqian  YI Xiaoyan 《海洋湖沼学报（英文）》2020,(3):795-801

Light is an important parameter in algal culturing.In this work,the effects of different light qualities on growth of the marine diatom Chaetoceros gracilis are evaluated.The cells were cultured under light quantum flux density of 60μmol photons/(m2·s)with nine light qualities:LED red light(LR),LED blue light(LB),LED red plus LED blue light(LR+LB),LED white light(LW),fluorescent white light(FW),and combinations of LW and FW lights with increased proportions of red or blue light(FW+LR,FW+LB,LW+LR,and LW+LB).Blue light promoted the growth of C.gracilis largely.Three light qualities,FW+LR,LW+LR,and LR,resulted in the lowest growth rate.Both chlorophyll and carotenoids reached the highest level under LB and the lowest level under LR among monochromatic light sources;however,increasing of the proportion of blue or red light in the white light induced an increase of the chlorophyll and carotenoid concentrations.Light absorption ability of microalgae was critical for the growth of these organisms,as we observed a positive correlation between the extinction coefficient at different wavelengths and the specific growth rate.These findings are of importance to improve the culturing of this alga in bioreactors.  相似文献   

Environmental Effects on Differential Organic Matter Enrichment of the Lower Cambrian Shale, Tarim Basin, NW China     

ZHAO Yawen  WU Guanghui  YI Yan  CHEN Yongquan  WU Yonghong  JING Bing  WANG Jian 《《地质学报》英文版》2023,97(5):1523-1537

Early Cambrian shale is an important petroleum source rock around the world. Because of little drilling data and poor seismic data, until recently, organic matter enrichment of the Lower Cambrian Yuertusi and Xishanbulake formations shale is still an enigma in the Tarim Basin, northwestern China. Total organic carbon (TOC), major and trace element data of Cambrian shale samples from five boreholes have been analyzed to decipher the mechanism of the organic matter enrichment. The results show that the shales deposited in the western restricted intraplatform have much higher TOC contents (3.2%–19.8%, on average 11.0%) than those from the eastern basin (2.2%–10.2%, on average 4.5%). The paleoproductivity proxies (Ba, Ba/Al, P/Al) in the western restricted platform are much higher than those in the eastern basin. The trace element indicators such as V/Cr, Ni/Co, Mo–TOC and MoEF–UEF suggest an anoxic environment across the basin, but a more restricted environment in the western intraplatform. The paleoproductivity rather than anoxic condition and hydrothermal activity are concluded to have resulted in the differentiation of the organic matter enrichment from the western intraplatform to eastern basin in the early Cambrian shales; the restricted environment was favorable for paleoproductivity and preservation of organic matter.  相似文献   

THE DECADAL CLIMATE VARIABILITY AND THE ANOMALOUS ENSO DEVELOPMENTS IN 1990S^*          下载免费PDF全文

ZHANG Qin  DING Yihui  YI Lan 《Acta Meteorologica Sinica》2002,16(1):1-20

By using the wavelet transform method,the ENSO (2-7 a) signal and the decadal variability (8-20 a) are filtered out from the long-term SST data sets in order to investigate characteristics of the decadal variability and its impact on the ENSO.It is found that there are two different kinds of decadal SSTA modes-horseshoe and horse saddle patterns in the tropical Pacific.The horseshoe pattern represents that the decadal SSTA variability in the central Pacific is in phase with that in the eastern Pacific.The horse saddle pattern is named that they are out of phase.The former constituted the decadal variability before 1990s and the latter mainly prevailed during 1990s.As the response of atmosphere to the ocean,two decadal wind patterns appear in association with the SST decadal modes.One is characterized by anomalous development of the zonal wind,the other by anomalous development of the meridional wind.These two kinds of modes can also be regarded as different phases of the decadal oscillation.Further studies have shown that the influences of the two kinds of modes on the ENSO are different.The horse saddle mode has a stronger impact on the ENSO than the horseshoe mode.A possible mechanism for the influence of the decadal variability on the ENSO signal is presented.The central part of the thermocline along the equatorial Pacific moves up or down simultaneously with its eastern part while the decadal variability bears the horseshoe pattern.But the two segments of the thermocline in the central and eastern Pacific act oppositely while the decadal variability shows the horse saddle pattern.In this case it has an-influence on the individual ENSO'events by the superposition of the decadal variability.  相似文献   

Soil organic carbon storage and soil CO_2 flux in the alpine meadow ecosystem     

TAO Zhen    SHEN ChengDe  GAO QuanZhou  SUN YanMin  YI WeiXi & LI YingNian School of Geography  Planning  Sun Yat-sen University  Guangzhou  China  Guangzhou Institute of Geochemistry  Chinese Academy of Sciences  Guangzhou  China  Northwest Plateau Institute of Biology  Chinese Academy of Sciences  Xining  China 《中国科学D辑(英文版)》2007,50(7)

High-resolution sampling,measurements of organic carbon contents and 14C signatures of selected four soil profiles in the Haibei Station situated on the northeast Tibetan Plateau,and application of 14C tracing technology were conducted in an attempt to investigate the turnover times of soil organic car-bon and the soil-CO2 flux in the alpine meadow ecosystem. The results show that the organic carbon stored in the soils varies from 22.12×104 kg C hm-2 to 30.75×104 kg C hm-2 in the alpine meadow eco-systems,with an average of 26.86×104 kg C hm-2. Turnover times of organic carbon pools increase with depth from 45 a to 73 a in the surface soil horizon to hundreds of years or millennia or even longer at the deep soil horizons in the alpine meadow ecosystems. The soil-CO2 flux ranges from 103.24 g C m-2 a-1 to 254.93 gC m-2 a-1,with an average of 191.23 g C m-2 a-1. The CO2 efflux produced from microbial decomposition of organic matter varies from 73.3 g C m-2 a-1 to 181 g C m-2 a-1. More than 30% of total soil organic carbon resides in the active carbon pool and 72.8%―81.23% of total CO2 emitted from or-ganic matter decomposition results from the topsoil horizon (from 0 cm to 10 cm) for the Kobresia meadow. Responding to global warming,the storage,volume of flow and fate of the soil organic carbon in the alpine meadow ecosystem of the Tibetan Plateau will be changed,which needs further research.  相似文献   

Earrhquake recurrence on whole active fault zones and its reation to that on indivdual fault -segments     

YI Gui-xi 《地震学报(英文版)》2000,13(5):563-574

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基于SBDART辐射传输模型的夜间辐射雾自动检测及时间序列分析     

张伟康  马慧云  邹峥嵘  何卓臣  赵国庆 《国土资源遥感》2014,(2)

如何确定合适的阈值来区分夜间辐射雾、晴空地表和中高云一直是雾检测研究的重点。圣巴巴拉DISORT大气辐射传输模型(Santa Barbara DISORT atmospheric radiative transfer,SBDART)可模拟雾顶亮度温度。基于该模型获取MODIS B20与B31波段的亮温差(brightness temperature difference,BTD),将其用于夜间辐射雾检测。以MODIS卫星数据为可行性试验数据,用国家卫星气象中心提供的地面验证数据进行验证,结果表明,使用该模型监测夜间雾的准确率达78.3%,误判率为21.7%,可靠性指标为0.643,Kappa系数为0.730。为进一步验证方法的稳定性,选取8景卫星序列图像进行时间序列分析,结果显示Kappa系数均值为0.744,说明应用当前阈值方法对MODIS夜间雾检测具有可适用性。该方法为夜间雾预报和夜间雾参数反演提供了有效的参考。  相似文献   

Enclosed Extent of the Saline Water and its Constraints on the Sedimentary and Salt Forming Characteristics: A Case Study of the Paleogene Playas in?Hoh Xil Basin     

GONG Daxing  YI Haisheng  ZHOU Jiayun  WU ChiHu  XIA Guoqing 《《地质学报》英文版》2014,88(Z1):320-322

正1 Introduction There is a long period of hot,arid climates in the Jurassic-Neogene,in the eastern of the Neo-Tethys where is been called Western Yunnan—Qiangtang tectonic belt(Zheng et al.,2010).Especially in the Paleogene,under the control of the planetary winds and the north subtropical high pressure belts,a ribbon arid,semi-arid  相似文献   

Study on Copper Exploration and Development Potential in Western China     

YE Jinhu  YI Jining  FANG Jie  KE Junjun  ZHANG Shunchang 《地质学报》2014,88(Z2):1315-1316

Please?refer?to?the?attachment(s)?for?more?details.  相似文献   

A numerical study on matching relationships of gravity waves in nonlinear interactions     

HUANG KaiMing  ZHANG ShaoDong  YI Fan 《中国科学:地球科学(英文版)》2013,(6):1079-1090

Applying a fully nonlinear numerical scheme with second-order temporal and spatial precision,nonlinear interactions of gravity waves are simulated and the matching relationships of the wavelengths and frequencies of the interacting waves are discussed.In resonant interactions,the wavelengths of the excited wave are in good agreement with the values derived from sum or difference resonant conditions,and the frequencies of the three waves also satisfy the matching condition.Since the interacting waves obey the resonant conditions,resonant interactions have a reversible feature that for a resonant wave triad,any two waves are selected to be the initial perturbations,and the third wave can then be excited through sum or difference resonant interaction.The numerical results for nonresonant triads show that in nonresonant interactions,the wave vectors tend to approximately match in a single direction,generally in the horizontal direction.The frequency of the excited wave is close to the matching value,and the degree of mismatching of frequencies may depend on the combined effect of both the wavenumber and frequency mismatches that should benefit energy exchange to the greatest extent.The matching and mismatching relationships in nonresonant interactions differ from the results of weak interaction theory that the wave vectors are required to satisfy the resonant matching condition but the frequencies are permitted to mismatch and oscillate with amplitude of half the mismatching frequency.Nonresonant excitation has an irreversible characteristic,which is different from what is found for the resonant interaction.For specified initial primary and secondary waves,it is difficult to predict the values of the mismatching wavenumber and frequency for the excited wave owing to the complexity.  相似文献   

Evidence of Middle Pleistocene hominin migration in the Qinling Mountains (central China) from the Miaokou Paleolithic site     

LIU Dengke  SUN Xuefeng  HU Xuzhi  YI Liang  GUO Xiaoqi  WANG Yichao  WANG Shejiang  LU Huayu 《地理学报(英文版)》2022,32(2):358-374

The Qinling Mountain Range (QMR) spans a large region in China and is an im-portant area of hominin activities.Many Paleolithic sites are found in Bahe,South Luohe,and Hanjiang river valleys in the northern,eastern,and southern part of the range,respectively.The Danjiang River valley acts as a channel connecting these valleys and stretches from the north to the south of the QMR.The previous dating of the Paleolithic sites in the Danjiang valley mainly relied on geomorphologic comparison,stratigraphic correlation,fossil charac-teristics,and Paleolithic artifacts,indicating a lack of absolute data.In this study,we con-ducted a detailed geochronological investigation of the entire valley,and selected an ideal site--the Miaokou profile.Based on the identification of the Ioess-paleosol sequences,opti-cally stimulated luminescence,and magnetostratigraphy,the Paleolithic artifacts of the Mi-aokou site located within the S5 and S6 layers of the profile belong to ～0.6-0.7 Ma.This suggests that the Paleolithic site is an old site in the Danjiang River valley,and this period also witnessed a rapid increase in the number of hominin sites during the Middle Pleistocene.Combining our results with previous reports across the QMR,we propose that the Danjiang River valley might have been a corridor for hominin migration,and is worthy of further inves-tigation.  相似文献