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1.
Variations of the suspended matter and the particulate organic carbon in the entry of the Gironde Estuary,France 总被引：1，自引：0，他引：1
The effects of using different types of glass fiber filters (GF/F, GF/C) and of sample treatments were evaluated. Studies
on the variation of suspended matter (SM) and particulate organic carbon (POC) showed that: 1) the transversal and day to
night variations are important and must be taken into account in order to get a correct river flux; 2) no regular seasonal
variations of SM and POC were observed, as they are controlled essentially by the climatological, hydrologic, physiochemical,
biological, and geological conditions of the drainage area.
Contribution No 2246 from the Institute of Oceanology, Chinese Academy of Sciences. 相似文献
2.
A one-year field study was conducted to determine the conversion ratio of phytoplankton biomass carbon (Phyto-C) to chlorophyll-a (Chl-a) in Jiaozhou Bay, China. We measured suspended particulate organic carbon (POC) and phytoplankton Chl-a samples collected in surface water monthly from March 2005 to February 2006. The temporal and spatial variations of Chl-a and POC concentrations were observed in the bay. Based on the field measurements, a linear regression model II was used to
generate the conversion ratio of Phyto-C to Chl-a. In most cases, a good linear correlation was found between the observed POC and Chl-a concentrations, and the calculated conversion ratios ranged from 26 to 250 with a mean value of 56 μg μg−1. The conversion ratio in the fall was higher than that in the winter and spring months, and had the lowest values in the
summer. The ratios also exhibited spatial variations, generally with low values in the near shore regions and relatively high
values in offshore waters. Our study suggests that temperature was likely to be the main factor influencing the observed seasonal
variations of conversion ratios while nutrient supply and light penetration played important roles in controlling the spatial
variations. 相似文献
3.
ImODUonONGrowingconcemovertheprobboofobnoxiouswaterbloornspromPtedagreatdealofresearchintothebiologyofblue-grmalgae(Reynolds&Walsby,l975,Reynothe,l984).PreviousstudiesonMimptiSwereaimedatitSphySinlogicalcharaCteristirsindudinggroWthandbuoyancyraegnolds,l975),0Vendteringandphotosynthesisfea-turesffokamuraetal.,l984,Takamura,l985),nutrientdemandsoprlofTetal.,l952,0kado&Sudo,l979).TherearerepoffethatMicropstiswasawidelydistributalspedesthatcouldeasilybloomWhenambientenvironrnentSweresuit… 相似文献
4.
The effects of estuarine processes on the fluxes of inorganic and organic carbon in the Yellow River estuary 总被引：1，自引：0，他引：1
Riverine carbon flux is an important component of the global carbon cycle. The spatial and temporal variations of organic
and inorganic carbon were examined during both dry and wet seasons in the Yellow River estuary. Concentrations of dissolved
organic carbon (DOC) and dissolved inorganic carbon (DIC) in the Yellow River during dry seasons were higher than those during
wet seasons. The effective concentrations of DOC (CDOC*) were higher than the observed DOC at zero salinity. This input of DOC in the Yellow River estuary was due to sediment desorption
processes in low salinity regions. In contrast to DOC, the effective concentrations of DIC were 10% lower than the DIC measured
at freshwater end, and the loss of DIC was caused by CaCO3 precipitation in low salinity region. Particulate organic carbon (POC) and particulate inorganic carbon (PIC) contents of
the particles stabilized to constant values (0.5%±0.05% and 1.8%±0.2%, respectively) within the turbidity maximum zone (TMZ)
and showed no noticeable seasonal variations. A rapid drop of PIC and rise of POC occurred simultaneously outside the TMZ
due to an intense dilution of riverine inorganic-rich particles being transported into a pool of aquatic organic-poor particles
outside the TMZ. Annually, the Yellow River transported 6.95×105 t of DIC, 0.64×105 t of DOC, 78.58×105 t of PIC and 2.29×105 t of POC to the sea. 相似文献
5.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅ“ｇｒｅｅｎｈｏｕｓｅｅｆｆｅｃｔ”ｒｅｓｕｌｔｉｎｇｆｒｏｍｔｈｅｉｎｃｒｅａｓｉｎｇｃａｒｂｏｎｄｉｏｘｉｄｅｉｎｔｈｅａｔｍｏｓｐｈｅｒｅｓｉｇｎｉｆｉ ｃａｎｔｌｙａｆｆｅｃｔｓｔｈｅｇｌｏｂａｌａｖｅｒａｇｅｔｅｍｐｅｒａｔｕｒｅ (Ｄｅｔｅｒ,1 978) ,ｈａｓｄｒａｗｎｔｈｅａｔｔｅｎｔｉｏｎｏｆｓｃｉｅｎｔｉｓｔｓａｒｏｕｎｄｔｈｅｗｏｒｌｄ .Ｓｃｉｅｎｔｉｓｔｓｃｏｎｓｉｄｅｒｔｈａｔｋｎｏｗｌｅｄｇｅｏｆｔｈｅｏｃｅａｎ’ｓｃａｐａｃｉｔｙｔｏａｂｓｏｒ… 相似文献
6.
Investigation of dissolved organic carbon (DOC) and particulate organic carbon (POC) at 12 stations in Yantal Sishili Bay in May, August, and November of 1997 and March and May of 1998 showed that DOC concentrations varied from 1.14 mg/L to 5.35 mg/L; that the average values at all staticrLs ineach entise varied from 1.52 mg/L to 2.12 mg/L; that POC concentrafions varied from 0.049 mg/L to 1.411mg/L; and averaged 0.159 mg/L to 0.631 mg/L in each cruise. Horizontal distribution of DOC was influ-enced by factors such as continental input, organism activity, temperature, aquieulture environment, etc. The higher POC concentration occurred along the coast. The vertical distribution of DOC and POC changed obviously in spring and summer, but not obviously in autumn and winter. DOC concentration was highest in summer and POC in spring; both were lowest in winter. The seasonal change of DOC was con-sistent with primary productivity seasonal variation, and that of POC was consistent with ehlorophyll-a sea-sanal variation. The seasonal change trend of the C/N ratio of dissolved organic matter was obvious, but the C/N ratio of particulate organic matter had no such trend. 相似文献
7.
During the Second Chinese National Arctic Expedition (CHINARE) from July to September 2003, depth profiles of dissolved and particulate 234Th in upper water columns were collected at two stations of BR03 and BR24 in the Bering Sea. 234Th was sampled by using a traditional Fe(OH)3 co-precipitation technique, which is a reliable approach to 234Th measurement. We observed 234Th excess at station BR03 below the euphotic zone, which was possibly due to the intensive remineralization of particulate matter. Particulate organic carbon (POC) export fluxes were estimated from a one-dimensional irreversible steady state model of 234Th fluxes together with measurements of the POC/234Th ratio on the suspended particles. The POC export fluxes from the euphotic zone were 11.66 and 11.69 mmol C m-2 d-1 at BR03 and BR24 stations,respectively. The ratios of POC fluxes to primary production at the two stations were about 0.5 and 0.59, respectively, probably due to the presence of large phytoplankton (in particular diatoms). 相似文献
8.
Concentrations of dissolved and particulate organic carbon (DOC and POC) were documented in 1996–1997 at 4 different trophic
state stations in Donghu Lake, a typical shallow eutrophic lake along the Changjiang River's middle reaches. The mean concentrations
of DOC were 15.11±3.26, 15.19±4.24, 14.27±3.43, and 13.31±3.30 mg/L in Station I, II, III, and IV, respectively. The DOC concentrations
of the studied area were very similar to that in other lakes along the Changjiang River's middle reaches. The POC mean of
the whole lake was 5.01 mg/L due to the large amount of organic detritus of both allochthonous and autochthonous origin. Significant
linear relationship was found between POC and chlorophyll a at all 4 stations, which presumably reflect that phytoplankton,
its exudates and its metabolic products were the main contributors to the POC pool in the water column. The slope of such
linear relationship at Station IV was significantly steeper than that at Station I, II and III. In addition, the DOC/POC ratios
(mean value: 4.40) indicated that the organic detritus was the most important component of the particulate organic matter;
in other works, next to organic detritus, phytoplankton dominated the particulate organic matter in Donghu Lake.
Project 39770146, 39430101 supported by NSFC and the State Key Laboratory of Freshwater Ecology and Biotechnology, affiliated
to the Institute of Hydrobiology, Chinese Academy of Sciences. 相似文献
9.
Land use effects on soil organic carbon,microbial biomass and microbial activity in Changbai Mountains of Northeast China 总被引：2，自引：0，他引：2
Xiangmin Fang Qingli Wang Wangming Zhou Wei Zhao Yawei Wei Lijun Niu Limin Dai 《中国地理科学(英文版)》2014,24(3):297-306
Land use changes are known to alter soil organic carbon （SOC） and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and microbial properties in the Changbai Moun- tains of Northeast China is meager. Soil carbon content, microbial biomass carbon （MBC）, basal respiration and soil carbon mineraliza- tion were studied in five selected types of land use： natural old-growth broad-leaved Korean pine mixed forest （NF）; spruce plantation （SP） established following clear-cutting of NF; cropland （CL）; ginseng farmland （GF） previously under NF; and a five-year Mongolian oak young forest （YF） reforested on an abandoned GF, in the Changbai Mountains of Northeast China in 2011. Results showed that SOC content was significantly lower in SP, CL, GF, and YF than in NF. MBC ranged from 304.4 mg/kg in CL to 1350.3 mg/kg in NF, which was significantly higher in the soil of NF than any soil of the other four land use types. The SOC and MBC contents were higher in SP soil than in CL, GF, and YF soils, yielding a significant difference between SP and CL. The value of basal respiration was also higher in NF than in SP, CL, GF, and YF. Simultaneously, higher values of the metabolic quotient were detected in CL, GF, and YF soils, indicat- ing low substrate utilization of the soil microbial community compared with that in NF and SP soil. The values of cumulative mineral- ized carbon and potentially mineralized carbon （Co） in NF were significantly higher than those in CL and GF, while no significant dif- ference was observed between NF and SP. In addition, YF had higher values of Co and C mineralization rate compared with GF. The results indicate that conversion from NF into agricultural land （CL and GF） uses and plantation may lead to a reduction in soil nutrients （SOC and MBC） and substrate utilization efficiency of the microbial community. By contrast, soils below SP were more conducive to the preservation of soil organic matter, which was reflected in the comparison of microbial indicators among CL, GF, and YF land uses. This study can provide data for evaluating soils nutrients under different land use types, and serve as references for the rational land use of natural forest in the study area. 相似文献
10.
To evaluate the particle dynamics and estimate the POC (particulate organic carbon) export flux from the euphotic zone in
the western Arctic Ocean, 234Th-238U disequilibrium was applied during the second Chinese National Arctic Research Expedition (July 15–September 26, 2003). The
POC export fluxes are estimated from the measured profiles of the 234Th/238U activity ratios and the POC/PTh ratios. The average residence times of the particulate and dissolved 234Th in the euphotic zone are 33 d and 121 d, and their average export fluxes are 480 dpm/m2d and 760 dpm/m2d, respectively. The scavenging and removal processes of particle reactive elements are active in the upper layer of the Chukchi
Sea. The average residence time of 234Th increases from shelf to basin, while the export fluxes of 234Th decrease. The estimated POC export fluxes from the euphotic zone vary from 2.1 to 20.3 mmol/m2d, indicating that the western Arctic Ocean is an important carbon sink in summer due to efficient biological pump. 相似文献
11.
通常岩石化学变异有两种趋势:地幔残余(R)趋势表明,地幔源曾遭受了亲岩浆元素的贫化或辉石矿物相的消耗过程;岩浆结晶趋势及其矿物解指示了玄武质(M_1)岩浆和超镁铁质(M_2)岩浆的两种结晶系列。松树沟岩体NiO— Cr_2O_3、MgO—FeO的图解结果表明与上述结论相同。因此,松树沟超镁铁岩亦可区分为地幔残余(R)型和岩浆结晶(M)型等两种成因类型,属复合成因岩体。 相似文献
12.
罗非鱼4个选育群体遗传结构SSR分析 总被引：2，自引：0，他引：2
采用SSR分子标记分析了吉富品系罗非鱼的两个家系(GF1和GF2)以及奥利亚罗非鱼(Fo)和奥本尼罗罗非鱼(Fn)群体的遗传结构。结果显示,扩增后等位基因数为3～8个,随引物不同而异,14对引物共扩增60个等位基因,扩增片断大小在102～267 bp之间。微卫星分析表明,奥本尼罗罗非鱼(Fn)的平均观测杂合度(0.764 3)和平均期望杂合度(0.519 6)均最高,吉富尼罗罗非鱼(GF1)平均多态信息含量(0.419 5)最高;吉富尼罗罗非鱼(GF2)平均观测杂合度(0.614 2),奥利亚罗非鱼(Fo)的平均期望观测度(0.446 6)、平均多态信息含量(0.359 2)最低;因此,吉富鱼(GF1)的遗传多样性最高,奥利亚的遗传多样性最低。Hardy-Weinberg平衡遗传偏离指数(D)奥利亚(Fo)和尼罗(Fn)(0.463 4和0.478 9)明显高于吉富的两家系(0.234 1和0.250 0)。Fo与GF2间遗传距离(0.477 0)最大;而GF1和GF2间的遗传距离(0.302 7)最小,遗传相似系数(0.607 3)最大,可推断新一代吉富罗非鱼与本地选育群体有相对较远的亲缘关系,更具杂种优势。 相似文献
13.
Observational data obtained during the TOGA-COARE IOP in the "warm pool" area of the West-ern Tropical Pacific were used to analyze some characteristics of the intraseasonal variations in the mixedlayer. The influence of westerly burst and rainfall on SST, salinity. and mixed layer depth are discussed.There are two pairs of counteracting processes in the "warm pool" mixed layer: (1) The increase of mixedlayer depth caused by local westerly bursts and the decrease of mixed layer depth caused by larger scaleeasterly relaxation;(2) the vertical mixing by local wind and the strong stratification due to rainfall in themixed layer. Some possible mechanisms through the interactions between the intraseasonal time scale varia-tions of the oceanic mixed layer and atmospheric low frequency oscillations are revealed. 相似文献
14.
为解决地物杂波区内降雨回波精确定量化问题,本文利用蒙特卡洛理论,在9836C微型计算机上建立了在不同速度方差的地物杂波区内,对不同速度方差的降雨回波模拟信号经地物杂波抑制器处理后的回波功率损失计算软件系统,并提出实现杂波区内降雨回波精确定量化综合处理方案。 相似文献
15.
Size-fractionated 210Po and 210Pb, in the size fractions >0.4 μm, >2 μm and >10 μm, were examined to determine the seasonal variability of particulate fluxes
in Xiamen Bay. Good correlations between 210Po and particulate organic carbon (POC) or non-Particulate Organic Matter (nPOM) suggested that 210Po can be used to trace the export fluxes of POC and nPOM. Both steady-state (SS) model and nSS model were used to evaluate
fluxes of size-fractionated 210Po, results showed that nSS model was better than the SS model in coastal areas. Based on the nSS model, size-fractionated
POC fluxes decreased with increasing particle size. For the particle size studied, maximum POC fluxes occurred in autumn,
followed by spring, winter, and summer. Fluxes of nPOM were an order of magnitude higher than the corresponding size-fractionated
POC fluxes. Differences between size-fractionated nPOM fluxes indicated that hydrodynamic conditions were the main factor
regulating transportation of particulate out of the inner Bay. In winter most particulates, including >10 μm particles, were
transported under the strongest hydrodynamic conditions. In contrast, only a fraction of the <2 μm particulates were transported
from the inner Bay in spring. This study suggested that 210Po is a powerful tracer of seasonal particulate export in coastal seas. 相似文献
16.
祝意青 《大地测量与地球动力学》1996,(2)
分析讨论了１９９１年１月２日和１９９２年１月１２日两次中强地震前重力异常变化及其与地震的对应关系，指出这两次地震都发生在重力变化高梯度带附近。 相似文献
17.
本文着重分析了青藏高原500hpa高压因伊朗高压脊东伸、分裂产生过程中和东移过程中,西风带波动、印度季风低压以及100hpa层流型的一系列变化,从而说明青藏高原500hpa高压产生和东移的环流背景。 相似文献
18.
Effects of land management practices on labile organic carbon fractions in rice cultivation 总被引：1，自引：1，他引：0
SHAO Jing＇an LI Yangbing WEI Chaofu XIE Deti 《中国地理科学(英文版)》2009,19(3):241-248
A research trial with four land management practices, i.e., traditional tillage-fallow (TTF), traditional tillage-wheat (TTW),
conservation tillage-fallow (CTF) and conservation tillage-wheat (CTW), was sampled in the 15th year after its establishment
to assess the effects of different management practices on labile organic carbon fractions (LOCFs), such as easily oxidizable
organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC) and microbial biomass carbon (MBC)
in a typical paddy soil, Chongqing, Southwest China. The results indicated that LOCFs were significantly influenced by the
combination of no-tillage, ridge culture and crop rotation. And, different combination patterns showed different effectiveness
on soil LOCFs. The effects of no-tillage, ridge culture and wheat cultivation on EOC, DOC, POC and MBC mainly happened at
0–10cm. At this depth, soil under CTW had higher EOC, DOC, POC and MBC contents, compared to TTF, TTW and CTF, respectively.
Moreover, the contents of LOCFs for different practices generally decreased when the soil depth increased. Our findings suggest
that the paddy soil in Southwest China could be managed to concentrate greater quantities of EOC, DOC, POC and MBC.
Foundation item: Under the auspices of Key Project of National Natural Science Foundation of China (No. 40231016) 相似文献
19.
本文讨论了在我国海平面研究中常用的线性回归和滑动平均方法确定平均海平面长趋势变化存在的问题,指出当海平面观测系列包含有周期变化成分时,上述两种方法通常不能得到正确的结果。建议先对观测序列作显著周期分析,然后以线性趋势项与显著周期项拟合观测序列的方法来确定平均海面的长趋势变化。 相似文献
20.
234Th-238u disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon (POC), 234Th (including both dissolved and particulate) and 238U in the water column at three stations were determined. The profiles of 234Th/238U activity ratio at the three stations all showed consistent 234Th deficit as compared to 238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate 234Th and a steady state box model, the dissolved 234Th scavenging rates, the particulate 234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol.m-2.d-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea. 相似文献