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1.
Cen  Jingyi  Wang  Jianyan  Huang  Lifen  Ding  Guangmao  Qi  Yuzao  Cao  Rongbo  Cui  Lei  L&#;  Songhui 《中国海洋湖沼学报》2020,38(3):722-732
Journal of Oceanology and Limnology - On May 24–29, 2019, a bloom occurring in Pingtan coastal areas of Fujian Province caused mass mortality of cage-cultured fish (Plectorhinchus cinctus and...  相似文献   

2.
In order to clarify the geographic distribution and change of natural Larix gmelinii forest in carbon storage in Daxing’anling mountains (Great Khingan Range) in North China’s Inner Mongolia, an area-irrelevant conversion equation of biomass from timber volume in the form of B = 0.6966 V was developed by using survey data. Based on the equation, the carbon storage was estimated at 190.172 Tg, and the average carbon density was 41.659 Mg/hm2 (area 4.565 × 106 hm2). Carbon stored in standing trees was predominantly distributed in mid-age and mature forests and mainly stocked in the northern part of the study area. Assuming the carbon density of intact area as the maximum value, the potential carbon storage in the entire study area would be 263.674 Tg, approximately 1.4 times of the actual level. Over the period of 1995 to 2010, the carbon storage and carbon density increased by 3.260 Tg and 0.224 Mg/hm2, respectively, indicating a weak carbon sink. Comparing with China’s national average level, the carbon density in this area is not as high as expected. Forest quality in terms of carbon capacity is expected to be enhanced by appropriate management schemes under the in-implementation program of forest protection.  相似文献   

3.
In this study, a coniferous tree species (Pinus tabuliformis Carr.) was investigated at a moderate-altitude mountainous terrain on the southern slope of the middle Qinling Mountains (QLM) to detect the trends in carbon isotope ratio (δ13C), leaf nitrogen content (LNC) and stomatal density (SD) with altitude variation in north-subtropical humid mountain climate zone of China. The results showed that LNC and SD both significantly increased linearly along the altitudinal gradient ranging from 1000 to 2200 m, whereas leaf δ13C exhibited a significantly negative correlation with the altitude. Such a correlation pattern differs obviously from that obtained in offshore low-altitude humid environment or inland high-altitude semi-arid environment, suggesting that the pattern of increasing δ13C with the altitude cannot be generalized. The negative correlation between δ13C and altitude might be attributed mainly to the strengthening of carbon isotope fractionation in plants caused by increasing precipitation with altitude. Furthermore, there was a remarkable negative correlation between leaf δ13C and LNC. One possible reason was that increasing precipitation that operates to increase isotopic discrimination with altitude overtook the LNC in determining the sign of leaf δ13C. The significant negative correlation between leaf δ13C and SD over altitudes was also found in the present study, indicating that increases in SD with altitude would reduce, rather than enhance plant δ13C values.  相似文献   

4.
Pure fraction (92% - 95%) of phagocytes (FP) and a mixture of amoebocytes (62%) and morula cells (38 % )-FPMC- of the holothurian Eupentacta fraudatrix ( Holothuroidea,Dendrochirota ) were obtained by using ficoll-verographine step gradient. Basal production of reactive oxygen species (ROS) in FP quantified by using reduction of nitroblue tetrazolium (NBT) was more than twice that in FPMC. Thermostable toxin of Yersinia pseudotuberculosis (TST) at differentconcentrations ( 0.2; 0.5; 2.5 μg/ml, but not 0.1 μg/ml) stimulated NBT reduction in FPMC after 24 h incubation. In FP, TST at concentrations of 0.1 and 0.2 μg/ml inhibited and at concentrations of 0.5 and 2.5 μg/ml stimulated NBT reduction after 24 h incubation. Maximal effect was observed in FP and FPMC at TST concentrations of 0.5 and 0.2 μg/ml, respectively. Addition of catalase (0.7 μg/ml) to the cells treated with TST (2.5 μg/ml) was followed by a decrease in NBT reduction compared to that under toxin treatment alone. TST stimulated superoxide dismutase activity in ccncentration-dependent manner (maximum at 0.5 μg/ml concentration in FP) after 24 htreatment, and this stimulation was prevented by a commercial catalase. Plant lectin concanavalin A stimulated NBT reduction more than 5-fold in FPMC compared to the control. With addition of TST, lectin stimulated ROS to lesser extent than that with lectin alone. When catalase, TST, and lectin were added into the FPMC simultaneously, ROS increase was similar to that under lectin treatment alone. On the whole, data obtained indicated that ROS generation in holothurian coelomocytes especially occurs in both stimulated and not stimulated phagocytes, and that changes in ROS production by these cells may be one of the mechanisms of antibacterial protection of holothurians.  相似文献   

5.
To study the influence of human activity on natural lake, chironomid fauna change in the 700–560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced a whole eutrophication process due to human hemp-retting in Post-Medieval based on the history record and pollen analysis, which was confirmed by mollusc and ostracod analysis. However, the response of chironomid and mollusc to retting was the strongest with ostracod a little behind. It proved that cultural eutrophication existed in history and could be recovered by itself despite of some long-term unachievable destroy. And it was most important for external nutrient to be cut off during lake restoration even in ancient times.  相似文献   

6.
To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat (48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose (δ13Ccellulose) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ13Ccellulose-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations (AMO). The results show that humification decreased and the δ13Ccellulose-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant drying condition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ13Ccellulose-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.  相似文献   

7.
1 Introduction The industrial location is always the focus in academic circles and any analysis on industrial location can not avoid the agglomeration mechanism formed as the result of the industrial location. The study on the industrial location has become the focus for the massive theoretical location problems about agglomeration since the 1970s, which has a great influence on the formation of the in- dustrial location. In order to make more study of its in- fluence, it is necessary to resea…  相似文献   

8.
To use the water resources reasonably in the midstream of Yinma River is of great significance to Changchun City which is short of water. With the runoff data of physical measuring, the paper analyses the characteristics surface rtmoff of the area, by means of the groundwater flow numerical simulation, and represents the characteristics of the groundwater runoff in the area. Based on combination analyses of the two runoffs, the authors point out the problem of the water resources use in this area and bring forward a resolution of conjunctive regulation and storage of the surface water and groundwater.  相似文献   

9.
Seaweeds are one of the largest producers of biomass in the marine environment. It has been well known that marine algae, especially brown algae was a rich source of biogenic compounds with antifouling potential that could be ideal alternatives of tributyltin (TBT). In this paper, antifouling potential of the brown algae Laminaria ‘sanhai’ was explored. Firstly, the dried alga was extracted and the antialgal and antilarval activities were investigated. The EC50 and LC50 values of crude extract of Laminaria ‘sanhai’ against diatom (Skeletonema costatum) and barnacle larval (Chthamalus challengeri) were 8.9 μg mL?1 and 12.0 μg mL?1 respectively. Then, guided by bioassay, the bioactive substances were isolated by liquid-liquid extraction. The antialgal and antilarval activities of isolated fraction were improved with the EC50 value of 7.4 μg mL?1 against S. costatum and LC50 value of 9.7 μg mL?1 against C. challengeri larvae. Identification by IR, Q-TOFMS and GC-MS of the isolated bioactive substances revealed the abundance of fatty acids. These fatty acids, most with 16, 18 or 20 carbon atoms, contained myristic, hexadecanoic, oleic, linolenic, arachidonic and eicosapentaenoic acids. The results indicated that both the crude extract and the isolated bioactive substances had high antialgal and antilarval activities with no highlighted cytotoxicity which made the brown algae Laminaria ‘sanhai’ a promising source of the environmentally friendly antifoulants.  相似文献   

10.
Surface water can be divided into three layers from top downward: surface microlayer (SML, thickness≤50 μm), subsurface layer (SSL, ≈25 cm) and surface layer (SL, 1–5m), among which the SML plays an important role on sea-air interaction because of its unique physical-chemical property. Carbon dioxide system including DIC (dissolved inorganic carbon), Alk (alkalinity), pH and pCO2 (partial pressure of CO2) in multilayered waters of the Yellow Sea was studied for the first time in March and May 2005. The results show that: DIC and Alk are obviously enriched in SML. The contents of DIC, Alk and pCO2 become lower in turn from SML, SSL to SL, higher in March and lower in May, whereas for pH it was opposite. The relationship between DIC and Alk is clearly positive, but negative between pH and pCO2. Meanwhile, pCO2 and temperature/salinity is also in positive relation, pCO2 decreases with latitude increase. DIC and Alk show a similar variation trend with the maximum at 02:00–03:00, but pH and pCO2 show an opposite pattern. In addition, the distribution patterns are similar to each other in the three layers. The Yellow Sea is shown to be a sink of atmospheric CO2 in spring by two methods: (1) comparing pCO2 in seawater and atmosphere; (2) turning direction of “pH-depth” curve. Calculation on the base of pCO2 data in SML in four models shows that carbon flux in spring in the area was about -6.96×106 t C.  相似文献   

11.
1 Introduction TheAntarcticcontinentissurroundedbyPacificOcean,theAtlanticOceanandthe IndianOcean,itistheisolatedcontinentfarthestfromthemankind.ItsSpecialgeography andclimateenvironmentmakethemankindverydifficulttobeclosetoit,whichlimits mankind'sinvestigationofitandstudytoagreatextent.Restrictioncausedofthegeograph icalenvironmentandtheclimatecanbebrokentoagreatextentwiththeaidofthemodern remotesensingtechnology,itdemonstratesincomparablesuperioritythatremotesensing technologyisusedin…  相似文献   

12.
The main task of provenance analysis is to determine the source of sediments and the position of parent rocks.Provenance analysis may find out the relationship between erosion districts and sediment zone,between the uplift and the depression in the process of basin development.The authors use the method of heavy mineral clustering analysis and estimate the provenance direction of Huanghua Depression in the Paleogene Kong 2 Member.Research shows that there were five provenance areas of Kong 2 Member in Kongnan area.They are western(Shenusi),northwestern(Cangzhou),eastern(Ganhuatun),northeastern and southeastern.The main provenance areas were northwestern and western,while the southern provenance could not be ruled out.And these areas are consistent with the known provenance areas.  相似文献   

13.
It was adopted that the fluorescence microscope, Gas-Flow Heating/Freezing System, Laser-Raman Spectroscopy, etc. are the multimedia techniques for analysing fluid inclusions of quartz veins in Budate Group, Hailar Basin. The results show that fluid inclusions in quartz veins are small ( 1~5μm) monophase, two-phase (liquid vapour) aqueous inclusions; the two-phase aqueous inclusions homogcniese to the liquid phase between 120 ~ 180℃, two dominant types for oil inclusions were determined in quartz veins: ① the primary inclusions, almostly gas, measurement by Laser-Raman Spectroscopy show that both gas phase are enriched in CH4 (94.50%~99.25% ) and C6H6 (0.75%~2.70%), under these conditions, inclusions may have come from juvenile fliud followingly the quartz veins formation. While the quartz veins exhibiting different striking luminescence has been proved by cathodoluminescence, it would be impossible to come from the deep magmas and strata. ② aqueous, liquid and two-phase (liquid vapour) oil inclusions, belong to secondary hydrocarbon inclusions. The oil inclusions of this stage represent mainly the large scale of oil accumulation, located within the quartz microfracture.  相似文献   

14.
Distribution, variation and impact factors of biomass of bacterioplankton from April to May 1999 in Bohai Sea were studied in DAPI method with epifluorescence microscopy. The biomass in surface waters showed a small day-night variation, varying from 0.13 to 2.51μg/dm^3 with an average of 0.84μg/dm^3. The biomass in bottom waters showed, however, a large variation, changing from 0.15 to 4.18μg/dm^3 with an average of 1.36μg/dm^3. The peak values occurred at 5 and 11 a.m. The bottom water biomass showed a significant correlation with particulate organic carbon (r=0.639, P〈0.05). Heterotrophic bacterioplankton biomass was high in nearshore waters and low in offshore areas with a high biomass zone around Huanghe (Yellow) River mouth, showing the same distribution of nutrients. In vertical distribution, heterotrophic bacteria biomass in bottom waters was higher than that in surface water.  相似文献   

15.
The main task of provenance analysis is to determine the source of sediments and the position of parent rocks. Provenance analysis may find out the relationship between erosion districts and sediment zone, between the uplift and the depression in the process of basin development. The authors use the method of heavy mineral clustering analysis and estimate the provenance direction of Huanghua Depression in the Paleogene Kong 2 Member. Research shows that there were five provenance areas of Kong 2 Member in Kongnan area. They are western (Shenusi), northwestern (Cangzhou), eastern (Ganhuatun), northeastern and southeast- ern. The main provenance areas were northwestern and western, while the southern provenance could not be ruled out. And these areas are consistent with the known provenance areas.  相似文献   

16.
Identifying the structure of protected mountain ecosystems is an important task for understanding conservation sustainability. The study area, the Firtina Valley, located in the Rize City on the Eastern Blacksea Coast, is one of the biological hotspots and a National Park of Turkey. In order to identify the structure of mountain ecosystems, we generated a GIS database for the main environmental parameters of the study area, including elevation,slope and aspect layers for topographic structure, 10year mean values of Normalized Difference Vegetation Index(NDVI), data for vegetation structure, annual mean temperature and precipitation layers for climatic structure, main soil groups for soil structure and stream flow accumulation, stream flow length and stream order layers for hydrological structure.To identify the complex relations among environmental factors in the study area a data reduction method is applied with Principal Component Analysis(PCA). PCA is performed using data of 16 layers from Geographical Information Systems(GIS). PCA analysis reduced 16 dimensions into 5 dimensions containing 75% of the variation in all data. It is also revealed that the topographic structure, mainly altitude, dominates the ecosystems of the Firtina Valley, but it should be considered that the interactions of environmental factors in an ecosystem dynamics are very complex. The ecosystem structure is determined by the environmental factors direct or indirect effects on energy regulation of an ecosystem. Therefore the relationship between topographic elements and other abiotic-biotic elements in the Firtina Valley are important for environmental assessment and sustainability of a protected area, and these effects are explained in this study.  相似文献   

17.
The changes that have taken place in Nigerian fisheries are reviewed. Artisanal fishery has continued to dominate the fisheries,contributing over 85% of total fish production. The inland water and coastal seas are fully exploited and the increase in fishery production is not likely. Aquaculture potentials remain untapped as much as deep-sea fisheries. The combined potential of the fisheries resources-freshwater,marine and aquaculture can meet over 90% of the nation's demand for fish. Opportunities for invest-ments,therefore,exist in the various subsectors,especially in the areas of storage,processing and preservation for the capture fishery and fish seed multiplication for aquaculture.  相似文献   

18.
Photochemical degradation of crude oil in seawater   总被引:2,自引:0,他引:2  
1 INTRODUCTION Marine photochemistry is a newly developed subject in marine sciences. Photochemical degrada- tion is important in decomposing and removing various organic contaminants in oceans (Ali et al., 1995a, b; Yang, 2000; Yang and Qi, 2002; 2003). …  相似文献   

19.
20.
Measurements of three chlorofluorocarbons(CFCs) :trichlorofluoromethane (CFC-11),dichlorodifluoromethane (CFC-12) and trichlorotrifluoroethane (CFC-113), along with methyl chloroform (CH3CCl3) and carbon tetrachloride (CCl4) were made in water samples from Lake Washington,using Electron Capture-Gas Chromatography (EC-GC).The samples were collected in mid-autumn, a period when the lake‘‘‘‘‘‘‘‘s upper layer undergoes rapid cooling,At the time of sam-pling,a strong vertical temperature gradient was present in the lake,with surface temperatures of -14℃,and near bottom(50 meters) temperatures of -8℃ ,The concentrations of dissolved CFC-12 and CFC-11 increased with depht ,as expected from the higher solubilities of these gases at lower temperatures ,Atmospheric measurements made at the sampling site at the time of the cruise ,showed that CFC-11 and CFC-12 saturations in the near surface samples were 100% and 106%,respectively,For the deepest sample (52 meters)CFC-11 and CFC-12 saturations were 102% and 126%,Because the surface layer of the lake respondes to changes in atmospheric CFCs on a time scale of several weeks ,the highere than equilibrium concentrations of CFC-12 observed at the time of sampling may reflect earlier episodes of elevated levels of atmospheric CFC-12 in this urban area.High concentrations of dissolved CFCs in runoff or industrial effluent might also lead to elevated CFC levels in the lake. The cold ,deep water of Lake Wahington is realtively isolated from the effects of surface gas exchange except during winter ,and the supersaturations observed in the deep layer may reflect pe-riods of elevated atmospheric CFC-12 levels from the previous winter season.These results were compared to summertime profiles of CFC-11 and CFC-12 made in 1994.  相似文献   

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