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1.
Rock weathering plays an important role in studying the long-term carbon cycles and global climatic change. According to the statistics analysis, the Huanghe (Yellow) River water chemistry was mainly controlled by evaporite and carbonate weathering, which were responsible for over 90% of total dissolved ions. As compared with the Huanghe River basin, dissolved load of the Changjiang (Yangtze) River was mainly originated from the carbonate dissolution. The chemical weathering rates were estimated to be 39.29t/(km2·a) and 61.58t/(km2·a) by deducting the HCO 3 − derived from atmosphere in the Huanghe River and Changjiang River watersheds, respectively. The CO2 consumption rates by rock weathering were calculated to be 120.84×103mol/km2 and 452.46×103mol/km2annually in the two basins, respectively. The total CO2 consumption of the two basins amounted to 918.51×109mol/a, accounting for 3.83% of the world gross. In contrast to other world watersheds, the stronger evaporite reaction and infirm silicate weathering can explain such feature that CO2 consumption rates were lower than a global average, suggesting that the sequential weathering may be go on in the two Chinese drainage basins. Foundation item: Under the auspices of Ministry of Science and Technology Project of China (No. G1999043075) Biography: LI Jing-ying (1974-), female, a native of Xinye of Henan Province, Ph.D., associate professor, specialized in environmental geochemistry. E-mail: wxxljy2001@public.qd.sd.cn  相似文献   

2.
The physiological responses of Nitzschia palea Kvtzing, a freshwater diatom, to elevated CO2 were investigated and compared with those of a marine diatom, Chaetoceros muelleri Lemmermann previously reported. Elevated CO2 concentration to 700 μl/L increased the dissolved inorganic carbon （D!C） and lowered the pH in the cultures of N. palea, thus enhancing the growth by 4%-20% during the whole growth period. High CO2-grown N. palea cells showed lower levels of dark respiration rates and higher Ik values. Light-saturated photosynthetic rates and photosynthetic efficiencies decreased in N. palea with the doubling CO2 concentration in airflow to the bottom of cultures, although the doubling CO2 concentration in airflow to the surface cultures had few effects on these two photosynthetic parameters. N. palea cells were found to be capable of using HCO5 in addition to gaseous CO2, and the CO2 enrichment decreased their affinity for HCO5 and CO2. Although doubled CO2 level would enhance the biomass of N. patea and C. muelleri to different extents, compared with the marine diatom, it had a significant effect on the specific growth rates of N. palea. In addition, the responses of photosynthetic parameters of IV. palea to doubled CO2 concentration were almost opposite to those of C. muelleri.  相似文献   

3.
Although the annual global sea-air CO2 flux has been estimated extensively with various wind-dependent-k parameterizations, uncertainty still exists in the estimates. The sea-state-dependent-k parameterization is expected to improve the uncertainty existing in these estimates. In the present study, the annual global sea-air CO2 flux is estimated with the sea-state-dependent-k parameterization proposed by Woolf (2005), using NOAA/NCEP reanalysis wind speed and hindcast wave data from 1998 to 2006, and a new estimate, −2.18 Gt C year−1, is obtained, which is comparable with previous estimates with biochemical methods. It is interesting to note that the averaged value of previous estimates with various wind-dependent-k parameterizations is almost identical to that of previous estimates with biochemical methods by various authors, and that the new estimate is quite consistent with these averaged estimates.  相似文献   

4.
The distributions and relationships of O2, CO2, and dimethylsulfide (DMS) in the Changjiang (Yangtze) Estuary and its adjacent waters were investigated in June 2014. In surface water, mean O2 saturation level, partial pressure of CO2 (pCO2), and DMS concentrations (and ranges) were 110% (89%–167%), 374 μatm (91–640 μatm), and 8.53 nmol L?1 (1.10–27.50 nmol L?1), respectively. The sea-to-air fluxes (and ranges) of DMS and CO2 were 8.24 μmol m?2 d?1 (0.26–62.77 μmol m?2 d?1), and ?4.7 mmol m?2 d?1 (?110.8-31.7 mmol m?2 d?1), respectively. Dissolved O2 was oversaturated, DMS concentrations were relatively high, and this region served as a sink of atmospheric CO2. The pCO2 was significantly and negatively correlated with the O2 saturation level, while the DMS concentration showed different positive relationships with the O2 saturation level in different water masses. In vertical profiles, a hypoxic zone existed below 20 m at a longitude of 123°E. The stratification of temperature and salinity caused by the Taiwan Warm Current suppressed seawater exchange between upper and lower layers, resulting in the formation of a hypoxic zone. Oxidative decomposition of organic detritus carried by the Changjiang River Diluted Water (CRDW) consumed abundant O2 and produced additional CO2. The DMS concentrations decreased because of low phytoplankton biomass in the hypoxic zone. Strong correlations appeared between the O2 saturation level, pCO2 and DMS concentrations in vertical profiles. Our results strongly suggested that CRDW played an important role in the distributions and relationships of O2, CO2, and DMS.  相似文献   

5.
The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs （greenhouse gases） fluxes （CO2, NO and N2O） in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga Mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production （GPP） of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production （NPP） was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production （NEP） was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively.  相似文献   

6.
The International Eq一lation of State of Seawater,1980 and the PraeticalSalinity Scale,1978 have been adoPted by theUNESCO江CES沼COR八APSOJoint Panel ono‘eanogral,hie Tables and Standards(JPOTS),and endorsed bythese organizati6ns(Miller‘〕and Poisson,1981;Uneseo,1981).Th已new equa-tion and the Praetieal Salinity Seale are to be used for all values Published fromJan .1,1982 .The new equation 15 aeeurate for use in all oeeanie surfaee waters,but eannot be aeeurately aPPlied to…  相似文献   

7.
One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L−1 CH3COONa and 0.88 mmol L−1 NaNO3 in heterotrophic condition, and 4 mmol L−1 CH3COONa and 3.52 mmol L−1 NaNO3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T. P. U. F. As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH3COONa and NaNO3 at 3 mmol L−1 and 3.52 mmol L−1 should respectively be used in order to achieve the highest growth rate and fatty acid content.  相似文献   

8.
A laboratory experiment was conducted to assess the bioaccumulation of Pb2+ and its effects on growth, morphology and pigment contents of Spirulina (Arthrospira) platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations (0, 5, 10, 30, 50 and 100 μg mL−1). The growth of S. platensis was adversely affected by Pb2+ at high concentrations (30, 50 and 100 μg mL−1). However, at low concentrations (5 μg mL−1), Pb2+ could stimulate its growth slightly. The pigment contents (chlorophyll α and β carotene) were decreased in a dose-dependent manner. The highest reductions (67% and 53% respectively in chlorophyll α and β carotene) were observed in 100 μg mL−1 treatment group. The LC50 (96 h) of Pb2+ was measured as 75.34 μg mL−1. Apart from a few cases of filament breakages at elevated concentrations (50 and 100 μg mL−1), morphological abnormalities are not specific. Metal bioaccumulation increased with Pb2+ concentrations, but decreased with exposure time. The maximum accumulated amount was 188 mg g−1 dry weight. The bioconcentration factor (BCF) reached to a peak at day 2, followed by a gradual reduction for all the exposure concentrations. S. platensis is able to tolerate considerably high Pb2+ concentrations. Consequently it can be used as a potential species to remove heavy metal from contaminated waters.  相似文献   

9.
The venerid clam (Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO2-enriched air at (400±25)×10-6 (ambient control), (800±25)×10-6 (high pCO2), or (1 200±28)×10-6 (extremely high pCO2), the atmospheric CO2 concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO2 conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.  相似文献   

10.
Effects of water temperature （17, 21, 25, 30 and 35℃） and body size （14.75-281.41 g initial body weight） on food consumption, growth, feed conversion, and dry matter content in orange-spotted grouper fed to satiation were investigated. The combined effect of temperature （T, ℃） and body weight （W, g） on maximum food consumption （Cmax, g/day） was described as： InCmax=-7.411＋0.828 InW＋0.317T4）.004 7T2, and the optimum feeding temperature was 33.9℃. The combined effect of temperature and body weight on growth （G） was described as： lnG=-4.461-0.2081nW＋0.394T-0.006 3T^2. The optimum growth temperature was 31.4℃, whereas overall growth rates were high at 25, 30 and 35 ℃. Feed conversion efficiencies （FCE, %）, increasing first and then decreasing with increasing temperature, averaged from 1.8 to 2.1 in terms of dry weight of food fish. The optimum temperature for FCE tended to be lower than that for growth or feeding. Dry matter content increased with both increasing water temperature （17, 25, 30 and 35℃） and body weight, and the combined effect of temperature and body weight on dry matter content （DM, %） was described as： lnDM =3.232＋0.01 4 lnW-0.004 4T＋0.001 2TInW.  相似文献   

11.
Soil respiration is a main dynamic process of carbon cycle in wetland. It is important to contribute to global climate changes. Water table and nutritious availability are significant impact factors to influence responses of CO2 emission from wetland soil to climate changes. Twenty-four wetland soil monoliths at 4 water-table positions and in 3 nitrogen status have been incubated to measure rates of CO2 emission from wetland soils in this study. Three static water-table controls and a fluctuant water-table control, with 3 nitrogen additions in every water-table control, were carried out. In no nitrogen addition treatment, high CO2 emissions were found at a static low water table (I) and a fluctuant water table (IV), averaging 306.7mg/(m2·h) and 307.89mg/(m2·h), respectively, which were 51%–57% higher than that at static high water table (II and III). After nitrogen addition, however, highest CO2 emission was found at II and lowest emission at III. The results suggested that nutritious availability of wetland soil might be important to influence the effect of water table on the CO2 emission from the wetland soil. Nitrogen addition led to enhancing CO2 emissions from wetland soil, while the highest emission was found in 1N treatments other than in 2N treatments. In 3 nutritious treatments, low CO2 emissions at high water tables and high CO2 emissions at low water tables were also observed when water table fluctuated. Our results suggested that both water table changes and nutritious imports would effect the CO2 emission from wetland. Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 90211003) and the Knowledge Innovation Program of Chinese Academy of Sciences (No. KACX3-SW-332) Biography: YANG Ji-song (1978-), male, a native of Chengwu of Shandong Province, Ph.D. candidate, specialized in environmental ecology and wetland biogeochemistry. E-mail: yangjisong@neigae.ac.cn  相似文献   

12.
Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate （SGR） of 10.47 at 25℃/40 μmol m^-2s^-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues.  相似文献   

13.
The effects of several nutritional factors on the growth and eicosapentaenoic acid (EPA) production of diatom Nitzschia laevis were studied. 4 LDM (quadrupled concentration of the nutrient salt) was the optimal concentration of nutrient salt for the growth and EPA production of N. laevis. The growth of N. laevis was inhibited when the glucose concentration was either lower than 10 gL−1 or higher than 15 gL−1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight (DW) and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL−1 was obtained in the presence of 150 mgL−1 Na2SiO3·9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150 mgL−1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity (⩽29) did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content (4.08%) and yield (110 mgL−1) were observed at the salinity of 36 and 29, respectively.  相似文献   

14.
Hyper-spectrum models for monitoring water quality in Dianshan Lake,China   总被引：1，自引：0，他引：1  
The correlation between water quality parameters and hyper-spectral reflectance is studied with models established for each parameter and applied in Dianshan Lake, in the upstream of the Huangpu River running through Shanghai, China. Models are for dissolved oxygen (DO in mg/L): R720/R680 = 20.362×(R720/R680)2-31.438×(R720/R680)+19.156; for turbidity (NTU): R*714.5 = 206.07× (R*714.5)2-582.5×R*714.5 + 423.24; and for total phosphorus (TP in mg/L): R*509.5 = 16.661× (R*509.5)2-32.646×R*509.5+16.116. The R2 values are 0.770 8, 0.660 4 and 0.738 7, respectively, showing strong positive relationships. The models were then applied to assess water quality of different times. Results are quite satisfactory for some samples.  相似文献   

15.
This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3.  相似文献   

16.
1 INTRODUCTION Bioavailability to the biota and the biogeo-chemistry of trace metals in marine environment areaffected by their chemical speciation in the naturalsystem (Bruland et al., 1991; Van den Berg andDonat, 1992; Wells et al., 1998). Therefore, thesetwo parameters, the ligands concentrations andconditional stability constants, are important todetermine the complexing capacity. Sea surface microlayer (SML), the thin interfa-cial boundary between ocean and atmosphere, playsan imp…  相似文献   

17.
1 INTRODUCTION Carbon dioxide (CO2) is principal greenhouse gas. Its air-water exchange is important in terrestrial ecosystems for climate change (Frankignoulle et al., 1998; Schimel et al., 2001). The direction of CO2 gas movement depends on the CO2 concentration gradient between air and surface water. The amount of CO2 exchange is related to the gas exchange coefficient, k. All lakes, with their small area but large atmospheric CO2 flux are important to under-stand the CO2 fluxes …  相似文献   

18.
To investigate the antitumor effect of bromophenol derivatives in vitro and Leathesia nana extract in vivo, six bromophenol derivatives 6-(2,3-dibromo-4,5-dihydroxybenzyl)-2,3-dibromo-4,5-dihydroxy benzyl methyl ether (1), (+)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-4-bromo-5,6-dihydroxy-1,3-dihydroisobenzofuran (2), 3-bromo-4-(2,3-dibromo-4,5-dihydroxybenzyl)-5-methoxymethyl-pyrocatechol (3), 2,2′,3,3′-tetrabromo-4,4′,5,5′-tetrahydroxy-diphenylmethane (4), bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (5), 2,2′,3-tribromo-3′,4,4′,5-tetrahydroxy-6′-ethyloxymethyldiphenylmethane (6) were isolated from brown alga Leathesia nana, and their cytotoxicity were tested by MTT assays in human cancer cell lines A549, BGC-823, MCF-7, B16-BL6, HT-1080, A2780, Bel7402 and HCT-8. Their inhibitory activity against protein tyrosine kinase (PTK) with over-expression of c-kit was analyzed also by ELISA. The antitumor activity of ethanolic extraction of Leathesia nana (EELN) was evaluated on S180-bearing mice. All compounds showed very potent cytotoxicity against all of the eight cancer cell lines with IC50 below 10 μg/mL. In PTK inhibition study, all bromophenol derivatives showed moderate inhibitory activity and compounds 2, 5 and 6 showed significant bioactivity with the inhibition ratio of 77.5%, 80.1% and 71.4%, respectively. Pharmacological studies reveal that EELN could inhibit the growth of Sarcoma 180 tumor and increase the indices of thymus and spleen to improve the immune system remarkably in vivo. Results indicated that the bromophenol derivatives and EELN can be used as potent antitumor agents for PTK over-expression of c-kit and considered in a new therapeutic strategy for treatment of cancer. Supported by the National High Technology Research and Development Program of China (863 Program, No. 2007AA09Z410) and Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-209)  相似文献   

19.
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   

20.
Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as β-1awsaritol （1）, saringosterol （2）, 24-hydroperoxy-24-vinyl- cholesterol （3）, β-stigmasterol （4）, stigmast-4-en-3α, 6β-diol （5）, 29-hydroxystigmasta-5, 24 （28）-dien-3β-ol （6）. All these compounds were obtained from this genus for the first time and they were inactive （IC50〉10μg/ml） against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.  相似文献   

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