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1.
A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions.During the 245-day incubation period,changes in the concentrations of TOC,major algal fatty acid components (14:0,16:0,16:1,18:1 and 20:5),and n-alkanes (C16-C23) were quantified in the samples.Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions.Adsorption of fatty acids onto cla... 相似文献
2.
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
3.
A 6.2 m thick core of Gucheng Lake sediment provided a 3600 years record of climate change. The contents of the TOC in the
core changed from 2.63% to 8.48%, and the δ13C values of organic matter were from −21.54% to −27.3%. The TOC/TN ratios indicated that the organic materials in sediments
were from lake plankton and land-derived plants.
The 2.9–22 m core interval with high TOC/TN ratios, low δ13C values and low contents of TOC indicated a cold climate stage. The 6.2–5.5 m and 0.4–0.1 m intervals were characterized
by low TOC/TN ratios, high δ13C values and high contents of TOC, and reflected temperate climate stages.
Project 49372129 supported by NSFC. 相似文献
4.
In Wuxi Wastewater Treatment Plant, the Anaerobic, anoxic and oxic (A2/O) process was employed to remove the nitrogen and phosphorus, which exhibited the positive results of the high removal efficiency for phosphorus with a range of 67.7% to 89.9% and an average value of 78.0. The effluent of phosphorus met the national discharge standard. The removal of TN was effected by both BOD variation of influent and wastewater temperature. TN removal was in the range of 28.5% to 55.8% with an average value of 39.4%. The energy cost was 0.15 kWh(m3d)-1 or 1.35 kWh(kgBOD·d)-1. The annual average sludge production was 46.3 m3d-1, the annual average dosage for the dewatering was 40 kgd-1. 相似文献
5.
Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact
of microzooplankton and Calanus sinicus on phytoplankton based on the Chlorophyll a (Chl-a) levels. The Chl-a growth rates (k) ranged from 0.60–1.67 d−1, while microzooplankton grazed the Chl-a at rates (g) of 0.29–0.62 dt-1. The addition of C. sinicus enhanced the Chl-a growth rate (Z) by 0.004–0.037 d−1 ind.−1 L. C. sinicus abundance ranged from 84.1–160.9 ind. m−3, which occupied 90.7%–99.1% of the copepod (>500 μm) population. The in-situ increase in phytoplankton by C. sinicus community was estimated to be 0.000 4–0.005 9 d−1. These results showed that microzooplankton were the main grazers of phytoplankton, while C. sinicus induced a slight increase in the levels of phytoplankton. 相似文献
6.
The transfer processes of organic pollutants during sewage-seawater mixing were simulated in three different mixing systems.
The release rate of organic matter from sewage particles to seawater was found to be about 0.02–0.04 d−1. The release processes can be simulated by an exchange-equilibrium kinetic model. Degradation of COD was observed in all
three mixing systems and can be described by a first order kinetic equation. The degradation rate constantk ranged between 0.04 and 0.07 d−1. These results have provided important parameters for estimation of environmental capacity. 相似文献
7.
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
8.
YUE Lixi MA Chunling CHI Zhenming 《中国海洋大学学报(英文版)》2006,5(4):333-338
Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension and oil-field produced water. The bacterial strain was identified as Klebsiella sp. MYC according to its morphological and biochemical characteristics and 16SrDNA sequence. The optimal medium for bioflocculant production by this bacterial strain was composed of cane sugar 20 g L^-1, KH2PO4 2 g L^-1, K2HPO4 5 g L^- 1, ( NH4)2SO4 0.2 g L^-1, urea 0.5 g L^- 1 and yeast extract 0.5 g L^- 1, the initial pH being 5.5. When the suspension of kaolin clay was treated with0.5% of Klebsiella sp. MYC culture broth, the flocculating rate reached more than 90.0% in the presence of 500mg L^-1 CaCI2, while the flocculating rate for oil-field produced water was near 80.0% in a pH range of 7.0 - 9.0 with the separation of oil and suspended particles from the oil-field produced water under similar conditions. The environment-friendly nature of the bioflocculant and high flocculating rate of the strain make the bioflocculant produced by Klebsiella sp. MYC an attractive bioflocculant in oil-field produced water treatment. 相似文献
9.
A great quartity of cosmic dust(spherules) was found in deep-sea sediments during May to July,1983manganese nodule investigations by the R/V“XIANGYANGHONG 16”in the area 7°-11°N,167°-178°Win the Pacific.Comprehensive study of the cosmic dust and determination with Laser Raman MolecularMicroprobe(LRMM) of the molecules in it showed that besides Fe-Fe,Fe~(3+)-O,Fe-Ni,Al-O,Fe-Obr-Si and Si-Onb,it also contained the organic molecules C-H-O and C-H-S-O,various no fixed form molecules of C,CH_2,CH_3 and volatile molecules CO_2,H_2O,OH~- and H_2S,etc…The study result has very important applications for exploring the origin of interplanetary dust parti-cles and life material. 相似文献
10.
Fatty acid composition and total lipid content of 8 strains of marine diatoms (Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa, Phaeodactylum tricornutum, Synedra fragilaroides) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major
fatty acids in most strains were 14∶0 (1.0%–6.3%), 16∶0 (13.5–26.4%), 16∶1n−7 (21.1%–46.3%) and 20∶5n−3 (6.5%–19.5%). The
polyunsaturated fatty acids 16∶2n−4, 16∶3n−4, 16∶4n−1 and 20∶4n−6 also comprised a significant proportion of the total fatty
acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other
microalgal groups. Significant concentration of the polyunsaturated fatty acid 20∶5n−3 (eicosapentaenoic acid) was present
in each strain, with the highest proportion in B222 (19.5%).
Project supported by the Hi-Tech “863” Programs of the China Ministry of Science and Technology (863-819-02-01). 相似文献
11.
Two hundred and thirty-five samples collected from Weinan loess section (L2 – S0) have been analyzed by TOC (total organic carbon) and pyrolysis hydrocarbons. The curve of TOC with depth has been set up
and compared well with other climatic markers. The main periods of TOC variation of the last 0.14 Ma are 67.08 ka and 18.29
ka, which is near with the periods of the variation of sunshine, showing that the TOC variation may be controlled by the variation
of 65°N sun-shine. The distribution of pyrolysis hydrocarbon and its parameters shows that there are two kinds of hydrocarbon
associated with climatic change. One is called hydrocarbon pyrolysted directly from organism (pHC2–1) which is in the range of T
max350°C – 500°C, and associated with atmospheric water. The other is called carbonate inclusion hydrocarbon (pHC2–2) which is in the range of T
max 500°C – 600°C and formed by evaporation and associated with dry climate. The formula calculating humidity has been deduced
Og=pHC2–1/(pHC2–1 + pHC2–2). The range of humidity of the section is 47% – 77% and the reducing order is S1–3, S1–2, S0, S1–1, S1–4, S1–1, L1–1, L1–3, and L1–5. And the trend of the humidity is still increasing today. 相似文献
12.
Effects of salinity, pH, nitrogenous and phosphate nutrients on the growth rate of four species of benthic diatoms were studied
by using the method of in situ optical density measurement. The optimal culture conditions for the four species of diatoms
are as follows: forAmphora coffeaeformis, s 35; pH 8.5; NO3
−−N 1.54, NH4
+−N, 7.0; CO (NH2)2−N, 2.5 (mg/L); PO4
3−−P 1.13 (mg/L); forCocconeis scutellum varparva, s 30; pH 8.5; NO
3
−
−N 3.08, NH
4
+
−N 3.5, CO(NH2)2−N 5.0 (mg/L); pO
4
3−
−P 0.283 (mg/L); forNavicula corymbosa s 25; pH 8.0; NO
3
−
−N 1.54, NH
4
+
−N 3.5 CO(NH2)2−N 5.0 (mg/L); PO
4
3−
−P 0.565 (mg/L); forNavicula mollis. s 25; pH 8.0; NO
3
−
−N 1.54, NH
4
+
−N 1.75, CO(NH2)2−N 1.25 (mg/L); PO
4
3−
−P 0.141 (mg/L).
Part of the results of this paper were exchanged in the Fourth Asian Aquaculture Forum. Oct. 16–20. 1995. Beijing, P. R. China. 相似文献
13.
Qiang Hao Yuming Cai Xiuren Ning Chenggang Liu Xin Peng Xuexi Tang 《中国海洋大学学报(英文版)》2011,10(2):157-164
The standing stock and primary production of benthic microalgae on tidal flats were measured seasonally at 3 transects (Puqing, Dahengchuang and Puqi) in Yueqing Bay during 2002 2003. The results showed that the integral chlorophyll a (Chl a) concentration in tidal flat mud exhibited a seasonal variation with the order of magnitude: winter (14.0 4.2 mg m-2) > spring (13.0 6.3 mg m-2) > autumn (7.7 5.9 mg m-2) > summer (4.6 3.2 mg m-2). The primary production showed an order of magnitude: spring (270.5 224.9 mgC m-2 d-1)>winter (238.7 225.5 mgC m-2 d-1)>autumn (214.1 56.2 mgC m-2 d-1)>summer (71.6 44.6 mgC m-2 d-1). Both chlorophyll a and primary production showed maximum values in the surface layer of sediment, and decreased rapidly with increasing depth due to sun light limitation. The results of variance analysis indicated that seasonal variation and tidal flat condition affected Chl a greatly, but had no significant effect on primary production. The annual primary production of benthic microalgae on tidal flats in Yueqing Bay was estimated at 16143 tons carbon, which is sufficient to support 1.02×105 tons shellfish production. The environmental factors affecting chlorophyll and primary production on the tidal flats in Yueqing Bay were discussed. By comparing with other bays on China’s coast, it was observed that Yueqing Bay is a region with high benthic microalgae standing crop and primary production, which may be related to the type of its sediment. 相似文献
14.
Preliminary studies on microzooplankton grazing were conducted with dilution method in Jiaozhou Bay from summer 1998 to spring
1999. Four experiments were carried out at St. 5 located at the center of Jiaozhou Bay. Chlorophyll a concentrations were
consistently dominated by netphytoplankton (net-, >20μm), except during the autumn 1998 cruise, when they were dominated by
nanophytoplankton(nano-, 2–20μm). The contribution of picophytoplankton (pico-, <2μm) to total chlorophyll a concentrations
(<200μm) varied considerably between cruises. Instantaneous growth coefficients(u) of phytoplankton varied from 0.098 to 1.947d−1, with mean value of 0.902d−1. Instantaneous coefficients(g) of microzooplankton grazing on phytoplankton ranged from 0.066 to 0.567d−1, mean value of 0.265d−1, which was equivalent to daily lose of 21.9% of the initial standing stock and 58.1% of the daily potential production.
Project No KZCX3-SW-214 supported by Chinese Academy of Sciences. 相似文献
15.
ZHANG Zhicui XUEChanghu GAO Xin LI Zhaojie WANG Qi 《中国海洋大学学报(英文版)》2006,5(3):257-262
Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid (FAA). The content of glycogen was high in January and March (2.89 and 2.82 g(100 g) ^-1 on average, respectively) and low in October (2.07g(100g)^- 1 on average). The low content of neutral lipids in October reflected a relatively poor nutritional value of oyster (1.42 g( 100 g)^- 1 on average). The main fatty acids of oyster were palmitic acid (16:0), oleic acid (18: 1), eicosapentaenoic acid (EPA, 20: 5(0 3) and docosahexaenoic acid (DHA, 22:6(0 3). The major FAAs of oyster were Taurine, Glutamicacid, Glycin, Alanine, Arginine and Proline. Taurine was the most abundant FAA with its content ranging from 603 mg(100 g) ^-1 to 1 139 mg( 100 g) ^-1. The high contents of glycogen, polyunsaturated fatty acid and FAA showed that oyster cultured along the eastern coast of Shandong Province was nutritionally good in January and March. 相似文献
16.
Partial pressure of CO2 (pCO2) was investigated in the Changjiang (Yangtze River) Estuary, Hangzhou Bay and their adjacent areas during a cruise in August 2004, China. The data show that pCO2 in surface waters of the studied area was higher than that in the atmosphere with only exception of a patch east of Zhoushan Archipelago. The pCO2 varied from 168 to 2 264 μatm, which fell in the low range compared with those of other estuaries in the world. The calculated sea-air CO2 fluxes decreased offshore and varied from -10.0 to 88.1 mmol m^-2 d^-1 in average of 24.4 ± 16.5 mmol m^-2 d^-1. Although the area studied was estimated only 2 × 10^4 km^2, it emitted (5.9 ± 4.0) × 10^3 tons of carbon to the atmosphere every day. The estuaries and their plumes must be further studied for better understanding the role of coastal seas playing in the global oceanic carbon cycle. 相似文献
17.
Two surveys were performed for determining bacteria biomass (BB), temperature, salinity, chlorophyll a (chl-a) and nutrient concentrations at 11 stations with three sampling depths in the high-incidence regions of red tide in the East
China Sea (ECS) in the spring of 2006. Temperature and salinity increased from nearshore to offshore region and from high
latitude to low latitude in the two cruises of 2006. BB were between 0.3–5.2 mgC m−3 (about 2.1 mgC m−3 on average) and 0.2–6.0 mgC m−3 (about 2.7 mgC m−3 on average) respectively in the two cruises. BB in the surface layer decreased from the Changjiang River estuary to high
sea and from low latitude to high latitude. The results showed that bacterial growth was regulated by temperature, primary
production and inorganic nutrient concentrations depending on different hydrographic conditions. In the surface and middle
layers where the primary production can supply enough organic substrate, temperature was the main factor to control bacteria
biomass. BB showed a good correlation between the surface and middle layers in both cruises. The distribution of nutrients
during both cruises showed a similar decreasing trend from nearshore region and high latitude to offshore region and low latitude.
High BB values were mainly recorded from samples in the middle layer where chl-a concentrations were also high, indicating primary production being strongly correlated with temperature over the ECS shelf.
In the offshore area, phosphate and silicate became limiting factors for phytoplankton growth with indirect influence on BB.
Bacteria played an important role in nitrogen regeneration process turning organic nitrogen to inorganic forms such as NH4
+. The increasing ratio of NH4
+/DIN could be a proof of that. 相似文献
18.
The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The fatty acid composition was assayed by gas chromatography-mass spectrometry, which indicated that the main fatty acids were C14:0, C16:0 and EPA. The highest EPA percentage 20.83% of total fatty acids was obtained at 20℃ with the temperature being set at 20, 24, and 28℃. Under different salinities and light intensities, the highest percentages of total polyunsaturated fatty acids (PUFAs) and EPA were 17.82% and 31.37% of total fatty acids, respectively, which were achieved at salinity 30 and 100μmol photon m-2s-1 illumination. The highest percentages of total PUFAs and EPA were 38.75% and 23.13% of total fatty acids, respectively, which were reached at an initial pH of 6 with the test range being from 5.0 to 9.0. 相似文献
19.
DYNAMIC CHANGES OF INORGANIC NITROGEN AND ASTAXANTI—IIN ACCUMULATION IN HAEMATOCOCCUS PLUVIALIS 总被引:1,自引:1,他引:0
This study on dynamic changes of culture color,astaxanthin and chlorophylls,inorganic N including N-NO3^-,N-NO2^- and N-NH4^ in batch culture of Haematococcus pluvialis exposed to different additive nitrate concentration showed(1)ast/chl ratio was over 0.8 for brown and red algae,but was usually less than 0.5 for green and yellow algae;(2)N-NO3^-,in general,was unstable and decreased,except for a small unexpected increase in nitrate enriched treatment groups;(3)measurable amounts of N-NO2^- and N-NH4^ were observed respectively with three change modes although no extemal nitrite and ammonia were added into the culture;(4)a non-linear correlation between ast/chl ratio(or color)changes and the levels of N-NO3^-,N-NO2^-,N-NH4^ in H.pluvialis culture;(5)up and down variation of the ast/chl ratio occurred simultaneously with a perceptible color change from yellow to brown(or red)when N-NO3^-,N-NO2^- and N-NH4^ fluctuated around 30,5,5μmol/L respectively;(6)existence of three dynamic modes of N-NO3^-,N-NO2^- and N-NH4^ changes,obviously associated with initial extemal nitrate;(7)the key level of total inorganic N concentration regulating the above physiological changes during indoor cultivation was about 50 μmol/L;and(8)0.5-10mmol/L of nitrate was theoretically conducive to cell growth in batch culture. 相似文献
20.
Liang Yanling 《中国海洋湖沼学报》1984,2(1):102-108
Branchiura sowerbyi in the Donghu Lake (Wuhan, China) completes its life cycle in one year. Its production rates were 6.7 g m−2 yr−1 (wet weight) during the period from April 1962 to May 1963 and 8.6g m−2 yr−1 during the period from August 1963 to August 1964. The standing stocks in corresponding periods were 1.9g m−2 (wet weight) and 1.1g m−2, and theP/B ratios were 3.6 and 7.8. Based on the standing stock during 1973–1975, an evaluation of recent productin levels ofB. sowerbyi in Donghu Lake has also been made (i.e. 5.7–33.5g m−2 yr−1). 相似文献