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1.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃａｒｂｏｎｃｙｃｌｅｉｎｓｈｒｉｍｐｐｏｌｙｃｕｌｔｕｒｅｅｃｏｓｙｓｔｅｍｓｈａｓｉｍｐｏｒｔａｎｔｆｕｎｃｔｉｏｎａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓ,ａｎｄｓｏｓｔｕｄｉｅｓｏｎｔｈｅｃａｒｂｏｎｃｙｃｌｅｔｈｅｒｅｃａｎｈｅｌｐｕｓｕｎｄｅｒｓｔａｎｄｔｈｅｒｅｇｕｌａｒｉｔｙｏｆｔｈｅｓｙｓｔｅｍ’ｓｍａｔｅｒｉａｌｃｙｃｌｅａｎｄｅｎｅｒｇｙｆｌｏｗ ,ｋｎｏｗｌｅｄｇｅｏｆｗｈｉｃｈｃａｎｂｅｕｓｅｄｔｏｗｏｒｋｏｕｔｆｅａｓｉｂｌｅｓｙｓｔｅｍｓａｎｄ…  相似文献   

2.
Emissions of biogenic sulfur gases (hydrogen sulfide (H2S) and carbonyl sulfide (COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H2S and COS both had distinct seasonal and diurnal variations. The H2S fluxes ranged from 0.09 μg/(m2·h) to 7.65 μg/(m2·h), and the COS fluxes ranged from–1.10 μg/(m2·h) to 3.32 μg/(m2·h). The mean fluxes of H2S and COS from the P. australis coastal marsh were 2.28 μg/(m2·h), and 1.05 μg/(m2·h), respectively. The P. australis coastal marsh was the emission source of both H2S and COS over the whole year. Fluxes of H2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.  相似文献   

3.
1 Introduction Vegetation is an important component of terrestrial eco- system, it plays an important role in global matter and energy cycle, carbon balance and climate change. CO2 has effects on global warming, photosynthesis function, Net Primary Productivity (NPP) and earth environmental condition. NPP is one of the important biophysical variables of vegetation activity, and is a beginning link of biogeochemical carbon cycle. Vegetation absorbs CO2 from atmosphere through photosynthesi…  相似文献   

4.
INTRODUCTIONMacrozoobenthos ,amajorgroupofaquaticfauna ,playsanimportantroleinthematerialcycleandenergyflowinawaterecosystem .Inrecentdecades ,interestinthebioenergeticsofthisgrouphasgrownrapidly .Aspectsofthebioenergeticsofmanybenthicfreshwaterspecieshavebeenpub lished .Owingtodifficultyinsamplecollectionandspecimenprocessing ,studiesofthebenthiccom munityhavereceivedlessattention .Withfisherydevelopmentandthelakeeutrophicationproblem ,investigationsontheecologicalfunctionofthelakecommun…  相似文献   

5.
Estimating carbon sequestration and nutrient accumulation rates in Northeast China are important to assess wetlands function as carbon sink buffering greenhouse gas increasing in North Asia. The objectives of this study were to estimate accreting rates of carbon and nutrients in typical temperate wetlands. Results indicated that average soil organic carbon(SOC), total nitrogen(TN) and total phosphorus(TP) contents were 37.81%, 1.59% and 0.08% in peatlands, 5.33%, 0.25% and 0.05% in marshes, 2.92%, 0.27% and 0.10% in marshy meadows, respectively. Chronologies reconstructed by 210 Pb in the present work were acceptable and reliable, and the average time to yield 0–40 cm depth sediment cores was 150 years. Average carbon sequestration rate(Carbonsq), nitrogen and phosphorus accumulation rates were 219.4 g C/(m~2·yr), 9.16 g N/(m~2·yr) and 0.46 g P/(m~2·yr) for peatland; 57.13 g C/(m~2·yr), 5.42 g N/(m~2·yr) and 2.16 g P/(m~2·yr) for marshy meadow; 78.35 g C/(m~2·yr), 8.70 g N/(m~2·yr) and 0.71 g P/(m2·yr) for marshy; respectively. Positive relations existed between Carbonsq with nitrogen and precipitations, indicating that Carbonsq might be strengthened in future climate scenarios.  相似文献   

6.
The energy budget ofBellamya earuginosa in a shallow algal lake, Houhu Lake (Wuhan, China) was investigated by the measurement of flesh production (32.8 kJ/(m2·a)), egestion (337.7 kJ/(m2·a)), metabolism (246.7 kJ/(m2·a)), and estimation of excretion (21.4kJ/(m2·a)). The net growth efficiency of the species is about 10.9%, which accords with the generally reported value for gastropods. In addition, the relationships between starvation respiration (R, mgO2/(Ind·d)), body weight (Wd, mg in dry wt) and temperature (T, °C) were also determined. The regression equationR=0.044Wd 0.537 e 0.061T was obtained by the least square method, The measured SDA of the species is 26.51% of its gross metabolism. Project No. 3960019 and 39430101 supported by NSFC and also a granted for the East Lake Ecological Experimental Station, CAS, Wuhan.  相似文献   

7.
Studies on secondary production lead to a better understanding of the functions of the macrobenthic ecosystem．Based on the macrobenthic data obtained at 6 sampling stations from April 2006 to January 2007,Brey's(1990)empirical formula was applied to calculate the secondary production of macrobenthos in the mangrove area of Tong'an Bay.The results showed that the mean annual secondary production of macrobenthos was 13.24gAFDW.m-2·a-1 The mean secondary production in the mangrove habitat was 12.22gAFDW．m-2·a-1,lower than that in the non-mangrove habitat,which was 15.29gAFDW．m-2·a-1.Two possible reasons existed for this difference.First,mollusk and crustacean,which contribute more to the secondary production,probably benefit from longer inundation period in the non-mangrove habitat.Second,the higher organic matter in the mangrove habitat results in hypoxia in the bottom sediment,which may decrease the secondary production.The annual mean production-to-biomass(P/B)ratio in Tong'an Bay was 1.17,with a ratio of 1.27 in the mangrove habitat and 0.96 in the non-mangrove habitat,which was coincident with the much higher density of Limnodriloides sp.and Corophium sp.in the mangrove habitat than in the non-mangrove habitat.The maximum secondary production and P/B ratio of macrobenthos both appeared at sampling station FL2 in April,2006(namely April-FL2)with values of 31.38gAFDW.m-2·a-1 and 2.20,respectively.The macrobenthic secondary production in Tong'an Bay is lower than those in other intertidal studies except that in Haitan Strait,the reason being the different sediment properties.The P/B ratio in Tong'an Bay was the lowest due to the high proportion of crustaceans in the macrobenthic community．  相似文献   

8.
Vertical profiles of chl-a and primary productivity in the middle continental shelf area and eddy area of the East China Sea were studied using data from a cruise in the East China Sea in February to March, 1997 and a cruise in July, 1998. The results showed that chl-a vertical distribution closely related to in situ hydrological and nutrient conditions. Chla-a concentration ranged from 0.22 to 0.35 mg/m3 and 0.93–1.09 mg/m3 in the eddy area and in the middle continental shelf area, respectively. In both areas, chl-a concentrations in deep layers were slightly higher than those in shallow layers, but was of the same order of magnitude. In summer, when a thermocline existed in the water column, highest chl-a concentrations appeared at the base of the thermocline layers in both areas. In the eddy area, chl-a concentration maximized at 31.743 mg/m3, and averaged 1.143 mg/m3 below 30 m depth. In the middle continental shelf area, the highest chl-a concentration was 2.120 mg/m3, the average was 1.168 mg/m3. The primary productivity reached 1418.76 mgC/(m2·d) in summer and 1360.69 mgC/(m2·d) in winter. In the eddy area, the primary productivity was 787.50 mgC/(m2·d) in summer and 159.04 mgC/(m2·d) in winter. Vertical carbon sinking rate from the deep layer to the bottom in both areas is also discussed in this paper. Contribution NO. 4183 from the Institute of Oceanology, Chinese Academy of Sciences. Project No. 49636210 supported by NSFC.  相似文献   

9.
A 4.34 liter two-stage air-lift photobioreactor incorporatingAnabaena variabilis ATCC29413 mutant PK84 was used to study H2 production. Results showed that H2 production increased with increasing light intensity from 47 μE/(m2·s) up to 190 μE/(m2·s), but that further increase of light intensity decreased the H2 production because of the inhibition due to the high pO2. The data also indicated that longer argon gas charge resulted in more H2 produced due to the increase of nitrogenase activities and heterocyst frequency, and that more than 1.3 L net H2 was produced from this computer controlled photobioreactor.  相似文献   

10.
Effects of temperature, salinity and light intensity on growth rates of Gracilaria lichenoides and G. tenuistipitata var. liui Zhang et Xia were tested. Eight to ten levels of each factor were first tested separately. The best growth rate was obtained under the conditions of 32°C, 30 and 240 μmol/(m2·s) for G. lichenoides, and 24°C, 20 and 200 μmol/(m2·s) for G. tenuistipitata, respectively. Then a uniform design was used to evaluate the optimal combinations of the three factors. The best conditions for the highest daily specific growth rates (% increase in wet weight) are determined to be 31.30°C, 32.10, and 287.23 μmol/(m2·s) for G. lichenoides (16.26%/d), and 25.38°C, 21.10, and 229.07 μmol/(m2·s) for G. tenuistipitata (14.83%/d), respectively. Supported by the 908 Special Program (908-02-04-07), the National Basic Research Program of China (973 Program, No. 2006CB400608), and K. C. Wong Magna Fund in Ningbo University  相似文献   

11.
CARBON DYNAMICS OF WETLAND IN THE SANJIANG PLAIN   总被引：2，自引：0，他引：2  
1INTRODUCTIONWetlandsplayanimportant roleintheprocessofcar-bonstorage.Thetotalcarbonstoredindifferentkindsofwetlandsisabout15%-35%ofthetotalcarboninthegloballandsoils(POSTetal.,1982;GORHAM,1991).Inaddition,wetlandsaresignificantnaturalsources fortheatmospheric CH4 (MOORE,1994).It isestimatedthatabout110×1012gCH4 originates fromanaerobicdecompositioninthenaturalwetlands,CH4 emission fromthenaturalwetlandsis15%-30%oftheglobalCH4 emission andtheCH4 emission from thepeat land at hi…  相似文献   

12.
Manila clam(Ruditapes philippinarum) was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010. The annual variations of major elemental composition, organic content, fatness and element ratio of Manila clam were examined. The element removal effect of clam farming in Jiaozhou Bay was analyzed based on natural mortality and clam harvest. The results indicated that the variation trend of carbon content in shell(Cshell) was similar to that in clam(Cclam). Such a variation was higher in summer and autumn than in other seasons, which ranged from 9.10 ± 0.13 to 10.38 ± 0.09 mmol g-1 and from 11.28 ± 0.29 to 12.36 ± 0.06 mmol g-1, respectively. Carbon content of flesh(Cflesh) showed an opposite variation trend to that of shell in most months, varying from 29.42 ± 0.05 to 33.64 ± 0.62 mmol g-1. Nitrogen content of shell(Nshell) and flesh(Nflesh) changed seasonally, which was relatively low in spring and summer. Nshell and Nflesh varied from 0.07 ± 0.009 to 0.14 ± 0.009 mmol g-1 and from 5.46 ± 0.12 to 7.39 ± 0.43 mmol g-1, respectively. Total nitrogen content of clam ranged from 0.50 ± 0.003 to 0.76 ± 0.10 mmol g-1 with a falling tend except for a high value in March 2010. Phosphorus content of clam(Nclam) fluctuated largely, while phosphorus content of shell(Pshell) was less varied than that of flesh(Pflesh). Pshell varied from 0.006 ± 0.001 to 0.016 ± 0.001 mmol g-1; while Pflesh fluctuated between 0.058 ± 0.017 and 0.293 ± 0.029 mmol g-1. Pclam ranged from 0.015 ± 0.002 to 0.041 ± 0.006 mmol g-1. Carbon and nitrogen content were slightly affected by shell length, width or height. Elemental contents were closely related to the reproduction cycle. The removal amounts of carbon, nitrogen and phosphorus from clam harvest and natural death in Jiaozhou Bay were 2.92×104 t, 1420 t and 145 t, respectively. The nutrient removal may aid to reduce the concentrations of nitrogen and phosphorus, the main causes of eutrophication, and to maintain the ecosystem health of Jiaozhou Bay.  相似文献   

13.
Grassland is a major carbon sink in the terrestrial ecosystem. The dynamics of grassland carbon stock profoundly influence the global carbon cycle. In the published literatures so far, however, there are limited studies on the long-term dynamics and influential factors of grassland carbon stock, including soil organic carbon. In this study, spatial-temporal substitution method was applied to explore the characteristics of Medicago sativa L.(alfalfa) grassland biomass carbon and soil organic carbon density(SOCD) in a loess hilly region with different growing years and management patterns. The results demonstrated that alfalfa was the mono-dominant community during the cutting period(viz. 0–10 year). Community succession began after the abandonment of alfalfa grassland and then the important value of alfalfa in the community declined. The artificial alfalfa community abandoned for 30 years was replaced by the S. bungeana community. Accordingly, the biomass carbon density of the clipped alfalfa showed a significant increase over the time during 0–10 year. During 0–30 year, the SOCD from 0–100 cm of the soil layer of all 5 management patterns increased over time with a range between 5.300 ± 0.981 kg/m2 and 12.578 ± 0.863 kg/m2. The sloping croplands had the lowest SOCD at 5.300 ± 0.981 kg/m2 which was quite different from the abandoned grasslands growing for 30 years which exhibited the highest SOCD with 12.578 ± 0.863 kg/m2. The ecosystem carbon density of the grassland clipped for 2 years increased 0.1 kg/m2 compared with the sloping cropland, while that of the grassland clipped for 10 years substantially increased to 10.30 ± 1.26 kg/m2. Moreover, the ecosystem carbon density for abandoned grassland became 12.62 ± 0.50 kg/m2 at 30 years. The carbon density of the grassland undisturbed for 10 years was similar to that of the sloping cropland and the grassland clipped for 2 years. Different management patterns imposed great different effects on the accumulation of biomass carbon on artificial grasslands, whereas the ecosystem carbon density of the grassland showed a slight increase from the clipping to abandonment of grassland in general.  相似文献   

14.
Shoot density, standing crop (above- and below-ground biomass) and habitat of salt marsh grass Porteresia coarctata were investigated along the coast of Bakkhali estuary, Cox’s Bazar, Bangladesh from January to December 2006. Shoot density of P. coarctata was influenced by season and was found to be higher (>2 500 shoots/m 2 ) in post-monsoon and minimal in monsoon season; plants were particularly active in vegetative propagation during pre-monsoon. Above-ground biomass was greater along the protected coast compared with the exposed one in this estuary. Below-ground biomass was higher (7.75-269.53 g DW/m 2 ) than that above ground (2.20-114.75 g DW/m 2 ). Standing crops of P. coarctata showed a negative relationship (R=-0.77; P<0.05) with sedimentation rate, while seasonal activity influenced sedimentation. The recorded sedimentation rate was lower (6.09 mg/(cm 2 ·d)) in pre-monsoon and highest (14.55 mg/(cm 2 ·d)) in monsoon season. The mean value of pore water salinity was higher (34.25±5.05) during post-monsoon and lowest (18.0±3.71) in monsoon season. The soil was sandy clay in this P. coarctata bed; it consisted of 86% sand, 13% clay and 1% silt. Soil organic matter dropped during the monsoon season (0.78%-0.67%) and was highest ((2.17±1.42)%-(2.3±1.47)%) during post-monsoon, probably owing to accumulation of decomposed peat on the marsh surface. The mean pore water NH 4 -N concentration ranged from 2.44±1.65 to 3.33±1.82 μg/L, with a minimum air temperature of 22.09°C in post-monsoon and a maximum of 31.16°C in pre-monsoon. Variations of physico-chemical parameters in the soil, water, and climate governed biological parameters of P. coarctata in the Bakkhali estuary, and were comparable with estuarine environments elsewhere.  相似文献   

15.
Primary productivity of ecosystem is important indicator about ecological assessment. Remote sensing technology has been used to monitor net primary productivity （NPP） of ecological system for several years. In this paper, the remotely sensed NPP simulation model of alpine vegetation in Qinghai Province of Tibet Plateau was set up based on the theory of light use efficiency. Firstly a new approach based on mixed pixels and Support Vector Machine （SVM） algorithm were used to correct simulated NPP values derived from Moderate Resolution Imaging Spectroradiometer （MODIS） data. Finally, spatial distribution and monthly variation characteristics of NPP in Qinghai Province detail. The result showed in 2006 were analyzed in that NPP of vegetation in Qinghai Province in 2006 ranged from o to 422 gC/m2/a and the average NPP was 151 gC/m2/a. NPP gradually increased from northwest to southeast. NPP of different vegetation types were obviously different. The average NPP of broad-leaved forest was the largest （314 gC/m2/a）, and sparse shrub was the smallest （101 gC/m2/a）. NPP in Qinghai Province significantly changed with seasonal variation. The accumulation of NPP was primarily in the period （from April to September） with better moist and heat conditions. In July, the average NPP of vegetation reached the maximum value （43 gC/m2）. In our model, the advantage of traditional LUE models was adopted, and our study fully considered typicalcharacteristics of alpine vegetation light use efficiency and environmental factors in the study area. Alpine vegetation is the most important ecological resource of Tibet Plateau, exactly monitoring its NPP value by remote sensing is an effective protection measure.  相似文献   

16.
To evaluate the diurnal and seasonal variations in soil respiration(Rs) and understand the controlling factors, we measured carbon dioxide(CO2) fluxes and their environmental variables using a LI-6400 soil CO2 flux system at a temperate Leymus chinensis meadow steppe in the western Songnen Plain of China in the growing season(May–October) in 2011 and 2012. The diurnal patterns of soil respiration could be expressed as single peak curves, reaching to the maximum at 11:00–15:00 and falling to the minimum at 21:00–23:00(or before dawn). The time-window between 7:00 and 9:00 could be used as the optimal measuring time to represent the daily mean soil CO2 efflux. In the growing season, the daily value of soil CO2 efflux was moderate in late spring(1.06–2.51 μmol/(m2·s) in May), increased sharply and presented a peak in summer(2.95–3.94 μmol/(m2·s) in July), and then decreased in autumn(0.74–0.97 μmol/(m2·s) in October). Soil temperature(Ts) exerted dominant control on the diurnal and seasonal variations of soil respiration. The temperature sensitivity of soil respiration(Q10) exhibited a large seasonal variation, ranging from 1.35 to 3.32, and decreased with an increasing soil temperature. Rs gradually increased with increasing soil water content(Ws) and tended to decrease when Ws exceeded the optimum water content(27%) of Rs. The Ts and Ws had a confounding effect on Rs, and the two-variable equations could account for 72% of the variation in soil respiration(p 0.01).  相似文献   

17.
Radioactive markers are useful in dating lead(Pb) deposition patterns from industrialization in sedimentary archives. As a well-known natural reserve in the world, Yancheng coastal wetland in Jiangsu Province is one of areas most sensitive to global sea level change and is located in the most developed and polluted region of China. Two cores were collected in Yancheng wetland in October 2013 and dated using ~(210)Pb and ~(137)Cs radiometric techniques. Sediments in both cores were sectioned into depth bands and examined systematically for dry bulk density, water content, magnetic susceptibility and grain-size. Multiple elements including Pb were also measured using inductively coupled plasma systems. Unsupported ~(210)Pb activities decreased with depth in both of the two cores, and ~(210)Pb chronologies were established(covering 150 years) using the constant rate of supply(CRS) model. The measured Pb contents ranged from 14.97 mg/kg to 29.40 mg/kg with average values of 17.17–22.79 mg/kg, and the Pb fluxes ranged from 41.70 mg/(m~2·yr) to 172.70 mg/(m~2·yr) with averages of 95.59–123.41 mg/(m~2·yr). Temporal variations of Pb flux, enrichment factors and Pb isotopes show a gradual and continuous increase over time and clearly reflect increased emissions from anthropogenic activities in the region. The Pb isotopic compositions show that most of Pb deposition in Yancheng wetland is input from natural sources by water flows and has the same levels of Pb as in the surface sediment of the Yangtze River and the Pacific mineral aerosol. We also stress the anthropogenic Pb contribution in Yangcheng wetland sediment and the reason of our Pb isotopes not showing anthropogenic signature is likely the instability of anthropogenic Pb in high Fe/Mn oxide conditions. Therefore, more attention should be paid to current local pollution problems, and society should take action to seek a balance between economic development and environmental protection.  相似文献   

18.
Reproductive rate of a marine planktonic copepodLabidocera euchaeta Giesbrecht in Xiamen Harbor bor was studied during the period from April 1986 to August 1987. Results showed that rate of egg production (F, eggs/(♀, d)) was positively correlated with temperature (T,oC) and body weight of spawning female (Wc, μgC) as:F=0.0637 (T−7)0.7445 Wc. Each month a maximum rate of egg production occurred at one of the five experimental temperatures (10°, 15°, 25°, and 30°C) near the monthly mean field temperature. The available food density (P, μgC/ml) had significant effect on specific rate of egg production (Fc, %C ♀/d) as:Fc=0.1732 (P-0.0179)/P. The gross efficiency of egg production of ca 62% in carbon was independent of food density snd ingestion rate. Observations on in situ egg production and hatching rate demonstrated that this species reproduces continuously all the year round, with summer as its high reproductive season and winter a low one. Ten generations a year is also suggested based on the number of the peaks of average population egg production rate. This agreed well with the result obtained from the generation-time equations. Egg-laying pattern was also observed and discussed.  相似文献   

19.
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   

20.
Carbon sequestration occurs when cultivated soils are re-vegetated. In the hilly area of the Loess Plateau, China, black locust(Robinia pseudoacacia) plantation forest and grassland were the two main vegetation types used to mitigate soil and water loss after cultivation abandonment. The purpose of this study was to compare the soil carbon stock and flux of these two types of vegetation which restored for 25 years. The experiment was conducted in Yangjuangou catchment in Yan′an City, Shaanxi Province, China. Two adjacent slopes were chosen for this study. Six sample sites were spaced every 35–45 m from summit to toe slope along the hill slope, and each sample site contained three sampling plots. Soil organic carbon and related physicochemical properties in the surface soil layer(0–10 cm and 10–20 cm) were measured based on soil sampling and laboratory analysis, and the soil carbon dioxide(CO2) emissions and environmental factors were measured in the same sample sites simultaneously. Results indicated that in general, a higher soil carbon stock was found in the black locust plantation forest than that in grassland throughout the hill slope. Meanwhile, significant differences in the soil carbon stock were observed between these two vegetation types in the upper slope at soil depth 0–10 cm and lower slope at soil depth 10–20 cm. The average daily values of the soil CO2 emissions were 1.27 μmol/(m2·s) and 1.39 μmol/(m2·s) for forest and grassland, respectively. The soil carbon flux in forest covered areas was higher in spring and less variation was detected between different seasons, while the highest carbon flux was found in grassland in summer, which was about three times higher than that in autumn and spring. From the carbon sequestration point of view, black locust plantation forest on hill slopes might be better than grassland because of a higher soil carbon stock and lower carbon flux.  相似文献   

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