Biodegradation of Nonylphenol Ethoxylate Surfactants in Biofilm Reactors     

Anubha Goel  Margit B. Müller  Mukesh Sharma  Fritz H. Frimmel 《洁净——土壤、空气、水》2003,31(2):108-119

The primary degradation of a technical nonylphenol ethoxylate surfactant with an average chain length of 10 ethoxylate units (NPEO‐10) was studied in a flow‐through system by means of miniaturized biofilm reactors (mBFR) with bacteria from an activated sludge plant. 5 mg/L of the test compound (total EO concentration) were spiked in synthetic wastewater (SWW) and fed to the reactors continuously for 64 days. Compound removal and the formation of degradation products (DP) were monitored under both oxic and anoxic conditions. Solid‐phase extraction and RP‐HPLC with fluorescence detection were employed for sample preparation and analysis. Better removal of the parent compound was seen with the oxic reactors (50 to 70%) than with the anoxic reactors (30 to 50%). Compared to SWW organic matter, the test compound proved to be of refractory nature. The appearance of degradation products in the effluent was earlier with anoxic reactors despite their lower elimination efficiency. After extraction of biomass only minor amounts of NPEO‐10 and metabolites were found, indicating that small amounts were present in adsorbed or intracellular form. Ultimate biodegradation of NPEO‐10 and of octylphenol ethoxylates (OPEO‐9.5; average chain length of 9.5 EO units) was tested by means of manometric respirometry at a theoretical oxygen demand (ThOD) of 100 mg/L. Whereas NPEO‐10 was biodegraded by only 26%, at best, in 28 days, OPEO‐9.5 degradation amounted to (40 ± 5)%.  相似文献   

Using GC-MS/Combustion/IRMS to determine the C/C ratios of individual hydrocarbons produced from the combustion of biomass materials--application to biomass burning     

Vincent P. O'Malley  Roger A. Burke  William S. Schlotzhauer 《Organic Geochemistry》1997,27(7-8)

Simultaneous mass spectral detection and stable carbon isotope analysis was performed on individual indigenous n-alkanes isolated from single C₄ and C³ plant species and on a series of aliphatic and polycyclic aromatic hydrocarbons (PAH) produced from the combustion of these same biomass materials. The analysis technique used a combined gas chromatograph-mass spectrometer/combustion/isotope ratio mass spectrometer (GC-MS/C/IRMS). Precision (2σ) for replicate measurements of individual compounds in standard solutions using this novel configuration ranged between 0.2 and 0.5‰ for n-alkanes and 0.3 and 0.8‰ for PAH. Accuracy of the n-alkane measurements ranged between 0.1 and 0.4‰ and that of the PAH measurements ranged between 0.2 and 0.9‰. Replicate GC-MS/C/IRMS measurements on the combustion-derived n-alkene/alkane pairs were performed to within a precision of between 0.1 and 1.1‰ and the precision for the combustion PAH was similar to the standard PAH solution. No notable isotopic effects were observed when altering the temperature of the combustion process from 900 to 700°C, or as a result of the individual n-alkenes/alkanes partitioning between the gaseous and condensate fractions. Combustion-derived n-alkenes/alkanes ranged from C₁₁ to C₃₁, and the C₄-derived n-alkenes/alkanes were approx. 8‰ more enriched in ¹³C than the C₃-derived compounds. Both the C₄ and C₃-derived n-alkenes/alkanes (C₂₀-C₃₀) were isotopically similar to the indigenous n-alkanes and were 2-3‰ more depleted in ¹³C than the lower mol. wt (C₁₁₁₁-C₁₉) n-alkenes/alkanes, suggesting an independent origin for the lower mol. wt compounds. Combustion-generated C₄ and C₃-derived 2-, 3-, and 4-ring PAH were also isotopically distinct (Δδ = 10‰). Unlike the n-alkenes/alkanes, no compound-to-compound variations were observed between the low and high mol. wt PAH. This study demonstrates that the isotopic composition of original plant biomass material is mainly preserved in the aliphatic hydrocarbons and PAH generated by its combustion. Consequently, analyses of these compounds in sediments impacted by fire occurrences may provide useful information about paleo-fire activity that may help elucidate the impact biomass burning may have had and could have on climate-biosphere interactions.  相似文献   

Changes of macrobenthos composition under different ENSO cycle conditions on the continental shelf off central Chile     

Javier Sellanes  Eduardo Quiroga  Carlos Neira  Dimitri Gutiérrez 《Continental Shelf Research》2007

The course of environmental conditions and shelf macrobenthic communities off Central Chile (∼36°S) during the strong 1997–98 El Niño (EN) event is compared with a subsequent and basically “normal” period (2002–2003). Changes in macrofaunal community, feeding mode structure, and biomass size spectra are contrasted over time with changes in oceanographic and sediment settings, in order to assess intra- and inter-annual changes in faunal composition during both ENSO periods.  相似文献   

Mapping forest biomass from space – Fusion of hyperspectral EO1-hyperion data and Tandem-X and WorldView-2 canopy height models     

《International Journal of Applied Earth Observation and Geoinformation》2015

Spaceborne sensors allow for wide-scale assessments of forest ecosystems. Combining the products of multiple sensors is hypothesized to improve the estimation of forest biomass. We applied interferometric (Tandem-X) and photogrammetric (WorldView-2) based predictors, e.g. canopy height models, in combination with hyperspectral predictors (EO1-Hyperion) by using 4 different machine learning algorithms for biomass estimation in temperate forest stands near Karlsruhe, Germany. An iterative model selection procedure was used to identify the optimal combination of predictors. The most accurate model (Random Forest) reached a r² of 0.73 with a RMSE of 14.9% (29.4 t/ha). Further results revealed that the predictive accuracy depended highly on the statistical model and the area size of the field samples. We conclude that a fusion of canopy height and spectral information allows for accurate estimations of forest biomass from space.  相似文献   

High environmental salinity reduces the reproductive potential of the spider crab Maja brachydactyla (Decapoda,Majidae)          下载免费PDF全文

Guiomar Rotllant  Carles G. Simeó  Glòria Macià  Alicia Estévez 《Marine Ecology》2015,36(3):496-505

The spider crab Maja brachydactyla is an important fisheries species in Europe. Adults were sampled in Ría de A Coruña (NW Spain) and transported to IRTA rearing facilities. Salinity and photoperiod changes and their effect on reproduction were tested in the laboratory. The number of newly hatched larvae per batch (presence of actively swimming newly hatched larvae in a broodstock tank) was counted and sampled to estimate dry weight and proximal composition. Keeping spider crab broodstock in a high salinity environment (38 ppt) significantly reduced the number of newly hatched larvae, reaching up to fivefold difference in winter. The number of newly hatched larvae produced under a natural photoperiod was 10‐fold higher than those produced using a fixed photoperiod at 34 ppt salinity during winter. No clear pattern of changes in larval dry weight, protein, lipid or carbohydrate composition was observed under the environmental conditions tested. The results show that the salinity used for broodstock maintenance, especially during the embryonic development, is an important factor causing changes in larval production of M. brachydactyla and with potential implications for recruitment success.  相似文献   

胶州湾口内海水中叶绿素浓度的周年变化和垂直分布   总被引：7，自引：2，他引：7  

潘友联  郭玉洁  曾呈奎 《海洋与湖沼》1995,26(1):21-27

于１９８３年１１月－１９８５年１１月在胶州湾两个观测站逐月进行了２周年的海水中叶绿素浓度的定点研究。结果表明，（１）胶州湾口表层海水中的叶绿素α平均浓度为３．０５（１．０２－１５．６２）ｍｇ／ｍ＾３；真光层中平均为２６．３４（９．９７－１０６．５９）ｍｇ／ｍ＾２；其季节变化呈春（３－４月）、秋（９－１１月）双峰型。（２）小型（＜７８μｍ）的浮游植物平均占海水中叶绿素α的８５．７６％。（３）叶绿素ａ  相似文献   

Temporal dynamics of subtidal Zostera marina and intertidal Zostera japonica on the southern coast of Korea     

Sang Yong Lee  Jeong Bae Kim  & Sung Mi Lee 《Marine Ecology》2006,27(2):133-144

The temporal dynamics of two seagrass species, Zostera marina and Z. japonica, were monitored monthly in Dadae Bay, Geoje Island, on the southern coast of Korea. Plant morphological characteristics, shoot density, biomass, leaf production, reproductive effort, and environmental characteristics were monitored from July 2001 to July 2002. Zostera japonica occurred in the intertidal zone and Z. marina occurred in the subtidal zone from 0.5 to 2.5 m below the mean low water level. Shoots and rhizomes were significantly larger in Z. marina than in Z. japonica, whereas the shoot density was greater in Z. japonica than in Z. marina. Despite differences in morphology and shoot density, biomass did not differ significantly between the species. Reproduction occurred from April to June in Z. marina and from May to July in Z. japonica. The proportion of reproductive shoots was approximately three times higher in Z. marina than in Z. japonica. Seasonal variation in the biomass of Z. japonica was caused by changes in both shoot size and density, whereas that of Z. marina was mainly caused by changes in shoot length. Leaf production in Z. marina and Z. japonica showed clear seasonal variation, and leaf production in Z. marina (2.6 ± 0.2 g DW·m⁻²·day⁻¹) was higher than that in Z. japonica (1.7 ± 0.2 g DW·m⁻²·day⁻¹). The mean plastochrone interval was not significantly different between the two species, whereas the leaf lifetime of Z. marina was longer (69 ± 7.8 days) than that of Z. japonica (59 ± 8.3 days). Our results indicated that seasonal leaf growth patterns in Z. japonica are correlated with irradiance and temperature, whereas those in Z. marina respond most to irradiance. Seasonal changes in irradiance appeared to control the temporal variation in above‐ground biomass in both species.  相似文献   

沐官岛潮间带底栖海藻春秋季节的群落构成、生物量、分布及其变化的初步研究   总被引：3，自引：0，他引：3  

刘剑华  张耀红 《海洋湖沼通报》1995,(1)

于1990年5月和11月份海藻生长繁殖季节，进行两次不同方位定性和定量采集工作，结果定性样品42种，东南方位种数大大超过其它3个方位，群落构成以红藻为主，定量样品两个季度月平均生物量也以东南方位最高。该岛主要优势种为鼠尾藻。  相似文献   

Effect of Nitrogen Sources on the Growth and Docosahexaenoic Acid Accumulation in Crypthecodinium cohnii   总被引：1，自引：0，他引：1  

王菊芳  陈峰等 《海洋通报(英文版)》2002,4(1):87-92

The effect of various nitrogen sources on the growth and docosahexaenoic acid (DHA) yield is determined in Cryphecodinium cohnii ATCC30556,Single nitrogen tryptone and peptone are suitable to growth,the dry weight biomass is up to 2.78g/L and 2.70g/L respectively on medium containing 0.34g/L nitrogen.Peptone is a favorable nitrogen source for DHA accumulation,DNA yield increases up to 338.56mg/L.Using peptone and KNO3 as a multiple nitrogen source,the highest biomass and DHA yield are obtained from medai containing 0.34g/L nitrogen in which the ratio of peptone-N:NO3^--N is 1:2 ,and the bionmass and DHA yield are 2.98g/L(DW) and 527.97mg/L respectively.  相似文献   

胶州湾大型底栖动物次级生产力初探   总被引：25，自引：1，他引：25  

李新正  王洪法  张宝琳 《海洋与湖沼》2005,36(6):527-533

根据1998—1999和2000—2004年在胶州湾10个大面观测站考察采集的大型底栖动物定量样品,利用Brey(1990)的经验公式进行了大型底栖动物栖息丰度、生物量、次级生产力和P/B值的研究计算,其中,平均栖息丰度在1998—1999年为381.7ind/m2,2000—2004年为304.6ind/m2;平均生物量以去灰干重计,1998—1999年为22.22g/m2,2000—2004年为16.30g/m2;平均次级生产力以去灰干重计,1998—1999年为18.65 g/(m2.a),2000—2004年为3.41g/(m2.a);P/B值在两个时间段均为1.05a-1。结果表明,胶州湾大型底栖动物次级生产力由湾口—湾北部的湾顶呈梯度升高,2000—2004年次级生产力较1998—1999年有所下降,湾顶的高分布区下降更为明显,且高分布中心向西偏移,而大型底栖动物群落的物种组成基本保持稳定。文中分析了次级生产力下降和偏移的原因。通过比较,发现胶州湾大型底栖动物次级生产力高于渤海,远高于南黄海和东海,验证了次级生产力受水深的影响,随水深加大而降低;P/B值较渤海高,较东海低,与南黄海大部分海域平均值接近,验证了P/B值随水温升高而升高,也说明了胶州湾大型底栖动物群落中个体小、生活史短、代谢快的种类所占的比例高于渤海,低于东海,与南黄海其它水域近似。  相似文献