生物土壤结皮铁代谢微生物组成及其功能基因对演替的响应     

王岩松  刘玉冰  王增如  赵丽娜  漆婧华  张雯莉 《中国沙漠》2020,40(3):193-200

采用微生物宏基因组学微阵列GeoChip 5.0技术,选择腾格里沙漠东南缘沙坡头地区不同年代人工固沙植被区的生物土壤结皮（BSC）为对象,分析BSC演替过程中参与铁代谢的功能微生物组成及其功能基因变化特征,研究微生物铁代谢对BSC演替的响应及调控。结果表明：真菌参与铁吸收和转运过程,古菌参与铁转运和贮存过程,细菌则在铁代谢吸收、转运和贮存过程中均起主要调控作用。门水平上,BSC铁代谢功能微生物组成变化对演替的响应不敏感,BSC铁代谢微生物主要为变形菌门（Proteobacteria）。BSC铁代谢功能基因多样性的显著提高和三类铁代谢过程基因信号强度达到最高水平需要经过61 a的演替。调控BSC铁吸收过程的主要功能基因为亚铁氧化酶编码基因iro;调控原核生物铁转运过程的主要功能基因,为羟基苯甲酰丝氨酸铁外膜转运体编码基因cirA和Fe（Ⅱ）转运蛋白编码基因feoB,真菌铁转运过程主要依靠含铁细胞转运体和铁氧化酶高亲和力的作用;调控铁贮存过程的主要功能基因为固定相类核蛋白编码基因dps。在BSC演替阶段末期,上述铁代谢功能基因强度的显著增加促进了微生物的铁代谢潜能。干旱、半干旱荒漠生态系统植被恢复过程中微生物铁代谢潜能的恢复需要较长时间。  相似文献   

铜藻(Sargassum horneri)在营养限制胁迫后对NH₄-N的超补偿吸收研究     

李大鹏  马增岭  李慧  丁刚  辛美丽  吴海一  郭文 《海洋与湖沼》2018,49(4):904-909

以经济马尾藻铜藻(Sargassum horneri)为研究材料,研究了其在营养限制胁迫后对NH_4-N的超补偿吸收情况。实验分营养限制和恢复营养两个阶段进行,每个阶段均设置饥饿处理组、饱和处理组和正常对照组。铜藻在低营养限制胁迫(饥饿)下培养10天后,恢复营养盐培养3天,分别采用次溴酸盐氧化法和锌镉还原法测定培养液中的NH_4-N和NO_3-N的浓度。本文研究发现,饥饿处理组中铜藻吸收氨氮的速率远高于正常对照组和饱和处理组,在恢复培养第一天时,饥饿处理组对NH_4-N的吸收速率最高为14.94μmol/(g·h),与正常对照组及饱和处理组间差异显著。在恢复培养的后两天,三个处理组中铜藻对NH_4-N的吸收速率差异慢慢变小,直至最后几乎相同。三组对NO_3-N没有表现出较高的吸收,最高仅为6.15μmol/(g·h),结果表明:氮源包括NH_4-N和NO_3-N时,铜藻优先选择吸收NH_4-N。实验后称重测定生长速率:对照组、饥饿处理组和饱和组生长率(SGR)分别为8.48%、8.86%、8.01%,ANOVA方差分析表明,三者存在显著差异(P=0.0320.05),从而证实了铜藻也存在超补偿生长的现象。  相似文献   

Immunotoxicity effect of benzo[α]pyrene on scallop Chlamys farreri     

Lin Zhang  Luqing Pan  Jing Liu 《中国海洋大学学报(英文版)》2009,8(1):89-94

The toxic effects of benzo[α]pyrene (B[α]P) at different concentrations (0.1, 0.5, 1, 2.5 and 7.5 μgL⁻¹) on scallop (Chlamy farreri) immune system were studied. The results showed that B[α]P had significant toxic effects on the haemocyte counts, neutral red uptake, phagocytosis, bacteriolytic and antibacterial activity (P<0.05), while the seawater control and acetone control had no significant differences. The haemocyte counts, neutral red uptake, phagocytosis and bacteriolytic activity in all B[α]P treatment groups as well as antibacterial activity in groups of 0.5, 1, 2.5 and 7.5 μgL⁻¹ B[α]P decreased significantly (P<0.05). Some of these indices tended to be stable on the sixth day and others on the ninth day, and the indices showed clear time- and concentration-response to B[α]P. Bacteriolytic activity in 0.1μgL⁻¹ B[α]P treatment group and antibacterial activity in 0.1 μgL⁻¹ and 0.5 μgL- B[α]P treatment groups increased at the beginning of exposure and reached their peaks on day 1 and day 6, respectively. Following that, both activities decreased gradually and became stable after day 9. When all the indices reached stability, they were significantly lower than those in control group (P<0.05), except for antibacterial activity in 0.1 μgL⁻¹ B[α]P treatment group (P>0.05). Thus, B[α] has evident toxic effects on scallop immune system, which supports the view that a relationship exists between pollution and immunomodulation in aquatic organisms.  相似文献   

利用稳定同位素(15N)示踪技术研究浮游藻类氮素吸收速率特征     

韩菲尔  赵中华  李大鹏  张路 《海洋与湖沼》2019,50(4):811-821

浮游藻类对溶解态氮的吸收同化是湖泊氮生物循环和水体富营养化发生机制探讨的关键环节。本文通过~(15)N稳定同位素添加实验以铜绿微囊藻(Microcystis aeruginosa)、海链藻(Thalassiosira sp.)、卡德藻(Tetraselmis sp.)、剧毒卡尔藻(Karlodinium veneficum)以及盐水隐藻(Rhodomonas salina)为研究对象,从浮游藻类氮素吸收时间、营养盐基质以及藻种差异三个方面研究五种藻类对铵氮(NH_4~+-N)、硝氮(NO_3~--N)、尿素氮(Urea-N)三种形态氮的吸收特征。研究发现:(1)浮游藻类对三种形态氮的吸收均在1h时吸收速率最高,其氮素吸收过程为快速吸收。(2)浮游藻类优先吸收还原态氮,其中NH_4~+-N吸收速率最高,当培养周期为1d和4d时浮游藻类对NH_4~+-N吸收速率的均值分别为4.05和4.15μmol/(L·h);浮游藻类对Urea-N吸收相对偏好系数为25.18—713.42,表现出对小分子溶解态有机氮的特定偏好性。(3)不同藻种对氮素吸收具有不同特征,其中,剧毒卡尔藻对三种形态氮的吸收速率均为最高,而铜绿微囊藻的吸收速率均为最低;不同藻种不同培养时间氮素吸收速率差异与浮游藻类生长周期等特性有关。不同浮游藻类对不同形态氮素表现出吸收特异性,对水体氮负荷和浮游藻类水华优势种形成将产生重要影响。  相似文献   

温度、氮浓度和氮磷比对长心卡帕藻(Kappaphycus alvarezii)吸收氮速率的影响   总被引：3，自引：0，他引：3  

刘建国  路克国  林伟  庞通  王莉 《海洋与湖沼》2008,39(5):529-535

分别在室内培养箱、海滨室外跑道池和不同自然海区,通过一次性和半连续添加营养、以及检测海区水质和藻体生长的方法,研究了不同氮浓度、温度和氮磷比条件下,长心卡帕藻氮吸收速率的变化和氮吸收速率随时间变化,以及栽培该藻的环境生态贡献。小型实验、中试放大和海区规模栽培结果表明:(1)在10—50μmol/L范围内,该藻吸收氮速率随氮浓度增加而增大;(2)当氮浓度一定时,氮磷比在1—50范围内对该藻吸收氮速率没有产生显著影响(P>0.05);(3)温度对该藻吸收氮速率有显著影响(P<0.05),其中温度在28℃时氮的吸收速率最高;(4)尽管一次性添加营养实验中长心卡帕藻吸收氮速率随时间变化表现出先快后慢的趋势,但是进一步的半连续添加营养实验证实,导致吸收速率下降系底物氮浓度限制,而不是藻本身吸收能力下降,结果还显示卡帕藻具有连续吸收同化无机氮能力;在自然光温度变化和不受底物浓度限制条件下,该藻藻体去除无机氮效率最大维持在0.3μmol/(gFW·h);(5)海南陵水黎安海湾水质数据显示,栽培该藻去除海水富营养化和净化水质作用显著,其去除海水富营养化的年贡献为33t氮素。  相似文献   

A SIMULATION OF CO_2 UPTAKE IN A THREE DIMENSIONAL OCEAN CARBON CYCLE MODEL     

金心  石广玉 《Acta Meteorologica Sinica》2001,(1)

A three-dimensional ocean carbon cycle model which is a general circulation model coupledwith simple biogeochemical processes is used to simulate CO_2 uptake by the ocean.The OGCMused is a modified version of the Geophysical Fluid Dynamics Laboratory modular ocean model(MOM2).The ocean chemistry and a simple ocean biota model are included.Principal variablesare total CO_2,alkalinity and phosphate.The vertical profile of POC flux observed by sedimenttraps is adopted,the rain ratio,a ratio of production rate of calcite against that of POC,and thebio-production efficiency should be 0.06 and 2 per year,separately.The uptake of anthropogenicCO_2 by the ocean is studied.Calculated oceanic uptake of anthropogenic CO_2 during the 1980s is2.05×10~(15)g(Pg)per year.The regional distributions of global oceanic CO_2 are discussed.  相似文献   

陕西泾阳冬小麦农田土壤水分的动态模拟研究     

周英 《南京气象学院学报》1992,15(2):73-81

  相似文献   

Nitrogen Uptake in Permanently Well-mixed Temperate Coastal Waters     

Stphane L'Helguen  Christian Madec  Pierre Le Corre 《Estuarine, Coastal and Shelf Science》1996,42(6):803-818

Uptake rates of ammonium, nitrate, urea and nitrite were measured for 1 year (1988) at a coastal station in the well-mixed waters of the western English Channel. Ammonium was the major form of nitrogen (N) utilized (48%) by phytoplankton, followed by nitrate (32%), urea (13%) and nitrite (7%). Seasonal changes of uptake of ammonium, nitrate and urea showed a broad, intense summer maximum. Nitrite uptake was low throughout the year except for a peak value in June. Uptake rates of ammonium and nitrate were independent of substrate concentrations, whereas those of urea and nitrite were not. The summer maxima of ammonium, nitrate and total N uptake, and the significant relationships of N-uptake index to ambient light, and of chlorophyll-a-specific N uptake to surface-incident light, indicate that light is the major factor controlling N uptake in these waters. This is due to the permanent vertical mixing which reduces the mean light available for N uptake to <15% of the incident light. Mixing also injects regenerated N continuously into the euphotic zone, thus alleviating nitrogen limitation and accounting for the larger proportion of regenerated N uptake in total N uptake.  相似文献   

Oxygen radicals production and actin filament disruption in bivalve haemocytes treated with benzo(a)pyrene     

Amagoia Gmez-Mendikute  Ainhoa Etxeberria  Igor Olabarrieta  Miren P. Cajaraville 《Marine environmental research》2002,54(3-5)

Haemocytes play an essential role in the internal defence of molluscs. It has been reported that organic xenobiotics commonly found as pollutants in the marine environment impair defence capabilities of haemocytes. The purpose of the present study was to investigate the effects of benzo(a)pyrene [B(a)P] on the integrity of the actin cytoskeleton and on endocytosis in haemocytes and to see if these effects are related to generation of reactive oxygen species. Haemocytes were exposed in vitro to B(a)P (0.5–40 μg/ml) for 1 h. Cell viability (using 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide or XTT assay) indicated that selected doses were sublethal. Uptake of neutral red was significantly decreased in a dose-dependent manner in B(a)P-treated haemocytes. Distribution of actin filaments, labeled with rhodamine-conjugated phalloidin, was altered in haemocytes treated with 20 or 40 μg/ml B(a)P. These effects could be related to an increased production of superoxide anion during B(a)P metabolism, as detected by the nitroblue tetrazolium (NBT) reduction assay in haemocytes treated with 10 μg/ml B(a)P.  相似文献   

Phosphorus metabolism in anthropogenically transformed lagoon ecosystems: The Comacchio lagoons (Ferrara, Italy)     

Yuri I. Sorokin  Franco Dallocchio  Fernando Gelli  Luciano Pregnolato 《Journal of Sea Research》1996,35(4):243-250

Inorganic phosphorus dynamics were investigated with the use of ³²P in the hypertrophic Comacchio lagoons (NE Adriatic) during an extremely dense, quasi-permanent bloom of picocyanobacteria. Concentrations of dissolved inorganic phosphate (DIP) in waters of the blooming lagoons were usually near the detection limit (0.01 μmoles·dm⁻³). DIP uptake rates by microplankton at near-ambient concentrations (0.01 to 0.1 μmoles·dm⁻³) were in the range of 9.6 to 16.1 nmoles P·dm⁻³·min⁻¹, and turnover times were 1.5 to 3 min. The turnover time was >40 h in the eutrophic coastal waters of the adjacent Adriatic Sea. The uptake rate of DIP depended on its initial concentration. In water samples artificially enriched with DIP, the uptake rate rose to its maximum of 0.10 to 0.13 μmoles P·dm⁻³·min⁻¹ (or 6 to 7 μmoles·dm⁻³·h⁻¹) when the initial concentration of DIP was elevated to 10 to 20 μmoles·dm⁻³. The potential capacity of microplankton in the water samples to consume and retain DIP was estimated at 25 μmoles·dm⁻³. Specific features are discussed of phosphorus metabolism in the anthropogenically transformed lagoon ecosystem with an anomalous food web with few animals.  相似文献