土壤理化特性对稻田CH4排放的影响

为了研究土壤理化特性对稻田CH4 排放的影响 ,室外盆栽试验于 2 0 0 0年水稻生长季在南京农业大学实施 ,1 8个供试水稻土分别取自江苏宜兴、江宁、六合、仪征及宝应等地 .所有供试土壤的季节性CH4 平均排放通量为 6 42± 2 70mg·(m2 ·h) - 1,最低和最高值分别为 1 96mg·(m2 ·h) - 1和 1 1 0 6mg·(m2 ·h) - 1,两者相差约 5 6倍 .单相关分析结果表明 :影响CH4 排放的主要土壤参数为质地、氮素状况及铜含量 .CH4 排放与土壤砂粒含量呈正相关 (r =0 5 2 8,p =0 0 2 4) ,与粘粒含量呈负相关 (r =-0 484,p =0 0 42 ) .氮素含量高的土壤CH4 排放较低 ,CH4 排放与土壤全氮、速效氮和铵态氮含量的线性相关系数分别为 -0 449(p =0 0 62 )、-0 61 1 (p =0 0 0 7)和 -0 649(p =0 0 0 4) .土壤铜含量直接影响CH4 的排放 ,CH4 排放与有效态铜和全铜含量的线性相关系数分别为 -0 5 94(p =0 0 0 9)和 -0 5 47(p =0 0 1 9) .本研究并未观测到CH4 排放与土壤有机碳含量有相关关系 ,这与前人报道的实验室培养测定结果及稻田CH4 排放随土壤有机质含量提高而增加的假设完全不同 .逐步回归分析表明 ,不同土壤间CH4 排放的变异性有 75 5 %可由土壤有效态铜含量、镁 (全量 )含量及有效铁含量与全量铁之     

In vitro establishment of continuous cell cultures and cell lines from ten colonial cnidarians

Continuous cell cultures from the ten taxa of sedentary colonial marine cnidariansStylophora pistillata, Porites lutea, Favia favus (Anthozoa, Hexacorallia, Madeporaria),Parerythropodium fulvum fulvum, Dendronephthya hemprichi, Nephthya sp.Heteroxenia fuscescence (Anthozoa, Octocorallia, Alcyonacea),Clathraria rubrinoides, Plexaura A (Anthozoa, Octocorallia, Gorgonacea) andMillepora dichotoma (Hydrozoa) were established in vitro. Primary cultures of various cell types (5 to 20 m) were obtained from colony fragments and/or planula larvae (collected in 1993 from coral reefs at Eilat, Red Sea and from the San Blas islands, Panama) using three dissociation approaches: a mechanical approach, chemical approach and a novel approach, spontaneous dissociation. Cells were cultured in a modified Leibowitz L15 medium, with 5 to 10% heat-inactivated fetal bovine serum, diluted in seawater. Cell proliferation was observed in primary cultures within 7 to 20 d following dissociation. When developed to secondary cultures, spindle-shaped cells (5 to 10 m) gradually replaced all other cell types seen in primary cultures ofS. pistillata, C. rubrinoides, P.f. fulvum andM. dichotoma. The spindle-shaped cells differentiated to several cell types when the diluted medium was replaced with a concentrated one, or when microbial contamination occurred. Secondary cultures of spindle-shaped cells from three species (S. pistillata, C. rubrinoides andM. dichotoma) were cloned. They gave rise to continuously proliferating cell lines (NIO-SPP-1, NIO-CR-1 and NIO-MD-1, respectively). A clone fromPlexaura planula, originated from one rounded cell, started to differentiate and gave rise to a heterogeneous culture. Samples of the above four cultures were frozen for future work. Rounded cells of various sizes (5 to 30 m) dominated secondary cell cultures ofH. fuscescence, D. hemprichi, Nephthya sp.,P. f. fulvum andF. favus. Several cell cultures fromP. lutea developed flattened cell interconnected by ectoplasmic networks characteristic of the eukaryotic unicellular organisms of the phylum Labyrinthulomycota. We propose that this culture methodology may be used as a ubiquitous protocol for producing tissue cultures from other cnidarians. The established cell lines may be used in a variety of disciplines in cnidarian biology and ecology.     

The Genetic Diversity of Native, Stocked, and Hybrid Populations of Brook Trout in the Southern Appalachians

Using mitochondrial DNA (mtDNA) restriction analysis and starch-gel electrophoresis of the CK-A2 locus product, we examined genetic variation in 311 brook trout (Salvelinus fontinalis) from 11 native, 5 hatchery-derived, and 8 hybrid populations in the southern Appalachian Mountains. Native southern Appalachian fish were genetically distinct from hatchery-derived fish. Southern and hatchery-derived fish were reliably distinguished based on three mtDNA restriction sites. Native southern haplotypes differed from hatchery-derived haplotypes by an average of 0.84%. Northern hatchery-derived haplotypes varied little in mtDNA compared to native southern haplotypes. Introgression of mtDNA haplotypes and the CK-A2 locus varied among populations, and introgression of allozyme and mtDNA markers was positively correlated. Continued introductions of nonnative strains of brook trout in the southern Appalachians could simplify the genetic structure of native brook trout populations and eliminate unique genotypes.     

The effect of export to the deep sea on the long-range transport potential of persistent organic pollutants

Background

Export to the deep sea has been found to be a relevant pathway for highly hydrophobic chemicals. The objective of this study is to investigate the influence of this process on the potential for long-range transport (LRT) of such chemicals.

Methods

The spatial range as a measure of potential for LRT is calculated for seven PCB congeners with the multimedia fate and transport model ChemRange. Spatial ranges for cases with and without deep sea export are compared.

Results and Discussion

Export to the deep sea leads to increased transfer from the air to the surface ocean and, thereby, to lower spatial ranges for PCB congeners whose net deposition rate constant is similar to or greater than the atmospheric degradation rate constant. This is fulfilled for the PCB congeners 101, 153, 180, and 194. The spatial ranges of the congeners 8, 28, and 52, in contrast, are not affected by deep sea export. With export to the deep sea included in the model, the spatial ranges of the heavier congener are similar to those of the lighter ones, while the intermediate congeners 101 and 153 have the highest potential for long-range transport.

Conclusions

Transfer to the deep ocean affects the mass balance and the potential for LRT of highly hydrophobic chemicals and should be included in multimedia fate models containing a compartment for ocean water.     

Forest conservation and the clean development mechanism: Lessons from the Costa Rican protected areas project

Deforestation is currentlythe source of about 20% of anthropogenicCO₂ emissions. Avoided deforestationhas, nonetheless, been ruled out as a CleanDevelopment Mechanism (CDM) category in theKyoto Protocol's first commitment period,because several methodological issues wereconsidered too difficult to resolve. Thispaper explores whether CDM issues such as(1) carbon quantification, (2)additionality and baseline setting, (3)leakage risks, (4) non-permanence risks,and (5) sustainable development can beadequately dealt with in large, diversifiedforest conservation projects. To this aim,it studies the case of the Costa RicanProtected Areas Project (PAP), anActivities Implemented Jointly (AIJ)project which was meant to consolidate thenational park system to avoiddeforestation, promote the growth ofsecondary forests and regenerate pastureson an area that, in total, covers 10% ofthe national territory. The case studyexamines how the issues mentioned abovehave been addressed in the project designand in the certification process. It isfound that baseline uncertainties are themajor problem in this case. Nonetheless,the case suggests the possibility toaddress CDM issues by specific requirementsfor project design and very conservativeand temporary crediting. Provided thatother case studies support this conclusion,eligibility of well-designed forestconservation projects under the CDM in thesecond commitment period may be worthconsidering, given the secondary benefitsof avoided deforestation.     

Male bill colour and age are associated with parental abilities and breeding performance in blackbirds

In monogamous bird species, male parental investment may influence offspring fitness and females may gain advantages through mating with males providing extensive paternal care. However, paternal care is a benefit that can only be assessed indirectly because mate choice precedes paternal activities. Individual quality and age, both signalled by morphological characteristics, may reflect parental abilities. Because they may reflect individual foraging abilities, carotenoid-based colorations have been proposed to honestly signal parental quality. The blackbird (Turdus merula), a socially monogamous species, exhibits biparental care and males show bills that vary from pale yellow to orange due to carotenoid pigments. In this study, we investigated whether male bill colour and age are associated with parental ability. Our results suggest that males with more orange bills and older males are better fathers. Indeed, male visit rate increased with their bill colour index independently of age, and brood condition was higher for adult males, compared to yearlings, independently of bill colour. Overall, the number of fledglings produced was positively influenced by both the age of males and the colour intensity of their bills. Males with more orange bills and adults had a greater number of fledglings and these males also had higher levels of prolactin, a hormone known to promote parental care. This latter finding suggests that prolactin may be the link between carotenoid based colorations and the intensity of paternal effort. Thus, male bill colour seems to honestly reveal male physiological adjustment to paternal activities.