基于CESM-EnSRF系统全球甲烷及臭氧卫星资料同化试验研究

臭氧(O3)与甲烷(CH4)均是大气中重要的微量气体,对全球气候变化有着重要的影响.为提高全球范围的臭氧、甲烷在气候模式中的预报效果,使用集合平方根滤波(En SRF)同化方法及地球系统模式(CESM)构建了CESM-En SRF卫星资料同化预报系统,并通过设计试验,将大气红外探测器(AIRS)的臭氧与甲烷观测资料同化到气候模式中,对模式的同化再预报效果进行系统的测试与评估.结果显示,臭氧、甲烷分析集合均值的偏差及均方根误差皆低于背景集合均值的偏差及均方根误差.臭氧、甲烷的同化再预报偏差及均方根误差较控制实验都得到改善,但对5 h Pa以上高度臭氧预报准确性的改进效果很小.随循环同化的进行,平流层臭氧与甲烷的平均同化改进率呈增加趋势,并逐渐趋于稳定;对流层平均同化改进率随时间变化不明显.试验表明,该系统可有效利用臭氧与甲烷的观测资料对模式场进行合理的改善,从而有效地提高臭氧、甲烷在气候模式中的再预报效果,但对于平流层顶-中间层高度(5 h Pa以上)臭氧预报准确度的提高,模式中臭氧光化学过程的准确模拟较同化观测资料具有更重要的作用.此外,循环同化对提高5~150 h Pa高度臭氧及1~200 h Pa高度甲烷在CESM模式中的预报效果最有效.     

Litter decomposition and nitrogen release in a sloping Mediterranean subtropical agroecosystem on the coast of Granada (SE, Spain): Effects of floristic and topographic alteration on the slope

On the coast of Granada (SE, Spain), an economically important area for subtropical fruit cultivation, the crops are grown on orchard terraces. Also, high amounts of fertilizers, often excessive, are used in this type of intensive agriculture. However, each year significant fractions of nutrients taken up by the trees return to the soil by fallen leaves. Using a litter-bag technique, we assessed the decomposition rates and N-release in various types of litter. Our main purpose was to compare two different agroecosystem scenarios: (1) an unaltered slope consisting mainly of a mixture of herbaceous plants (Papaver rhoeas, Convolvulus sp., Malva sylvestris, Reseda phyteuma, Anacyclus sp., Sinapis arvensis, Medicago sp.) among spontaneous perennial woody shrubs (Genista umbellata, Olea europaea, Lavandula officinalis, Phlomis purpurea, Retama sphaerocarpa), and (2) an altered slope cultivated with subtropical trees on terraces: loquat (Eriobotrya japonica), mango (Mangifera indica), avocado (Persea americana), and cherimoya (Annona cherimola), with groundcover plantings of aromatic, medicinal, and melliferous plants (AMMPs) on the taluses of the terraces, which are usually used for erosion control: Lavandula dentata, Thymus mastichina, Satureja obovata, Rosmarinus officinalis, Anthyllis cytisoides. In the leaves from the subtropical crops, we found the highest decomposition rates in cherimoya and the lowest in mango (1.30 and 0.64 years⁻¹, respectively). Leaves from mango and loquat registered initial peaks of N immobilization and later N-release, which was highest in cherimoya and avocado leaves (71.2 and 56.8% of the initial remaining N). In the spontaneous woody shrubs, O. europaea and G. umbellata were the slowest in decomposing (1.18 and 1.01 years⁻¹, respectively) contrary to L. officinalis, which decomposed fastest (2.22 years⁻¹). Only L. officinalis and P. purpurea registered a net N-release at the end of the study. The AMMPs showed different decomposition patterns: L. dentata registered the highest decomposition rates and Rosmarinus the lowest (1.9 and 1.1 years⁻¹, respectively). T. mastichina, L. dentata, and S. obovata had the highest N-release, whereas R. officinalis and A. cytisoides showed N immobilization (183 and 122% of the initial N). Knowledge of the dynamics of nutrient release and litter decomposition will be useful for predicting nutrient availability and nutrient cycles in these types of agroecosystems where subtropical orchards are grown on terraces.     

基于固定化氮循环细菌技术的镇江金山湖生态工程效果研究

通过细菌筛选、载体分析、固定化氮循环菌制备,获取了高效固定化氮循环细菌;采用固定化氮循环细菌技术对镇江金山湖富营养化水体进行了治理研究.结果表明,经过固定化氮循环细菌释放试验,金山湖示范工程区水体和水生植物根区氨化细菌、亚硝化细菌、硝化细菌和反硝化细菌数量明显增加,重建的金山湖示范工程区水体水质明显改善,TN、NH⁺₄-N、NO^-₃-N和NO^-₂-N平均比示范工程前分别降低44.70％、 67.17％、 31.79％和74.21％,氨氮达到Ⅱ类、总氮达到Ⅳ类水标准.固定化氮循环细菌技术对于荒漠化水体生态重建与修复具有重要意义.     

Development of cycling skills in 7- to 12-year-old children

Objective: Cycling is a complex skill consisting of motor skills such as pedalling, braking, and steering. Because the ability to perform cycling skills is based on the age-related development of the child, experience and age-related reference values are of interest in light of customized testing and training.

Methods: One hundred thirty-eight children from the second (7–8 years), fourth (9–10 years), and sixth (11–12 years) grades performed a practical bicycle test consisting of 13 test items with specific points of interest. Moreover, age at onset of cycling, cycling to and from school, independent mobility, and minutes cycling per week were estimated using a parental questionnaire.

Results: It is found that cycling skills are strongly related to age with 11- to 12-year-old children outperforming 7- to 8-year-old children for 11 test items and 9- to 10-year-old children for 8 test items.

Conclusions: Next to age, age at onset of cycling also contributed to cycling skills. Therefore, our results suggest that cycling skills are associated with physical and mental maturation. Subsequently, age-related reference values are provided to customize testing and training.     

Salt Marsh Diking and Restoration: Biogeochemical Implications of Altered Wetland Hydrology

Experimental short-term desalination and drainage of salt marsh cores in greenhouse microcosms caused Spartina production to increase after one growing season, reflecting decreased salt stress and sulfide toxicity. However, production thereafter declined, likely due to pyrite oxidation and acidification in drained treatments and sulfide accumulation in waterlogged treatments. A survey of longer-term (decadal) effects of diking on peat composition of Cape Cod, Massachusetts, USA, marshes revealed acidification, Fe(II) mobilization, and decreased organic content in drained sites. Despite the aerobic decomposition of organic matter, abundant nutrients remained as sorbed NH₄ and mineral-bound PO₄. In diked, seasonally waterlogged sites, porewater alkalinity, sulfide, ammonium and orthophosphate were much lower, and organic solids higher, than in adjacent natural marsh. Seawater was added to cores from diked marshes to study the effects of tidal restoration. Salination of the drained peat increased porewater pH, alkalinity, ammonium, orthophosphate, Fe, and Al; copious ammonium N, and Fe(II) for sulfide precipitation favored Spartina growth. Salination of diked–waterlogged peat increased sulfate reduction and caused 6–8 cm of sediment subsidence. The resulting increase in porewater sulfides and waterlogging decreased vigor of transplanted Spartina alterniflora. Results indicate that seawater restoration should proceed cautiously to avoid nutrient loading of surface waters in drained sites or sulfide toxicity in diked–waterlogged marshes.     

Characterization of the genes involved in nitrogen cycling in wastewater treatment plants using DNA microarray and most probable number-PCR

To improve nitrogen removal performance of wastewater treatment plants (WWTPs), it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study characterized the quantity and diversity of nitrogen cycling genes in various processes of municipal WWTPs by employing two molecular-based methods:most probable number-polymerase chain reaction (MPN-PCR) and DNA microarray. MPN-PCR analysis revealed that gene quantities were not statistically different among processes, suggesting that conventional activated sludge processes (CAS) are similar to nitrogen removal processes in their ability to retain an adequate population of nitrogen cycling microorganisms. Furthermore, most processes in the WWTPs that were researched shared a pattern:the nirS and the bacterial amoA genes were more abundant than the nirK and archaeal amoA genes, respectively. DNA microarray analysis revealed that several kinds of nitrification and denitrification genes were detected in both CAS and anaerobic-oxic processes (AO), whereas limited genes were detected in nitrogen removal processes. Results of this study suggest that CAS maintains a diverse community of nitrogen cycling microorganisms; moreover, the microbial communities in nitrogen removal processes may be specific.

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It's a dirty job but someone has to do it: The role of marine benthic macrofauna in organic matter turnover and nutrient recycling to the water column

Benthic macrofaunal populations through their feeding, bioturbation, burrow construction and sediment irrigation activities have profound influences on organic matter inputs to marine sediments (biodeposition) and on the vertical distribution of deposited organic matter within the sediment. These effects in turn influence the rates and pathways of organic matter mineralisation, and element cycles. Similarly, bioturbation, burrow construction and burrow irrigation are major determinants of sediment-water column fluxes of oxygen and nutrients.

In this review, I discuss the influences of the different benthic macrofaunal feeding (functional) groups on mineralisation processes and sediment-water column fluxes of particulate and dissolved nutrients. How these effects influence diagenic processes, the balance between aerobic and anaerobic processes, and the redox status of the surficial sediments. Finally, I discuss some of the limitations of the predominantly laboratory techniques which have been used to study “macrofaunal effects” and how this hinders the inclusion of the effects in quantitative sediment biogeochemical models.     

Nutrient balance in the ecosystem of the North Western Adriatic Sea

The effects of biological processes on dissolved inorganic nutrients, dissolved organic nitrogen (DON) and phosphorus (DOP) are considered in the north western Adriatic Sea. The budgets of these nutrients, which represent the sum of production and consumption processes in comparison to advection, are discussed with regard to dissolved inorganic nitrogen ( 15 N labelled) uptake, which basically indicates the biological demand of this fraction of nitrogen by phytoplankton community. The presented data show that, although important, the continental input of dissolved inorganic nitrogen (DIN), mainly nitrate, is utilised and recycled within the coastal marine environment (budget of m 15 r µmol-N·dm m 3 ). In fact, during four cruises (June, 1996; February, 1997; June, 1997; February, 1998), phytoplankton production was mainly driven by regenerated nutrients ( f h 0.4). Regarding dissolved inorganic phosphorus (DIP), the negative budgets observed in most cases (down to m 0.4 r µmol-P·dm m 3 ) confirm, above all, its scarce availability in this basin. Recycling processes rather than continental inputs regulate the availability of this nutrient. In addition, the comparison between DIN and DIP budgets indicates that, in this ecosystem, dissolved inorganic phosphorus is recycled faster than nitrogen through the living particulate and dissolved organic pools. As a consequence of biological activities, a strong production of dissolved organic nitrogen (DON) can occur in summer (up to +22 r µmol-N·dm m 3 ) while DOP shows a more independent behaviour both with respect to its accumulation in the environment and to the observed nitrogen variations.     

Effects of different endogenous fungi on the mass loss and nutrient content of leaf litter of Cunninghamia lanceolata北大核心CSCD

To explore the role of endophytic fungi in the decomposition of litter, the endophytic fungi Penicillium sp. strain CG2 (A), Fusarium flavum strain AY13 (B), and Talaromyces strain AJ14 (C) of Cunninghamia lanceolata were added to experimental pots in different forms (mycelium, sterilized fermentation broth, single fungus, and mixed fungi), and a control treatment (CK) was set up (no fungi added). At 10, 30, 60, 90, and 120 days after litter decomposition, a study on the decomposition dynamics of C. lanceolata litter under different treatments was performed. The results showed that the rate of leaf mass loss was the highest in the sterilized fermentation broth treatment A after 120 days, and that there was a significant difference (P < 0.05) between the mycelium treatment AC and the control treatment after 60 days (23.97% higher than the control group). On day 60, the litter carbon content from the mycelium treatment A was significantly different from that of the control (P < 0.05), showing a 16.74% lower value, whereas the litter carbon content of the mycelium treatment B was 21.13% lower than that of the control after 90 days. The nitrogen content of the litters of most mycelium and sterilized fermentation broth treatments was increased compared to that of the control group; there was significant difference (P < 0.05) between the sterilized fermentation broth treatment A and the control (P < 0.05), with a 17.05% higher value than that of the control. Similar to nitrogen, the litter phosphorus content also increased; there was a statistically significant difference between the mycelium treatment A and the control group, with treatment A showing a 46.67% higher value than the control group. The potassium content was 28% lower than that of the control group under the sterilized fermentation broth treatment C, a result that was significantly different from that of the control group (P < 0.05). After treatment for 90 days, the ratio of carbon to nitrogen was the lowest under the treatments with the mycelium A and the mycelium B, with values 25.54% and 25.11% lower than that of the control group, respectively, and a statistically significant difference from that of the control group (P < 0.05). The ratio of carbon to phosphorus was the lowest under the treatment with mycelium A after 60 days, and the result was significantly different from that of the control (P < 0.05), with a 43.05% lower value than the control. Thus, the three endophytic fungi had different effects on the mass loss rate and nutrient content of the litter. The Penicillium sp. strain CG2 (A) had statistically significant effects on the mass loss and nutrient content of leaf litter, which was within the range of fungi fertilizer reference values for the breeding of C. lanceolata. © 2018 Science Press. All rights reserved.     

不同类型生态浮床对富营养河水脱氮效果及微生物菌群的影响

通过设施大棚内容积为1.5 m3的人工模拟池试验,研究了框式与传统旱伞草浮床对富营养河水氮素转化及微生物菌群的影响. 传统浮床是以聚乙烯泡沫板为载体,栽植陆生植物来削减水体氮磷和有机物质等,从而达到净化水质的效果. 框式浮床是以塑料镂空支架为载体,除种植陆生植物外还添加填料等组件的新型浮床. 结果表明:①2种浮床对水体中TN,NH₄+-N和NO₃--N均有显著的去除效果,其中框式浮床和传统浮床的NH₄+-N去除率分别高达91%和86%,TN去除率也分别达到74%和64%,NO₃--N去除率分别为49%和31%. ②2种浮床系统有效地提高了水体中微生物和氮循环细菌总数和种群数量,尤其是框式浮床不同时期均比空白对照高出2～3个数量级. ③氮循环细菌的数量跟水体氮素去除有显著相关性. 其中水体ρ(NH₄+-N)和氨化菌数量呈显著正相关,ρ(NH₄+-N)和硝化菌数量呈极显著负相关,ρ(NO₃--N),ρ(TN)和反硝化菌数量之间呈极显著负相关. ④框式浮床的独特结构使之比传统浮床的去氮能力更强. 其中,填料系统吸附贡献率为8%,植物吸收的去氮贡献为16.5%,微生物系统脱氮则为75.5%;而传统浮床植物系统吸收贡献率为31.8%,微生物系统脱氮贡献率为68.2%. 说明浮床系统中植物吸收只是系统去氮的一种途径,微生物脱氮在2种浮床脱氮途径中占主导作用.