Biomass distribution patterns of ecotones between forest andswamp in Changbai Mountaion

This paper studied the biomass distribution patterns of Lanix olgensis/swamp ecotones and Betula platyphlla/swamp ecotones in Changbai Mountain so as to provide theory foundation for the management of these nature resources, by setting up sample belts, investigating initial data along the environmental gradients change, and establishing regression models. By means of regression models, the biomass of communities, layers, tree species and organs was calculated. In this system, it was found that the community biomass inreased gradually along the environmental gradients change from swamp to forest in Changbai Mountain. Furthermore, the ecotoneal biomass distributed mainly over tree layer. The tree biomass distributed mainly in two or three dominate tree species.

考虑生物质能和农业柔性负荷的农业产业园区综合能源系统规划方法

农业产业园区规划是实现农业产业园区用能低碳灵活的基础,而生物质资源高值化利用和农业柔性负荷对于促进农业产业园区的合理规划十分重要。因此,该文提出了一种考虑生物质能和农业柔性负荷的农业产业园区综合能源系统(integrated energy system,IES)规划方法。首先,为实现秸秆高值化利用,引入热解气化炉生产生物质气和生物炭,并通过高厌氧发酵粪污制沼,实现生物质的充分利用。其次,引入农作物日积温作为确定种植业热负荷参与需求响应量的衡量指标,并结合农业负荷特性建立农业柔性负荷模型。然后,以园区投资运行总成本最小为优化目标,考虑设备投资约束和满足农业生长需求的农业用能约束及生物质能成本等运行约束,建立农业产业园区规划模型。随后,为减小天气概率分布不确定性对农业生产和园区供能的影响,基于历史天气数据生成盒式不确定性集合,构建农业产业园区IES分布鲁棒优化模型。最后,通过算例结果分析得出,该文所提的农业产业园区IES规划方法可以显著减少碳排放和系统总成本,并充分利用生物质资源。

Community structure of picoplankton abundance and biomass in the southern Huanghai Sea during the spring and autumn of 2006

During spring and autumn of 2006, the investigations on abundance, carbon biomass and distri- bution of picoplankton were carried out in the southern Huanghai Sea （Yellow Sea, sHS）. Three groups of picoplankton-Synechococcus （Syn）, Picoeukaryotes （PEuk） and heterotrophic bacteria （BAC） were identified, but Prochlorococcus （Pro） was undetected. The average abundance of Syn and PEuk was lower in spring （5.0 and 1.3×10^3 cells/cm^3, respectively） than in autumn （92.4 and 2.7×0^3 cells/cm^3, respectively）, but it was opposite for BAC （1.3 and 0.7×10^6 cells/cm^3 in spring and autumn, respectively）. And the total carbon biomass of picoplankton was higher in spring （37.23×11.67） mg/m^3 than in autumn （21.29×13.75） mg/m^3. The ratios of the three cell abundance were 5：1：1 341 and 30：1：124 in spring and autumn, respectively. And the ratios of carbon biomass of them were 5：7：362 and 9：4：4 in spring and autumn, respectively. Seasonal distribution characteristics of Syn, PEuk, BAC were quite different from each other. In spring, Syn abundance decreased in turn in the central waters （where phytoplankton bloom in spring occurred）, the southern waters and inshore waters of the Shandong Peninsula （where even Syn was undetected）; the high values of PEuk abundance appeared in the central and southern waters and the inshore of the Shandong Peninsula; the abundance of BAC was nearly three order of magnitude higher than that of photosynthetic picoplankton, and high values appeared in the central waters. In autumn, Syn abundance in central waters was higher than that in surrounding waters, while for PEuk abundance, it decreased in turn in the inshore waters of the Shandong Peninsula, the southern waters and the central waters; BAC presented a complicated blocky type distribution. Sub-surface maximum of each group of picopalnkton appeared in both spring and autumn. Compared with the available lit- eratures concerning the studied area, the range of Syn abundance was larger, and the abundance of BAC was higher. In addition, the conversion factors for calculating picoplanktonic carbon biomass were discussed, with the conversion factors which are different from previous studies in the same surveyed waters. The result of regression analysis showed that there was distinct positive correlation between BAC and photosynthetic picoplankton in spring （r=0.61, P 〈0.001）, but no correlation was found in autumn.

Study on spatial and temporal distribution of planktonic amphipoda in the East China Sea

Quantitative distribution of planktonic amphipoda in the East China Sea is analyzed and the relation with environmental factors and mackerel and scad fishing grounds is studied. The result shows that the characteristic of biomass is great seasonal and interannual variety during the passing three decades. The distribution of planktonic amphipoda basically reflects the movement, decay and intensification of the different water systems in the survey area.

The decline process and major pathways of Microcystis bloom in Taihu Lake, China

Eutrophication has become a serious concern in many lakes, resulting in cyanobacterial blooms. However, the mechanism and pathways of cyanobacteria decline are less understood. To identify and define the growth and decline of Microcystis blooms in Taihu Lake of China, and to illuminate the destination of surface floating blooms, we investigated the biomass distribution and variations in colony size, morphology, and floating velocity from October 2008 to September 2009. The results showed that the Microcystis bloom declined in response to biomass decrease, colony disaggregation, buoyancy reduction, and increased phytoplankton biodiversity, and these indicative parameters could be applied for recognition of the development phases of the bloom. Three major decline pathways were proposed to describe the bloom decline process, colony disaggregation （Pathway I）, colony settlement （Pathway II）, and cell lysis in colonies （Pathway III）. We proposed a strategy to define the occurrence and decline of Microcystis blooms, to evaluate the survival state under different stress conditions, and to indicate the efficiency of controlling countermeasures against algal blooms.

Effects of plant species richness on stand structure and productivity

Aims Aboveground biomass production commonly increases with species richness in plant biodiversity experiments.Little is known about the direct mechanisms that cause this result.We tested if by occupying different heights and depths above and below ground,and by optimizing the vertical distribution of leaf nitrogen,species in mixtures can contribute to increased resource uptake and,thus,increased productivity of the community in comparison with monocultures.Methods We grew 24 grassland plant species,grouped into four nonoverlapping species pools,in monoculture and 3-and 6-species mixture in spatially heterogeneous and uniform soil nutrient conditions.Layered harvests of above-and belowground biomass,as well as leaf nitrogen and light measurements,were taken to assess vertical canopy and root space structure.Important Findings The distribution of leaf mass was shifted toward greater heights and light absorption was correspondingly enhanced in mixtures.How ever,only some mixtures had leaf nitrogen concentration profiles predicted to optimize whole-community carbon gain,whereas in other mixtures species seemed to behave more‘selfish’.Nevertheless,even in these communities,biomass production increased with species richness.The distribution of root biomass below ground did not change from monocultures to three-and six-species mixtures and there was also no indication that mixtures were better than monocultures at extracting heterogeneously as compared to homogeneously distributed soil resources.We conclude that positive biodiversity effect on aboveground biomass production cannot easily be explained by a single or few common mechanisms of differential space use.Rather,it seems that mechanisms vary with the particular set of species combined in a community.