A new method for high-resolution bivalve growth rate studies in hydrothermal environments

The age and shell growth rate of deep-sea hydrothermal bivalves were investigated for the first time using in situ chemical staining combined with high-resolution micro-increment analysis. A staining chamber developed for this purpose was applied to a patch of Bathymodiolus thermophilus mussels at 2,500 m depth at the 9°47′N vent field on the East Pacific Rise (EPR) in May 2010. This approach minimizes disturbance of the mussels in their habitat. Bathymodiolus thermophilus grows according to a circalunidian rhythm, with one increment formed each day, and displays tide-related growth rate variability. Based on the von Bertalanffy growth rate model, the largest shell collected (SL = 20.5 cm) would be 10.0 year old, with a growth rate of 4.2–1.1 cm year^?1 as the shell ages. This fast growth rate is consistent with the instability of the environment in this section of the EPR and observed recolonization rates and could reflect a specific adaptation of this species.     

环鄱阳湖浅层地下水水化学特征的时空变化

系统采集了鄱阳湖周边地下水,分析测定各单元的水化学参数.结果表明,环鄱阳湖浅层地下水整体偏酸性,呈低矿化度,局部地区出现微咸水.环鄱阳湖浅层地下水丰、枯水期的优势阴离子为HCO3-,阳离子为Ca2+和Mg2+.运用SPSS软件做离子相关性分析,各离子间均呈正相关性,说明可能有相同的来源.地下水的水化学类型整体表现为HCO3-Ca-Mg型,丰水期相对于枯水期出现较多的NO3-型和SO24-型水体,局部区域优势阴离子改变,出现了NO3-型、Cl-型地下水,可能受到农业化肥和工业废水排放的影响.整体上地下水的水化学类型受当地岩石类型的影响比较大,个别地区受人为的活动干扰较为强烈.     

底泥浸出液对脊尾白虾抗氧化解毒酶及相关基因表达的影响

以脊尾白虾(Exopalaemon carinicauda)糠虾幼体为实验材料,研究底泥浸出液对抗氧化解毒酶和基因表达的影响。用长江口水域的底泥浸出液与过滤海水按等比例间距稀释成4个体积浓度水平(1∶4,1∶2,1∶1,1.5∶1),以过滤海水为对照组,每一个浓度组设3个平行样本,进行20 d的毒性实验。结果表明:实验进行20 d,底泥浸出液对糠虾幼体肌肉组织CAT酶活性有一定的诱导作用,浸出液浓度与CAT酶活性表现出正相关的剂量效应关系。实验开始10 d,不同浸出液胁迫下,GST酶活性均出现增加受到诱导,实验20 d后,GST酶活性下降受到抑制作用,但不同浸出液浓度胁迫下抑制和诱导效应关系不明显。虾类肌肉组织3种基因(CAT、GSTD和HSP70)表达量基本都表现为实验开始10 d时升高,而实验20 d后表达量下降,仅为10 d数值的百分之一左右,表明底泥浸出液对CAT、GSTD和HSP70的3种基因的mRNA转录水平表达在一定时间内有一定的诱导作用,但胁迫时间过长时,则产生较明显的抑制作用。     

我国削减并逐步替代全氟辛烷磺酸盐(PFOS)的策略与建议

全氟辛烷磺酸盐(PFOS)具有低表面张力、良好的热稳定性和化学稳定性等特性,作为含氟表面活性剂被广泛应用于卫生、消防与电镀等工业领域。但是,PFOS具有高持久稳定性,会在环境、人体与动物组织中富集,因此2009年《斯德哥尔摩公约》将PFOS列为新增POPs受控物质。目前,我国还在生产和使用PFOS,如何对其进行有效控制,削减并逐渐替代PFOS及其衍生物,是我国面临的巨大挑战。在介绍了PFOS的生产与应用现状基础上,结合其替代技术,提出了削减和逐步替代PFOS的策略。     

Multi-scale foraging variability in Northern gannet (Morus bassanus) fuels potential foraging plasticity

The survival of marine predators depends on behavioural plasticity to cope with changes in prey distribution. Variability in behaviour might predict plasticity and is easier to assess than plasticity. Using miniaturized GPS loggers over several breeding seasons in two Norwegian Northern gannet (Morus bassanus) colonies, we investigated if and how the variability within and between individuals, but also between colonies and years, affected foraging strategies. Results revealed strong individual variability (foraging trip durations, foraging effort and different foraging areas). Individuals from both colonies showed preferred commuting routes, flight bearings and feeding hotspots. Individuals from the largest colony used larger and more foraging areas than individuals from the small colony. Feeding hotspots and foraging ranges varied amongst years in the largest colony only. Our study demonstrated that gannets show flexibility by changing prey fields that are driven by shifting oceanographic conditions.     

Part I : <Emphasis Type="Italic">a priori</Emphasis> study of erosion and deposition with large eddy simulation of turbulent flow over multiple 2D sandy Gaussian hills

The micro-scale prediction of sand trapping or take-off over hilly terrains is a crucial issue in semi-arid regions for soil depletion. In this context, large eddy simulations around one or several hills are performed in order to provide statistical parameters to characterize the flow at micro-scales and provide data for mesoscale modelling. We focus on the determination of recirculation zones since they play an important role in solid particle erosion or entrapment. A new wall modeling adapted from Huang et al. (J Turbul 17:1–24, 2016) for rough boundary layers is found to improve the prediction of the recirculation zone length downstream of an isolated hill and is used for all the numerical cases presented here. A geometrical parameterization of the recirculation zones is proposed. When the recirculation region is assumed to have an ellipsoidal shape, the total surface of the recirculation can be obtained from this new parameterization and easily extrapolated to more general dune configurations. Numerical results are compared with experiments performed in our laboratory (Simoëns et al. in Procedia IUTAM 17:110–118, 2015) and good agreement is achieved. We explore general aerodynamic cases deduced from the urban canopy scheme of Oke (Energy Build 11:103–113, 1988). In this scheme the momentum and mass exchange between the upper layer and the space between hills is sorted according to the streamwise hill spacing within three basic cases of skimming, wake or isolated flow. The study of the recirculation zones, the mean velocity and Reynolds stress profiles around an isolated or two consecutive hills with different distances shows that the double hill configuration with 3H separation behaves as much as a whole to the upcoming flow. The vortex formed between the crests does not strongly affect the overall evolution of the outer flow. By an a priori prediction of the preferential zones of erosion and accumulation of fictive particles, it is shown that isolated dunes present more deposition and less erosion than two-hill configurations. The results presented in this study will be discussed in the presence of Lagrangian transport of sand particles above 2D Gaussian hills in future work.     

Modelling forest management within a global vegetation model—Part 1: Model structure and general behaviour

This article describes a new forest management module (FMM) that explicitly simulates forest stand growth and management within a process-based global vegetation model (GVM) called ORCHIDEE. The net primary productivity simulated by ORCHIDEE is used as an input to the FMM. The FMM then calculates stand and management characteristics such as stand density, tree size distribution, tree growth, the timing and intensity of thinnings and clear-cuts, wood extraction and litter generated after thinning. Some of these variables are then fed back to ORCHIDEE. These computations are made possible with a distribution-based modelling of individual tree size. The model derives natural mortality from the relative density index (rdi), a competition index based on tree size and stand density. Based on the common forestry management principle of avoiding natural mortality, a set of rules is defined to calculate the recurrent intensity and frequency of forestry operations during the stand lifetime. The new-coupled model is called ORCHIDEE-FM (forest management).The general behaviour of ORCHIDEE-FM is analysed for a broadleaf forest in north-eastern France. Flux simulation throughout a forest rotation compare well with the literature values, both in absolute values and dynamics.Results from ORCHIDEE-FM highlight the impact of forest management on ecosystem C-cycling, both in terms of carbon fluxes and stocks. In particular, the average net ecosystem productivity (NEP) of 225 gC m⁻² year⁻¹ is close to the biome average of 311 gC m⁻² year⁻¹. The NEP of the “unmanaged” case is 40% lower, leading us to conclude that management explains 40% of the cumulated carbon sink over 150 years. A sensitivity analysis reveals 4 major avenues for improvement: a better determination of initial conditions, an improved allocation scheme to explain age-related decline in productivity, and an increased specificity of both the self-thinning curve and the biomass-diameter allometry.     

Rice straw-base power generation: a potential and economic cost–benefit analysis for a small power plant (10 MWe) in Vietnam

Journal of Material Cycles and Waste Management - The main objective of the study is to explore the economic feasibility of power generation from rice straw, a potential biomass energy resource, in...     

BDD电极电化学氧化降解废乳化液

废乳化液是机械加工过程产生的一种高浓度有机废液,属于危险废物.通过实验研究了 BDD电极电化学氧化处理废乳化液的降解效果,考察了电流密度、电解质种类及浓度、初始pH值和反应温度对降解效率的影响.结果表明:BDD电极电化学氧化可有效降解废乳化液中的有机物,当采用Na2S2O8为电解质,电流密度超过60 mA/cm2时,降...