Valuing seafood: The Peruvian fisheries sector

There are tradeoffs in managing fisheries, and ideally such tradeoffs should be known when setting fisheries policies. An aspect of this, which is rarely considered, is the spin-off effect of different fisheries: the economic and social benefits that fisheries generate through processing through distribution and on to the end consumer. This study evaluated the benefits generated in the Peruvian marine fisheries sector through a comprehensive value chain analysis, based on a newly-developed combined ecosystem-economic modeling approach, which was integrated in the widely-used Ecopath with Ecosim approach and software. The value chain was parameterized by extensive data collection through 35 enterprise types covering the marine fisheries sector in Peru, including the world's biggest single-species fishery for anchoveta. While anchoveta is what is known about Peruvian fisheries, the study finds that anchoveta accounts for only 31% of the sector contribution to GDP and for only 23% of the employment. Thus, while anchoveta indeed is the fundamental fish species in the Peruvian ecosystem, there are other fisheries to be considered for management. The study indicates that the economic multipliers for Peruvian fisheries were 2.9 on average over the industry, and that these varied surprisingly little between fleets and between seafood categories indicating that the multipliers can be used beyond Peru to generalize the spin-off effect of the value chain. Employment multipliers vary much more across types of fisheries, but also around an average of 2.9; here it was clear that longer value chains result in more employment.     

中国区域虚拟水战略优势度评价

提出虚拟水战略优势度的概念并对其概念内涵及影响因素进行分析,从4个方面构建包含12个具体指标的综合定量评价指标体系;运用数学方法对中国31个省级行政区虚拟水战略优势度进行定量评价.发现中国虚拟水战略优势度存在显著的地域差异,区域优势度等级存在"两头多,中间少"的结构特点和"东部高、西部低","南部和北部高、中间低"带状空间分布规律.其中北方4省市和东南8省区优势度最大,是全球虚拟水战略背景对其影响最深远的区域,也是中国虚拟水研究及虚拟水战略实践的关键区域.     

水资源价值模型评价研究

水资源价值是指水资源使用者为了获得水资源使用权需要支付给水资源所有者的货币额,它与水价是不同的概念,合理的水价应包括水资源价值。目前可以用来求算水资源价值的模型不同程度地存在各种问题,必须加以完善和发展。影子价格模型只反映水资源的稀缺程度和水资源与总体经济效益之间的关系,其结果不能代替水资源价值;边际机会成本模型存在着应用困难较大、替代选择多样性、结论缺乏可比性、忽略了水质等问题;供求价格模型仅仅通过水资源量决定水资源价值是不科学的;模糊数学模型是潜力较大的最新模型,其缺点是影响水资源的各项因素的模糊评价较复杂,权重的确定是多样的。     

天山巩乃斯河流域季节性积雪化学成分特征与时空变化分析

巩乃斯河流域积雪阴、阳离子的空间变化以Ｋ＋＋Ｎａ＋、Ｃａ２＋与ＳＯ２－４和ＨＣＯ－３等离子最明显;Ｋ＋＋Ｎａ＋与ＳＯ２－４、Ｃａ２＋与ＨＣＯ－３变化基本同步．从新降雪阴、阳离子的时间变化上看,隆冬季节积雪深厚范围广,相应离子含量低．调查区积雪对局地人类活动所造成的污染有较明显的记录．     

重庆市主城区降雨酸度的影响因子分析

重庆市是我国酸雨较严重的地区之一，其酸沉降状况具有代表意义。本分析了重庆市2000年和200l年的降雨指标(离子组分、pH、电导率)和空气质量指标(SO2和NO2)，降雨指标采用离子色谱法和电极法，空气质量指标采用紫外脉冲荧光法和化学发光法分析。结果表明，大气颗粒物、SO2及NO2对降水的酸度有不同影响。大气颗粒物中的碱式钙盐可明显降低雨水酸度，其可能来源为建筑施工；含有SO4^2-、NO3^-和NH4^ 的酸式盐可有效增加雨水酸度。大气中的SO2对降雨酸度增高贡献较大，而NO2贡献不明显。较小的[NO3^-]/[SO4^2-]值(0．125)显示重庆市的固定源的污染比流动污染源更强。     

古玉器的化学风化机理初探之一——粉末态模拟实验

矿物的溶解和分解是矿物风化的重要过程,因此探明矿物的溶解和分解过程将有助于揭示其风化机理。古玉在长期的埋藏过程中,处于土壤及土壤水的溶解反应体系中。本文初步模拟古玉埋藏的酸、碱性土壤环境,通过对不同材质玉料的粉末形态在酸、碱缓冲溶液中的浸泡实验,初步探讨了不同材质玉料在酸、碱环境下的风化机理。     

长春市城区大气湿沉降中重金属及pH值调查

为弄清长春市城区大气降水pH值及重金属湿沉降状况,于2006年8月-2007年7月在3个采样点分4季系统收集了大气降水样品12件,采用全谱直读电感耦合等离子体质谱仪(ICP-MS)分析了As、Cd、Cu、Pb、Zn、Cr,采用原子荧光光度法(AFS)分析了Hg.结果表明:长春市大气降水年平均pH值为6.43,总体上为中性雨;降水中重金属质量浓度较低,Hg、Cr、Cu、Zn、As、Pb、Cd分别为0.042、3.59、9.25、148.6、18.44、21.71、0.933 μg/L,且受气象条件(如气温、风速、相对湿度等)影响明显,同时随区域的不同而略有差异.总体而言,除Cr外,各重金属元素质量浓度在春冬季明显高于夏秋季,汽车厂附近区域大气降水中重金属质量浓度最低.经估算,As、Cd、Cr、Cu、Hg、Pb和Zn湿沉降通量分别为2.13、0.21、1.70、3.74、0.019、6.82、65.78 mg/(m2·a),且主要集中在3-9月.     

南海北部珊瑚高分辨率硼同位素组成及其对珊瑚礁海水pH变化的指示意义

造礁珊瑚是研究热带海洋高分辨率气候环境演变的重要载体。对采自海南岛南部三亚湾的活体滨珊瑚SY10进行了约为月分辨率的碳、氧、硼同位素组成分析,并利用珊瑚δ11B重建了海水pH。结果显示,所测量样品的δ13C变化范围为–3.32‰~–1.76‰,δ18O为–6.13‰~–4.78‰,δ11B为23.51‰~26.23‰,且这些珊瑚样品的碳、氧、硼同位素组成均存在明显的季节性周期波动。其中pH与δ18O之间存在明显的正相关关系,高的pH值更倾向于在低温的季节出现,这意味着短时间尺度该处珊瑚礁海水pH可能主要不是受海水CO2溶解度控制,而是与生物活动有密切的关系。利用SY10珊瑚样品硼同位素组成重建的海水pH值变化范围为7.77~8.37,并呈季节性周期波动,这种大幅度的周期波动与我们对三亚珊瑚礁海水pH进行现场观测所得到的结果以及前人的研究成果相符,说明了利用珊瑚δ11B重建海水pH记录是可靠的。     

沉积物粘土混浊水电导率与pH值相关性研究——以渤海湾西岸平原XZ、MD钻孔为例

对渤海湾西岸平原XZ、MD钻孔样品的粘土混浊水电导率(以下简称EC)和pH测定值进行相关分析,结果显示EC与pH都呈高度负相关,两孔的相关系数分别为-0.830(P P r=0.089,P >0.05)外,其他各沉积带均显示较明显的负相关.但负相关性也有所不同,XZ孔海陆过渡相沉积带(Ⅱ带,r=-0.740,P r=-0.434,P r=-0.403,P r=-0.482,P <0.05)也有较明显的负相关性.这表明沉积物EC与pH相关程度的差异,亦可在一定程度上反映出其沉积环境的不同.     

Stochastic water balance model for rainfall recharge quantification in Ruataniwha Basin,New Zealand

Quantification of groundwater recharge is important for water resources management. Different methods can be used to estimate groundwater recharge. The most suitable approach depends on site characteristics. Water balance model was used in this study to quantify groundwater recharge from rainfall in Ruataniwha Basin, Hawke’s Bay, New Zealand. Because it is a closed basin, this method was determined to be more suitable than any other method. The basin is fed by surface water flow and rainfall, without any lateral groundwater flow. Records of surface water inflow and outflow are available with a certain degree of reliability. To cope with uncertainty in different components of water balance, different sampling methods were used. The Mean Value Latin Hypercube Sampling (MVLHS) was used and compared with Latin Hypercube Sampling (LHS), and Monte Carlo Simulation (MCS). It was found the groundwater recharge from rainfall is about 415 million m³/year. Results of this study have revealed that MVLHS converges faster and with lower variance than LHS and MCS.