ABUNDANCE AND PRODUCTION OF LIMNODRILUS HOFFMEISTERI (OLIGOCHAETA: TUBIFICIDAE) IN ALGAE-DOMINATED LAKE HOUHU (WUHAN, CHINA)

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The Role of Microphytobenthic Primary Production in a Mediterranean Mussel Culture Area

The production and biomass of microphytobenthos in a Mediterranean mussel farm was studied during 1991–92. Gross and net microphytobenthic production and respiration were calculated from oxygen fluxes in transparent and black bell jars at two stations; sediments under a mussel table and reference sediments, both located at 5 m depth. Net oxygen fluxes were mainly negative under the mussel tables (average −19·5 mg O₂ m⁻² h⁻¹, CV=132%), and microphytobenthos production could not meet the sediment oxygen demand; in the reference sediments, microphytobenthos production was responsible for net oxygen production (average +13·0 mg O₂ m⁻² h⁻¹, CV=118%). Benthic respiration rates were, on average, 47·3 mg O₂ m⁻² h⁻¹(CV=82%) under the tables and 27·7 mg O₂ m⁻² h⁻¹(CV=45%) in reference sediments. Aerobic respiration could remineralize less than 2% of the biodeposited carbon under the tables, implying that a large amount of organic material is accumulating under the tables, and that most of the degradation will be anaerobic. Gross microbenthic production showed sharp changes between 1991 and 1992 under the mussel tables and for reference sediments (averages 20·98 mg O₂ m⁻² h⁻¹, CV=135% and 33 mg O₂ m⁻² h⁻¹, CV=48%, respectively). Despite the negative oxygen balance in the sediments under the tables, microphytobenthos was more productive than phytoplankton in bottom waters. Per unit area, phytoplankton was more productive than microphytobenthos at both stations, especially in the area of the mussel tables, where phytoplanktonic production was enhanced by the excretion products of mussels. Microphytobenthos was composed mainly of diatoms in the sediments under the tables, while in reference sediments, the population was more diverse, with algae containing chlorophyllbalso present. Chlorophyllaconcentration in sediments under the tables was 207 mg m⁻²(CV=73%) and 95 mg m⁻²(CV=28%) in reference sediments; the stock of plant pigments was increased under the tables by biodeposition. Microphytobenthos constitutes a compartment with an important contribution in biomass, but also in oxygen production.     

An annual cycle of recruitment,growth and production in a Malaysian population of the trochacean gastropod Umbonium vestiarium (L.)

From July 1981 to July 1982 Umbonium vestiarium (L.) on a north Penang sand shore numbered 573–11 077 m^?2 (mean 4126 or 53·1 g dry tissue) near MLWN and 2164–12 414 m^?2 (mean 6500 or 59·8 g dry tissue) further downshore. Heavy recruitment of young became evident in June and July 1982 and a closely corresponding cohort of young was present in July 1981. Progression of this cohort indicated that young settling in May–June grew to full size (11–13 mm diameter) by January–March the following year and that virtually all died during their second year, presumably having spawned in March–May. Recruitment of young was chiefly on the lower shore but adults came to be more abundant and predominant on the upper shore. There is some evidence of migration upshore during growth.Production is estimated at 105·4 g dry tissue m^?2 y^?1 (2118 kj) at the lower shore level and this is almost double the 58·8 g m^?2 y^?1 (1176·6 kj) at the higher level. These values represent almost the entire secondary production across much of the sand flats.Possible causes of such a marked annual cycle in the very weakly seasonal tropics of the Malacca Strait are considered and it is suggested that monsoonal changes in wind, wave action and salinity might be involved.     

塔河油田碳酸盐岩缝洞型油藏远井储集体定量化表征及动用技术

塔河油田奥陶系碳酸盐岩储层主要储集空间为溶洞和裂缝,直接钻遇溶洞比例达50%。针对目前远井储集体特征认识模糊、动用难度大等问题,基于物质平衡原理及注水指示曲线、液面恢复曲线等资料,对远井储集体的规模、裂缝导流系数、地层能量进行定量化研究,形成了一套远井储集体参数定量化表征技术。基于远井储集体特征,运用酸化、高压注水、复合措施等方法提高对远井储集体的动用,并在塔河油田推广应用,高效井占75%以上,有较好的应用前景。     

融合高时空分辨率数据估算植被净初级生产力

植被净初级生产力NPP(Net Primary Production)遥感估算与分析,有赖于高时空分辨率的遥感数据,但目前中高分辨率的遥感数据受卫星回访周期及天气的影响,在中国南方地区难以获取连续时间序列的数据,从而影响了高精度的区域植被净初级生产力的遥感估算。为此,提出一种基于多源遥感数据时空融合技术与CASA模型估算高时空分辨率NPP的方法。首先,利用多源遥感数据,即Landsat8 OLI数据与MODIS13Q1数据,采用遥感数据时空融合方法,获得了时间序列的Landsat8 OLI融合数据;然后,基于Landsat8 OLI时空融合数据,并采用CASA模型,以长株潭城市群核心区为例,进行区域植被NPP的遥感估算。研究结果表明,基于时间序列Landsat融合数据估算的30m分辨率的NPP具有良好的空间细节信息,且估算值与实测值的相关系数达0.825,与实测NPP数据保持了较好的一致性。     

针对贵州省县级公共气象服务系统集约化建设的研究和思考

贵州省气象局自2014年起在全省县、区级气象部门部署了公共气象服务系统,该系统上线后对县级公共气象服务发挥了重要作用,随着云计算、大数据技术的发展,业务系统的集约化程度逐步提高,现有的县级公共气象服务系统已不能满足用户大量增长的服务需求,该文通过对该系统在县级部署和应用情况的分析,从技术和管理的角度,深入探讨系统在集约化方面存在的问题和不足,并提出了相关改进措施,对县级公共气象服务建设具有一定参考价值。     

克拉玛依油田二厂八区套管破损机制研究

克拉玛依油田二厂八区井区经过长期开采出现了大量的套管破损问题。对套管破损位置进行总结归纳发现,套管破损主要存在于白垩系吐谷鲁群、侏罗系齐古组、二叠系乌尔禾组等地层中。对研究区连井进行地层对比、地震数据体进行波阻抗反演和砂体分析,发现研究区内白垩系吐谷鲁群和侏罗系齐古组的砂体十分发育,广泛存在于整套地层中。砂体中流体的渗流作用对套管的腐蚀为套管破损的主要因素。泥岩吸水蠕变膨胀、油层出砂和固井质量不合格为套管破损的其他因素。     

Correlations Between Biogenic Components and Dust Input and Their Change Mechanism on Hess Rise,Central North Pacific,During the Late Quaternary*

The study of marine export production is helpful to trace the changes of oceanic and global carbon reservoirs. Dust input is an important factor inspiring marine export production. Measurements of carbonate, Opal, TOC and C_org/N were performed on Core SO202-37-2, which was retrieved from Hess Rise, central North Pacific during the German SO202-INOPEX Expedition, for reconstructing variations of the local export production and dust input. The core age model is constructed via morphologically correlating its foraminifer oxygen isotope record with those of Core H3571 and the LR04 stack. XRF-Ti/Ca can be used as a proxy for dust input and its distribution pattern is consistent with that of Opal content, possibly indicating that dust input may have affected the local export production, i.e. the local export production increased (decreased) with enhancing (declining) dust input during interglacial (glacial) periods. Fluctuations in dust input might be due to southward/northward migration of the Westerly Jet over the dust source regions during interglacial and glacial periods. Although global dust output increased during glacial periods, meridional migration of the Westerly Jet in this area made the distribution pattern of the dust deposition in the study area different from that of other areas.     

桂林市东区地下水硝酸盐污染现状与成因分析——以白竹干村为例

桂林市东区为一较完整的水文地质单元,为桂林市区主要的地下水供水水源地和未来城市中心区,漓江是该区域的排泄基准面。在简述桂林东区地下水硝酸盐整体含量的基础上,以东区白竹干村为例,对这一地段的岩溶地下水硝酸盐污染概况及成因进行分析,结果表明:由于桂林市城市化趋势向东发展,导致东区浅层地下水硝酸盐含量增加,含量介于4.47~41.36 mg/L,均值为16.7 mg/L,受硝酸盐污染程度较高,应通过加强水质监测,对生活污水、垃圾以及禽畜粪便进行妥善处理,村民应合理施肥,控制氮肥和农药的用量,改善当地饮用水卫生状况。