1998年8月台湾海峡温度和叶绿素a含量的垂直分布特征

根据1998年8月台湾海峡温度、盐度、叶绿素a的观测结果，讨论了调查期间叶绿素a的垂直分布特征，结果表明，夏季台湾海峡西部海域存在明显的上升流，较高的叶绿素a含量均位于低温高盐的涌升水中，叶绿素a最大值出现存在上升流区边缘、温跃层附近，台湾海峡东部海域由高温、低盐、低营养盐水占据，叶绿素a含量明显较海峡西部海域低。     

干旱区绿洲荒漠带土壤水盐异质性及生态环境效应研究——以黑河中游张掖绿洲为例

对黑河中游地区典型绿洲的土壤含水量与含盐量分析表明,在无灌溉情况下,绿洲及绿洲边缘过渡带表层土壤含水量水平分异明显,由绿洲区的20%左右递减到绿洲荒漠生态过渡带的2.9%。绿洲荒漠带土壤水分变化反映了人类利用绿洲水资源的程度,在绿洲地下水资源开发过度和绿洲边缘人类活动剧烈的区域均存在着生态裂谷,对绿洲生态系统的稳定极为不利。绿洲荒漠带土壤可溶性盐分含量的水平分异表现为绿洲土壤可溶性盐分含量比绿洲荒漠生态过渡带和荒漠区低;绿洲界外区不同荒漠类型土壤含盐量变化不同,在绿洲外围沙质荒漠区,土壤含盐量较低,在绿洲外围砾质荒漠（戈壁）区,土壤含盐量明显高于绿洲区;荒漠区土壤含盐量的垂直变化表明,含盐量最高的聚集层一般不在表层,而在40～60 cm的亚表层。受土壤水盐分异的影响,绿洲外围荒漠植被类型出现分异,从高位绿洲到中位绿洲,外围区荒漠植被的耐旱性和耐盐性均增加。     

《地质灾害与环境保护》论文统计分析与评价

以《地质灾害与环境保护》杂志为对象，对其1994～2001年中的发文量、研究内容、作者的地区分布、系统分布进行了统计与分析、展示了该期刊的研究特色及近8年的发展状况，揭示了该学科的研究水平。     

旅游网络地图及其研究内容探析

旅游网络地图的研究对网络地图的发展以及网络时代旅游业的发展都有着非常重要的意义.由于缺乏基于地图学和旅游学的旅游网络地图研究,旅游网络地图的发展受到影响.首先探讨了旅游网络地图的概念及特点,然后对大量旅游网站进行了旅游网络地图的现状调查,分析了存在的主要问题,最后针对这些问题并结合旅游网络地图的发展趋势,提出了旅游网络地图设计的主要研究内容及研究思路.     

论地缘政治学的核心——地理要素

近代以来,以领土为物质基础的民族或者国家间的竞争和合作均发生在特定的地理空间之内。人们对地理空间与民族或者国家间相互关系影响的认识反映在国际关系理论中。就是地缘政治学,换言之,地缘政治是在对国际上各种政治力量及其相互关系进行地理空间分析的基础上,为维护国家利益制定适当的对外政策和战略的一种理论。地缘政治最基本的内核是地理要素．即地理位置、国土幅员、邻国、地形与气候、资源以及距离等。科学认识地缘政治学基本的地理要素．是正确把握、运用地缘政治学的先决条件。     

Sedimentary labile organic carbon and pore water redox control on species distribution of benthic foraminifera: A case study from Lisbon-Setúbal Canyon (southern Portugal)

Rose Bengal stained benthic foraminifera were studied from 11 cores collected along two depth transects off southern Portugal: one in the Lisbon-Setúbal Canyon and the other along the canyon edge. The total standing stocks and distribution of foraminifera were investigated in relation to sediment and pore water geochemistry. Nitrate was used as a redox indicator, sedimentary chlorophyll a and CPE (chloroplastic pigment equivalents) contents as a measure of labile organic matter, and total organic carbon as a measure of bulk organic matter availability.The canyon sediments were enriched in organic carbon and phytopigments at all water depths in comparison with the canyon edge. Water depth seemed to control sedimentary phytopigment content, but not total organic carbon. No significant correlation was seen between pigment and total organic carbon content.The abundance of calcareous foraminifera correlated with the phytodetritus content, whereas a weaker correlation was observed for the agglutinated taxa. Therefore, calcareous foraminifera appear to require a fresher food input than agglutinated taxa. The foraminiferal species composition also varied with pigment content and nitrate penetration depth in the sediment, in line with the TROX concept. Phytopigment-rich (surficial CPE content >20 μg/cm³) sediments with a shallow nitrate penetration depth (∼1 cm depth) were inhabited by generally infaunal species such as Chilostomella oolina, Melonis barleeanus and Globobulimina spp. As the nitrate penetration increased to ∼2 cm depth in sediment and the pigment content remained relatively high (>15 μg/cm³), Uvigerina mediterranea and Uvigerina elongatastriata became dominant species. With declining CPE content and increasing nitrate penetration depth, the foraminiferal assemblages changed from the mesotrophic Cibicides kullenbergi-Uvigerina peregrina assemblage to the oligotrophic abyssal assemblage, mainly consisting of agglutinated taxa.     

Assessing the benefit of satellite-based Solar-Induced Chlorophyll Fluorescence in crop yield prediction

Large-scale crop yield prediction is critical for early warning of food insecurity, agricultural supply chain management, and economic market. Satellite-based Solar-Induced Chlorophyll Fluorescence (SIF) products have revealed hot spots of photosynthesis over global croplands, such as in the U.S. Midwest. However, to what extent these satellite-based SIF products can enhance the performance of crop yield prediction when benchmarking against other existing satellite data remains unclear. Here we assessed the benefits of using three satellite-based SIF products in yield prediction for maize and soybean in the U.S. Midwest: gap-filled SIF from Orbiting Carbon Observatory 2 (OCO-2), new SIF retrievals from the TROPOspheric Monitoring Instrument (TROPOMI), and the coarse-resolution SIF retrievals from the Global Ozone Monitoring Experiment-2 (GOME-2). The yield prediction performances of using SIF data were benchmarked with those using satellite-based vegetation indices (VIs), including normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and near-infrared reflectance of vegetation (NIRv), and land surface temperature (LST). Five machine-learning algorithms were used to build yield prediction models with both remote-sensing-only and climate-remote-sensing-combined variables. We found that high-resolution SIF products from OCO-2 and TROPOMI outperformed coarse-resolution GOME-2 SIF product in crop yield prediction. Using high-resolution SIF products gave the best forward predictions for both maize and soybean yields in 2018, indicating the great potential of using satellite-based high-resolution SIF products for crop yield prediction. However, using currently available high-resolution SIF products did not guarantee consistently better yield prediction performances than using other satellite-based remote sensing variables in all the evaluated cases. The relative performances of using different remote sensing variables in yield prediction depended on crop types (maize or soybean), out-of-sample testing methods (five-fold-cross-validation or forward), and record length of training data. We also found that using NIRv could generally lead to better yield prediction performance than using NDVI, EVI, or LST, and using NIRv could achieve similar or even better yield prediction performance than using OCO-2 or TROPOMI SIF products. We concluded that satellite-based SIF products could be beneficial in crop yield prediction with more high-resolution and good-quality SIF products accumulated in the future.     

Towards a more ecologically relevant assessment of the impact of heavy metals on the photosynthesis of the seagrass, Zostera capricorni

This in situ study used photosynthetic activity (measured as chlorophyll a fluorescence) and photosynthetic pigment concentrations to assess the effect of copper, cadmium, lead and zinc on the seagrass Zostera capricorni. Custom-made portable in situ exposure (PIE) chambers were developed so seagrasses could be dosed within the meadow. Z. capricorni was exposed to 0.1 and 1 mg l⁻¹ of metal solutions for 10 h. During this time and for the subsequent four-day recovery period, the effective quantum yield of photosystem II (PS II) (ΔF/Fm^′) was measured. While the results were variable, copper and zinc exposed samples had a depressed ΔF/Fm^′ during the exposure period. Samples exposed to zinc recovered to pre-exposure levels but those exposed to copper did not. Cadmium and lead did not impact on the chlorophyll a fluorescence and the chlorophyll pigment data supported these findings. This study presents an innovative new application of chlorophyll a fluorescence stress assessment.     

用MODIS卫星数据来分析格陵兰海叶绿素和气溶胶光学厚度之间的关系

主要利用卫星数据MODIS Aqua研究在北极格陵兰海(10°W-10°E,70°N-85°N)2003-2009年间叶绿素a(Chl a)与气溶胶厚度(AOD)的分布以及它们之间的耦合关系.研究发现,Chl a和AOD在一定的区域里有着带有滞后期的耦合关系.同时通过统计软件EVieWS的滞后回归分析发现,Chl a滞...     

三门湾主要经济贝类胃含物中微、小型藻类组成

本文对采自三门湾泥滩、沙滩、岩礁潮间带的主要经济贝类彩虹明樱蛤、缢蛏、僧帽牡蛎、青蚶、光滑河篮蛤胃含物中的微、小型藻类组成进行了鉴定分析。结果表明, 5种经济贝类胃含物中共鉴定出微、小型藻类143种,其中,硅藻占75.5%;甲藻占12.6%;绿藻门和金藻门占5.6%;蓝藻门和隐藻占4.2%;其他类占2.1%。胃含物中出现的细胞个体中,小于20μm的主要微型藻类是中肋骨条藻、盔状舟形藻、尤氏直链藻、小环藻、海链藻等;细胞个体大于20μm的主要小型藻类是琼氏圆筛藻、海生斑条藻、短柄曲壳藻、钝角齿状藻等。