大兴安岭中段东坡龙江盆地早白垩世植物化石新材料

报道大兴安岭中段东坡龙江盆地早白垩世18属31种植物大化石和18属21种孢粉化石。该植物群以有节类、真蕨类、银杏类及茨康类最为丰富,其次为苏铁类、本内苏铁类及化石果类,时代可能为早白垩世早中期。根据植物特征及伴生的热河生物群生物特点,龙江盆地早白垩世总体上可能处于温暖湿润的季节性变化的暖温带,并伴有短暂的干旱、半干旱气候,古环境应为沼湖环境,并在湿地和山坡上生长着不同的生物群落。     

延长植物群在塔里木的发现兼论中国晚三叠世植物地理分区的西端界线

报道延长植物群——晚三叠世北方型植物群在塔里木的发现 ,结合塔里木中三叠世和吐鲁番晚三叠世以及两地早、中侏罗世均产北方型植物群的证据 ,阐明我国南北晚三叠世植物分区的西端界线仍应划在昆仑山而不是天山     

热带水库消落区植物群落物种组成与结构特征——以海南松涛水库为例

消落区是河流、湖泊和水库因阶段性或长期性的水位涨落而反复淹没或出露而形成的一种特殊的季节性湿地.消落区植被在维持水陆生态系统的动态平衡、生物多样性、生态安全及生态服务功能等方面发挥着重要作用.通过样方法调查分析了海南松涛水库消落区植物组成、区系特点以及群落分布特征.结果显示：松涛水库消落区共有维管植物40科101属115种,其中被子植物36科97属111种,蕨类植物4科4属4种.植物区系以热带性为主,外来入侵种较多,且既耐水淹又耐干旱植物众多;群落以草本、灌木植物为主,乔木较少且大多以幼苗形式存在.主要群落类型为以铺地黍（Panicum repens）为优势种的复合群落,个别区域零散分布有美洲蟛蜞菊（Wedelia trilobata）、光荚含羞草（Mimosa sepiaria）、猪屎豆（Crotalaria pallida）、马松子（Melochia corchorifolia）、假臭草（Praxelis clematidea）和铺地黍等单优群落.消落区不同海拔区间群落分布存在明显差异,物种多样性从高到低呈显著递减趋势.研究结果可为松涛水库消落区植被恢复工作提供科学指导.     

甘肃玉门华夏和安加拉混生植物群的发现及其意义

本文报道了发现于甘肃玉门大山口上二叠统肃南组华夏和安加拉混生植物群,含16属26种。根据植物分子的组成,植物群的时代属于晚二叠世早期,相当于二叠纪(三分)的吴家坪期(Wuchiapingian)。这些保存颇佳的植物化石对于研究华夏和安加拉两个植物区系的关系提供了新的依据,具有重要的古植物地理学意义。     

中国更新世环境巨变的孢粉植物群记录

通过对已有３８个剖面的孢粉时间序列分析,探讨了１．６ＭａＢＰ－０．８ＭａＢＰ的植被与环境巨变,划分出两个孢粉带及两个孢粉气候事件,提出该时段是更新世环境最恶劣的时期该时期植被稀疏,北方一般以森林草原和草原为主,西北地区出现荒漠或荒漠草原,南方以森林及灌丛草原为主,表明当时气候冷干,降温幅度可达１５－１７℃,降水量减少３００－５００ｍｍ。     

安徽升金湖自然保护区湿地草本种子植物区系研究

对安徽升金湖湿地自然保护区的湿地草本植物区系进行了初步分析,研究表明,该区共有湿地草本种子植物59科173属275种,以禾本科（Gramineae）、菊科（Compositae）、莎草科（Cyperaceae）等为优势科,而以菱科（Trapaeeae）、三白草科（Saururaceae）、茨藻科（Najadaceae）等为该植物区系的表征科;以蓼属（Polygonum）、苔草属（Carex）、蒿属（Artemisia）等为优势属,但属的组成较为分散,寡种属和单种属占总属数的97．69％,表明该区植物成分较为复杂,物种多样性指数较高。从分布区类型看,科以热带成分占明显优势（30．52％）;属泛热带分布属最多（21．39％）,北温带分布成分次之（13．87％）,总体上温带成分（38．73％）略多于热带性成分（34．10％）。表明该植物区系地理成分复杂,过渡性明显,分布区类型多样,具有热带、亚热带与暖温带的多重性质,但以亚热带性质为主。     

Development of a diatom-based model for inferring total phosphorus in southeastern Australian water storages

Diatom-based transfer functions for inferring epilimnetic total phosphorus (TP) have been developed from a data set of 33 southeastern Australian water storages. Regular institutional monitoring of these sites has allowed comparison of models developed from TP data covering different time periods. A model based on mean annual TP performs better than models derived from winter maximum TP, spring minimum TP or TP nearest the time of diatom sampling. A mean annual TP model (WA-PLS 2 component) has a jack-knifed diatom-inferred versus measured TP correlation coefficient (r ² _jack) of 0.69 and a root-mean-square-error of prediction (RMSEP) of 0.246 log₁₀g TP l^–1, while alternative models have RMSEP > 0.27. Deletion of two samples with uncharacteristic species composition and environmental conditions improved performance of the mean annual TP model (r ² _jack= 0.74; RMSEP = 0.233 log₁₀g TP l^–1). Comparison with other published diatom-TP calibration models indicates that this model performs relatively well, with possible contributing factors including the extensive characterisation of TP (with an average 15 determinations making up the annual mean) and the dominance of planktonic diatoms in most sites. Downcore application of the model will allow the reconstruction of reservoir nutrient histories since commissioning, and thus provide a basis for understanding and management of reservoirs.     

甘肃宝积山盆地中侏罗世植物群特征及古生态、古气候研究

本文对甘肃宝积山盆地窑街组植物大化石进行了系统研究,经鉴定共有19属50种,结合已有的宝积山盆地中侏罗世植物化石资料,发现甘肃宝积山盆地中侏罗世植物群由27属73种组成。其中,银杏类植物10属30种,真蕨类植物5属26种,松柏类植物5属6种,楔叶类植物3属5种,苏铁类植物2属4种,裸子植物球果和种子化石2属2种。基于当前植物群组成特征,对植物化石埋藏学特性进行分析,确定植物化石主要为原地埋藏或亚原地埋藏,少数属种为异地埋藏,并通过对化石类群古生态特征进行分析,结合现生植物的生存环境,初步重建了宝积山盆地中侏罗世植物群落,划分为四个植物群落:岸边—湿地楔叶类植物群落、低地蕨类—苏铁类植物群落、坡地银杏类植物群落和高地松柏类植物群落。通过对植物群组成特征和植物化石叶相特征的统计分析,并与其他气候带植物群特征进行对比,推断中侏罗世时期甘肃宝积山盆地为温暖潮湿的暖温带气候。     

An in situ iron-enrichment experiment in the western subarctic Pacific (SEEDS): Introduction and summary

To test the iron hypothesis in the subarctic Pacific Ocean, an in situ iron-enrichment experiment (SEEDS) was performed in the western subarctic gyre in July–August 2001. About 350 kg of iron (as acidic iron sulfate) and 0.48 mol of the inert chemical tracer sulfur hexafluoride were introduced into a 10-m deep surface mixed layer over an 80 km² area. This single iron infusion raised dissolved iron levels to 2.9 nM initially. Dissolved iron concentrations rapidly decreased after the infusion, but levels remained close to 0.15 nM even at the end of the 14-day experimental period. During SEEDS there were iron-mediated increases in chlorophyll a concentrations (up to 20 μg l⁻¹), primary production rates, biomass and photosynthetic energy conversion efficiency relative to waters outside the iron-enriched patch. The rapid and very high accumulation of phytoplankton biomass in response to the iron addition appeared to be partly attributable to shallow mixed-layer depth and moderate water temperature in the western subarctic Pacific. However, the main reason was a floristic shift to fast-growing centric diatom Chaetoceros debilis, unlike the previous iron-enrichment experiments in the equatorial Pacific and the Southern Ocean, in both of which iron stimulated the growth of pennate diatoms. The iron-mediated blooming of diatoms resulted in a marked consumption of macronutrients and drawdown of pCO₂. Biological and physiological measurements indicate that phytoplankton growth in the patch became both light- and iron-limited, making phytoplankton biomass relatively constant after day 9. The increase in microzooplankton grazing rate after day 9 also influenced the net growth rate of phytoplankton. There was no significant increase in the export flux of carbon to depth during the 14-day occupation of the experimental site. The export flux between day 4 and day 13 was estimated to be only 13% of the integrated primary production in the iron-enriched patch. The major part of the carbon fixed by the diatom bloom remained in the surface mixed layer as biogenic particulate matter. Our findings support the hypothesis that iron limits phytoplankton growth and biomass in a ‘bottom up’ manner in this area, but the fate of algal carbon remains unknown.     

南海晚第四纪的硅藻遗体及其地质意义：Ⅰ.硅藻种类及其生态环境

南海北部和中部三个晚第四纪柱样沉积物中，鉴定出硅藻５６属１９３种和变种。其中，相对含量大于１０％的硅藻种有１５种，相对含量５％－１０％的种有９种，相对含量１％－５％的种有４１种，依据硅藻的地理分布，确定了其中１８种常见硅藻的生态环境。