Observations on the small-scale distribution of estuarine phytoplankton

Analyses of phytoplankton collections from Narragansett Bay, Rhode Island and the Damariscotta River, Maine, USA showed that statistically significant differences in population density can usually be demonstrated within any series of collections when the collecting interval is more than 10 cm. Individual species in any series are in general over-dispersed. Phytoplankton patches ranging in size from <1 m to 12 m were tentatively identified. No correlation was found between temperature or salinity and the small-scale distribution of individual species. Possible causes of the inhomogeneities observed in phytoplankton distributions are considered.Contribution No. 17 from the Ira C. Darling Center for Research, Teaching, and Service, University of Maine.     

磷形态对磷在水-沉水植物-底质中分配的影响

研究了以磷酸二氢钾、焦磷酸钠、六偏磷酸钠、甘油磷酸钠、ATP-Na为磷源的Hoagkand培养液培养黑藻时，不同形态磷进入水体后在上覆水、黑藻和底质中分配及含量的变化；获得各物质形态磷在水-沉水植物-底质中的分配比例。研究结果表明，水体中磷丰要分配在上覆水和底质中，不同形态磷分配比例不同。黑藻对各形态磷均能吸收利用，吸收最相对较少，受水体中磷形态的影响。当外源磷增加时，磷在上覆水和底质中的分配比例趋于平衡，平衡点因外源磷形态的不同而变化。沉水植物足水体中磷在上覆水与底质中分配的重要影响因素。底质对磷的吸附作用相对沉水植物对磷分配的影响较小。     

The geographical distribution of plant latex

Summary Latex is a widespread defence in plants against natural enemies and a literature-based summary of latex-producing angiosperms shows records in 40 families, and more than 20,000 species are estimated to bear laticiferous structures of some kind. This is considerably higher than the usually quoted figure of 12,500 species. There are more tropical than temperate latex-bearing families, both in absolute numbers and proportionally. Proportions of latex-bearing families are similar both in tropical and in more widespread or cosmopolitan families. Significantly more latex-bearing species belong to tropical than either to temperate or to widespread taxa, both in absolute and in relative terms. These differences may be related to the higher diversity of natural enemy species and to higher rates of herbivory in the tropics.     

植物根系对土壤抗侵蚀能力的影响

植物根系增加土壤的抗侵蚀能力主要通过两种方式一是通过根系在土体中交错、穿插,网络固持土壤;二是通过改善土壤的物理性质,提高土壤自身的水力学性质,从而增强土体的抗侵蚀能力.植物根系能明显增强土壤的抗冲性、土壤的渗透性及土体的剪切强度等水力学性质.根系在提高土壤抗侵蚀能力、防止土壤侵蚀方面具有重要作用.     

根系分泌物及其在植物营养中的作用

论述了根系分泌物的种类和影响因素，根系分泌物在植物营养中的调节作用、异种克生作用，根系分泌物与根际微生物的相互作用。在铁胁迫条件下，许多高等植物都能产生一系列生理和形态方面的适应性反应，禾本科植物通过根际特定分泌物——麦根酸类物质来自动调节其体内的铁营养状况；在磷胁迫条件下，根系分泌的低分子有机酸种类主要有柠檬酸、草酸、酒石酸和苹果酸，它们在植物根际的富集能明显促进土壤中磷的释放，提高作物对磷的吸收，缓解植物的磷胁迫；在锌胁迫条件下，双子叶植物的根系分泌物对锌的活化作用不明显，而禾本科植物的根系分泌物可以活化石灰性土壤中难溶性锌。     

Influence of dead coral substrate morphology on patterns of juvenile coral distribution

This study examines the abundances of three morphological categories of juvenile corals (massive, branching and encrusting) on two different types of natural substratum, dead massive and dead branching corals. The overall results show that the morphological characteristics of dead coral substratum have a significant influence on the coral recruitment patterns with respect to the morphology of the recruits: juvenile corals of massive and branching types were more abundant on substrates of corresponding morphology. The results obtained from this study suggest that dead coral might attract coral larvae that are morphologically similar. On the other hand, it may be the result of post-settlement mortality. Whatever the mechanism shaping the patterns is, it seems that the physical morphology of the dead coral substrate has a significant influence on the coral recruit assemblage. Hence, we suggest that substrate morphology can be an important qualitative factor for coral settlement and a possible determinant of community structure.     

Seamount endemism questioned by the geographic distribution and population genetic structure of marine invertebrates

Previous studies have suggested that the high diversity associated with the Norfolk seamounts (Southwest Pacific) could reflect endemism resulting from limited dispersal due to hydrological phenomena. Crustaceans of the family Galatheidae are thoroughly studied in the New Caledonia economic zone permitting the analysis of species distribution pattern between the New Caledonia slope and Norfolk ridge seamounts. This analysis has shown that, qualitatively, the same species are sampled on seamounts and on the New Caledonia slope. Local endemism was never detected. However, on each seamount, and therefore on a small surface, a very high number of species are usually sampled, suggesting that seamounts are biodiversity hot spots. Then, to evaluate whether the seamounts constitute patches of isolated habitat, we explore the pattern of genetic diversity within several species of crustaceans and gastropods. Analysis of the intra-specific genetic structure using the mitochondrial marker COI reveals that populations of two Galatheidae species (Munida thoe and Munida zebra), polymorphic for this marker, are genetically not structured, both among seamounts and between the seamounts and the island slope. The genetic structure over a similar sampling scheme of two Eumunida species (Chirostylidae, the sister family of Galatheidae) and a planktotrophic gastropod (Sassia remensa) reveals a similar pattern. Population structure is observed only in Nassaria problematica, a non-planktotrophic gastropod with limited larvae dispersal. Thus, the limitation of gene flow between seamounts appears to be observed only for species with limited dispersal abilities. Our results suggest that the Norfolk seamounts rather than functioning as areas of endemism, instead, may be highly productive zones that can support numerous species in small areas.     

Effects of plant size and distribution on the numbers of invertebrate species and individuals inhabiting the brown alga Pelvetia fastigiata

The invertebrates living on specimens of the brown alga Pelvetia fastigiata, growing in the intertidal zone at La Jolla, California (USA) in November 1975 were enumerated. Within 7 collecting sites, larger plants generally shelter more animal species and individuals than smaller plants. The number of species on a given plant can be described as an equilibrium number; numbers of species and individuals can become similar on defaunated and transplanted algae of comparable sizes placed at the same experimental site. Such equilibria are site-specific because the colonization, immigration and loss rates of animals differ among the sites studied. Relationships between plant size and the number of animal species and individuals on P. fastigiata also differ among the collecting sites. The between-site differences are related to tidal level, to habitat diversity and to habitat patch-size. Small isolated plants without epiphytes shelter few species. The faunas of larger isolated plants at mid-tide levels generally include many thallus-dwelling, tubiculous, vagrant and epiphyte-dwelling species, but few such species commonly inhabit plants within aggregations of P. fastigiata. Within aggregations, the plants host relatively few epiphytes and thus lack habitat diversity, and the net emigration rates of many animals including epiphyte-dwellers are relatively high. Plants within aggregations, however, usually shelter more animal indivuduals than isolated plants. Thus, faunal diversity is reduced, not increased within the largest patches of P. fastigiata.     

开放式空气CO2浓度升高对水稻根系形态的影响

在FACE（free-air carbon dioxide enrichment）技术平台上，采用水培的研究方法，观测了大气CO2浓度升高和两种氮水平下水稻根系形态的变化。结果表明，在水稻各生育期，CO2浓度升高都极显著增加了根干质量，且主要增加于根粗为2．0～2．5mm／n的部位。根系形态的各项指标均对高CO2浓度有积极的响应，在抽穗期尤为明显；N处理的差异很明显，低氮条件下根系表现为根长、根尖数和根表面积增加，常氮条件下根粗和发根数增加。各生育期的根冠比在高CO2浓度下极显著增加，尤其在LN处理下。水稻从分蘖期到抽穗期，因地上部分的增幅大，根冠比表现为逐渐降低的趋势。     

Effects of environmental parameters on the oxygen consumption of four marine invertebrates: a comparative factorial study

The oxygen consumption curves of two decapod crustaceans (Palaemon serratus, Penaeus monodon) and two prosobranch molluscs (Trunculariopsis trunculus, Nassarius mutabilis) have been detected in the entire pO₂ interval from 0 to 160 mmHg, under different conditions of temperature and salinity. From the experimental curves, physiological parameters such as the initial oxygen consumption velocity, the Q ₁₀ values and the oxygen independence indices have been measured. The latter parameters have been obtained using normalised plots which allow their better evaluation. The effects of temperature, salinity and oxygen partial pressure on the oxygen-consumption features have been studied using a factorial experimental plan which allows measurement of the effects of each experimental variable as well as the effects of synergistic interactions between different variables. Received: 27 March 2000 / Accepted: 13 November 2000     

Effects of fluvial instability on the bed morphology in vegetated channels

Environmental Fluid Mechanics - Flume experiments are conducted to investigate the effect of streambed instability in channels with randomly-distributed vegetation, varying vegetation density and...     

Types of larval development in marine bottom invertebrates,their distribution and ecological significance: a re-evaluation

The distribution of various types of larval development among marine bottom invertebrates has been discussed on the basis of ecological evidence by Thorson (1936, 1946, 1950, 1952) and Mileikovsky (1961b, 1965). The information at hand is reviewed anew in this paper and is re-evaluated in the light of modern pertinent literature. The interrelationships between certain larval types and their distribution are not as rigid and direct as originally assumed. This can be proved even by the copy book example of the distribution of the various forms of development among species of the coastal gastropod genus Littorina. Especially among species with wide distributional areas, local populations may exhibit greater diversity in larval types than has previously been thought. Different types of larval development have now become known to exist in different populations of opisthobranch gastropods and lamellibranchs, i.e., in invertebrate groups in which such variability had been ruled out by Thorson. Variability in the type of larval development within given species — as a function of geographical, seasonal and other environmental parameters —is also more common in other marine bottom invertebrates than formerly considered. Marine bottom invertebrates are characterized not only by the 3 main different types of larval development proposed by Thorson (pelagic, direct, viviparous), but also by a fourth type: demersal (free non-pelagic) development. This fourth type occurs at all water depths and in all geographic zones of the oceans. The most important of the 4 types is pelagic (planktotrophic) development. Thorson's rule (decrease in numbers of species possessing pelagic development from the Equator towards the Poles, and from shallow-shelf waters to greater oceanic depths) is well substantiated by new data. However, one correction is necessary: pelagic development is not completely absent in the abyssal zone, as was proposed by Thorson (1950, and later), but is represented in it by at least several species belonging to various groups of invertebrates, and is also fairly common in the bathyal zone. A detailed analysis of the distributional pattern of the different types of development of marine bottom invertebrates must further take into consideration asexual reproduction with all its different modifications. Asexual reproduction in benthonic invertebrates is ecologically significant because of its common occurrence in nature; in numerous species it is also important as a biological supplement to sexual reproduction. The vast majority of species inhabiting the shallow-shelf zone and, partly, the higher levels of the slope zone of ocean areas located roughly between the polar circles, reveals development by means of planktotrophic larval stages. In the highest latitudes and on the slopes to abyssal depths—characterized by low water temperatures, scarcity of food, increasing hydrostatic pressure and other environmental peculiarities—other types of larval development prevail and, progressively, replace pelagic development with increasing latitude or depth. The distributional patterns of the various types of development among marine bottom invertebrates form one of the most important factors determining the basic distributional dynamics of the whole benthos in all oceans, both in the geological past and at the present time.Dedicated to the memory of Professor G. Thorson —founder of modern reproductive and larval ecology of marine bottom invertebrates.     

大气CO2浓度升高对植物光合作用的影响

大气CO2浓度不断升高以及由此带来的温室效应已成为全球变化研究的热点问题之一。CO2作为植物光合作用的底物,其浓度升高必然对植物的光合作用产生影响。大气CO2浓度升高对植物光合作用的影响主要体现在:对不同植物的光合色素含量均有影响,但结果有所差异;短期处理光合速率提高,而长期处理则可能出现光合适应,其适应机理目前尚存在分歧;不同光合类型植物的叶片形态结构有不同的响应结果,叶绿体超微结构也明显变化;生物量和产量提高。此外,CO2浓度升高与其它环境因子相互作用对植物的光合作用也具有重要影响。大气CO2浓度升高条件下对木本植物的研究、在分子水平上的深入研究以及在不同环境下的研究将成为未来研究的主要方向。     

RQ of benthic marine invertebrates

This study investigated an incubation method which employed simultaneous measurement of CO₂ production and O₂ consumption rates to calculate the RQ (respiratory quotient; CO₂ production rate: O₂ consumption rate) of individual benthic marine invertebrates. Carbon dioxide production rates were calculated from changes in CO₂ concentration determined using seawater pH. O₂ consumption rates were calculated from changes in O₂ concentration with a correction applied for O₂ flux across the air/water interface due to gaseous exchange. Species examined were Triphyllozoon sp. cf. moniliferum (MacGillivray 1860), a bryozoan; Herdmania momus (Savigny), a solitary ascidian; Poneroplax albida (Blainville 1825), a chiton; and Haliotis roei (Gray 1826), an abalone. Six individuals of each were collected on 14 November 1985 from the limestone walls of a cave in a nearshore reef off Marmion, Western Australia. After acclimation for 6 h in experimental conditions, rates of CO₂ production and O₂ consumption were measured. A minimum period of 4 h was required to obtain consistent RQ values for each species. The standard error (SE) of the (calculated) RQ ratio was 14 to 33% of the mean in incubations of 4 h, and less than 14% in incubations of 4 to 12 h. The RQ is commonly used as an indicator of unknown catabolic substrates by comparing it with biochemically determined limits for known substrates. This study provides a strong argument against using the RQ of individual animals to draw any conclusions about catabolic substrates. Unexplained variation in the components of the RQ of an individual, measured over short time periods, and the potential involvement of stored reserves in catabolism, over longer time periods, obscure the relationship between the RQ of individual animals and the ratio's biochemically determined limits.     

High pressure effects on marine invertebrates and fishes

A survey of literature and of new information from the author's laboratory is presented concerning the comparative pressure physiology of marine invertebrates and fishes. Short term experiments on littoral marine animals have revealed that the taxonomic groups exhibiting the greatest resistance to high pressures are those with the greatest vertical distributions in the deep sea, namely, echinoderms, molluscs, amphipods, isopods and polychaetes. Shallow water species which possess high thermal and osmotic resistance also show an exceptionally high degree of pressure resistance. The relative differences in genetic pressure resistance of lower marine invertebrates are the same in whole, intact animals and in isolated, surviving tissue pieces. Adaptation of nonregulating euryoecous invertebrates to higher temperatures, higher osmotic concentrations and higher calcium contents of the tissues results in increased pressure resistance. Under pressure, the optimum cellular pH shifts downward to a lower pH range.Lecture presented on October 23, 1967 at Duke University, Marine Laboratory, Beaufort (USA); on November 6, 1967 at the Instituto di Biologia Marinha of the University of São Paulo (Brasil); and on November 8, 1967 at the Institute of Marine Science of the University of Miami (USA).     

生长调节剂对春玉米氮素积累、转运及籽粒蛋白质含量的影响

为探讨生长调节剂对玉米的影响,文章通过不同生长调节剂(主要成分为羧甲基壳聚糖)处理玉米,研究了生长调节剂对春玉米功能叶片、茎杆、籽粒中氮素含量的变化。结果表明,不同配方的生长调节剂能够促进春玉米功能叶中全氮、蛋白氮的转运;提高春玉米茎秆中氮素的转运量以及玉米的产量;加速籽粒中蛋白质的积累,从而提高玉米的品质。并以施生长调节剂配方2 吐温80(PGR2)的配方效果最好。实验中应用的生长调节剂是一种有效的促进玉米氮白质积累的生长调节剂。     

能源植物黄连木在我国的地理分布规律

为了更好地开发利用生物柴油能源植物黄连木（Pistacia chinensis Bunge）,对其在我国的地理分布规律进行了系统调查研究,结果表明：黄连木的地理分布范围为北纬18°09′～40°09′、东经96°52′～123°14′,资源遍布我国华北、华南、西南、华中、华东与西北地区的25个省、自治区、直辖市;分布区地形以高原、山地为主,土壤母岩以石灰岩为主,土壤类型以褐土为主,跨越我国温带、亚热带、热带地区;黄连木的水平分布区主要位于云南潞西—西藏察隅—四川甘孜—青海循化—甘肃天水—陕西富县—山西阳城—河北顺平—北京西山一线以东、以南,整体上呈现连续分布的特征,局部地区有一定的间断分布;从我国西部到东部,其垂直分布的上限与下限均呈现逐渐降低的趋势,从南方到北方,这种降低趋势不太明显;黄连木在我国的资源分布区可以划分为集中分布区、次集中分布区、零星分布区和沿海地带零星分布区四种类型。     

盐沼植物群落研究进展：分布、演替及影响因子

盐沼是全球温带及亚热带地区的主要滨海湿地类型之一,在我国分布广泛。盐沼湿地生态系统敏感、脆弱且具有重要的生态系统服务功能。理解盐沼植物群落时空分布动态的一般规律与生态学机制,是开展盐沼生态系统研究的基础与关键。海陆交界的特殊环境特征是影响盐沼湿地植物群落的空间分布及演替过程的主要因素。在海洋潮汐作用下,盐沼湿地中的盐度、水淹强度、氧化还原电位等非生物因子往往呈梯度分布,这也导致了生物群落中种内、种间关系的变化。在非生物及生物因子的共同作用下,盐沼植物群落也往往沿高程梯度呈带状分布。环境变化是盐沼植物群落演替的驱动因素,在海岸线相对较为稳定的盐沼,植物群落的演替多属自发演替,而在靠近的大型河口的一些持续淤涨的盐沼,植物群落演替通常属于异发演替。沿海地区的水产业、流域上游及沿海地区的工程、污染及生物入侵等直接或间接的人类活动已对盐沼湿地植物群落的产生了深刻影响。经过数十年发展,国际上盐沼植物群落学研究的热点领域主要包括盐沼植物群落与其他生物群落的相互关系、植物群落在盐沼生态系统过程中的作用等。在全球变化背景下,盐沼植物群落对气候变化与海平面升高也日益成为盐沼植物群落学相关的热点。     

天气条件对福州近地层臭氧分布的影响

利用2009—2010年福州市近地层臭氧连续观测资料,并结合气象资料分析不同天气型对臭氧浓度变化的影响,以及臭氧浓度与气象要素的相关性。结果表明:在高压后部、地面倒槽等6种天气型影响下,福州市臭氧浓度值较高;在低涡锋面、台风(热带辐合带)等4种天气型影响下,臭氧浓度值较低。导致福州市臭氧平均浓度值最高的天气型是台风(热带辐合带)外围,最低的是低涡锋面系统。高压后部、地面倒槽和锋前暖区等强暖性、且非常不利于污染物扩散的天气型易造成臭氧浓度超标。臭氧浓度与气象要素关系密切,与温度、日照、太阳辐射显著正相关,与云量、相对湿度、降水量显著负相关,受偏南和偏东风影响,平均风速较大时,臭氧浓度较高,在SSE方位上臭氧小时浓度超标率最高。