Biological consequences of el nino

Observations of the 1982-1983 El Ni?o make it possible to relate the anomalous ocean conditions to specific biological responses. In October 1982 upwelling ecosystems in the eastern equatorial Pacific began a series of transitions from the normal highly productive condition to greatly reduced productivity. The highly productive condition had returned by July 1983. Nutrients, phytoplankton biomass, and primary productivity are clearly regulated by the physical changes of El Ni?o. Evidence from 1982 and 1983 also suggests effects on higher organisms such as fish, seabirds, and marine mammals, but several more years of observation are required to accurately determine the magnitude of the consequences on these higher trophic levels.     

Some marine ecological phenomena: chemical basis and biomedical potential

Analysis of secondary metabolites derived from marine organisms has revealed a broad spectrum of novel molecular architecture. The function of these compounds in their natural habitat is linked to various aspects of species survival, and the compounds have also served as characteristic chemical markers through successive trophic levels. Fundamental questions concerning the locus of synthesis in complex and intricate assemblies of plants and animals and the pathways of biosynthesis are beginning to be answered. It is now apparent that the marine environment gives rise to some distinctive chemistry, which is generated along characteristic pathways. Some of the newly described compounds have already become valuable tools in biomedicine.     

The evolution of modern eukaryotic phytoplankton

The community structure and ecological function of contemporary marine ecosystems are critically dependent on eukaryotic phytoplankton. Although numerically inferior to cyanobacteria, these organisms are responsible for the majority of the flux of organic matter to higher trophic levels and the ocean interior. Photosynthetic eukaryotes evolved more than 1.5 billion years ago in the Proterozoic oceans. However, it was not until the Mesozoic Era (251 to 65 million years ago) that the three principal phytoplankton clades that would come to dominate the modern seas rose to ecological prominence. In contrast to their pioneering predecessors, the dinoflagellates, coccolithophores, and diatoms all contain plastids derived from an ancestral red alga by secondary symbiosis. Here we examine the geological, geochemical, and biological processes that contributed to the rise of these three, distantly related, phytoplankton groups.     

海洋无脊椎动物多不饱和脂肪酸合成代谢机理研究进展

近年来,人们对水产品质量安全、优质的动物蛋白以及脂肪来源的关注度越来越高。海洋无脊椎动物不仅是优质食物蛋白的重要来源,也是人体获取多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）的主要食物来源。研究表明,几乎所有的PUFA都来自于水生生态系统中的初级生产者,海洋中主要初级生产者微藻生产出PUFA进入食物链后,较高营养级生物可通过生物转化或修饰产生新的PUFA。关于初级生产者和脊椎动物中PUFA合成代谢的研究较多,但位于两者之间无脊椎动物PUFA的生物合成代谢途径却知之甚少。因此,本文对五类海洋无脊椎动物（多孔动物、刺胞动物、软体动物、甲壳动物和棘皮动物）PUFA的合成代谢途径以及参与其过程中重要酶和关键基因的研究进展进行了总结,以期为更深入地理解海洋无脊椎动物PUFA的合成代谢与调控体系提供有价值的参考资料。     

Arctic seabirds transport marine-derived contaminants

Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arctic contamination, because local pollution sources are rare. We show that arctic seabirds, which occupy high trophic levels in marine food webs, are the dominant vectors for the transport of marine-derived contaminants to coastal ponds. The sediments of ponds most affected by seabirds had 60 times higher DDT, 25 times higher mercury, and 10 times higher hexachlorobenzene concentrations than nearby control sites. Bird guano greatly stimulates biological productivity in these extreme environments but also serves as a major source of industrial and agricultural pollutants in these remote ecosystems.     

Magnification of secondary production by kelp detritus in coastal marine ecosystems

Kelps are highly productive seaweeds found along most temperate latitude coastlines, but the fate and importance of kelp production to nearshore ecosystems are largely unknown. The trophic role of kelp-derived carbon in a wide range of marine organisms was assessed by a natural experiment. Growth rates of benthic suspension feeders were greatly increased in the presence of organic detritus (particulate and dissolved) originating from large benthic seaweeds (kelps). Stable carbon isotope analysis confirmed that kelp-derived carbon is found throughout the nearshore food web.     

Carbon-13 and carbon-14 abundances in alaskan aquatic organisms: delayed production from peat in arctic food webs

Inputs of terrestrial peat carbon to the nearshore Alaskan Beaufort Sea from erosion and fluvial transport are of the same magnitude as in situ primary production within 10 kilometers of shore. Nevertheless, carbon-13/carbon-12 ratios and carbon-14 abundances in marine organisms show that only small amounts of the terrestrial carbon are transferred beyond the microbial level. Freshwater organisms, however, are heavily dependent on peat, as shown by pronounced seasonal radiocarbon depressions in resident fish and ducks. Tundra ponds and lakes are areas where accumulated terrestrial peat carbon is apparently transferred to aquatic insect larvae and passed on to higher organisms. The lack of functionally analogous abundant marine prey organisms may explain why peat carbon is not efficiently transferred to apical food web species in the marine environment.     

Climate impact on plankton ecosystems in the Northeast Atlantic

It is now widely accepted that global warming is occurring, yet its effects on the world's largest ecosystem, the marine pelagic realm, are largely unknown. We show that sea surface warming in the Northeast Atlantic is accompanied by increasing phytoplankton abundance in cooler regions and decreasing phytoplankton abundance in warmer regions. This impact propagates up the food web (bottom-up control) through copepod herbivores to zooplankton carnivores because of tight trophic coupling. Future warming is therefore likely to alter the spatial distribution of primary and secondary pelagic production, affecting ecosystem services and placing additional stress on already-depleted fish and mammal populations.     

扎龙湿地水体重金属沿食物链的生物累积分析

采用原子吸收法,对苍鹭(Ardea cinerea)卵、雏鸟的肝、肾、肌肉、羽毛4种组织器官及泥鳅(Misgurnus bipartitus)、细鳞斜颌鲴(Plagiognathops Microlepis)、葛氏鲈塘鳢(Perccotus glehni)、麦穗鱼(Pseudorasbora parva)、银鲫(Carassius auratus gibelio)及湖(?)(Phoxinus percnurus)6种鱼类组织内的Cu、Zn、Mn、Cd、Pb等重金属的含量进行了测定,分析了这几种重金属在鱼体内及卵和雏鸟体内含量的分布关系,结果表明:重金属Cu、Zn、Mn、Pb和Cd在苍鹭体内各组织中积累量不同,其总含量依次为Zn>Cu>Mn>Cd>Pb;在25日龄苍鹭雏鸟各组织中,肝脏和羽毛的5种金属的含量较其它组织器官高。在扎龙湿地生态系统不同营养级生物体内,重金属Cu、Zn、Mn、Pb、Cd的含量随食物链等级的升高而积累放大,水体中重金属的含量最低,鱼体内重金属含量次之,而苍鹭体内重金属含量最高,体内积累量沿生物营养等级而递增的规律性很强。在此基础上,探讨了重金属元素经食物链产生的生物累积放大作用对位于食物链最高营养级鸟类生存所构成的潜在威胁,从而为珍稀水禽保护及管理措施的制定提供一些依据。     

Energetics, patterns of interaction strengths, and stability in real ecosystems

Ecologists have long been studying stability in ecosystems by looking at the structuring and the strengths of trophic interactions in community food webs. In a series of real food webs from native and agricultural soils, the strengths of the interactions were found to be patterned in a way that is important to ecosystem stability. The patterning consisted of the simultaneous occurrence of strong "top down" effects at lower trophic levels and strong "bottom up" effects at higher trophic levels. As the patterning resulted directly from the energetic organization of the food webs, the results show that energetics and community structure govern ecosystem stability by imposing stabilizing patterns of interaction strengths.     

Direct coupling of marine invertebrate spawning with phytoplankton blooms

Spawning of green sea urchins and blue mussels may be triggered by a heat-stable metabolite released by various species of phytoplankton. Mussels require a higher phytoplankton density for a maximum response than urchins, perhaps because mussels are exposed to higher concentrations of phytoplankton as a result of their filtering activity. Phytoplankton as a spawning cue appears to integrate numerous physical and biotic factors indicating favorable conditions for larval growth and survival. Evolution of similar direct coupling of the larval phase with phytoplankton blooms may be common among marine invertebrates.     

Trophic cascades in a formerly cod-dominated ecosystem

Removal of top predators from ecosystems can result in cascading effects through the trophic levels below, completely restructuring the food web. Cascades have been observed in small-scale or simple food webs, but not in large, complex, open-ocean ecosystems. Using data spanning many decades from a once cod-dominated northwest Atlantic ecosystem, we demonstrate a trophic cascade in a large marine ecosystem. Several cod stocks in other geographic areas have also collapsed without recovery, suggesting the existence of trophic cascades in these systems.     

微塑料的环境行为及其生态毒性研究进展

微塑料污染已经成为全球关注的环境问题。本文对不同环境介质中微塑料的来源、迁移、分布特征及其对生物体的毒性效应等方面的研究现状进行了系统的总结和评述。微塑料的来源主要包括直接进入到环境中的初生微塑料和大块塑料破裂、分解形成的次生微塑料,其可在大气、水体(淡水和海洋)和陆地环境之间进行迁移。需建立统一的微塑料样品采集、分离和鉴定方法,并结合准确高效的溯源分析技术,进一步探索其环境行为与归趋。微塑料(含自身的添加剂)被生物摄取后会造成物理损伤、引发生物体的行为、生理学和分子学反应,并可能与其他污染物形成复合污染,产生联合毒性效应。通过同位素示踪与分子生物学新技术的联用,重点研究微塑料的生物累积和在食物链中的传递效应,尤其是对人体健康的潜在威胁,以期为微塑料污染的生态风险评估提供理论依据。     

赤潮藻拮抗微生物研究进展

受水体富营养化的影响,沿海地区日趋频繁地暴发赤潮,给水生生态环境带来严重的破坏并造成巨大的经济损失。目前国际上治理赤潮的主要方法有物理法、化学法和生物法,其中赤潮藻拮抗微生物作为一种具有潜在防治赤潮的生物,已经引起研究人员的特别关注。文章重点介绍了目前已经报道的赤潮藻拮抗微生物,如病毒、细菌、真菌和原生动物等存在、丰度、生态作用等方面的研究概况,提出加强对微藻拮抗微生物的应用、生态分布和生态意义等方面的研究,以达到防治赤潮的目的。     

五里湖生态系统能量流动模型初探

根据2009年五里湖的渔业资源和生态环境调查数据,利用EwE 6.0构建五里湖生态系统的生态通道模型。该模型包括大型鲌、其他食鱼性鱼类、湖鲚、鲤、鲫、野杂鱼、鲢、草食性鱼类、大型虾蟹类、软体动物、其他底栖动物、浮游动物、沉水植物、其他维管束植物、浮游植物和碎屑等17个功能组,基本覆盖了五里湖生态系统能量流动的主要过程。模型分析表明：2009年五里湖生态系统处在趋于成熟时期。生态网络分析表明,生态系统各功能组的营养级范围为1~3.958,能量流动主要有6级,来自初级生产者的能量效率为4.4%,来自碎屑的传递效率为5.1%,平均能量传递效率为4.9%。生态系统功能组直接来源于碎屑的比例占总流量的60%,来源于初级生产者的比例为44%。生态系统的总初级生产计算量/总呼吸量（TPP/TR）、连接指数（CI）、系统聚合度（A）、Finn′s循环指数（FCI）、Finn′s平均能流路径长度(FCL )和系统杂合度（SOI）分别为1.339、0.277、0.267、0.155、3.393、0.119。     

棘皮动物结合素研究进展

结合素(bindin)属于配子识别蛋白的重要种类之一,是雄性海洋生物精巢或精子中特有的凝集素样的不溶性颗粒蛋白。在海洋生物体外受精过程中,当顶体反应发生时,精子释放出成熟的bindin蛋白可特异性地识别特定卵子表面的蛋白受体,进而促进精卵结合,在保障海洋生物体外受精准确性和维系海洋生物物种独立性、稳定性等方面具有重要意义。棘皮动物属后口动物,是无脊椎动物的高等类别,棘皮动物的受精生物学和性别选择机制一直是基础生物学研究和水产养殖研究的热点和焦点内容。本研究中就近年来棘皮动物结合素bindin基因的结构信息、生物功能以及分子进化特点进行综述,以期为进一步了解棘皮动物结合素bindin的功能、分子进化特点及其在棘皮动物配子识别和性别选择中的作用提供参考。     

海洋生物微塑料检测方法及污染现状研究进展

海洋微塑料污染问题是全球研究热点,现有研究表明微塑料在海洋环境中无处不在,对海洋生态的威胁逐渐加重,伴随着海洋食品的兴起,人们也越来越重视微塑料污染对人体健康的危害。本文通过对海洋生物体内微塑料污染情况的概述,系统分析了微塑料对海洋生物造成的影响。主要针对微塑料检测的前处理方法以及组分的鉴定方法展开综述,对不同方法的优缺点进行比较,指出在微塑料检测研究中多种方法综合应用效果最佳。基于现阶段海洋微塑料的研究状况,从科学研究和管控方面讨论了目前研究中存在的问题,展望了未来的研究方向。     

Bioluminescent and red-fluorescent lures in a deep-sea siphonophore

Bioluminescence (light production) and fluorescence (re-emission of absorbed radiation as light) are found in an unaccountably diverse array of marine organisms, where their functions are largely unknown. Here we report a deep-sea siphonophore that twitches glowing lures to attract fish. This is rare evidence of bioluminescence used for prey attraction among nonvisual marine organisms. The lures also contain red fluorescent material that shifts the wavelength of emitted light. The existence of a red-luminescent invertebrate suggests that long-wavelength light plays a greater role in marine interactions than previously suspected.     

Fishing down marine food webs

The mean trophic level of the species groups reported in Food and Agricultural Organization global fisheries statistics declined from 1950 to 1994. This reflects a gradual transition in landings from long-lived, high trophic level, piscivorous bottom fish toward short-lived, low trophic level invertebrates and planktivorous pelagic fish. This effect, also found to be occurring in inland fisheries, is most pronounced in the Northern Hemisphere. Fishing down food webs (that is, at lower trophic levels) leads at first to increasing catches, then to a phase transition associated with stagnating or declining catches. These results indicate that present exploitation patterns are unsustainable.     

Coherent sign switching in multiyear trends of microbial plankton

Since the 1990s, phytoplankton biomass on the continental shelf of Nova Scotia and in the Labrador Sea has undergone sustained changes in the spring and fall, which are accompanied by changes in bacterioplankton that are dampened in amplitude but coherent in the direction of change. A reversal of trend in biomass change, so-called sign switching, occurs both in time and in space. Thus, whenever (spring or fall) and wherever (Scotian Shelf or Labrador Sea) phytoplankton increase or decrease, so also does bacterioplankton. This tandem sign switch indicates coupling of the trophic levels at a multiyear time scale and contributes to an ecological fingerprint of systemwide forcing.