Multi-species response to rapid environmental change in a large estuary system: A biochronological approach

The sensitivity of species to environmental change is dependent on their ecological requirements (i.e. specialist v. generalist), and hence likely to be species-specific. Identifying species level variation in environmental sensitivity informs assessments of community vulnerability and assists in developing adaptive management strategies. We investigated species-specific sensitivity in fish to understand the vulnerability of differing life histories and ecological requirements to rapid environmental alteration (i.e. drought). Biochronologies of fish growth, based on increment widths in otoliths, were analysed using a mixed modelling approach. We assessed multi-decadal responses in fish growth to environmental variation in the terminal system of Australia’s largest river, for three long-lived fish species with differing life histories and ecological requirements: a freshwater specialist and two estuarine generalists. Biochronologies were between 20 and 38 years long, spanned a decade of severe drought and showed considerable inter-annual variation in growth. Precipitation influenced the growth of the obligate freshwater specialist, Macquaria ambigua ambigua. Temperature and salinity influenced the growth of the two estuarine generalists: Argyrosomus japonicus (estuarine opportunist) and Acanthopagrus butcheri (estuarine dependent), respectively. These results suggest that generalisations about how species respond to environmental change may mask species-specific responses to dependent on the constraints of their ecological requirements (i.e. specialist v. generalist). These findings also highlight the importance of considering the diversity of life history strategies that inhabit an ecosystem when developing conservation and management strategies.     

PHD2基因在鲸类低氧信号通路中的功能

为研究鲸类低氧适应的分子机制,文章克隆了不同低氧耐受能力的3个鲸类物种,抹香鲸(Physeter macrocephalus)、白鲸(Delphinapterus leucas)和长江江豚(Neophocaena phocaenoids asiaeorientalis)的脯氨酸羟化酶2(PHD2)。通过对其序列进行分析,发现3个物种PHD2的氨基酸序列非常保守。通过对这3个物种的PHD2的功能进行探究发现:3个物种的PHD2在常氧情况下均可以降解3个物种的HIF-α(包括HIF-1α和HIF-2α)蛋白,而在低氧(O₂浓度小于2%)情况下,PHD2则无法明显降解HIF-α蛋白。在常氧下,鲸类的PHD2降解HIF-α是依赖于识别鲸类的HIF-1α上LTLLAP和LEMLAP,HIF-2α的LAQLAP和LETLAP氨基酸片段,推测PHD2是通过对HIF-α序列中的脯氨酸位点进行羟基化修饰后,被VHL-E3泛素连接酶复合体所识别,发生泛素化降解。而在低氧条件下,PHD2的活性受到抑制HIF-α不能被VHL-E3泛素连接酶复合体识别,发生降解。研究对3种不同低氧耐受能力...     

南水北调与生态平衡

水是人类赖以生存繁衍的重要资源。我国人口逐年增长,而淡水资源数量有限。多变的自然降水及频繁的旱涝灾害,一直决定着我国农业收成乃至整个国民经济的盛衰。     

Metal exchanges in the fauna-sediment system. The case of Nereis diversicolor and Scrobicularia plana in the Bou Regreg estuary (Morocco)

This study identifies the types and quantities of metals retained by Nereis diversicolor and Scrobicularia plana in a predominantly arid estuary environment.Certain abiotic parameters and a number of physiological processes linked to metabolic and reproductive functions play a decisive role in the seasonal influence of metal levels on the tissues of these organisms.Given the deposivoric diet of the organisms, the sedimentary bed would appear to be the principal source of metal accumulation.The following classification illustrates the bioaccumulation of metals: 209-1The possibility that these metals may be carried into the estuary by sewage water from the cities of Rabat and Sále should certainly not be ignored.     

长江三角洲核心区绿地系统时空演变特征及生态服务价值评估

在经济建设与环境保护矛盾突出的背景下,研究区域绿地系统时空演化特征,探讨人为因素对绿地系统生态服务的影响,对于改善绿地资源管理、促进区域永续协调发展具有重要意义。本研究基于景观生态学研究方法和生态服务价值当量因子评估法,运用ArcGIS 10.2软件的空间分析功能,对1990-2015年长江三角洲核心区绿地系统时空演化特征及生态服务价值进行了分析。结果表明:(1)长三角核心区绿地景观规模随时间的变化具有阶段性特征,呈现先扩大后缩减的态势;绿地景观与其他土地利用类型的转移存在阶段性与指向性特征;绿地景观格局总体上表现为初期集聚同质化、后期破碎异质化。(2)长三角核心区绿地系统生态服务价值随时间变化明显,不同绿地景观类型有不同的阶段性特征;长三角核心区绿地系统生态服务类型中,调节服务对于绿地系统整体生态服务价值贡献最大。(3)长三角核心区绿地系统生态服务价值在空间上呈现南北不均衡的特征,总体上呈南高北低态势,其中杭州市绿地系统生态服务价值在不同阶段均最高。区域地形地貌是影响区域生态服务价值的一个重要因素。     

珠江口城市段近岸表层水体浮游细菌分离方法比较

为了更好地分离珠江口未/难培养的浮游细菌,本研究以珠江河口三个样点的水体为研究对象,同时采用了纯培养和免培养的方法,对不同培养基的分离效果进行了探索。在纯培养实验中,本研究选择了7种不同的分离培养基,共分离获得153株菌;同时,将扩增子分析结果作为分离效果的参考,所有环境样品中共包含3 553个操作分类单元（operational taxonomic units,OTUs）。对三个样点微生物类群的多样性进行比较,纯培养结果显示珠江口下游珠海样点多样性最高,其次为中大和虎门样点;免培养则显示虎门样点多样性最高;对比7种不同的分离培养基,Z7（R₂A）培养基的分离效果最好,分离菌株数和分离类群的α多样性最高,Z1（改良ISP 2）次之;主坐标分析结合韦恩图的结果表明相比其余的培养基,Z1和Z7培养基分离获得的菌群兼具普遍性和特异性,进一步证明了这两种培养基的分离效果较佳;冗余分析结果表明K₂HPO₄、酵母粉、可溶性淀粉、MgSO₄·7H₂O、麦芽膏和葡萄糖与特定类群的分离有相关关系,其中K₂HPO₄的影响最为显著（P<0.05）。本文通过7种不同培养基对河口微生物分离效果的探究,有助于我们在研究未知微生物的营养特性时,选择成分和组成更合理的培养基来提升河口微生物纯培养的分离效率。     

长江江豚重要栖息地清节洲水域鱼类群落结构

长江清节洲水域是长江江豚的重要栖息地之一,为了解该水域鱼类群落结构特征,于2017年4月、7月、10月和2018年2月对该水域鱼类群落进行了季节性调查。调查共采集鱼类38种,隶属于5目8科29属,其中鲤科鱼类占优势,占总种类数的68.4%。相对重要性指数结果显示鱼类群落优势种为贝氏?（Hemiculter bleekeri）、似鳊（Pseudobrama simony）、银鲴（Xenocypris argentea）和刀鲚（Coilia nasus）。按生活习性划分,定居性鱼类占绝对优势,占总种数的78.9%;在空间上,中上、中下和底层鱼类分布较为均衡,占总种数的比例依次为36.8%,28.9%和34.2%;从食性上划分,杂食性和肉食性鱼类较多,分别占总种数的44.7%和39.5%。Shannon-Weiner指数、Simpson指数、Margalef指数和Pielou均匀度指数依次分别为0.820~1.711,0.601~0.981,1.640~3.423和0.249~0.592。单因素方差分析表明,除春夏季与秋冬季的Margalef指数存在显著性差异（P<0.05）,各指数在时间和空间均无显著性差异（P>0.05）。与历史资料相比,该区域鱼类群落呈现物种多样性降低和群落结构小型化的趋势。因此,建议加强该水域鱼类资源的监测和保护,以维护长江生态系统的稳定与江豚栖息地的适合度。     

Length–weight relationships of seven fish species in the Yangtze River Estuary and its adjacent waters,Eastern China

The length–weight relationships (LWRs) for seven fish species belonging to five families in the Yangtze River Estuary and its adjacent waters are presented. Cynoglossus gracilis, Cynoglossus macrolepidotus, Ctenotrypauchen chinensis, Collichthys niveatus, Ophichthus apicalis and Erisphex potti were collected monthly in 2009 using trammel nets (the size of smaller mesh net was 1.5 m × 15 m × 4 panels with mesh sizes of 2.5, 3.4, 4.3 and 5.8 cm; the size of larger-mesh net was 2.4 m × 30 m × 4 panels with mesh sizes of 5.0, 6.0, 7.0 and 8.0 cm; soaking overnight). Lophiogobius ocellicauda were collected December in 2020 using shrimp trawl nets (mesh size 2.0 cm). The precision of measurement for the fish specimens is 0.1 cm total length and 0.1 g total weight. The estimated ranges of the parameters a and b for the seven fish species were from 0.0001 to 0.0289 and 2.718 to 3.541, respectively. Two new maximum total length were recorded for Ctenotrypauchen chinensis and Ophichthus apicalis.     

长江中游鱼类资源量的估算

为了解长江中游的鱼类资源现状,于2018年5和6月以及9和10月在宜昌、石首、洪湖、武汉和湖口5个江段进行了渔获物调查工作。通过统计各江段的渔业捕捞情况,计算年捕捞量。用体长股分析方法,对铜鱼(Coreius heterodon)、鳊(Parabramis pekinensis)和瓦氏黄颡鱼(Tachysurus vachelli)的资源量进行估算,并以此推算各江段的鱼类总资源量。结果显示,宜昌江段的鱼类年总资源量1077.36 t,其中,铜鱼为623.25 t;石首江段的年总资源量为2190.74 t,铜鱼为698.19 t;洪湖江段的鱼类年总资源量为58.57 t,其中,瓦氏黄颡鱼为0.41 t;武汉江段的鱼类年总资源量1010.54 t,其中,鳊为148.65 t;湖口江段的年鱼类总资源量14.55 t,瓦氏黄颡鱼为0.032 t。估算结果可以为长江中游鱼类资源保护措施的制定提供数据参考。