渤海湾天津近岸海域大型底栖动物群落结构及次级生产力的初步研究

为了解渤海湾天津近岸海域大型底栖动物现状,于2014年5月和8月分两个航次对该海域14个站位大型底栖动物栖息密度、生物量和生物多样性进行调查,同时用Brey(1990年)经验公式计算年次级生产力(P)以及年次级生产力与年生物量(B)的比值(P/B)。结果表明:渤海湾天津近岸海域大型底栖动物隶属7门9纲29种,包括软体动物、节肢动物、多毛类、棘皮动物和其他底栖动物;年平均栖息密度为56.07 ind./m~2,年平均生物量(湿质量)为52.98 g/m~2,Shannon-Weiner多样性指数平均为1.64,Margalef物种丰富度指数平均为0.59,Pielou均匀度指数平均为0.88,年平均生物量为9.54 g/m~2(去灰分干质量),年平均次级生产力为6.12 g/(m~2·a)(去灰分干质量),P/B值平均为0.70 a~(-1)。研究表明:本调查海域的次级生产力与整个渤海湾相近,高于南黄海和东海,低于海坛海峡和胶州湾;P/B值较其他海域偏低,说明渤海湾近岸海域大型底栖动物群落中,生活史短、代谢快的小型种类所占比例低于其他海区;整个渤海湾天津近岸海域(63 km~2)大型底栖动物年次级生产力约为386 t(去灰分干质量),或是2144 t(鲜质量)。     

鱼山渔场披山海域虾类群落结构及其与环境因子的关系

为分析鱼山渔场披山海域虾类种类组成、优势种、生物多样性等群落结构特征,根据2015年11月、2016年2月、5月、8月在鱼山渔场披山海域进行底拖网生物资源调查所获得的15个站位资料,定量分析了其群落结构的相似性,以及群落结构与水文环境因子间的关系。结果表明:本次调查共鉴定出虾类15种,隶属于8科11属,其中优势种为脊尾白虾Exopalaemon carinicauda、哈氏仿对虾Parapenaeopsis hardwickii、中华管鞭虾Solenocera crassicornis、细巧仿对虾Parapenaeopsis tenella、中国毛虾Acetes chinensis、葛氏长臂虾Palaemon gravieri和日本鼓虾Alpheus juponicus共7种;不同季节的虾类种类组成差异较大,优势种类组成变化较大,其中以秋季的虾类种类数最多,冬季最少;优势种种类数春季最多,冬季最少;不同季节渔获种类的水深分布有较大差异,虾类种类以5~10 m水深带分布较多,小于5 m水深带较少;多样性指数冬季低于其他季节,其中小于5 m水深带较高,10~15 m水深带较低,虾类多样性指数随水深的增加呈递减趋势。研究表明,水深、底层水温、表层盐度、底层盐度和化学需氧量是影响调查海域虾类种类组成和群落结构特征的主要环境因子。     

獐子岛海域浮游植物群落周年变化及其与环境因子的关系

为了解獐子岛海域扇贝底播养殖区浮游植物群落的周年变化特征,于2011—2012年对该水域浮游植物及其理化环境进行了12个航次的逐月调查。结果表明:利用采水样品的Utermhl倒置显微镜分析方法,共鉴定出浮游植物53属119种,夏、秋季物种组成以甲藻和金藻为主,冬、春季以硅藻为主,裸藻、甲藻次之;各月平均细胞丰度变化为(17~312)×103cells/L,年平均为77×103cells/L,在春季(3、4月)和秋季(9、10、11月)出现两个丰度高峰;物种多样性程度在秋季较好,具槽帕拉藻Paralia sulcata、柔弱几内亚藻Guinardia delicatula、太平洋海链藻Thalassiosira pacifica等硅藻物种在全年保持优势,梭状角藻Ceratium fusus、小等刺硅鞭藻Dictyocha fibula、运动异双鞭藻Eutreptiella gymnastica分别在夏、秋、春季形成优势;物种分布与环境因子的典范对应分析和冗余分析显示,水温和溶解氧是调查区浮游植物群落周年变化的关键驱动因素,溶解态无机N、P营养盐对细胞的丰度分布、优势种演替亦有明显的控制作用。研究表明:獐子岛海域浮游植物饵料丰富、丰度水平稳定,适宜扇贝生长和可持续的底播养殖;具槽帕拉藻、太平洋海链藻、梭状角藻等物种皆可以作为养殖区的饵料指示种。     

Mercury in different environmental compartments of the Pra River Basin, Ghana

Artisanal gold mining (AGM) with metallic mercury has a long history in Ghana. It is believed to be over 2,000 years old. Today, AGM has escalated in a new dimension consuming about half of the country where gold lode deposits exist along riverbanks or rivers are alluvial-gold rich. The Pra River in southwestern Ghana is a site of on going application of metallic mercury in prospecting gold, and this paper examines mercury (Hg) contamination in the different environmental compartments in its watershed. Samples of water, sediment, soil and biota (i.e., human hair and fish) were collected from locations along the course of the river during the rainy and dry seasons of 2002 and 2003, respectively. Besides the obvious Hg point sources along the Pra and its tributaries, the obtained results show that Hg levels and speciation in the studied aquatic system are controlled by precipitation, which drives the hydrology and differences in flow regimes versus seasons. The seasonal difference in Hg speciation suggests that methyl mercury (MeHg) found in the aqueous phase and riverine sediments is likely of terrestrial origin where its production is favored during the rainy season by high soil water and organic matter content. The use of the enrichment factor (EF) for the assessment of sediment quality indicated moderate to severe contamination of surface sediments in the rainy season, while in the dry season, the EF index indicates nearly no pollution of surface sediments. Accordingly, most of the Hg introduced into this river system is likely transported to depositional downstream terminal basins (e.g. the river delta and the Gulf of Guinea). With regard to biota, Hg measured in hair in the dry period was higher than data obtained on samples collected during the wet period. This could be explained at least in part by the shift in diet as a result of abundance of fish in the local markets and the concurrent increase and more active fishing during the dry season. Mercury data obtained on a very limited number of fish samples collected during the dry period only are also presented.     

Effects of a diesel spill on freshwater macroinvertebrates in two urban watercourses,Wiltshire, UK

The impacts of a spill of approximately 9800 L of diesel on a small stream and the River Ray (near Swindon, Wiltshire, UK) were examined using kick-net sampling of freshwater macroinvertebrate families at impacted and reference sites. Initial impacts (10 days after the spill) 50 m downstream of the spill were severe, with only 9% survival of individuals (excluding oligochaete worms) and 56% survival of invertebrate families. The percentage survival of macroinvertebrates increased progressing downstream from the spill, with no detectable impacts beyond approximately 4 km downstream. The crustacean families Asellidae and Gammaridae were particularly sensitive to the diesel spill. The recovery of the macroinvertebrate community was assessed 13.5 months after the spill. At this time, recovery was almost complete, with only minor impacts at the sites closest to the spill. The use of live laboratory sorting of samples from impacted sites provided essential information on the impacts of the diesel spill.     

路域生态系统环境功能与稳定性的初步研究

阐述了路域生态系统的概念 ,分析了该系统内的环境特征 ,总结了该系统的环境功能 ,即减噪降尘、净化空气、稳固路基、美化路容等 ,提出了影响该系统稳定的因素 ,为路域生态系统的设计和保护提供了参考依据     

河流硅藻指数在太子河水生态健康评价中的应用研究

为了用硅藻指数评价太子河的水生态健康状况,于2012年5月对太子河河岸不同土地利用方式(森林用地、森林耕作用地、耕地和城镇建设用地)下的38个采样点位进行了调查研究,并应用6项硅藻指数(硅藻生物指数IBD、硅藻属指数IDG、特定污染敏感指数IPS、欧盟硅藻指数CEE、硅藻营养化指数TDI和戴斯指数DESCY)对太子河的水生态环境进行健康评估。结果表明:MRPP结果显示,太子河流域4种土地利用类型具有显著的空间异质性(P<0.05);太子河流域香农多样性指数、均匀度指数和物种丰富度的平均值分别为2.96、0.72和18,物种密度为7.83×106cells/cm2;根据相关分析显示,硅藻指数之间、硅藻指数与水环境因子之间具有显著的相关性(P<0.05);根据K-S检验,6项硅藻指数均符合正态分布;根据线性回归方程分析,D-IBI与IBD、IPS、IDG、CEE、TDI、DESCY均呈显著的线性回归关系(P<0.05),表明6项硅藻指数在太子河流域具有较好的适用性;用硅藻指数评价太子河流域的结果显示,太子河上游地区水生态健康状况较好,中游地区水生态健康状况一般,下游地区水生态健康状况较差。     

(Tri)butyltin biotic degradation rates and pathways in different compartments of a freshwater model ecosystem

Experiments were conducted in controlled temperate freshwater ecosystems (microcosms) to determine the persistence and biogeochemical dynamic of tributyltin (TBT) and its degradation products. TBT and its derivatives were monitored simultaneously for 23 days (552 h) in sediment-water systems, with or without macroorganisms (macrophytes: Elodea canadensis and gastropods: Lymnaea stagnalis). Biphasic TBT removal from the water column was significantly enhanced by the presence of biota. The persistence of TBT in biota was assessed by a kinetic approach of the different bioaccumulation pathways and associated metabolisms adopted by the snails and the macrophytes in response to the TBT contamination. Furthermore, sediment acted for the final sink for butyltins in both types of microcosms, with more than 70% of TBT and its metabolites recovered in this compartment after two weeks of exposure. Degradation pathways in sediments of both biotic and abiotic microcosms appeared to represent a key process in TBT cycle and were characterized by half-lives in the range of one month. Specific transformation and transfer pathways of TBT as reactional mechanisms are discussed and modelled assessing in detail the role of each compartment with regards to the fate of TBT in the model aquatic ecosystems.     

Community structure of planktons and macrozoobenthos,with special reference to pollution in the River Khan (India)

This paper presents an assessment of water quality of the River Khan, which passes through Indore and is subjected to sewage and industrial pollution. The analysis of various pollution parameters showed an increase when the sewage and industrial channels joined the river. Changes in the biotic communities, such as phytoplankton, zooplankton and macrozoobenthos, have been explained numerically with the help of a diversity index and showed a decrease in diversity values with an increase in pollution, along with a correlation with physico‐chemical aspects. Genera tolerant to various degree of pollution has also been identified. The extend of pollution by certain heavy metals such as Cu, Zn, Ni, Cr, Cd and Hg has also been studied.     

Effects of pesticides on community structure and ecosystem functions in agricultural streams of three biogeographical regions in Europe

There is a paucity of large-scale field investigations on the effects of organic toxicants on stream macroinvertebrate community structure and ecosystem functions. We investigated a total of 29 streams in two study areas of France and Finland for pesticide exposure, invertebrates and leaf-litter breakdown. To link pesticide exposure and community composition we applied the trait-based Species At Risk (SPEAR) indicator system. In the French region, pesticide stress was associated with a decrease in the relative abundance and number of sensitive species in the communities. The presence of undisturbed upstream reaches partly compensated the effects of pesticide contamination. Functional effects of pesticides were identified by a 2.5-fold reduction of the leaf-litter breakdown rate that was closely correlated with the structural changes in the contaminated streams. No effects of pesticides were observed in Finnish streams since contamination with pesticides was very low. In a follow-up analysis, the SPEAR approach successfully discriminated between reference and contaminated sites across different biogeographical regions, also including results of a previous field study in North Germany. Furthermore, change of the community structure was detectable at a concentration range as low as 1/100 to 1/1000 the acute 48 h-LC50 of Daphnia magna. Our findings demonstrate that pesticides may influence the structure and function of lotic ecosystems and that the SPEAR approach can be used as a powerful tool in biomonitoring over large spatial scales.     

Agricultural phosphorus flow and its environmental impacts in China

The transfer of nutrients from agricultural land to waters attracts the attention of policy makers as well as scientists as it plays an increasingly significant role in affecting the water environment. It is therefore essential to first understand the nutrient flow in agricultural systems and then correspondingly formulate a series of cost-effective policies and best management practices (BMPs). On the basis of an emission inventory analysis (EIA) and a nutrient full balance (NFB) calculation, this paper presents a partial substance flow analysis (SFA) method, as well as an Agricultural Phosphorus Flow Analysis (AgiPhosFA) model, to describe the phosphorus (P) flow in the agricultural systems in China and assess the impact of human activities on waters driven by agriculture and rural life. It is estimated that average P input and output were 28.9 kg ha(-1) a(-1) and 14.2 kg ha(-1) a(-1) respectively in China in 2004, while the total P utilization efficiency (Plant uptake P/P input) in agriculture was 45.7% leading to an average P surplus of 14.7 kg ha(-1) a(-1). Excessive P application through mineral fertilizer in the arable farming system has led to the accumulation of soil P and constituted a risk to the recipient water quality, whereas the grassland grazing system is confronted with a severe P deficit problem which has resulted in widespread grass degradation. Therefore it may be an efficient way to mitigate the problems simultaneously by regulating and balancing the P flows between the two systems. Uncertainties of the method and model are also discussed in terms of model conceptualization, data and parameters, and spatial and temporal variability.