基于沟渠库厂联合运用的金属矿区酸性废水防控措施研究

[目的]金属矿区酸性矿山废水外排防控一直是个难题。探索酸性矿山废水源头控制与末端治理相结合的防控技术体系,为金属矿区酸性废水的防控提供新的解决思路。[方法]以广东省大宝山矿区为研究案例,坚持"源头防控,末端治理"的原则,构建基于沟渠库厂联合运用的酸性废水综合防控技术体系。[结果]建设截排水系统实施雨污分流,从源头上减少酸性废水产生量;清淤腾空拦泥库调蓄库容2.81×106 m3,并建设4.50×104 t/d处理规模的污水处理厂,对酸性废水进行未端治理,达到在5a一遇降雨条件下丰水期酸性废水不外排的防控目标。[结论]通过沟(截水沟)、渠(排水渠)、库(拦泥库)、厂(污水处理厂)的联合运用,可以控制酸性矿山废水在设计标准下不外排,该技术体系可用于类似矿山酸性废水的治理。     

饲料投喂及清淤对养殖库湾水环境的影响

为探究缩减饲料投喂量及清淤对养殖库湾水环境的影响,在鲢、鳙放养密度均为20 g/m~3的基础上,设置4个处理组库湾,分别为B1(不清淤、饵料投喂减半)、B2(清淤、不投饵)、B3(清淤、饵料投喂减半)和B4(不清淤、饵料投喂正常),实验周期为9个月。结果显示:4个库湾的总氮浓度、总磷浓度、高锰酸盐指数、藻类生物量从低到高分别为B2、B4、B1、B3,B2、B1、B4、B3,B2、B1、B4、B3,B2、B1、B3、B4(P0.05),浮游动物生物量之间无显著性差异(P0.05)。由此可见,B2无论是在营养盐的控制还是在藻类的控制方面均取得了最佳的效果。作为养殖库湾,其主要功能是得到更高的鱼产量。在达到养殖水质要求的情况下,为了得到更高的鱼产量,应合理地利用饵料。因此,对于养殖用水的处理,要根据具体的水质条件,采用合理的修复方式,实现水质改善和养殖生产的双赢。     

清洁疏浚物掩埋对两种底栖生物存活的影响

为研究不同粒度疏浚物掩埋对于海洋底栖生物的致死效应影响,采用长江口地区的疏浚物模拟不同粒度、不同厚度掩埋菲律宾蛤仔(Ruditapes philippinarum)以及双齿围沙蚕(Perinereis aibuhitensis),并研究其存活情况。结果表明:菲律宾蛤仔和双齿围沙蚕掩埋后为了生存表现出垂直迁移行为,不同粒度疏浚物掩埋深度在一定范围内与菲律宾蛤仔的死亡率之间有显著的正相关关系;粒度为63~125μm时,菲律宾蛤仔96 hLC50为6.8 cm(95%置信区间为2.8~10.7 cm);粒度为63μm以下时,菲律宾蛤仔96 h-LC50为11.1 cm(95%置信区间为4.2~18.0 cm);而掩埋深度与双齿围沙蚕死亡率之间没有显著相关关系。实验结果表明不同粒度疏浚物掩埋对于不同底栖生物致死效应不同。     

塔里木河下游生态输水及河道生态整治工程探讨

通过近几年向塔里木河下游的应急生态输水，水流到达塔里木河尾间台特玛湖，沿岸地下水位上升，沿河部分地段植被长势得以恢复，局部地区生态环境改善。为了从根本上解决塔里木河下游的生态环境问题．探讨了下游河道生态整治工程，包括河道疏浚输水线路选择和设置生态闸的问题。大西海子水库下游河道疏浚工程有3条输水线路可供选择，通过投资、占地、施工、管理、防洪等综合比较，选择在大西海子水库主坝上新建一座放水闸方案。方案在技术上和经济上是可行的。本着尽量少而又要满足河道疏浚后沿岸植被生长需水的原则，分析了沿岸生态闸设置的必要性和保护的生态植被的面积，并探讨了今后生态输水方式的选择与生态闸的开启顺序。     

种植沉水植物和疏浚底泥对氮磷营养水平的影响

通过对五里湖沉积物进行不同疏浚深度(30 cm和60 cm)沉水植物恢复实验研究,结果表明:对于未种植水草的疏浚沉积物来说,疏浚并不能很好地降低水体中氮磷水平,在一定时间内,氮磷水平有恢复增加的可能;种植菹草的疏浚沉积物,除在开始阶段氮磷水平有所增加外,随时间的延长,对上覆水中的氮磷有很好的控制。所以将底泥疏浚与沉水植物的恢复相结合起来,在控制湖泊内源污染方面将达到更好的效果。     

Revisiting two sympatric European seahorse species: apparent decline in the absence of exploitation

1. Seahorses are marine fish with several life history characteristics hypothesized to make them resilient but are of conservation concern because of their international trade and habitat loss.
2. Surveys of two unexploited European seahorse species (Hippocampus guttulatus and Hippocampus hippocampus) in Ria Formosa lagoon, Portugal, were repeated seven years after their populations in the lagoon were found to be among the densest in the world.
3. Population densities of both species declined significantly between 2001/2002 and 2008/2009 surveys (94% and 73% for H. guttulatus and H. hippocampus respectively). H. guttulatus declines were not associated with any environmental changes measured (i.e. percentage live benthic habitat cover, depth, temperature, water current speed, horizontal visibility). H. hippocampus declined more where current speed had decreased.
4. At the low densities found in 2008/2009, occurrence for both species was best predicted by depth: seahorses were found in deeper locations throughout the lagoon. Other important predictors were temperature for H. guttulatus (found at sites warmer than average) and current speed for H. hippocampus (found in locations with faster currents).
5. The large declines in seahorse densities made it difficult to compare results over time. Presence–absence and abundance modelling at multiple scales can help to ensure that data are comparable even when populations fluctuate drastically.

Copyright © 2012 John Wiley & Sons, Ltd.     

Patterns and impacts of fish bycatch in a scallop dredge fishery

1. Dredging for marine bivalves can cause considerable damage to benthic invertebrates and habitats. However, it is largely unknown how dredging affects fish communities. In this study patterns and impacts of fish bycatch in scallop dredges around the Isle of Man, in the north Irish Sea, were investigated by analysing data from fisheries‐independent surveys conducted between 1992 and 2005.
2. Almost all (97.6%) tows of the survey gear generated fish bycatch, with a total of approximately 50 species recorded. Cuckoo ray (Leucoraja naevus) and monkfish (Lophius piscatorius) dominated the bycatch, accounting for 46.82% of the total. Three other species of particular commercial or ecological interest; lemon sole (Microstomus kitt), plaice (Pleuronectes platessa) and lesser spotted dogfish (Scyliorhinus caniculus), were also abundant. Most of the cuckoo ray, monkfish and plaice captured were juveniles, whereas lesser spotted dogfish and lemon sole were a mixture of juveniles and adults.
3. In general, rates of fish bycatch appeared low, but this may be at least partly because background fish densities around the Isle of Man were also low. There was considerable spatial, temporal, and species‐specific variation in fish bycatch, and the finer meshed dredges traditionally used to catch queen scallops (Aequipecten opercularis), caught significantly more fish than the great scallop (Pecten maximus) dredges.
4. The density of lesser spotted dogfish bycatch increased significantly over the 14 years of the study whereas the density of monkfish decreased significantly. These patterns appear to reflect differences in the susceptibility of the two species to capture and damage by scallop dredging, and/or have been caused by regional trends in stock levels. An assessment of the impact of the local great scallop dredge fishery indicated that it may be catching substantial numbers of monkfish.
5. Given the recent expansion of scallop dredging around the UK, such effects should be factored into ecosystem‐based management plans.

Copyright © 2012 John Wiley & Sons, Ltd.     

From shallow to deep waters: habitats used by larval lampreys (genus Petromyzon and Lampetra) over a western European basin

Abstract –  Habitat requirements of lamprey ammocoetes (Petromyzon marinus and Lampetra genus) were investigated, for the first time, from shallow to deep waters, at different spatial scales across the Gironde‐Dordogne continuum, thanks to a water suction dredge. Fish‐habitat relationships were assessed through two complementary statistical analyses: habitat‐use curves and habitat suitability models using the Boosted Regression Trees (BRT) technique. Analyses were performed on a small‐size data set that was characterised by the low prevalence of lamprey. The sea lamprey larvae occurred in deeper areas than their Lampetra genus counterparts. ‘Pools’ of 2 m’ depth and more were optimal habitats for the former species. Among the environmental variables retained to model lamprey occurrences, the mesohabitat (a categorical variable) was demonstrated to be highly influential, in terms of fine grain‐size substratum and vegetation cover. These preliminary results suggest that monitoring using the water suction dredge method may contribute to sea lamprey conservation.     

水系疏浚弃土改良为路基填料的试验研究

提出了一种将水系疏浚弃土改良后用于公路路基填筑的方法.对杭甬运河绍兴段开挖出的两种有代表性的弃土:粉土(土样a)和粉质粘土(土样b),掺入不同比例的土壤固化剂,制作成直径和高度均为5 cm的试样,在规定的龄期进行无侧限抗压强度试验,以求证该方法的可行性和固化剂的最佳掺入量.结果表明,土壤固化剂对两种土样的加固效果均较显著,固化剂掺入量aw≥4%时,两种土样均已满足公路底基层填料的强度要求,aw≥10%时,固化土a可以做为公路基层填料.分析了两种固化土的应力-应变(σ-ε)曲线,当aw＜2%时,固化土的σ-ε曲线与素土接近,呈加工硬化型,当aw≥2%时,σ-ε曲线呈加工软化型.固化剂使土样a的脆性减弱,可塑性增强,对土样b的作用正好相反.经现场试验证明该方法既经济又具有技术可行性.     

Using ecological trajectories to track long-term taxonomic and functional changes in benthic shallow soft-bottom communities (Bay of Saint-Brieuc,English Channel)

1. Taxonomic and functional trajectories of benthic assemblages were studied in shallow soft-bottom sediments in the bay of Saint-Brieuc (Western English Channel). Changes were assessed at different spatial and temporal scales using a macrobenthic dataset based on 38 stations sampled in 1987 and 2019, coupled with data from one station sampled annually between 2005 and 2019 as part of the European Water Framework Directive monitoring programme.
2. Taxonomic trajectories indicated 1) changes in the structure and distribution of benthic assemblages, 2) an homogenization of the assemblages, and 3) significant functional shifts.
3. Fishing activities and nutrient enrichment are probably strong drivers of the observed changes, as suggested by the higher mortality rate of fragile, flexible, tubiculous and burrowing species, and the increase in the abundance of opportunistic species in the assemblages. Certain populations of macroinvertebrates seem jointly controlled by climate change and by the aforementioned local factors of disturbance.
4. The Community Trajectory Analysis framework appears as a new and interesting method to track ecological changes in marine ecosystems by measuring change with respect to a baseline state, to help define ecological recovery (station returning to the initial ecological state) and departure (station presenting increased changes over time), and to analyse trajectory similarity.
5. According to the degradation of habitat over time, we identify the need for the implementation of knowledge-based conservation strategies, especially within Natura 2000 sites.