若干水华相关藻类对太湖水体异味物质贡献的初步研究

太湖水体中嗅味物质2-甲基异莰醇(MIB)和土臭素(Geo)的出现与水华发生在时间上高度重叠,为探寻水华中常见藻类与嗅味的关系,本研究通过对实验室培养藻株和野外水样比较分析,探寻了部分藻株与太湖水体嗅味物质的关系.分析实验室培养的15株蓝藻(其中11株微囊藻)、4株绿藻和4株硅藻,仅硅藻培养物测定出了Geo,所有藻株均未检测出MIB;对太湖典型水样分析结果显示,水体中MIB与Geo的浓度与微囊藻细胞浓度无相关性;实验室模拟微囊藻水华腐败结果显示,无论是好氧还是厌氧条件下均未产生MIB和Geo;这些数据结果说明湖水中MIB和Geo与水华主要种群微囊藻无直接关系.在鱼腥藻水华中测出了高浓度的MIB,周年水样分析结果显示鱼腥藻细胞数与MIB浓度变化规律一致,因此鱼腥藻可能是MIB的重要来源.但实验室培养的Anabaena sp.PCC7120无论是在缺氮还是有氮培养条件下均不产MIB和Geo,说明嗅味物质的产生具有藻株特异性.     

高温微风条件下太湖流域风场时空特征分析

适宜太湖蓝藻水华大面积形成的诸多因素中,气象因素主要是高温、微风.据此对太湖周边17个常规气象观测站的7年报文资料进行筛选,选择的17个站点同时满足时间为14点、气温大于2590、风速小于等于4m/s的风场进行分析,研究发现太湖流域风场空间特征以东南风居多,而且不同风向的背景风场吹过水面后.在下风向湖面及湖岸附近都存在...     

Remote sensing based water quality monitoring in Chivero and Manyame lakes of Zimbabwe

Lakes Chivero and Manyame are amongst Zimbabwe’s most polluted inland water bodies. MEdium Resolution Imaging Spectrometry level 1b full resolution imagery for 2011 and 2012 were used to derive chlorophyll-a (chl_a) and phycocyanin (blue-green algae) concentrations using a semi-empirical band ratio model; total suspended matter (TSM) concentrations were derived from the MERIS processor. In-situ measured chl_a was used to validate the remotely sensed values. Results indicate that remote sensing measurements are comparable with in situ measurements. A strong positive correlation (R² = 0.91; MAE = 2.75 mg/m³ (8.5%)) and p < 0.01 (highly significant)) between measured and modeled chl_a concentrations was obtained. Relationships between optically active water constituents were assessed. Measured chl_a correlated well with MERIS modeled phycocyanin (PC) concentration (R² = 0.9458; p < 0.01 (highly significant)) whilst chl_a and TSM gave (R² = 0.7344; p < 0.05 (significant)). Modeled TSM and PC concentrations manifested a good relationship with each other (R² = 9047; p < 0.001 (very highly significant)). We conclude that remote sensing data allow simultaneous retrieval of different water quality parameters as well as providing near real time and space results that can be used by water managers and policy makers to monitor water bodies.     

贝加尔湖Aulacoseira硅藻细胞壳的形态多样性及其在人类活动影响下的变化

We have investigated the frustule ultrastructure of Baikalian Aulacoseira: A.baicalensis (K.Meyer) Sim. and of thin-wall, spore-producing Aulacoseira which has long been designated as A. islandica (O.Muller) Sim. or A.islandica ssp. helvetica (O.Muller) Sim. (now A.skvortzowii Edlund, Stoermer,Taylor). It was found that the disagreement on the name of spore-forming Aulacoseira is due to the destruction of its vegetative frustules in the process of breaking free of the organic content, while ultrastructure data on A.islandica from different Russia''s regions can reflect signatures of different species.A. baicalensis is characterized by great polymorphism. A. baicalensis starts its development from the initial cell (auxospore). The morphological characteristics of the frustule undergo the drastic changes in the course of the life cycle. It sequentially changes the morphology and structure of its valves. Its cells evolve through several stages of development:from cyclotella-like cells to narrow and short reproducing cells. In the influence zone of the Baikalsky Pulp-and-Paper Plant (BPPP), waste waters, disturbances in the frustule structure both in vegetative and generative cells have been detected.     

Air-sea CO2 exchange of beach and near-coastal waters of the Chukchi Sea near Barrow, Alaska

Partial pressure of CO₂ in equilibrium with sample water (pCO₂) for the coastal water in the Chukchi Sea was continuously observed in summer, 2008. Average daily CO₂ flux calculated from the pCO₂ and gas transfer coefficients ranged from −0.144 to −0.0701 g C m⁻² day⁻¹ depending on which gas transfer coefficient was used. The pCO₂ before the landfast ice sheets melted appeared to be highly biologically controlled based on the following information: (1) the diurnal pattern of pCO₂ was strongly correlated with Photosynthetic Photon Flux Density (PPFD); (2) high chlorophyll density was observed during periods of peak uptake; and (3) the day-to-day variation in the pCO₂ strongly correlated with the presence or absence of near-shore ice sheets. The lowest pCO₂ of 35 ppm together with the highest PPFD of 1362 μmol E m⁻² s⁻¹ were observed in the afternoon on June 28 in the presence of sea ice. The very low pCO₂ observed in late June was likely caused by high photosynthetic rates related to high phytoplankton densities typically observed from spring to early summer near the ice edge, and by water low in salinity and CO₂ released by melting sea ice early in the season.     

湖泊蓝藻水华防控方法综述

由于人类活动和全球气候变化的叠加影响,湖泊富营养化和蓝藻水华仍是未来相当长一段时间内的水生态环境问题.蓝藻水华暴发会引发湖泊生态系统的灾害和饮用水安全风险,因此湖内蓝藻水华防控必不可少.现有蓝藻水华防控长效方法主要基于营养盐控制理论、浅水湖泊稳态转换理论和生物操纵理论,技术措施包括内源营养盐控制、生态修复、生物操纵.应...     

The generation of phytoplankton patchiness by mesoscale current patterns

 Elken et al. (1994) suggested that phytoplankton patchiness can be generated by mesoscale eddies in light-limited, nutrient-replete environments. This hypothesis is explored using two ecological models of different physical complexity. The model results support the idea that the coupling of mesoscale eddy circulation and phytoplankton growth leads to differential growth rates and thus generates variability in phytoplankton distributions. The specific circulation of a cyclonic eddy isolates a phytoplankton population in its core. Due to the reduced vertical mixing, a higher growth rate is supported in the core, and phytoplankton concentrations increase compared to the surrounding environment. A one-dimensional model is used to explore the hypothesis in general and to perform sensitivity studies. A more realistic simulation uses a coupled three- dimensional model for the western Baltic Sea. Starting from vertically and horizontally homogeneous distributions for nutrients and plankton, the models generate patchiness due to the proposed mechanism. The described mechanism may apply for other mesoscale variable environments during light-limited growth periods as well, e.g., the frontal region of the Southern Ocean. Received: 31 March 2001 / Accepted: 31 August 2001     

A Comprehensive Review on Microalgae-Based Biorefinery as Two-Way Source of Wastewater Treatment and Bioresource Recovery

In the past few years, microalgae have gained huge recognition from the scientific community due to their potential applications in the production of a broad array of bio-based products varying from biofuels to nanoparticles. Due to their elevated growth rate, high tolerance to various types of abiotic stresses, and complex metabolic capacity, microalgae can be used as promising tools for the attainment of a circular bioeconomy. Moreover, they can simply utilize nutrients from wastewater for biorefinery purposes, resulting in resource recovery coupled with wastewater treatment. However, due to their sub-optimal yields and high production costs, microalgae-based bio-products have not yet been commercialized. This review provides insights into the employment of microalgae as an efficient bioresource for the treatment of wastewater with simultaneous enactment as a biorefinery to produce biofuels, biochar, bioplastic, fertilizers, and other high-value bioproducts. Furthermore, the application of microalgal nanoparticles in wastewater treatment and prospects for genetic modification of microalgae for enhanced biorefinery capabilities have also been briefly highlighted.