藻类对生物发光法检测水体中细菌总数的影响

以上海市区的丽娃河、苏州河以及银锄湖三种水体为研究对象,研究藻类干扰对生物发光法检测水体中细菌总数的影响。分别测定了三种水体中的藻类数量,并对其中的藻类鉴定到了种的水平。对采自三种水体的水样分别采用2μm混合纤维素酯微孔滤膜过滤。结果表明,过滤是提高生物发光法测定水体中细菌总数灵敏度的一种必要而有效的手段。     

Prymnesium parvum: The Norwegian Experience1

Johnsen, Torbjørn M., Wenche Eikrem, Christine D. Olseng, Knut E. Tollefsen, and Vilhelm Bjerknes, 2010. Prymnesium parvum: The Norwegian Experience. Journal of the American Water Resources Association (JAWRA) 46(1):6-13. DOI: 10.1111/j.1752-1688.2009.00386.x Abstract: In Norwegian waters, Prymnesium parvum has been reported from Oslofjorden in the south to Spitzbergen in the north. However, blooms of P. parvum have only been reported from the Sandsfjorden system in Ryfylke, Western Norway where the salinity of the permanent brackish layer (2-5 m) typically is in the range of 4-7 psu during the summer months. The first bloom on record occurred in 1989, and it killed 750 metric tons of caged salmon and trout which was a significant economic loss to the fish farming industry. Toxic blooms occurred as well in subsequent years and the number of fish farms in the area decreased considerably as did the occurrence of P. parvum. In 2005, fish farming was reintroduced to the area and again, in 2007 a toxic bloom of P. parvum killed 135 metric tons of caged fish. The Norwegian Institute for Water Research has, in collaboration with “Erfjord Stamfisk” fish farm, set up a monitoring program that includes light microscopy cell counts of Prymnesium, water quality measurements, and observation of the caged fish. A submergible fish net was mounted over the fish pens and during the toxic outbreak of P. parvum in July-August 2007, which was as previous years confined to the upper brackish water layer, the fish nets were lowered to 10 m depths below the surface and fish feeding was temporarily stopped. Despite substantial weight loss, the fish survived the toxic bloom and the economic loss was minimal. Monitoring of P. parvum bloom dynamics in 2007 revealed that populations were initially dominated by the nonmotile forms which were gradually replaced by the flagellated forms. Toxicity was observed when the flagellated cells dominated populations in the summer. Chrysochromulina, solitary small Chaetoceros species, and small centric diatoms co-existed with P. parvum during the monitoring period (June-October).     

Prymnesium parvum Control Treatments For Fish Hatcheries1

Barkoh, Aaron, Dennis G. Smith, and Gregory M. Southard, 2010. Prymnesium parvum Control Treatments for Fish Hatcheries. Journal of the American Water Resources Association (JAWRA) 46(1):161-169. DOI: 10.1111/j.1752-1688.2009.00400.x Abstract: In 2001, the ichthyotoxic microalga Prymnesium parvum caused massive fish kills and adversely affected fish production at the Texas Parks and Wildlife Department (TPWD) Dundee State Fish Hatchery. Since then, we have investigated several P. parvum bloom and ichthyotoxicity control treatments to develop management strategies that allow fish production and prevent the spread of the alga into unaffected hatcheries and impoundments. Current control successes include treatments for ponds, water supply, and a hazard analysis and critical control point program. For pond treatment, ammonium sulfate (as 0.14-0.25 mg/l un-ionized ammonia nitrogen for temperatures above 15°C), copper sulfate (2 mg/l), Cutrine^®-Plus (0.2-0.4 mg/l as copper), or potassium permanganate (3 mg/l above the potassium permanganate demand) controls P. parvum blooms. Copper sulfate at 1 mg/l controls P. parvum but is unable to eliminate ichthyotoxicity whereas potassium permanganate at 2 mg/l above the potassium permanganate demand controls ichthyotoxicity. For water treatment, ultraviolet (UV) light at 193-220 mJ/cm² doses or ozone at 0.4-1.2 mg/l for 6 min destroy P. parvum cells and reduce or eliminate ichthyotoxicity. A combination UV and ozone treatment appears to provide the best results; however, successful treatments depend on dosage relative to cell density and toxin concentration. To prevent the spread of the alga, hatchery fish delivery units and equipment are cleaned with household bleach (10% solution for 15 minutes) or hydrogen peroxide (62.5-12,500 mg/l for 0.25-24 hours). These treatments are tailored to water quality conditions and the fish species cultured at affected TPWD hatcheries. We recommend that other users test these treatments before applying them to ponds or other impoundments containing fish or other aquatic life.     

Potential Methods for Managing Prymnesium parvum Blooms and Toxicity,With Emphasis on Clay and Barley Straw: A Review1

Hagström, Johannes A., Mario R. Sengco, and Tracy A. Villareal, 2010. Potential Methods for Managing Prymnesium parvum Blooms and Toxicity, With Emphasis on Clay and Barley Straw: A Review. Journal of the American Water Resources Association (JAWRA) 46(1):187-198. DOI: 10.1111/j.1752-1688.2009.00402.x Abstract: Harmful algal bloom (HAB) control and mitigation is a complex problem in ecosystem management. Phytoplankton play an important role in aquatic ecosystems as primary producers and food sources for many commercially important shellfish and there are limited options for targeting just a single species within the community. Chemical treatments (e.g., algaecides), rotting barley straw, nitrogen and phosphorus manipulation, and clay and/or flocculants are but a few techniques tested or used to reduce fish kills or shellfish contamination during a HAB event. Prymnesium parvum control has focused on the use of chemicals, nutrient manipulation, and clay flocculation. However, many HAB control methods have been rejected due to their effects on ecosystems, high costs, or limited effects on target organisms. For example, rotting barley straw (Hordeum vulgare) is considered to be an environmentally friendly alternative, but has been found to have very different results on the phytoplankton community depending on the dominating taxa and is ineffective against P. parvum and dinoflagellate blooms. Clay flocculation is a useful control/mitigation technique during fish kills in marine aquaculture sites in South Korea and can be effective in freshwater if the correct combination of clay and flocculent is used. Toxins produced by P. parvum and Karenia brevis also bind to phosphatic clay, thereby removing and/or neutralizing the toxins, but there is concern that the clay will have a negative effect on sessile organisms. Some shellfish suffer high mortalities and significant impacts on somatic and reproductive tissue growth at high clay loads; however, benthic communities appear to be unchanged after five years of clay treatment in South Korea. There are likely site-specific and ecosystem-specific characteristics that make generalizations about control options difficult and require careful assessment of options at each location.     

Impact of Land-Based Sources On Marine Environment: Phytoplankton Blooms Within an Annual Cycle

The discharge water into the western region of Alexandria (Egypt), creates suitable conditions for the acceleration of the phytoplankton growth; daily replenishment of nutrients and development of density stratified water column. Water transparency and ammonia concentrations seem to be affecting the variations of the numerical standing crop. Eight phytoplankton bloom pulses of different causative species were observed. Asterionella glacialis represents a newly recorded red tide species in the neritic waters of Alexandria.     

Optimization of pretreatment conditions for enhanced sugar release

Present investigation was done to evaluate various algal genera found in water bodies of Varanasi city. The potential of any biomass for biofuels (bioalcohols, biohydrogen, etc.) production depends on the quantity of extractable sugar present in it. Acid (H₂SO₄) and alkali (NaOH) pretreatment were performed, and H₂SO₄ was chosen due to its nearly double yield as compared with alkaline pretreatment. Response surface methodology was utilized for the optimization of operating parameters such as treatment temperature, time, and acid concentration. Sugar yield up to 0.33 g/g of dry biomass was obtained using cyanobacterial biomass of Lyngbya limnetica, at 100°C, 59.19 min, and H₂SO₄ concentration of 1.63 M.     

典型湖泊有机聚集体时空特征及驱动因子

有机聚集体(OA)是水体中物质循环和能量流通的重要枢纽,但在不同营养水平湖泊中的比较研究仍相当匮乏.于2019～2021年间,采集了不同季节贫营养抚仙湖、中营养天目湖、中度富营养太湖和重度富营养星云湖表层水样,利用扫描电镜、表面荧光显微镜和流式细胞仪等研究了4个典型湖泊中OA及其附着细菌的时空变化特征.结果表明：(1)抚仙湖、天目湖、太湖和星云湖中,OA丰度的年均值分别为1.4×10⁴、 7.0×10⁴、 27.7×10⁴和16.0×10⁴ind·mL^-1; OA附着细菌丰度的年均值分别为0.3×10⁶、 1.9×10⁶、 4.9×10⁶和6.2×10⁶ cells·mL^-1;附着细菌占总细菌的比值分别为30%、 31%、 50%和38%.(2)夏季OA丰度显著高于秋冬季;但夏季附着细菌占总细菌的比值为26%,显著低于其它3个季节.(3)湖泊营养状态是影响OA及其附着细...     

溶藻细菌BS03分离、鉴定及其对塔玛亚历山大藻生长的影响

从福建漳江口红树林区筛选出一株对产贝毒赤潮原因藻——塔玛亚历山大藻(Alexandrium tamatense)具有强溶藻能力的细菌,命名为BS03,通过生理生化及16S rDNA序列分析对该菌株进行鉴定,并探讨了菌株BS03对塔玛亚历山大藻的溶藻特性和溶藻代谢产物的初步性质.结果发现,菌株BS03属于微泡菌属(Microbulbifer sp.)相似性达99％;对塔玛亚历山大藻的杀藻效果具有一定浓度效应,在一定浓度范围内处理浓度越高,溶藻效果越好;菌株BS03对处于不同生长时期的塔玛亚历山大藻都表现出较好的杀藻效果,其中对处于延滞期的塔玛亚历山大藻表现出最佳的杀藻效果,处理96 h后,抑藻率达98.17％;不同生长期菌株对塔玛亚历山大藻溶藻作用无明显差异;菌株BS03通过间接作用方式溶藻,所分泌的胞外活性物质的分子量小于1 kDa,耐酸碱、具热稳定性,推测为非蛋白质、非核酸和非多糖类物质.     

Cyanobacteria-/cyanotoxin-contaminations and eutrophication status before Wuxi Drinking Water Crisis in Lake Taihu, China

After the appalling “Wuxi DrinkingWater Crisis”, increasing investigations concerning the contaminations of cyanobacterial blooms and their toxins in Lake Taihu have been performed and reported in the last two years. However, information regarding these issues before the crisis in 2007 remained insu cient. To provide some background data for further comparisons, the present study reported our investigations conducted in 2004, associated with the cyanotoxin contaminations as well as the eutrophication status in Lake Taihu. Results from the one-year-study near a drinking water resource for Wuxi City indicated that, unlike the status in recent two years, cyanobacteria and chlorophyta are the co-dominance species throughout the year. The highest toxin concentration (34.2 ng/mL) in water columns occurred in August. In bloom biomass, the peak value of intracellular toxin (0.59 g/mg DW) was determined in October, which was lag behind that in water column. In addition, MC-RR was the major toxin variant throughout the year. During the study period, nutrients levels of total nitrogen and phosphorus were also recorded monthly. Results from the present study will lead to a better understanding of the eutrophication status and the potential risks before “Wuxi Drinking Water Crisis”.     

环境因子对水华暴发的影响研究

水华是当水体藻类开始大量生长和繁殖并且聚集,最终达到一定浓度的现象。综述国内大型浅水湖泊及水库中影响水华暴发的环境因素的研究现状,分析水体营养条件以及适宜的气象、水文、生物条件等有利于藻类生长或聚集的环境影响因子,同时简介中国水华污染现状。对水华暴发研究领域的未来发展具有一定参考价值。