湛江红树林湿地水体重金属污染评价及来源分析

通过研究湛江红树林湿地水体重金属的含量、空间分布特征和来源及环境因子的影响,旨在为红树林湿地保护提供理论依据。选取湛江市范围内10处红树林湿地、共38个采样点,其中廉江(样点1~6)、遂溪(样点7~10)、雷州西海岸(样点11~12)、徐闻五里(样点13~16)、徐闻和安(样点17~21)、雷州东海岸(样点22~25)、麻章(样点26~29)、坡头(样点30~32)、霞山特呈岛(样点33~35)、东海岛(样点36~38),采集各样点水面下0.5 m处的3个混合水样用于理化指标测定,利用水质质量指数法对Cr、Cu、Pb、Cd、Ni、Hg 6种重金属的污染水平进行综合评价;利用最小显著差异检验(LSD)进行单因素方差分析,比较不同研究区域水体重金属及理化性质差异;利用主成分分析判断湛江红树林湿地水体重金属的来源,并基于其特征值(1)判断主成分,并判断每个主成分中载荷量大的因子。结果表明,研究区水体中Fe、Mn、Cu、Cr、Cd、Pb、Ni和Hg等重金属含量较低,各区县水质综合污染指数平均值均小于1,除了霞山特呈岛、雷州东西海岸的个别样点外,总体上未出现明显的重金属污染;重金属单因子污染指数显示Cu和Ni污染问题相对突出。主成分分析结果显示,Fe和Cr为自然来源,Hg、Pb和Cu与人类活动中农业生产和生活污水排放密切有关,Mn、Ni和Cd主要来自工业综合污染。重金属与水体环境因子的RDA分析表明,TOC和pH是影响水体重金属分布的显著性因子。     

夏季扎龙湿地底栖动物双向指示种(TWINSPAN)分类与水质生物监测

2011年夏季对扎龙湿地夏季底栖动物种群结构和水质状况进行了综合研究,期间应用双向指示种(TWINSPAN)分析技术,以7个采样点的数据为基础,对各采样点进行了归纳分类。结果显示:扎龙地区水域可以划分为3个类型,6#翁海排干和7#东升水库污生指数(IBP)最小,水质最好,其次为2#采样点,水质稍差,为轻度污染,1#、3#、4#、5#水质较前两组差,3(#扎龙湖)和5(#龙湖)样点已达到β-中污染,但根据污生指数评价标准分析,扎龙湿地整体水质属于轻污染。     

天鹅洲、黑瓦屋长江故道湿地水质的模糊综合评价

将模糊数学的基本原理引入到湿地水质评价中,对天鹅洲、黑瓦屋长江故道湿地水质状况进行综合评价研究。根据监测断面水质污染特点,确定7个指标作为评价因子,建立评价因素矩阵,计算出影响因子的权重。在此基础上构建了湿地水质模糊综合评价模型,计算出天鹅洲、黑瓦屋长江故道各监测断面的水质级别,证明两故道湿地的污染物主要是氨氮、总磷和有机物。     

基于环境因子和浮游植物的珠三角河网水质评价

为了从常用的水质评价方法中筛选出适合珠三角河网的方法,该研究对2015年珠三角河网的水环境因子和浮游植物数据进行了初步的评价分析。运用自组织映射模型(SOM)从6种浮游植物评价指数中筛选出香农指数、均匀度指数、丰富度指数和生物量指数4种相似性高的指数,将上述指数和环境因子的水质评价结果进行对比分析。结果显示,基于溶解氧和氨氮的水质评价结果可以较好地反映城市周边与其他区域的空间差异,而总氮和总磷不适用于研究水域的水质等级评价;基于香农指数和生物量指数的水质评价结果可以较好地反映出城市周边与其他区域的差异,均匀度指数和丰富度指数不适用于研究水域的水质等级评价。除总氮、总磷外,其他环境因子和4种浮游植物指数的评价结果均反映为研究水域水质整体良好,城市周边站位水质略差。研究表明,溶解氧、氨氮、香农指数、生物量指数是适合研究水域水质等级评价的环境因子和浮游植物评价指数。     

济南济西湿地公园浮游动物功能类群及其对环境因子的响应

为了解黄河流域湿地水生生物群落结构特征及生态环境现状，于2020年4月至2021年3月调查了济南段城市湿地—济西湿地公园浮游动物群落结构，监测分析了水环境因子变化特征及水环境质量状况。结果表明：济西湿地公园全年共采集鉴定出浮游动物4大类66种，平均密度为181.8 ind./L，平均生物量为0.210mg/L；浮游动物划分为7个功能群，春季、夏季、冬季均以功能群RF和PF为主，最高占比分别为62.86%、20.75%，秋季以功能群RF和SCF为主，占比分别为58.54%、12.20%；浮游动物Shannon-Wiener指数(H'')、Pielou均匀度指数(J)和Margalef丰富度指数（D）平均值分别为2.50、0.71、2.31；综合营养状态指数水质评价结果显示济西湿地公园水质整体处于中营养化水平；Pearson相关性分析表明WT、COND、DO、NO2--N、SS、TP、PO43-和Chl-a是显著影响浮游动物功能群的主要环境因子。该研究对济西湿地的生态效应评估和水资源保护具有一定的指导意义。     

海浪河春季底栖动物TWINSPAN分类及水质初步评价

应用双向指示种(TWINSPAN)技术对海浪河春季的7个采样点进行分类和水质评价研究;共采集到环节动物、软体动物和节肢动物3大类,包括4纲7目9科14属共18种;结合污染指数,TWINSPAN分析结果表明海浪河春季采样点划分为四个类型,海浪河大桥6#点水质最好,其次为海南桥7#采样点,河夹大坝1#、2#点水质较差,3#、4#、5#采样点水质最差,但根据污染指数评价标准来看,水质都处于不同程度的污染状态。     

草海高原湿地湖泊水质时空变化及水质分区研究

针对草海水质污染状况,开展水质季节变化特征研究,为草海湿地污染治理及保护提供依据。在草海湿地湖泊设置了15个采样点,于2014年8月、11月和2015年1月、4月,分4季进行水样采集。以所测水质参数为基础,运用水质综合评价和GIS空间分析方法,研究草海湿地水环境质量时空变化,并基于营养状态对湖泊水体进行了分区。研究表明:(1)草海TP、TN、CODMn、Chl-a 4种主要水质指标浓度在春季高于其他3个季节,浓度分别达到0.03、0.98、6.30和0.025 mg/L,空间分布呈现由东至西逐渐降低的趋势,草海入水口及码头区域要明显高于湖泊其他区域。(2)草海湖泊营养状态为中营养级别,按4个季度的综合营养状态指数(TLI)平均值分为3个区域,A区为东北角入水口及西海游客码头,长年处于富营养状态,为富营养状态区,53.9≤TLI≤63.0,水质处于Ⅳ与Ⅴ类等级;B区为临近县城及入水口区域,季节性富营养状态,为中营养状态区,41.2≤TLI≤46.6;C区为草海湖泊中心延续到阳关山的下游出水口区域,为贫中营养状态区,35.8≤TLI≤39.7;B区和C区水质全年为Ⅲ类等级。(3)各区域主要污染物指标以Chl-a、TN为主,A区形成的主因是城市污水注入,B区形成的主因是农业面源污染。控制城市污水和农药、化肥施用量是治理草海湖泊水环境的重要途径。     

环渤海主要城市近岸海域水质状况综合评价

为客观评价环渤海13个城市近岸海域水质状况,验证雷达图指数、内梅罗指数和主成分指数在渤海近岸海域水质评价中的作用,基于渤海195个监测站位3、5月两次实测水质数据,选取化学需氧量、无机氮、总氮、活性磷酸盐、总磷和石油类物质作为评价因子,对环渤海主要城市近岸海域水质状况进行了综合评价和等级划分。结果显示,渤海近岸海域主要污染物为无机氮和总磷,其次为石油类物质;葫芦岛、秦皇岛、大连和烟台的近岸海域水质状况较好,而位于辽东湾北岸辽河口附近的盘锦、锦州、营口以及位于莱州湾西侧的滨州的近岸海域水质状况较差;3类水质综合指数对海水中盐度和悬浮物浓度敏感性较强,且相互之间及其与水质优良面积比例存在显著相关性,表明所选择的3类水质指数能够真实反映渤海近岸海域水质状况。本研究将为渤海水质评价与综合治理成效评估提供方法上的借鉴。     

秀丽高原鳅自然栖息地及人工驯养池水质评价研究

2015年全年对秀丽高原鳅(Triplophysa venusta)主要分布流域漾弓江上游鹤庆段开展水质调查,对洗马池、白龙潭、清水河、寺庄龙潭、美龙潭、西龙潭、人工驯养池及驯养池水源8个监测点的水温(T)、pH、溶解氧(DO)、氨氮(NH3-N)、总氮(TN)、总磷(TP)、高锰酸盐指数(CODMn)7个指标进行采样监测,采用模糊综合评价法和综合水质标识指数法对采样点水质现状进行评价;分析了人工驯养池和自然栖息地水质差异。结果显示:驯养池与自然栖息地部分水质指标差异显著;自然栖息地中,清水河夏季水质为Ⅲ类,主要污染物为TN,其余监测点各季节水质均满足水体环境功能区规划要求;驯养池夏季水质评价结果为Ⅳ类,主要污染物为TN。     

阳澄西湖及其入湖港口的水质评价与分析

为了探明阳澄西湖湖区及其入湖港口的水质现状,为其后续水环境治理提供参考,选取湖区6个位点和4个港口,于2016年5月至2017年3月监测其水质,逢单月月初采样;监测的水质参数包括水深(H)、酸碱度(pH)、溶解氧(DO)、透明度(SD)、悬浮物(TSS)、总氮(TN)、氨氮(NH~+_4-N)、亚硝酸盐氮(NO~-_2-N)、总磷(TP)、活性磷酸盐(PO■-P)、叶绿素a (Chl-a)、高锰酸盐指数(COD_(Mn))、总有机碳(TOC)。运用主成分分析法探讨了水体主要污染因子,采用皮尔逊相关性分析法探究湖区TN、TP对Chl-a浓度的影响。结果显示,阳澄西湖水质综合营养状态指数年均值为57.9,主要水质参数的时空分布表现为枯水期(5-7月)优于丰水期(11-1月),湖区优于入湖港口,北部优于南部。湖区TN和TP年均值为2.63 mg/L和0.217 mg/L,Chl-a年均值为21.74μg/L,且以9月最低。主成分分析显示,NH~+_4-N、NO~-_2-N、PO■-P、TP、TN是湖区水质主要的污染因子,TP、NH~+_4-N、NO~-_2-N、TN是港口水质的主要污染因子。皮尔逊相关性分析显示,阳澄西湖的Chl-a浓度与TN呈正相关(P0.01),与TP的相关性不显著(P0.05),且相关系数为负值。研究表明,阳澄西湖的Chl-a对营养物质的响应不灵敏,后续治理中需加强对外源氮磷的拦截。     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.