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1.
《齐鲁渔业》2013,(4):56-56
海水吸收大气中过量的二氧化碳会导致海洋酸化,人类工业活动也加快了海洋酸化速度。但一项最新研究显示,一些浮游生物可以通过进化来逐渐适应酸化环境。  相似文献   

2.
正海水吸收空气中的二氧化碳形成碳酸增加了海水的酸度,这种现象被称为海水酸化。据估测,到2100年,海水pH平均值将因此下降约0.3~0.4,至7.8~7.9[1]。海水pH值是海洋生态系统的关键因子,即使细微变化都将对海洋化学产生深刻影响[2],从而影响大多数海洋生物的生理、生化、代谢、生长、繁殖与生存,最终可能会导致海洋生态系统发生不可逆的变化,进而影响人类。海洋酸化  相似文献   

3.
《现代渔业信息》2012,(2):166-171
全球海洋酸化正在加剧西班牙国家研究委员会(CSIC)、加泰罗尼亚高等研究院(ICREA)及巴塞罗那自治大学的研究人员警告说,人类排放的二氧化碳已经严重改变了海水的化学结构,海洋正以前所未有的速度酸化。其相关研究成果发表在《科学》杂志上。研究表明,海洋酸化正影响着海洋生物和生态系统。在过去的300万年中,海洋化学环境发生了较大变化,但目前海洋水质的酸化速度要比过去的任何一个时间点都要快,这或将为整个海洋生态系统带来毁灭性的灾难。人类活动排放的二氧化碳有30%进入了海洋,这直接导致了海洋的酸化。海洋酸化威胁到了一些海洋生物种类的生存。比如,海洋酸化降低了珊瑚、软体动物等生  相似文献   

4.
正自工业革命以来,人类活动和工农业发展使大气中的CO_2水平以前所未有的速度上升~[1-2],海洋吸收CO_2量不断增加,海水pH值下降,这种由大气CO_2体积分数升高导致海水酸度增加的过程称为海洋酸化[3]。与工业革命前相比,目前海洋的pH值已经下降了0.1,预测到本世纪末将再下降0.3至0.4~[4-6]。与此同时,大气中CO_2含量上升导致全球气候变暖,水温升高。因此,由于CO_2升高  相似文献   

5.
一项国际间的研究试图揭示海洋酸化对贝类等海洋生物的影响。该研究成果发表在最新一期的《全球变化生物学》杂志上。研究结果表明,海洋酸度增加将影响贝类骨骼的大小与重量。贝类等海洋动物是海鸟、海豹等食肉动物的重要食物来源,同时也是人类海产品生产的重要组成部分。因此,海洋酸化引发的这些变化将会最终影响到人类及大型海洋动物。来自英国南极调查局(BAS)和国家海洋学中心(NOC)、澳大利亚詹姆斯库克大学和墨尔本大学以及新加坡国立大学的科研人员,调查了生活在极地到热带海域12种不同环境下的4种有壳类的外壳厚度及骨骼大小。  相似文献   

6.
<正>海洋酸化(OA)是由于大气中的二氧化碳溶解到海洋中的数量不断增加而导致的。酸化对商业捕鱼业和水产养殖业的有害影响是可以预见到的。在此,我们调查了海洋酸化对澳大利亚昆士兰州的对虾和扇贝渔业的影响,并比较了野生捕捞渔业和水产养殖业应对海洋酸化的适应能力和缓解措施。通  相似文献   

7.
海水酸化对海洋生物代谢的影响及机理   总被引:1,自引:0,他引:1  
<正>2013年,Boytchev[1]在《Nature》发表论文指出:全球变暖,不断增加碳排放量所导致的后果并非是唯一令人忧心的。由于大气中CO2含量升高,更多的CO2溶至海洋,使海水酸性增强的现象称为海水酸化[2]。海水酸化是复杂、漫长的过程,但其本质是附加的CO2和H2O反应形成H2CO3,放出H+,增加了海水的酸性。增多的H+和碳酸盐离子结合形成碳酸氢盐,导致碳酸根离子减少[3]。  相似文献   

8.
《水产科技》2007,(5):43
澳大利亚科学家表示:温室气体正导致全世界海洋的酸积累,这对珊瑚和海洋生物构成了严重威胁。当过多的二氧化碳溶解在海洋中时,就引发了全球变暖的副作用——海洋酸化,这会使得具有骨骼的珊瑚和浮游生物很难进行钙化。研究这个问题的科学家称:酸化正在悄悄地破坏海洋环境,尤其对澳大利亚的大堡礁珊瑚区域的甲壳类动物和浮游生物产生了潜在的影响。  相似文献   

9.
全球环境变化与人类活动对渔业资源的影响   总被引:12,自引:0,他引:12  
近 10年来 ,世界渔业生产持续增长 ,但不同地区、不同鱼种类的渔业资源和产量的波动却十分显著 ,如智利年渔获量 1994年高达 784万t,1998年仅 35 6万t[1] 。全球环境变化与人类活动是使世界渔业资源分布与产量发生不同程度变动的重要原因之一[2~ 7] 。全球环境变化问题的研究作为一项国际超级科学计划 ,其重点研究领域包括全球气候变迁、海洋环境变化、生态环境破坏及人类活动等[8] 。此课题的研究对于提高人类预测环境变化的能力、实现世界渔业可持续发展有积极意义1 海洋 -大气相互作用对渔业资源的影响海洋与大气间各种物理量 (物质…  相似文献   

10.
为探究大黄鱼(Larimichthys crocea)早期发育阶段低氧和酸化胁迫对其消化生理的影响,实验设置4个处理组,分别为对照组[溶解氧(DO)=7.0 mg·L~(-1),pH=8.1]、低氧组[溶解氧(DO)=3.5 mg·L~(-1),pH=8.1]、酸化组[溶解氧(DO)=7.0 mg·L~(-1),pH=7.3]和低氧-酸化组[溶解氧(DO)=3.5 mg·L~(-1),pH=7.3],每个处理组4重复,每个重复放置大黄鱼受精卵4.0×10~4粒,并在实验开始后(记录为0 d)和受精卵孵化后1 d、3 d、5 d、10 d、15 d、20 d、27 d分别测定其淀粉酶、胰蛋白酶和脂肪酶活性。实验结果表明:低氧胁迫对大黄鱼早期发育阶段消化酶活性的影响均较为明显;其中对淀粉酶活性的影响主要发生在10 d以后;对胰蛋白酶活性的影响更为明显,其酶活性在前10 d各时间点均显著高于对照组。低氧胁迫和酸化胁迫对脂肪酶活性的影响均主要发生在5~10 d仔鱼刚开口阶段,此阶段低氧胁迫和酸化胁迫均导致脂肪酶活性相比同期对照组显著降低。酸化胁迫对胰蛋白酶的影响则主要体现在5 d之前,导致此阶段胰蛋白酶活性明显较高。低氧-酸化双重胁迫对大黄鱼早期发育阶段消化酶活性的影响相比单一因子胁迫有一定的加剧作用。  相似文献   

11.
12.
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.  相似文献   

13.
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.  相似文献   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

15.
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.  相似文献   

16.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.  相似文献   

17.
18.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

19.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

20.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

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