Sub-Lethal Effects of Elevated Concentration of CO<Subscript>2</Subscript> on Planktonic Copepods and Sea Urchins

Data concerning the effects of high CO₂ concentrations on marine organisms are essential for both predicting future impacts of the increasing atmospheric CO₂ concentration and assessing the effects of deep-sea CO₂sequestration. Here we review our recent studies evaluating the effects of elevated CO₂ concentrations in seawater on the mortality and egg production of the marine planktonic copepod, Acartia steueri, and on the fertilization rate and larval morphology of sea urchin embryos, Hemicentrotus pulcherrimus and Echinometra mathaei. Under conditions of +10,000 ppm CO₂ in seawater (pH 6.8), the egg production rates of copepods decreased significantly. The survival rates of adult copepods were not affected when reared under increased CO₂ for 8 days, however longer exposure times could have revealed toxic effects of elevated CO₂ concentrations. The fertilization rate of sea urchin eggs of both species decreased with increasing CO₂ concentration. Furthermore, the size of pluteus larvae decreased with increasing CO₂ concentration and malformed skeletogenesis was observed in both larvae. This suggests that calcification is affected by elevated CO₂ in the seawater. From these results, we conclude that increased CO₂ concentration in seawater will chronically affect several marine organisms and we discuss the effects of increased CO₂ on the marine carbon cycle and marine ecosystem. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effect of temperature and salinity on survival and growth of Crangon uritai (Decapoda: Crangonidae) larvae reared in the laboratory

Larvae of the decapod Crangon uritai were reared in the laboratory in a factorial experiment employing three temperatures (9, 12 and 15 °C) and three salinities (29‰, 32‰ and 35‰) from hatching to the post‐larval stage. The effects of temperature and salinity on survival, intermolt period (IP) and molt increment (MI) were investigated. Larvae from one brood were subdivided into groups of 20 and reared in glass bowls containing filtered sea‐water at a number of temperature–salinity combinations. The reared larvae were transferred daily to the clean bowls prepared with newly hatched Artemianauplii, and number of molts and mortality within each bowl were recorded. The zoeal size (carapace length) was determined from exuvia and dead larvae, and the IP was also recorded. Larvae of C. uritai completed larval development only at 15 °C temperature. The first zoeal stage completed their development at all temperature–salinity combinations and exhibited the highest survival rate. IP at each stage increased with increasing size and greatly decreased with increasing temperature, and intermolt duration (range of days) increased with larval development especially at the lower temperature. Although the MI decreased with increasing size, it was little affected by temperature. This led to a better growth rate with increasing temperature.     

Effects of low pCO2 conditions on sea urchin larval size

Ocean acidification results from an increase in the concentrations of atmospheric carbon dioxide (CO₂) impacts on marine calcifying species, which is predicted to become more pronounced in the future. By the end of this century, atmospheric pCO₂ levels will have doubled relative to the pre‐industrial levels of 280 ppm. However, the effects of pre‐industrial pCO₂ levels on marine organisms remain largely unknown. In this study, we investigated the effects of pre‐industrial pCO₂ conditions on the size of the pluteus larvae of sea urchins, which are known to be vulnerable to ocean acidification. The larval size of Hemicentrotus pulcherrimus significantly increased when reared at pre‐industrial pCO₂ level relative to the present one, and the size of Anthocidaris crassispina larvae decreased as the pCO₂ levels increased from the pre‐industrial level to the near future ones after 3 days' exposure. In this study, it is suggested that echinoid larvae responded to pre‐industrial pCO₂ levels. Ocean acidification may be affecting some sensitive marine calcifiers even at the present pCO₂ level.     

Vertical distribution and growth performance of Baltic cod larvae – Field evidence for starvation-induced recruitment regulation during the larval stage?

Besides variable egg survival, previous studies suggested that the larval stage may be the most critical phase in determining Baltic cod recruitment variability, and that larvae need to conduct an ontogenetic vertical migration from hatching depths (>50 m) to upper layers with increased food availability in order to initiate first feeding, improve their nutritional condition and growth, and avoid starvation. Recently, detailed information on the stage-resolved vertical distribution of main Baltic copepod species, including the preferred larval Baltic cod prey species Pseudocalanus acuspes, has become available. Therefore, the vertical distribution of Baltic cod larvae in August 2007 and their depth-dependent nutritional condition and growth were investigated. RNA–DNA based methods were used to estimate growth, including a novel approach to estimate growth performance by relating observed specific growth rates (SGR) of field caught larvae to temperature-dependent reference growth rates (G_ref) for fast-growing laboratory reared fish from the literature. This standardization to G_ref was found to have a great potential to improve investigations on the growth and ecology of larval fish. The need for early larvae to migrate to shallower layers was corroborated, while larger size classes were found at increasingly greater depths. This may reflect a continuation of the ontogenetic vertical migration in order to follow increasingly larger prey items at greater depths and to save energy in cooler waters below the thermocline. Larval growth generally declined with increasing depth, but the decline in growth became less pronounced in larger size classes. This indicates that larger larvae were better in coping with the ambient environment and the available prey field at greater depths. Generally, Baltic cod larvae grew poorly compared to larvae from other studies, which is discussed in relation to differences in predation and a possible food–temperature trade-off for larvae in the highly stratified Baltic Sea. Comparison with earlier results showed a higher frequency of starving larvae and lower frequencies of larger larvae after the first-feeding stage in 1994 and 1995. As this was a period of low Baltic cod recruitment despite favourable conditions for egg survival, it is concluded that larval starvation mortality has a high potential to contribute to recruitment variability in Baltic cod.     

海洋酸化对海水青鳉胚胎骨骼发育的影响

本文在实验室模拟近期海洋酸化水平,对海洋酸化对海水青鳉鱼(Oryzia melastigma)胚胎骨骼发育的影响进行了初步研究。实验中,通过往实验水体中充入一定浓度CO2气体酸化海水。对照组CO2分压为450×10-6,两个处理组CO2浓度分别为1 160×10-6和1 783×10-6,对应的水体pH值分别为8.14,7.85和7.67。将海水青鳉鱼受精卵放入实验水体中至仔鱼孵化出膜,对初孵仔鱼经骨骼染色、显微拍照,挑取了仔鱼头部、躯干及尾部骨骼染色清晰的28个骨骼参数的长度进行了显微软件测量及数据统计分析。结果发现,酸化处理对实验鱼所测量的骨骼长度影响均不显著。因此推测,未来100~200年间海洋酸化对海水青鳉鱼的胚胎及初孵仔鱼的骨骼发育没有显著影响。     

香港牡蛎二倍体及三倍体幼虫生物学特征比较

为了评估香港牡蛎二倍体及三倍体幼虫生物学特征,于2013~2015年,在湛江和北海两地比较了二倍体及三倍体幼虫生长、存活及变态差异,计算了三倍体优势率,评估了倍性与环境效应互作对其表型性状的影响。结果表明:三倍体D形幼虫显著大于二倍体幼虫,之后,伴随着个体增长,生长优势逐渐增大,15日龄时的三倍体优势率为8.9%~9.1%。三倍体幼虫存活力与二倍体相当,未出现大量致死现象。三倍体变态规格显著大于二倍体,其优势率为5.1%~5.3%;三倍体变态时间显著低于二倍体,但其变态率与二倍体相当,不存在显著差异(p>0.05)。经过双因子分析模型的方差分析检测,发现倍性和环境效应都会对香港牡蛎幼虫生长产生显著影响(p<0.001),环境是影响幼虫存活率及变态的主要因子(p<0.05)。     

三氯异氰尿酸对脊尾白虾幼体存活及发育的影响

三氯异氰尿酸(Trichloroisocyanuric acid ,TCCA)是水产养殖中常用的水质消毒剂, 使用不当会给生产和环境带来危害。为指导脊尾白虾(Exopalaemon carinicauda)人工育苗过程中TCCA 的安全用药,作者利用静水试验法研究了TCCA 对脊尾白虾幼体的急性毒性及对幼体发育的影响。实验设7 个浓度梯度组(1.0、1.5、2.0、2.5、3.0、3.5、4.0 mg/L)和1 个空白对照组, 每组3 个平行。急性毒性实验持续96 h 后结束, 用正常育苗海水代替TCCA 溶液, 正常管理直到幼体全部变态为仔虾, 评估短时间的TCCA 处理对脊尾白虾幼体发育的影响。结果表明, TCCA 对脊尾白虾幼体在24、48、72 和96 h 的半致死浓度分别为3.81、3.03、2.71 和2.47 mg/L, 其安全浓度为0.25 mg/L; 随着TCCA 浓度的升高, 脊尾白虾幼体变态存活率显著降低(P<0.05), 但能成功变态为仔虾个体的变态持续时间及仔虾体长与对照组无明显差异(P>0.05)。本实验结果可以为脊尾白虾人工育苗安全用药提供参考和依据。     

海蜇(Rhopilema esculentum)浮游幼体对褐牙鲆(Paralichthys olivaceus)卵和初孵仔鱼捕食的比较研究

利用实验生态学方法研究不同个体大小的海蜇浮游幼体[平均伞径(2.5±0.1),(4.1±0.2),(11.7±0.5),(21.1±0.6)mm]对不同密度(10,30,50,80ind/L)的褐牙鲆卵[卵径(0.92±0.01)mm]和初孵仔鱼[全长(3.01±0.08)mm]的捕食率,解析海蜇浮游幼体对初孵仔鱼的捕食率随捕食时间(0.5,1,2,3,4,5h)的变化特征。结果表明,各个体组海蜇浮游幼体对卵的捕食率均显著低于对仔鱼的捕食率;它们对卵的捕食率与卵密度和海蜇个体大小的关系不显著,但对仔鱼的捕食率随海蜇个体大小及仔鱼密度的增大而显著升高;伞径21.1mm的个体对仔鱼的捕食率在开始捕食后1h时达到最大值[17.3ind/(predator.h)],此后随捕食时间的延长而逐渐下降。在自然水域中,如果二者发生时空上的匹配关系,海蜇浮游幼体对仔鱼的捕食可能影响褐牙鲆的早期存活及其资源补充量的变动。     

条斑星鲽幼鱼变态期间核酸及蛋白的变化

本试验测定了条斑星鲽(Verasper moseri)幼鱼变态过程中DNA、RNA、蛋白及其比值的变化,作为评价幼鱼变态阶段生长潜能的指标。结果表明,试验期间培育水温为16.5～18.0°C,DNA、RNA及蛋白的变化都带有发育阶段特异性。DNA含量在34～42日龄增加缓慢,然后快速增加直至44日龄,在45日龄和46日龄分别保持下降和上升趋势。蛋白含量和RNA含量的变化趋势相似,在试验期间保持快速增长的趋势。RNA/DNA比值从试验开始至35日龄呈上升状态,36日龄时下降,38日龄时达到最高值5.01,然后显著下降(P0.05),在试验结束时达到最低值1.76。蛋白/DNA在40日龄时达到最高值58.64,在46日龄时达到最低值21.28。RNA、DNA及蛋白含量跟全长和体质量有明显的线性关系(P0.05)。RNA/DNA与全长和体质量的关系比蛋白/DNA与全长和体质量的关系密切。蛋白/DNA比值的变化趋势跟RNA/DNA比值类似,但前者的变化滞后于后者,表明RNA/DNA比值是评价条斑星鲽生理状况的更有效的生理指标。     

Pure compound and sediment elutriate embryo larval assay of winter flounder from the Hudson/Raritan Estuary and Long Island Sound

Winter flounder (Pseudopleuronectes americanus), a demersal egg layer, is at risk from dioxins and metals in the sediments of the Hudson/Raritan Estuary (the Estuary). The effects of tetrachlorodibenzo-p-dioxin (TCDD), mercuric chloride and sediment elutriates on the embryos of winter flounder from four sites in the Estuary, and a reference site: Long Island Sound (LI) were examined. Embryos were exposed from 2 days after fertilization until 2 days post hatch. TCDD absorption by embryos/larvae ranged from 13 to 44%, with an average 23.4%. One experiment, with the LI population showed a LD₅₀ of 1.8 pg/larva (2.6 ng/g) and LD₁₀ of 0.9 pg/larva (1.4 ng/g). Major observed lesions included pericardial edema (PE), and spinal lesions (SL). Background lesion occurrence in controls was 0.31 lesions/individual, and 0.27 major lesions/individual. NOELs were observed for PE 0.3–0.5 pg/larva, and SL 1.4–9.0 pg/larva. PE and SL are good indicators of low and high dose effects of TCDD in winter flounder, respectively. With mercuric chloride all populations showed 50% mortality at 100 μg/l, and 50% lesions at 25–50 μg/l. Three of seven sediment elutriates collected from the Estuary were acutely toxic. Site-specific variability in sediment toxicity and breeding stock sensitivity to known contaminants was observed. Future studies should incorporate metamorphosis from larva to juvenile. (USEPA:CR825437, NIEHS:ES07148).     

Impacts of CO2-driven seawater acidification on survival, egg production rate and hatching success of four marine copepods

Ecological experiments were conducted to examine the effects of seawater containing elevated par- tial pressure of carbon dioxide (p CO2 800 × 10 -6 , 2 000 × 10 -6 , 5 000 × 10 -6 and 10 000 × 10 -6 ) on the survival and reproduction of female Acartia pacifica, Acartia spinicauda, Calanus sinicus and Centropages tenuiremis, which are the dominant copepods in the southern coastal waters of China. The results show that the effects of elevated p CO2 on the survival rates of copepods were species-specific. C. sinicus, which was a macro-copepod, had a higher survival rate (62.01%-71.96%) than the other three species (5.00%-26.67%) during the eight day exposure. The egg production rates of C. sinicus, A. spinicauda and C. tenuiremis were significantly inhibited by the increased p CO2 and the exposure time duration. There were significantly negative impacts on the egg hatching success of A. spinicauda and C. tenuiremis in the p CO2 2 000 × 10 -6 and 10 000 × 10 -6 groups, and, in addition, the exposure time had noticeably impacts on these rates too. This study indicates that the reproductive performances of copepods were sensitive to elevated p CO2 , and that the response of different copepod species to acidified seawater was different. Furthermore, the synergistic effects of seawater acidification and climate change or other pollutant stresses on organisms should be given more attention.     

翡翠贻贝幼体附着和变态的离子控制

于１９９３年５－１２月在厦门大学海滨实验场,以人工培养的悲翠贻贝幼体作为实验材料,在人工海水中添加３－１５ｍｍｏｌ／Ｌ     

棘颊雀鲷人工繁殖与育苗的初步研究

为了解棘颊雀鲷(Premnas biaculeatus)在人工饲养条件下繁殖和仔鱼培养对光照、水温及饵料的要求,采用实验生物学的方法,在严格控制的条件下培养亲鱼、胚胎和仔鱼.结果表明,在(26±1)℃和14L:10D的光暗周期下,2 000 1x和500 1x两种光照强度对亲鱼产卵周期和卵的受精率并没有明显的影响,但是...     

Neurophysiological control of swimming behaviour,attachment and metamorphosis in black-footed abalone (Haliotis iris) larvae

Experiments were conducted to test the effect of a range of chemicals on larval responses in swimming behaviour, attachment and metamorphosis of the black-footed abalone (Haliotis iris). The effect of antibiotics on larval survival was first tested within negative (filtered seawater) and positive (GABA at 10^?5, 10^?4 and 10^?3 mol L^?1) control assays over 3 days. This experiment corroborated the effectiveness of using antibiotics to improve survival of larvae without obvious synergistic interactions with the GABA inducer or confounding effects of potential bacterial interactions. Chemical treatments (acetylcholine, potassium chloride, dopamine and glutamine) were then tested at various concentrations for their ability to modulate swimming behaviour and induce larval attachment and metamorphosis over 14 days. Generally, larval state shifted from swimming to attached, and from attached to metamorphosed, in the control and treatments over time. However, the peak percentage of attached and metamorphosed larvae varied in time among chemicals and concentrations. While overall percent metamorphosis was minimally enhanced after 14 days of exposure to some chemical treatments at certain concentrations, all treatments displayed significant capacities to down-regulate larval swimming and induce early attachment and metamorphosis. Mortality was recorded throughout the duration of the experiment, and was generally low (<20%) across controls and most treatments for exposures of less than 12 days. Interpretations of specific results from this study are used to elucidate neurophysiological control of larval activities for this abalone species. Comparisons with other marine invertebrates highlight the specificities of chemical cues and endogenous regulatory mechanisms across relatively closely related taxa.     

珠母贝人工繁育优化技术的研究

在室内水泥池分别进行了移池培育、不同种类附着器、光照强度、水流和冲洗对珠母贝附着幼虫变态和稚贝存活的研究,结果表明:附着密度为2.18个/cm~2±0.50个/cm~2时,移池培育,其变态幼虫密度为0.95个/cm~2±0.13个/cm~2,20 d稚贝存活密度0.41个/~2±0.08个/cm~2,移池培育显著提高附着幼虫变态和稚贝存活;附着板、附着绳、网片、小石块变态幼虫密度分别为0.70个/cm~2±0.08个/cm~2、1.38个/cm~2±0.15个/cm~2、0.97个/cm~2±0.12个/cm~2、1.04个/cm~2±0.28个/cm~2,稚贝存活密度分别为0.36个/cm~2±0.06个/cm~2、0.62个/cm~2±0.07个/cm~2、0.45个/cm~2±0.07个/cm~2、0.60个/cm~2±0.08个/cm~2,附着绳显著提高附着幼虫变态和稚贝存活;光照强度为300～600 lx时变态幼虫密度为0.87个/cm~2±0.07个/cm~2,20 d稚贝存活密度0.45个/cm~2±0.08个/cm~2,强光不利于幼虫的变态和稚贝存活;水流速为2.3 cm/s时变态幼虫密度为1.08个/cm~2±0.07个/cm~2,20 d稚贝存活密度0.87个/cm~2±0.07个/cm~2,冲洗的变态幼虫密度为1.64个/cm~2±0.19个/cm~2,20 d稚贝存活密度1.00个/cm~2±0.12个/cm~2,水流或冲洗显著提高附着幼虫变态和稚贝存活.     

化学物质诱导变态后紫贻贝稚贝的生长及存活

在以往实验的基础上,跟踪调查了筛选出的化学诱导物质对紫贻贝(Mytilus edulis)幼虫变态后的生长和成活率的影响,并比较了其与相同条件下自然诱导物、微生物膜诱导后的稚贝的生长和成活率.实验结果表明,肾上腺素、苯肾上腺素、可乐宁、KCI和NH_4Cl 5种化学物质均成功地诱导了该种幼虫的变态,其变态后稚贝同微生物诱导变态后的稚贝以相同的速度生长,且在培育过程中无死亡稚贝出现.因此,这些化学物质可作为该种养殖以及海洋防污染研究中幼虫变态的有效人工诱导物.     

海水酸化对米氏凯伦藻和盐生杜氏藻种群增长和种间竞争的影响

大气中CO_2浓度升高导致的海水酸化改变了海洋生物赖以生存的化学环境,将对其生长、繁殖和代谢产生深远影响。本研究采用实验生态学的方法,以米氏凯伦藻(Karenia mikimotoi)和盐生杜氏藻(Dunaliella salina)为研究对象,探究在海水酸化条件下两种微藻种群增长和种间竞争关系的变化。结果发现:(1)在单培养体系中,随着二氧化碳浓度升高,米氏凯伦藻的环境负载能力(K)升高,而对其生长率进入拐点的时间(T_p)、内禀增长率(r)、进入指数增长期(T_(Ep))和静止期的时间(T_(Sp))均无显著性影响;对盐生杜氏藻而言,二氧化碳浓度升高显著降低了盐生杜氏藻的T_p和r值,而对其K、T_(Ep)、T_(Sp)均无显著性影响;(2)在共培养体系中,两种微藻的K值均受到显著抑制,与单培养体系相比差异显著(P0.05);二氧化碳升高改变了两种微藻的竞争关系,微藻之间的竞争表现为向有利于米氏凯伦藻的方向发展。(3)米氏凯伦藻去藻过滤液对盐生杜氏藻产生抑制作用,二氧化碳浓度升高加剧了这种抑制作用。     

光周期对罗氏沼虾幼体生长及能量收支的影响

于１９９５年２－５月,在Ｌ：Ｄ为４：２０,８：１６,１２：１２和２４：０四种光周期条件下,用卤虫无节幼体作饵料增减罗氏沼虾幼体,测定其生长能量收支。结果表明,随着光照时间的延长幼体生长率增大,两者关系为：ｇ＝６．５２４５＋３．６０４５ｌｎＴ,但周期对幼体Ｃ,Ｎ含量和Ｃ：Ｎ值没有显著的影响;     

乳铁蛋白对大黄鱼仔鱼生长、存活和抗应激能力影响的研究

用不同水平(分别为T1组:0 mg/L;T2组:50 mg/L;T3组:100 mg/L;T4组:150 mg/L)乳铁蛋白(lactoferrin,简称LF)强化的卤虫(Artemia franciscana)幼体投喂9~23日龄大黄鱼(Pseudosciaena crocea)仔鱼。结果表明,摄食LF强化卤虫幼体的大黄鱼仔鱼其生长无明显改善(P0.05),但大黄鱼仔鱼的成活率和抗应激能力显著提高,T3(60%)和T4(80%)组的成活率显著高于T1(40%)和T2(30%)组(P0.05)。T4组大黄鱼仔鱼的耐干露能力最强,T4组和T3组的抗高盐度(65)应激能力明显的强于T1和T2组(P0.05),T4组和T3组之间无明显的差异(P0.05)。经4 h高温(32°C)曝露后,T1和T2组的仔鱼全部死亡,T4组和T3组的成活率分别为30%和23.3%。即仔鱼的成活率和抗应激能力受卤虫强化LF水平的影响显著,LF强化的有效剂量为不低于100 mg/L强化水体。     

Effects of heavy metals on the development and survival of abalone Haliotis midae larvae

Despite a growing abalone Haliotis midae industry in South Africa, few studies have measured the effects of heavy metals on larval survival and growth in the face of recent increases in marine pollution. The aim of this study was to quantify the effect of copper on survival and zinc on development of H. midae larvae. Larvae 24 hours old were exposed to either copper (0–30 μg l^–1) or zinc (0–200 μg l^–1) for 48 h before mortality or larval development respectively were quantified. Copper significantly reduced survival, with an LC₅₀ of 5.58 μg l^–1 (5.07–6.15, 95% CI). Although the concentrations of zinc used in the study did not have a significant effect on mortality, there was a significant effect on the incidence of abnormal larvae with an EC₅₀ of 102.25 μg l^–1 (96.68–105.94, 95% CI). At concentrations above the EC₅₀, more than 50% of the larvae showed severe developmental abnormalities. Results suggest that copper poses the greatest risk to abalone larvae as the LC₅₀ was similar to the target concentration for this metal for South African coastal waters. By contrast, zinc is potentially less problematic, with the EC₅₀ for larval development being four times the target concentration for this metal.