山东半岛沿岸颗石藻化石的长期记录及其对东亚冬季风的响应

本研究对南黄海西北部山东半岛沿岸的沉积柱140年的颗石藻(Coccolithophores)样品进行了种类组成和丰度分析。结果显示,共发现颗石藻8种,平均丰度为9.76×10~6个/g,丰度范围为(5.07～14.21)×10~6个/g。其中,大洋桥石藻(Gephyrocapsa oceanica)和赫氏艾密里藻(Emiliania huxleyi)是丰度较高的主要物种,平均丰度分别为4.96×10~6、4.55×10~6个/g。通过比较沉积记录与气候参数发现,颗石藻丰度的长期变化与东亚冬季风的替代指标海平面气压(SLP)有一定相关性,黄海沿岸流受季风影响,随着东亚冬季风的增强而加强,沿岸流带来了物质输入,为研究区域的颗石藻提供了丰富的营养盐,从而支撑了较高的颗石藻丰度。     

东海陆架区的颗石藻

利用扫描电子显微镜,研究了2007年5月东海陆架区航次调查的颗石藻物种组成,给出了调查海区的颗石藻物种名录,并拍摄了出现的颗石藻物种的显微图像。本次调查共记录颗石藻物种23种,隶属于9个科、4个目,其中绝大多数为异晶颗石藻Heterococcolithophore,少数为同晶颗石藻Holococcolithophore。从出现频率来看,皮球石科Syracosphaeraceae的物种居多,特别是条结藻属Syracosphaera的物种,共出现了7种,占到总物种数的30%之多。赫氏艾密里藻Emiliania huxleyi (Lohmann) Hay & Mohler和大洋桥石藻Gephyrocapsa oceanica Kamptner在本次调查的所有采样站点中都有出现,并且记录了赫氏艾密里藻的3种变型（Type A、Type B/C和Type C）。4种新纪录是皮球石科的两种异晶颗石藻：历史条结藻Syracosphaera histrica Kamptner和边孔条结藻Syracosphaera marginaporata Knappertsbusch;具覆球藻科Calyptrosphaeraceae的两种同晶颗石藻：乳突具覆石藻Calyptrolithophora papillifera (Halldal) Heimdal和粗毛盔球藻Corisphaera strigilis Gaarder,并对它们的形态特征进行了描述。东海陆架区外海受黑潮（Kuroshio）影响的区域,其独特的栖息地环境,有利于颗石藻的快速生长与繁殖,因而出现了较多的颗石藻物种。     

颗石藻光合作用与钙化作用的研究现状

对颗石藻的生物学种类、形态特征、分布特点做了简单概括,探讨了影响颗石藻光合作用与钙化作用的多种因素,包括光照、温度、营养盐与海水酸化,揭示了光合作用与钙化作用之间的偶联机制,对颗石藻的利用价值做出了展望。     

不同氮营养盐对赫氏颗石藻和三角褐指藻中DMSP含量的影响

二甲基巯基丙酸内盐(dimethylsulfoniopropionate,DMSP)是地球上重要的有机硫化合物之一,在全球硫循环和气候调节等方面发挥着重要作用。浮游植物是海洋环境中DMSP的主要生产者,而氮营养盐是影响浮游植物产生DMSP的重要因素之一。本研究以赫氏颗石藻(Emiliania huxleyi)(DMSP高产量藻)与三角褐指藻(Phaeodactylum tricornutum)(DMSP中等产量藻)为对象,通过室内培养实验,对比分析了在不同氮营养盐浓度及不同氮营养盐类型条件下,2种藻培养液中颗粒态DMSP (DMSPp)的含量及其与藻密度、单细胞DMSPp含量的关系。研究发现,不同氮营养盐浓度或氮营养盐类型对赫氏颗石藻单细胞DMSPp含量影响较小(P>0.05),培养液中的DMSPp浓度主要受藻细胞密度影响;而不同氮营养盐浓度或氮营养盐类型对三角褐指藻单细胞的DMSPp含量影响显著(P<0.05),培养液中的DMSPp浓度主要受藻的单细胞DMSPp含量影响。例如,对于三角褐指藻来说,低NO₃^-浓度(0μmol/L)...     

不同种类浮游植物对CO2浓度升高的响应

本研究采用实验生态学的方法,以金藻、硅藻、绿藻3个门中的4种常见饵料藻叉鞭金藻(Dicrateria sp.)、三角褐指藻(Phaeodactylum tricornutum)、小球藻(Chlorella vulgaris)和亚心形扁藻(Platymonas subcordiformis)为研究对象,分析比较不同浮游植物的细胞数量和质量对CO2浓度升高引起的海水酸化的响应情况。结果显示,与对照组相比,(1) CO2浓度升高显著提高了这4种藻的生长速率(P<0.05);其中,亚心形扁藻平均比生长速率最高,比对照组高出13.5%;小球藻次之,为5.9%;叉鞭金藻和三角褐指藻均为2.2%。(2) CO2浓度升高使浮游植物细胞内的碳(C)含量增加、氮(N)含量降低,C/N提高;种间差异较大,其中,亚心形扁藻的C/N、C/P值、小球藻的C/P值和三角褐指藻的C/N值显著提高,叉鞭金藻不显著。(3) CO2浓度升高使小球藻单位细胞叶绿素a含量显著提高,小球藻通过提高光合作用能力促进生长,而另外3种藻叶绿素a含量与对照组无显著差异;三角褐指藻最大光化学量子产量(Fv/Fm)在实验初期显著升高;叉鞭金藻非光化学淬灭(NPQ)显著降低,快速光曲线初始斜率(α)显著增加;三角褐指藻和亚心形扁藻潜在的最大光合作用能力(rETRmax)显著升高(P<0.05),但CO2浓度升高对4种藻的光化学淬灭(qP)均没有显著影响(P>0.05)。可见,亚心形扁藻、小球藻和三角褐指藻在高CO2浓度下虽然生长速率加快,但营养质量降低。不同种类的浮游植物对CO2浓度升高的响应不同,这种差异可能会使未来海洋浮游植物群落结构发生变化;浮游植物C/N、C/P值的改变可能通过食物链对次级生产者,诸如浮游动物、滤食性贝类等产生影响。     

二氧化碳和阳光紫外辐射对坛紫菜丝状体光合生理特性的影响

为了探索大型海藻生活史丝状体阶段对于海洋酸化与紫外辐射的响应,实验选取经济海藻坛紫菜的自由丝状体作为实验材料。实验设置两个CO2浓度,正常CO2浓度(390 ppmv)和高CO2浓度(1 000 ppmv);3种辐射处理,PAR处理(仅接受可见光)、PA处理(滤除UV-B)、PAB处理(全波长辐射)。研究结果表明,高CO2显著提高了坛紫菜自由丝状体的生长速率,但高CO2处理下坛紫菜自由丝状体中藻红蛋白、藻蓝蛋白、叶绿素a、类胡萝卜素及紫外吸收物质UVACs分别降低了7.3%、9.3%、19.8%、16.5%和18.7%。高CO2处理的坛紫菜自由丝状体最大光化学效率Fv/Fm,光能利用效率(α)及最大相对电子传递速率(rETRmax)都显著高于正常CO2处理。太阳模拟器下处理的坛紫菜自由丝状体,PAR与PA处理下的抑制率,正常CO2与高CO2处理间无显著差异,然而在PAB处理下,高CO2处理的抑制率要高于正常CO2处理,这可能与其体内紫外吸收物质含量下降有关。PAR处理下的抑制率,无论是在正常CO2还是在高CO2处理下,都显著低于PA及PAB处理,而PA与PAB之间无显著差异。在未来海洋持续酸化的背景下,UV辐射的增加将会影响到坛紫菜自由丝状体的光合生理及生长。     

中国海洋酸化及生态效应的研究进展

正[海洋吸收大气CO2会导致海洋酸化1-5],影响海洋生物的生长、繁殖和代谢等过程,最终影响海洋生态系统平衡及其对人类的服务功能[6]。此外,由上升流或富营养化导致的近海酸化进程要远快于大洋,对生物会造成更大的环境胁迫[7]。因此,海洋酸化已成为继全球变化和环境污染后严重影响和威胁人类社会发展的第三大环境问题[8]。由于缺乏海洋酸化及其生态效应的观测研究,目前尚     

海洋尖尾藻对2种海洋微藻的摄食特征研究

为研究海洋尖尾藻对双色藻和齿状纹石藻的摄食特征,分别采用2种海洋微藻为饵料培养海洋尖尾藻,分析海洋尖尾藻对2种海洋微藻的摄食过程、培养液颜色变化特征和摄食规律。结果显示,海洋尖尾藻摄食双色藻时将藻丝一段一段慢慢裹入纵沟,而齿状纹石藻整个细胞同时被裹入纵沟。海洋尖尾藻接种6 h后,对2种海洋微藻的摄食率均为100%。随着海洋尖尾藻细胞初始密度(双色藻培养液中分别为0.8×104、2.4×103和0.8×103个/mL,齿状纹石藻培养液中分别为3.9×103、2.4×103和1.7×103个/mL)降低,其种群在初始密度为3.4×107个/mL的双色藻培养液中达到稳定期所需时间增加,分别为接种后第3、4和6天,双色藻被摄食完毕所需时间也增加,分别为接种后第5、10和15天;海洋尖尾藻种群在初始密度为6.6×105个/mL的齿状纹石藻培养液中达到稳定期所需时间增加,分别为接种后第4、5和12天,齿状纹石藻被摄食完毕所需时间也增加,分别为接种后第6、7和13天。研究表明,海洋尖尾藻对不同大小和体制类型的双色藻和齿状纹石藻的摄食过程不同,培养方式对培养液颜色变化产生影响,饵料藻种类以及饵料藻和海洋尖尾藻最初浓度配比会影响海洋尖尾藻摄食,15 d培养过程中双色藻种群和齿状纹石藻种群均向海洋尖尾藻种群发生了演替。     

大型藻类规模化养殖水域海-气界面CO2交换通量估算

选择山东俚岛湾大型藻类养殖水域作为研究区域,根据2011年4、8、10月和2012年1月4个航次的大面调查获得的pH、总碱度(TA)、叶绿素a等基础数据,分析了该区域表层海水溶解无机碳(DIC)体系各分量的浓度、组成比例及时空变化特征,估算了海-气界面CO2的交换通量。结果表明,该区域表层海水DIC、HCO-3、CO2-3及CO2的年平均浓度分别为2024.8±147.0、1842.4±132.1、170.0±42.8和12.4±2.5μmol/L。养殖区与非养殖区之间DIC、HCO-3浓度差异不显著(P>0.05),而CO2浓度差异极显著(P<0.01)。表层海水pCO2和海-气界面CO2的交换通量的年平均值分别为287.8±37.9μatm和-32.7±17.2mmol/m2.d,养殖区与非养殖区之间、不同季节之间均差异极显著(P<0.01)。大型藻类的养殖活动有利于海洋对大气CO2的吸收。     

渔业科技前沿

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     

海洋酸化对栉孔扇贝钙化、呼吸以及能量代谢的影响

通过Alkalinity anomaly technique测定了栉孔扇贝Chlamys farreri在不同酸度条件下的钙化率和呼吸率,发现栉孔扇贝的钙化和呼吸活动受酸化影响显著,均随着酸化的加剧出现了明显下降。当pH降低到7.9时,栉孔扇贝的钙化率将会下降33%左右;当pH降到7.3左右时,栉孔扇贝的钙化率将趋近于0,栉孔扇贝无法产生贝壳,而此时栉孔扇贝碳呼吸率(RC)与耗氧率(RO)也分别下降了14%和11%。随着酸化的加剧,栉孔扇贝的能量代谢方式也会发生改变。这些变化都可能影响到栉孔扇贝的生存。     

The effects of elevated pCO2 on growth,shell production and metabolism of cultured juvenile abalone,Haliotis iris

Reduced seawater pH and elevated pCO₂ are important considerations in tank‐based abalone aquaculture, while sea‐based farms may be at risk to ocean acidification reductions in pH. Juvenile Haliotis iris (5–13 and 30–40 mm shell length) were reared in two, 100‐day experiments at ambient pH_nbs (~ 8.1, 450 μatm CO₂), pH 7.8 (~1000 μatm CO₂) and pH 7.6 (~1600 μatm CO₂). Seawater pH was measured and adjusted automatically by bubbling CO₂ into water in replicated flow through tanks. Two separate trials were run, in winter (8.8°C) and summer (16.5°C). Survival and growth were monitored every 30 days, and post experiment measurements of morphometrics and respiration rate undertaken. Growth of shell length and wet weight were negatively affected by reduced pH, with a 2 to 3‐fold reduction in growth of both size classes between ambient and pH 7.6 treatments in the summer experiment. For small juveniles, growth reductions were in conjunction with decreases to shell weight, while large juveniles showed greater resilience in shell production. No changes to respiration rate occurred, suggesting that juveniles may maintain physiological functioning while tolerating dissolution pressure or that they are unable to upregulate metabolism to compensate for pH effects. These data show that CO₂ driven reductions in pH can impact growth, metabolism and biomineralization of abalone, and indicate that water quality and ocean acidification are of importance in aquaculture of the species.     

Effects of elevated pCO2 on the early development of the commercially important gastropod,Ezo abalone Haliotis discus hannai

We used an up‐to‐date, a high accuracy CO₂ manipulation system to investigate the sensitivity of organisms to CO₂ acidification, rearing marine calcifiers under elevated CO₂ in running water. We evaluated the effects of elevated partial pressures of carbon dioxide (pCO₂) in seawater on larvae of the commercially important marine gastropod Ezo abalone Haliotis discus hannai. In larval Ezo abalone, no effect of exposure to <1100 μatm pCO₂ seawater was observed in fertilization, malformation, or mortality rates until 15 h after fertilization. However, compared to control larvae in seawater (450 or 500 μatm pCO₂), the fertilization rate and the hatching rate (15 h after fertilization) decreased with increased pCO₂ exposure (1650 and 2150 μatm pCO₂) and the malformation rate increased significantly, with the larval shell length being smaller 75 h after hatching. These results suggest that ocean acidification will potentially impact the marine population of Ezo abalone as a human food source in the future.     

大型海藻碳汇效应研究进展

大型海藻光合作用是海域初级生产力的来源之一,是海洋碳循环中关键的一环。大型海藻可通过光合作用有效地吸收海水中溶解的无机碳以及大气中的CO2,将其转化为有机碳并释放O2,光合作用的产物除支持生态系统外,还以有机物的形式埋藏在沉积物中,进而形成碳的汇。大型海藻的养殖和增殖对CO2的减排、减缓海洋酸化、扩增海洋碳汇效应以及缓解气候变化都有重要意义。本文就大型海藻碳汇机理、潜力以及大型海藻碳汇能力的扩增途径进行了综述,为大型海藻碳汇效应研究的发展提供了依据。     

Nutrition and income from molluscs today imply vulnerability to ocean acidification tomorrow

Atmospheric carbon dioxide (CO₂) emissions from human industrial activities are causing a progressive alteration of seawater chemistry, termed ocean acidification, which has decreased seawater pH and carbonate ion concentration markedly since the Industrial Revolution. Many marine organisms, like molluscs and corals, build hard shells and skeletons using carbonate ions, and they exhibit negative overall responses to ocean acidification. This adds to other chronic and acute environmental pressures and promotes shifts away from calcifier‐rich communities. In this study, we examine the possible implications of ocean acidification on mollusc harvests worldwide by examining present production, consumption and export and by relating those data to present and future surface ocean chemistry forecast by a coupled climate‐ocean model (Community Climate System 3.1; CCSM3). We identify the ‘transition decade’ when future ocean chemistry will distinctly differ from that of today (2010), and when mollusc harvest levels similar to those of the present cannot be guaranteed if present ocean chemistry is a significant determinant of today’s mollusc production. We assess nations’ vulnerability to ocean acidification‐driven decreases in mollusc harvests by comparing nutritional and economic dependences on mollusc harvests, overall societal adaptability, and the amount of time until the transition decade. Projected transition decades for individual countries will occur 10–50 years after 2010. Countries with low adaptability, high nutritional or economic dependence on molluscs, rapidly approaching transition decades or rapidly growing populations will therefore be most vulnerable to ocean acidification‐driven mollusc harvest decreases. These transition decades suggest how soon nations should implement strategies, such as increased aquaculture of resilient species, to help maintain current per capita mollusc harvests.     

Effect of Hybrid Abalone,Haliotis discus hannai × Haliotis discus discus,Cultivation on the Carbon Cycle: Carbon Source/Sink

Respiration, calcification, and bio‐deposition of hybrid abalone, Haliotis discus hannai × Haliotis discus discus, fed on different foodstuffs have been measured to evaluate the effect of hybrid abalone culture on carbon source/sink in coastal areas. Fed with Laminaria japonica, Undaria pinnatifida, Gracilaria lemaneiformis, U. pinnatifida, and Ulva pertusa, alternated mutually, the carbon bio‐deposition rate of hybrid abalone was 24.29 ± 6.39, 65.40 ± 10.55, 21.48 ± 5.99, and 29.28 ± 6.47 µg/g/h, respectively. Hybrid abalone fed on U. pinnatifida had a higher carbon bio‐deposition rate compared to that fed on other foodstuff (P < 5%). Rate of CO₂ released by respiration of hybrid abalone fed on the experimental foodstuff was 24.53 ± 8.57, 32.73 ± 7.99, 29.31 ± 6.39, and 33.67 ± 12.37 µg/g/h, respectively. Results indicated that calcification presented less relationship with body weight type of the foodstuff. The rate of CO₂ released by calcification into seawater and atmosphere was 2.77 ± 1.89 and 6.53 ± 3.36 µg/g/h, respectively. The total rate of CO₂ released because of bio‐deposition, respiration, and calcification processes was 16.19 ± 4.67 µg/g/h, while the total rate of carbon sequestered in shells and tissues was 8.94 ± 2.07 µg/g/h. The study revealed that hybrid abalone culture is a source of CO₂.     

The potential impacts of ocean acidification: scaling from physiology to fisheries*

Views expressed on the potential impact of ocean acidification range from wholesale degradation of marine ecosystems through to no discernable impact with minimal consequences. Constraining this range of predictions is necessary for the development of informed policy and management. The direct biological impacts of acidification occur at the molecular and cellular level; however, it is the expression of these effects at the population and ecosystem level that is of societal concern. Here, we consider the potential impact of ocean acidification on fisheries with particular emphasis on approaches to scaling from physiological responses to population‐ and ecosystem‐level processes. In some instances, impacts of ocean acidification may lead to changes in the relative species composition at a given trophic level without affecting the overall productivity, whilst in other instances, ocean acidification may lead to a reduction in productivity at a given tropic level. Because of the scale at which ecological processes operate, modelling studies are required. Here, ocean acidification is situated within ongoing research into the ecological dynamics of perturbed systems, for which many models have already been developed. Whilst few existing models currently explicitly represent physiological processes sensitive to ocean acidification, some examples of how ocean acidification effects may be emulated within existing models are discussed. Answering the question of how acidification may impact fisheries requires the integration of knowledge across disciplines; this contribution aims to facilitate the inclusion of higher trophic level ecology into this ongoing debate and discussion.     

Effect of temperature and phytoplankton concentration of Partitioned Aquaculture System water on freshwater mussel filtration

The freshwater mussel Elliptio complanata was provided green algal‐dominated water from a Partitioned Aquaculture System (PAS) over a range of water temperatures (6.1–32.4 °C) and suspended particulate organic carbon (POC) concentrations (<1–32.2 mg C L^?1) to determine filtration rates as mg POC kg^?1 wet tissue weight h^?1. The lowest filtration rates were observed at lowest temperatures and POC concentrations while the highest rates were at intermediate temperatures and the highest POC levels. The predicted filtration rate (PFR) in response to water temperature and POC concentrations was as follows: ln PFR=1.4352+0.1192 POC+0.1399 T?0.0001 T³. Within the experimental conditions, PFRs at any POC concentration increased with increased water temperature to a peak at 22 °C and then decreased. The maximum PFR occurred at 22 °C and 32 mg C L^?1 and the minimum PFR at 7 °C and 1 mg C L^?1. A model to describe the mussel filtration rate responses to PAS water conditions involves both water temperature and POC concentration.     

Effects of acidified seawater on early life stages of scleractinian corals (Genus Acropora)

Ocean acidification, caused by increased atmospheric carbon dioxide (CO₂) concentrations, is currently an important environmental problem. It is therefore necessary to investigate the effects of ocean acidification on all life stages of a wide range of marine organisms. However, few studies have examined the effects of increased CO₂ on early life stages of organisms, including corals. Using a range of pH values (pH 7.3, 7.6, and 8.0) in manipulative duplicate aquarium experiments, we have evaluated the effects of increased CO₂ on early life stages (larval and polyp stages) of Acropora spp. with the aim of estimating CO₂ tolerance thresholds at these stages. Larval survival rates did not differ significantly between the reduced pH and control conditions. In contrast, polyp growth and algal infection rates were significantly decreased at reduced pH levels compared to control conditions. These results suggest that future ocean acidification may lead to reduced primary polyp growth and delayed establishment of symbiosis. Stress exposure experiments using longer experimental time scales and lower levels of CO₂ concentrations than those used in this study are needed to establish the threshold of CO₂ emissions required to sustain coral reef ecosystems.