Assessing the effects of long-term ocean acidification at volcanic CO2 vents

目的：确定沿海栖息地CO2水平升高的生态效应。在CNRS Roscoff和MBA普利茅斯的8个月培训期间，学生将监测碳酸盐化学和岩池栖息地生物群的变化。学生将接受一个监督团队的培训，该团队在使用天然类似物进行基于生态系统的海洋酸化研究方面处于世界领先地位。然后，学生将应用这些技能来监测pH值的空间和时间变化（总规模）和海水碳酸盐化学（DIC和总碱度）在Pantelleria和Vulcano（西西里）沿海栖息地，那里的气体喷口很浅（<10米深），海岸线的平均二氧化碳分压水平为380，1000和2000 ppm，类似于最近在自然界中描述的PI关闭伊斯基亚。这些气体排放点是经过精心挑选的，适合于检验下列假设：1）近期海洋酸化水平（2100年情景）可能会增强海草和某些入侵性大型藻类在自然环境中的生长和繁殖，2）慢性高碳酸血症可能导致底栖生物多样性的总体减少，包括许多钙化物种的丧失，对潮间带和潮下带生境的生态系统功能产生负面影响，3）移植实验，加上沿着pCO2梯度取样，证实某些物种可以通过改变骨骼矿物学来适应长期酸化，4）活跃的后生动物（如虾和鱼）可以承受高水平的二氧化碳作为成年人，但不完成他们的生活史在自然酸化的网站。这种方法是创新的，因为生态系统的影响很难使用BIOACID和EPOCA方案所采用的方法进行评估，这些方法在数周至数月的时间尺度内操纵水族馆和中型生态系统中的二氧化碳水平。该奖学金旨在满足英国OA科学计划，该计划指出“也可以从天然CO2富集区的研究中获得强大的见解”。该奖学金解决了目标3.1，3.3，并将获得数据，以提高我们对商业重要物种的OA影响的理解。首席主管是EPOCA计划内的PI，也是他们的“海洋酸化研究最佳实践指南”的合著者，这将是该奖学金的方法论基础。将使用沉积物（例如有孔虫）中的手持岩心和岩石上的0.5平方米样方，对380至平均1000和2000 ppm CO2的重复样地的底栖生物多样性和生物量进行比较。将部署沉降板来调查不同pCO2水平下的补充过程，并将使用移植实验（珊瑚藻、贻贝和牡蛎）来确定长期暴露于高CO2水平对钙化、繁殖力和生长的影响。将测量海草（Posidonia）和大型藻类（Sargassum、Asparagopsis）的光合作用（使用PAM）、繁殖和生长。学生将研究钙化藻类，有孔虫和珊瑚是否可以根据Bijma的BIOACID组的监督下周围海水中的CO2含量来适应它们的矿物学，使用原子力和拉曼显微镜来研究对钙化生物的精细和超微结构的影响。在2012年的实地考察期间，将使用重复的视觉计数来评估虾类和鱼类的多样性、行为和丰度，记录与CO2监测区有关的妊娠雌鱼和鱼巢的分布，因为幼鱼阶段最容易受到OA影响。要测试的假设的范围是不是太雄心勃勃的博士研究，鉴于我们的监督跟踪记录，初步调查武尔卡诺和潘泰莱里亚和我们的经验在伊斯基亚。

Objective: to determine the ecological effects of elevated CO2 levels in coastal habitats. In an 8 month training period at CNRS Roscoff and the MBA Plymouth the student will monitor variations in carbonate chemistry and biota of rockpool habitats. The student will be trained by a supervisory team that is world-leading in ecosystem based ocean acidification research using natural analogues. The student will then apply these skills to monitor spatial and temporal variability in pH (Total Scale) and seawater carbonate chemistry (DIC and total alkalinity) on coastal habitats off Pantelleria and Vulcano (Sicily) where gas vents are shallow (<10 m depth) and have shorelines with mean pCO2 levels of 380, 1000 and 2000 ppm, similar to those recently described in Nature by the PI off Ischia. These gas vent sites have been chosen carefully and are suited to test the following hypotheses; 1) near-future levels of ocean acidification (year 2100 scenarios) may enhance the growth and reproduction of sea grasses and certain invasive macroalgae in natural settings, 2) chronic hypercapnia can lead to an overall reduction in benthic biodiversity, including the loss of numerous calcified species, with negative effects on ecosystem function in intertidal and subtidal habitats, 3) transplant experiments, coupled with sampling along pCO2 gradients, confirm that some species can adapt to long-term acidification by altering skeletal mineralogy, 4) active metazoans (e.g. shrimp and fish) can withstand high levels of CO2 as adults but do not complete their life-histories at naturally acidified sites. This approach is innovative as ecosystem effects are difficult to assess using methods adopted by the BIOACID and EPOCA programmes, whereby CO2 levels are manipulated in aquaria and mesocosms over timescales of weeks-months. This studentship is designed to meet the UK OA Science Plan which states that 'Powerful insights may also be gained from studies of areas with natural CO2 enrichment'. The studentship addresses Aims 3.1, 3.3 and will also obtain data to improve our understanding of OA impacts for commercially important species. The lead supervisor is a PI within the EPOCA program and co-author of their 'Guide to Best Practices in Ocean Acidification Research' which will be the methodological basis of this studentship. Comparisons will be made of benthic biodiversity and biomass on replicate plots from 380 to mean 1000 and 2000 ppm CO2 using hand-held cores in sediments (e.g. for foraminifera) and 0.5 m2 quadrats on rock. Settlement plates will be deployed to investigate recruitment processes at different levels of pCO2 and transplant experiments (of coralline algae, mussels and oysters) will be used to determine the effects of long-term exposures to high CO2 levels on calcification, fecundity and growth. Photosynthesis (using PAM), reproduction and growth will be measured on seagrass (Posidonia) and macroalgae (Sargassum, Asparagopsis). The student will examine whether calcified algae, foraminifera and corals can adapt their mineralogy depending on the amounts of CO2 in the surrounding seawater under supervision in Bijma's BIOACID group using Atomic force- and Raman-microscopy to study the impact on the fine- and ultra-structure of calcified organisms that grew at high CO2. During field excursions in 2012 repeated visual counts will be used to assess the diversity, behavior and abundance of shrimps and fish recording the distribution of gravid females and fish nests in relation to CO2 monitoring zones, as juvenile stages can be the most vulnerable to OA effects. The range of hypotheses to be tested are not too ambitions for doctoral research, given our supervisory track-record, preliminary surveys of Vulcano and Pantelleria and our experience at Ischia.