Ocean Acidification-Category 1- Impact of ocean acidification on survival of early life stages of planktonic copepods in the genus Calanus in the northern

虽然对世界海洋预计酸化影响的关注集中在钙化生物上，但非钙化浮游生物也可能易受影响。在这个项目中，研究人员将评估海洋酸化对高纬度海洋中突出的哲水蚤属三种浮游桡足类繁殖成功的影响。C.在北大西洋沿海和深海的大部分地区，finmarchicus在中型浮游动物生物量中占据主导地位。C. glacialis和较大的C. hyperboreus是北冰洋最丰富的浮游桡足类之一。以往的研究表明，C.在海水中增加CO2和降低pH值会严重抑制finmarchicus卵，但仅在极端水平下进行测试。研究者实验室的初步结果表明，C.在海水CO2浓度增加时，对应于pH值在7.9和7.5之间，finmarchicus的死亡率显著降低。如果这些初步结果得到证实，在下一个世纪，地表pH值可能下降到7.7-7.8的预测提出了对哲水蚤种群动态影响的问题。C.例如，finmarchicus目前位于缅因州海湾的南部边缘。较高的表层温度和较低的pH值的组合可能会抑制繁殖成功在夏末/秋季开花，PI假设是至关重要的，以维持在这个地区的越冬股票。研究人员将收集C。在加拿大同事的协助下，对来自缅因州海湾的雌性C. glacialis和C.从深较低的圣劳伦斯河口hyperboreus女性。他们将进行实验室实验，在自然海水的控制下测量哲水蚤无节幼体阶段的孵化成功，发育和生长，并在一系列处理中严格控制二氧化碳浓度，pH值和温度，以代表北方海洋未来可能的状态。在一次研究巡航中，调查人员将测量整个缅因州湾（包括其深水盆地）目前的表层和深层pCO 2和pH值。该研究将评估预测北方海洋二氧化碳水平增加将影响哲水蚤物种种群动态的假设。利用研究巡航的结果和最近开发的一维，基于个体的生命周期模型，PI将详细探索较高温度和较低的表面和深层pH值对C种群动态的影响。更广泛的影响：富含脂质的哲水蚤物种被认为是北大西洋和北冰洋食物网初级生产和更高营养级之间的关键中间环节。较高的表面温度和较低的pH值对繁殖成功率的影响可能会导致北方海洋远洋生态系统的能量转移和结构发生深刻变化。在缅因州湾，C. finmarchicus是鲱鱼、沙矛鱼和鲭鱼以及濒危的北方露脊鲸的主要猎物，因此需要全面评估海洋酸化对其种群动态的影响。本研究将提供跨学科的培训，以研究生和本科生实习。数据将存放在一个公认的数据存档中心，并通过在科学会议上的演讲和同行评审的研究文章传播结果。公共宣传将计划作为缅因州研究所社群活动的一部分，包括与科恩互动学习中心相关的学习机会，该中心针对缅因州的五年级和六年级学生。

While attention concerning impacts of predicted acidification of the world's oceans has focused on calcifying organisms, non-calcifying plankton may also be vulnerable. In this project, the investigator will evaluate the potential for impacts of ocean acidification on the reproductive success of three species of planktonic copepods in the genus Calanus that are prominent in high latitude oceans. C. finmarchicus dominates the mesozooplankton biomass across much of the coastal and deep North Atlantic Ocean. C. glacialis and the larger C. hyperboreus are among the most abundant planktonic copepods in the Arctic Ocean. Previous research showed that hatching success of C. finmarchicus eggs was severely inhibited by increased CO2 and lower pH in seawater, but only tested at an extreme level. Preliminary results in the investigator's laboratory indicate that hatching success of C. finmarchicus is substantially reduced at increased seawater CO2 concentrations corresponding to pH levels between 7.9 and 7.5. Predictions of likely decline of surface pH levels to 7.7-7.8 over the next century raise questions about impacts on Calanus population dynamics if these preliminary results are confirmed. C. finmarchicus, for example, is presently at the southern edge of its range in the Gulf of Maine. The combination of higher surface layer temperature and lower pH may inhibit reproductive success during the late summer/fall bloom, which the PI hypothesize is critical to sustain the overwintering stock in this region. The investigators will collect C. finmarchicus females from the Gulf of Maine and, with the assistance of Canadian colleagues, C. glacialis and C. hyperboreus females from the deep lower St. Lawrence Estuary. They will conduct laboratory experiments in which hatching success, development and growth of Calanus nauplius stages are measured in controls of natural seawater and at a series of treatments in which CO2 concentrations, pH and temperature are rigorously controlled to represent possible future states of the northern ocean. The investigators will measure present surface and deep pCO2 and pH across the Gulf of Maine, including its deep basins, during a research cruise. The study will evaluate the hypothesis that predicted levels of CO2 increase in the northern ocean will impact population dynamics of the Calanus species. Using the results from the research cruise and a recently developed 1-D, Individual-Based life cycle model, the PI will explore in detail scenarios of impact of higher temperature and lower surface and deep pH on population dynamics of C. finmarchicus in the Gulf of Maine.Broader impacts: The lipid-rich Calanus species are considered key intermediary links between primary production and higher trophic levels in North Atlantic and Arctic Ocean food webs. Impacts of higher surface temperature and lower pH on reproductive success may potentially lead to profound changes in energy transfer and structure of pelagic ecosystems in the northern oceans. In the Gulf of Maine, C. finmarchicus serves as primary prey for herring, sand lance, and mackerel, as well as the endangered northern right whale, warranting thorough evaluation of ocean acidification effects on its population dynamics. This research will provide cross discipline training to a graduate student and undergraduate student interns. Data will be deposited in a recognized data archiving center and results disseminated through presentations at scientific meetings and peer reviewed research articles. Public outreach will be planned as part of the Gulf of Maine Research Institute community activities, including learning opportunities associated with the Cohen Center for Interactive Learning directed at fifth and sixth graders in the state of Maine.