Collaborative Proposal: Optimizing Recruitment of Neocalanus copepods through Strategic Timing of Reproduction and Growth in the Gulf of Alaska

合作提案：通过阿拉斯加湾繁殖和生长的战略时机优化新桡足类的补充

• 批准号: 1459826
• 负责人: Russell Hopcroft
• 金额: $ 41.5万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459826&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Optimizing; Recruitment; Neocalanus

The Gulf of Alaska supports a diverse and productive marine community that includes many commercially important fishes. Toward the base of this food web are small planktonic crustaceans that serve as the primary food source for many of these fish, as well as seabirds and marine mammals. The copepod Neocalanus flemingeri is one of these crustaceans, and it experiences rapid population growth during each spring's algal, or phytoplankton, bloom. An apparent mismatch between the presence of the youngest stages of the copepod, or nauplii, in early winter and the unpredictable timing of the spring phytoplankton bloom several months later raises important questions about when females reproduce and how this relates to survival and growth of nauplii. Two types of dormancy, diapause in adult females and physiological quiescence in nauplii, may be the key to the success of this copepod species. Timing and duration of the egg-laying period by adult females is linked to emergence from diapause. In addition, nauplii may enter a state of physiological quiescence while food resources are low, resuming growth after phytoplankton levels increase. This research will address a long-standing goal of biological oceanographers to understand dormancy and its role in controlling population cycles in marine copepods. It will use new technologies in molecular biology called transcriptomics to catalog the messages used by the cells to control copepod life processes, in this case those related to dormancy in adults and nauplii. Undergraduate students and a postdoctoral investigator will be trained in interdisciplinary research, and students from Native Hawaiian and Native Alaskan groups will be targeted for participation. Fishing is a major industry in the Gulf of Alaska, and outreach will focus on communicating the role copepods play in marine ecosystems. New content, including images, will be generated for existing websites: the Seward Line long-term observation program, the Alaska Ocean Observing System and the Gulf Watch Alaska Program. Recruitment to the Neocalanus flemingeri spring population is dependent on successful emergence from diapause followed by reproduction, survival, and growth of the next generation. Individual-based models have made significant progress in predicting population growth in calanoid copepods using food, temperature, and advection as key environmental factors. Few of these models include predictors for naupliar recruitment, however, because little is known about this part of the life cycle given sampling difficulties and the lack of biomarkers to evaluate physiological state. This study will leverage existing monitoring efforts to track the N. flemingeri population during the winter and early spring. The research team will combine laboratory and field approaches to determine duration and synchronization of reproduction in emerging females and strategies for naupliar survival during low food conditions. Zooplankton samples will be processed to enumerate nauplii to species and to determine physiological condition of both nauplii and adult females. Gene expression studies will develop molecular markers for female dormancy and reproductive readiness and for naupliar growth and possible dormancy, which in turn will be used to evaluate field collected individuals. This will be the first comprehensive study to combine molecular and traditional tools to connect diapausing adults, naupliar production, and the resulting spring population of copepodites.

阿拉斯加湾支持一个多样化和多产的海洋社区，包括许多商业上重要的鱼类。在这一食物网的底部是小型浮游甲壳类动物，它们是许多鱼类以及海鸟和海洋哺乳动物的主要食物来源。桡足类新哲水蚤（Neocalanus flemingeri）就是其中一种甲壳类动物，在每年春天的藻类或浮游植物水华期间，它的数量都会迅速增长。一个明显的不匹配之间存在的最年轻的阶段的桡足类，或无节幼体，在初冬和不可预测的时间春季浮游植物盛开几个月后提出了重要的问题，当女性繁殖，以及如何这涉及到生存和生长的无节幼体。两种类型的休眠，滞育的成年女性和生理静止的无节幼体，可能是成功的关键，这桡足类物种。成虫产卵期的时间和持续时间与滞育的出现有关。此外，无节幼体可能在食物资源不足时进入生理静止状态，在浮游植物水平增加后恢复生长。这项研究将解决生物海洋学家的长期目标，了解休眠及其在控制海洋桡足类种群周期中的作用。它将使用分子生物学中称为转录组学的新技术来分类细胞用于控制桡足类生命过程的信息，在这种情况下，这些信息与成虫和无节幼体的休眠有关。本科生和博士后研究员将接受跨学科研究的培训，夏威夷土著和阿拉斯加土著群体的学生将成为参与的目标。渔业是阿拉斯加湾的主要产业，外联活动将侧重于宣传桡足类在海洋生态系统中的作用。将为现有网站制作新的内容，包括图像：苏厄德线长期观测方案、阿拉斯加海洋观测系统和海湾观察阿拉斯加方案。 新哲水蚤春季种群的补充依赖于滞育的成功出现，然后是下一代的繁殖、生存和生长。基于个体的模型在利用食物、温度和平流作为关键环境因子预测哲水蚤桡足类种群增长方面取得了重大进展。然而，这些模型中很少有包括无节幼体招募的预测因子，因为对于给定采样困难和缺乏生物标志物来评估生理状态的生命周期的这一部分知之甚少。这项研究将利用现有的监测工作，以跟踪N。flemingeri种群在冬季和早春。该研究小组将联合收割机结合实验室和现场的方法，以确定持续时间和同步的生殖新兴女性和战略无节幼体生存在低食物条件。 浮游动物样本将被处理，以计算无节幼体的种类，并确定无节幼体和成年雌性的生理状况。基因表达研究将开发雌性休眠和生殖准备以及无节幼体生长和可能的休眠的分子标记，这反过来又将用于评估实地收集的个体。 这将是第一个全面的研究，联合收割机分子和传统的工具，连接滞育成人，无节幼体生产，并由此产生的春季人口桡足类。