Planktonic Omnivores and Stable Isotopes: Developing, Validating and Field-testing a Multi-species Functional Response Model

浮游杂食动物和稳定同位素：开发、验证和现场测试多物种功能响应模型

• 批准号: 2023349
• 负责人: Ryan Woodland
• 金额: $ 89.68万
• 依托单位: University of Maryland Center for Environmental Sciences
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2023349&HistoricalAwards=false
• 关键词: Planktonic; Omnivores; Stable; Isotopes; Developing

Diagrams of food webs are typically drawn as boxes that show linkages between predators and prey. While these are useful models of how energy is transferred along a food chain, real food webs are more complex. Predator diets are often variable making it difficult to establish predator-prey links in marine communities. This project is investigating prey switching in a key member of coastal food webs, the shrimp-like mysid, Neomysis americana. Prey switching affects community structure and an organism’s resilience to environmental perturbation, but it is not easy to quantify. This project is using a combination of laboratory experiments and field sampling to develop a food web model that predicts mysid feeding patterns in the environment. This realistic and predictive food web model uses traditional gut analysis and analytical techniques that follow carbon and nitrogen as it is incorporated into the bodies of the mysids. In addition, mysid food preferences are being determined in the laboratory across a full range of diet possibilities. The calibrated gut analysis and chemical marker data in combination with feeding experiments are incorporated into the model, which then predicts mysid feeding on mixed diets under different environmental conditions. These predictions are validated against field data. Broader impacts include benefits to society for a better understanding of how coastal food webs work. Doctoral students and undergraduate students are being trained in experimental and field research. Increasing diversity in STEM fields is occurring through a partnership with two community colleges (College of Southern Maryland, Chesapeake College) to recruit summer interns for research experiences. Outreach activities include the development of educational materials for grade-appropriate hands-on laboratory experiments and training opportunities for middle and high school teacher groups in the use of these materials in their classrooms. This project is developing and field-testing a generalizable approach to understand and predict complex predator-prey relationships in marine food webs. The research plan involves building and validating a multispecies functional response (MSFR) model for an omnivorous consumer, the mysid Neomysis americana. These models predict diet for consumers that feed on multiple types of prey under differing prey concentrations and identify conditions under which prey switching occurs in the environment. Recent and time-integrated diet tracking with gut contents, bulk stable isotope (SI) and compound-specific amino acid stable isotope (AA-CSI) analysis are validated in the lab and used to reconstruct diet of Neomysis in the field. The proposed research is testing specific hypotheses about Neomysis’ consumption rates and prey preferences and the effectiveness of integrating SI and AA-CSI into MSFR models. Laboratory experiments are determining prey-specific functional response curves by Neomysis under varying prey concentrations and environmental (temperature) conditions using grazing experiments. Experimental results are incorporated into a temperature-dependent MSFR model for a 5-compartment simplified food web (Neomysis, adult copepod, copepod nauplii, phytoplankton, detritus). A complementary element of the project is the experimental determination of bulk SI (𝛿13C and 𝛿15N) and AA-CSI (𝛿15N) equilibration rates and trophic enrichment factors for Neomysis and each prey type. The predator-prey dynamics of Neomysis in the environment are being modeled using the lab-validated MSFR approach and field data, including prey concentrations, gut contents, and prey and Neomysis SI and AA-CSI data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

食物网图通常被画成方框，显示捕食者和猎物之间的联系。虽然这些都是能量如何沿着沿着转移的有用模型，但真实的食物网要复杂得多。 捕食者的饮食往往是可变的，因此很难在海洋群落中建立捕食者与猎物的联系。这个项目正在调查沿海食物网的一个关键成员，虾样糠虾，美洲新糠虾的猎物转换。猎物转换会影响群落结构和生物体对环境扰动的恢复力，但不容易量化。 该项目结合实验室实验和实地采样，开发一个食物网模型，预测糠虾在环境中的摄食模式。这个现实和预测性的食物网模型使用传统的肠道分析和分析技术，跟踪碳和氮，因为它被纳入糠虾的身体。此外，糠虾的食物偏好正在实验室中确定，包括各种饮食可能性。校准的肠道分析和化学标记物数据结合喂养实验被纳入模型，然后预测糠虾在不同环境条件下的混合饲料喂养。这些预测验证现场数据。更广泛的影响包括使社会更好地了解沿海食物网的运作方式。正在对博士生和本科生进行实验和实地研究方面的培训。通过与两所社区学院（南马里兰州学院、切萨皮克学院）合作，招募暑期实习生进行研究，STEM领域的多样性正在增加。推广活动包括为适合年级的实验室动手实验编写教材，并为初中和高中教师团体提供在课堂上使用这些教材的培训机会。 该项目正在开发和实地测试一种可推广的方法，以了解和预测海洋食物网中复杂的捕食者-被捕食者关系。该研究计划包括建立和验证一个多物种功能反应（MSFR）模型的杂食性消费者，糠虾美洲新糠虾。这些模型预测饮食的消费者，在不同的猎物浓度和确定条件下，猎物切换发生在环境中的多种类型的猎物。最近和时间整合的饮食跟踪与肠道内容物，散装稳定同位素（SI）和化合物特异性氨基酸稳定同位素（AA-CSI）分析在实验室中进行了验证，并用于重建新糠虾的饮食领域。该研究旨在验证新糠虾的消费率和猎物偏好的特定假设，以及将SI和AA-CSI整合到MSFR模型中的有效性。实验室实验是通过放牧实验确定新糠虾在不同猎物浓度和环境（温度）条件下的猎物特异性功能反应曲线。实验结果被纳入一个温度依赖MSFR模型的5室简化的食物网（新糠虾，成年桡足类，桡足类无节幼体，浮游植物，碎屑）。该项目的一个补充要素是实验测定新糠虾和每种猎物类型的散装SI（β13 C和β15 N）和AA-CSI（β15 N）平衡率和营养富集因子。使用实验室验证的MSFR方法和现场数据，包括猎物浓度，肠道内容物，猎物和Neomysis SI和AA-CSI数据，对环境中Neomysis的捕食者-猎物动态进行建模。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。