Recruitment Success in Infauna: Geochemical Cues

动物群的成功招募：地球化学线索

• 批准号: 9811433
• 负责人: James R Nelson
• 金额: --
• 依托单位: Skidaway Institute of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2000-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9811433&HistoricalAwards=false
• 关键词: Recruitment; Success; Infauna; Geochemical; Cues

Recruitment success in infauna: geochemical cues This study will address two questions about recruitment, an important determinant of community dynamics: 1) what are the qualities of the sediment surface to which recruits are responding? and 2) what processes (physical, biological and chemical) control availability and acceptability of sites? Recent experiments and models suggest that some new recruits respond to substances common to a variety of habitats, namely porewater solutes such as ammonium and oxygen. These solutes appear to be indicative of habitat quality and disturbance history -- both of which may strongly influence survivorship of recruits. Most biologically active sedimentary systems are characterized by steep solute gradients within the top sediment layers, driven by organic matter decomposition (diagenesis) and transport processes (Bemer 1980). Most disturbances result in changes in chemistry that render the surficial sediments more suboxic or anoxic in character. The steep gradients in chemical properties in sediments and the changes in surficial chemistry that accompany disturbance provide a broadly available and potentially significant chemical signal for new recruits. This study will examine the hypothesis that organisms use this diagenetic information in the site selection process. This study will examine the significance of surficial sediment chemistry to the decision making phase for primary and secondary recruitment from an experimental and mathematical point of view. The research will address the following: (1) separate the signal provided by solutes from that provided by other, more commonly evaluated factors such as grain size and organic matter content; (2) evaluate the generality of the responses of new recruits to solute signals both experimentally and mathematically, for example, do organisms which as adults inhabit different sedimentary environments respond similarly to solute signals as new recruits; and (3) evaluate the implications of the disturbance-surficial chemistry link, for example how do the severity of the disturbance and the steepness of the solute gradients interact, and are the circumstances under which new recruits will accept a given location predictable on the basis of the solute profile and disturbance history? The study is expected to develop coupled experiments and models with an evaluative and predictive capacity; an understanding of the degree to which new recruits of species with significantly different adult distributions use solutes that are broadly distributed, but environmentally informative, as chemical cues to habitat suitability; and an appreciation for the influence of disturbance on surficial solute distributions and the adaptive significance of the responses of new recruits to disturbance signals. Overall, the integrated modeling and experimental approach will provide a predictive tool for evaluating recruitment patterns and choices in a variety of nearshore habitats.

本研究将解决两个问题，这是群落动态的一个重要决定因素：1)新生物响应的沉积物表面质量是什么？2)哪些过程（物理的、生物的和化学的）控制着场地的可用性和可接受性？最近的实验和模型表明，一些新成员对各种栖息地常见的物质有反应，即孔隙水溶质，如铵和氧。这些溶质似乎表明了栖息地质量和干扰历史，这两者都可能强烈影响新兵的生存。大多数具有生物活性的沉积体系的特征是，在有机质分解（成岩作用）和运移过程的驱动下，顶部沉积层内的溶质梯度很陡（Bemer 1980）。大多数扰动导致化学变化，使表层沉积物在性质上更具亚氧性或缺氧性。沉积物中化学性质的陡峭梯度和伴随扰动的表面化学变化为新成员提供了广泛可用的潜在重要化学信号。本研究将检验生物体在选址过程中使用这种成岩信息的假设。本研究将从实验和数学的角度探讨表层沉积物化学对初级和次级招募决策阶段的意义。该研究将解决以下问题：(1)将溶质提供的信号与其他更常用的评估因素（如粒度和有机质含量）提供的信号分开；(2)从实验和数学两方面评估新成员对溶质信号反应的普遍性，例如，成年后生活在不同沉积环境中的生物对溶质信号的反应是否与新成员相似；(3)评估干扰-表面化学联系的含义，例如干扰的严重程度和溶质梯度的陡峭度如何相互作用，以及在溶质剖面和干扰历史的基础上，新成员接受给定位置的情况是否可预测？预计该研究将开发具有评价和预测能力的耦合实验和模型；了解具有显著不同成虫分布的新物种在多大程度上使用广泛分布但具有环境信息的溶质作为生境适宜性的化学线索；并对干扰对表面溶质分布的影响以及新成员对干扰信号的响应的适应意义进行了评价。总体而言，综合建模和实验方法将为评估各种近岸栖息地的招聘模式和选择提供预测工具。