Recruitment Success in Infauna: Geochemical Cues

在底栖动物中招募成功：地球化学线索本研究将解决两个问题的补充，群落动态的一个重要决定因素：1）什么是沉积物表面的质量，新兵作出反应？以及2）哪些过程（物理、生物和化学）控制场地的可用性和可接受性？最近的实验和模型表明，一些新成员对各种生境中常见的物质作出反应，即孔隙水溶质，如铵和氧。这些溶质似乎是栖息地质量和干扰历史的指示-这两者都可能强烈影响新兵的生存。大多数生物活性沉积系统的特点是，在有机物分解（成岩作用）和迁移过程的驱动下，顶部沉积层内的溶质梯度很大（Bemer，1980年）。大多数扰动导致化学变化，使表层沉积物的性质更加亚氧或缺氧。沉积物中化学性质的陡峭梯度和伴随扰动的表面活性剂化学变化为新招募的生物提供了广泛可用且可能具有重要意义的化学信号。本研究将检验生物体在选址过程中利用成岩信息的假设。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补充决策阶段的意义。研究将解决以下问题：（1）将溶质提供的信号与其他更常见的评估因素（如粒度和有机质含量）提供的信号分开;（2）在实验上和数学上评估新兵对溶质信号的响应的一般性，例如，生活在不同沉积环境中的成年生物对溶质信号的反应是否相似？以及（3）评估扰动-表面活性剂化学联系的含义，例如扰动的严重性和溶质梯度的陡度如何相互作用，以及在何种情况下，新成员将接受一个给定的位置可预测的基础上的溶质配置文件和干扰的历史？预计这项研究将开发具有评价和预测能力的耦合实验和模型;了解成年分布明显不同的新物种在多大程度上使用分布广泛但提供环境信息的溶质作为生境适宜性的化学线索;以及干扰对表面活性剂溶质分布的影响和新兵对干扰信号反应的适应意义。总体而言，综合建模和实验方法将提供一个预测工具，评估招聘模式和选择在各种近岸栖息地。

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.