Recruitment Success in Infauna: Geochemical Cues

在动物群中成功招募：地球化学线索这项研究将解决与招募有关的两个问题，这是群落动态的一个重要决定因素：1)新招募人员响应的沉积物表面的质量是什么？以及2)什么过程(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，一些新兵对各种栖息地共有的物质--如氨和氧气等孔隙水溶质--有反应。这些溶质似乎表明栖息地质量和干扰历史--这两者都可能强烈地影响新兵的生存。大多数生物活跃的沉积系统的特点是，在有机质分解(成岩作用)和运输过程的驱动下，表层沉积物中的溶质梯度很大(Bemer 1980)。大多数扰动会导致化学性质的变化，使表层沉积物的性质变得更亚氧或更缺氧。沉积物中化学性质的陡峭梯度和伴随扰动而来的表面化学变化为新兵提供了广泛可用的潜在重要化学信号。这项研究将检验一种假设，即生物体在选址过程中使用这种成岩信息。本研究将从实验和数学的角度探讨表层沉积物化学对一次和二次补给决策阶段的意义。这项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(如颗粒大小和有机质含量)提供的信号分开；(2)从实验和数学两个方面评估新兵对溶质信号的反应的普遍性，例如，成年后生活在不同沉积环境中的生物体对溶质信号的反应是否与新兵相似；以及(3)评估扰动-地表化学联系的影响，例如扰动的严重程度和溶质梯度的陡度是如何相互作用的，以及根据溶质分布和扰动历史，新兵接受给定地点的情况是否可预测？这项研究预计将开发具有评估和预测能力的耦合实验和模型；了解成虫分布差异较大的物种的新兵在多大程度上使用广泛分布但对环境有信息的溶质，作为生境适宜性的化学线索；了解干扰对地表溶质分布的影响以及新兵对干扰信号的反应的适应意义。总体而言，综合建模和实验方法将为评估各种近岸生境的招募模式和选择提供一种预测工具。

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.