The effects of animal-sediment interactions on biogeochemical processes at the sediment -water interface

沉积中的成岩作用在生物地球化学活性元素的旋回和埋藏中起着核心作用。海洋底栖动物的活动极大地影响了早期成岩作用，改变了表面沉积物中的物质运输和反应分布以及海底大部分沉积物-水交换。在这个项目中，纽约州立大学石溪分校的研究人员将使用新开发的光学传感器和模型，继续研究、概念化和量化这些生物成因对生物地球化学循环的具体影响，并将在底栖生物的同步和非生态特征的背景下进行研究。生物结构的取食、挖洞和灌溉创造了复杂的、随时间变化的缺氧和缺氧微环境网络。这些生物成因微环境的尺度和宏观几何模式决定了再矿化途径的绝对和相对速率、微生物丰度和活动、硫酸盐还原/硫化物氧化或碳酸盐溶解-沉淀等反应之间的耦合以及元素埋藏。这种生物多样性实际上是不可能用传统方法精确测量或量化的。一套平面光学传感器设计用于测量pH， pCO2, O2, H2S，同时H2S / O2和Fe2+在高分辨率（~50 - 100 ìm）的单张二维图像，面积为~ 100 - 300 cm2，将进一步优化和应用作为最近资助的研究的一部分。正在进行的新的外泌酶和Ca2+传感器的开发将完成。这些传感器将用于直接研究实验室微观世界中功能不同的动物产生的三维溶质分布，以及原位自然群落，使用设计用于平面光电器件的沉积物剖面相机。在先前用切尼弗提斯（Nephtys incisa）进行的微观实验的基础上，将在多种密度和恒定的生物量或生物体积下检查选定的额外个体物种和功能类型混合物的影响。生物成因结构和相关的再矿化速率模式将被量化和关于结垢的假设？氧化还原反应关系测试。生物结构周围微生物活动的直接测量将由光学传感模式指导。设计用于模拟多尺度灌溉洞穴效应的扩散反应细胞将与光学传感器一起使用，以检测瞬态和准稳态氧化还原反应平衡以及微生物活性作为扩散运输尺度的函数，并与类似尺度的自然结构进行比较。代表性大型动物管状材料的组成、结构和降解模式将在实验室和野外实验中进行研究，这些材料代表了沉积碳、氮、磷和金属循环的重要途径，但尚未得到充分的研究。实验结果将纳入综合概念和数学模型。更广泛的影响：目前的研究将促进对底栖生物群落和沉积物化学之间相互作用的预测，基于机械的理解，它们对社会重要性的生物地球化学循环的影响，以及污染物的命运。结合生物地球化学应用的平面光学传感器的进一步发展和优化，将大大改善早期成岩作用的概念和定量模型的基础，有助于实验设计，并扩大用于管理目的的生物地球化学过程的实际原位监测能力。农业和土壤研究也可能受益于平面传感器的应用。这些能力将继续通过跨学科合作得到促进和共享。实时光学传感器图像也提供了一种有效的手段来传达底栖生物地球化学过程的动态和重要性，并吸引非专业人士。平面光电传感器图像和原位化学spi系统将被纳入教育和研究工具，也将被用作在公共论坛上提高对底栖生物过程的普遍认识的一种方式。研究生和本科生教育和技术培训将继续与实验室和实地研究密切结合。研究结果将在国内和国际会议上发表，并在同行评议的国际科学期刊上发表。

Diagenetic processes in sedimentary deposits play a central role in the cycling and burial of biogeochemically reactive elements. The activities of marine bottom-dwelling animals dramatically impact early diagenesis, altering material transport and reaction distributions in surface sediments and sediment-water exchange over much of the seafloor. In this project, researchers at the State University of New York at Stony Brook will continue to examine, conceptualize, and quantify specific aspects of these biogenic effects on biogeochemical cycles using newly developed optical sensors and models, and will do so within the context of syn- and autecological characteristics of benthos. Feeding, burrowing, and the irrigation of biogenic structures create complex, time-dependent networks of oxic and anoxic microenvironments. The scaling and macro-geometrical patterns of these biogenic microenvironments determine absolute and relative rates of remineralization pathways, microbial abundances and activities, the coupling between reactions such as sulfate reduction/sulfide oxidation or carbonate dissolution - precipitation, and elemental burial. Such biogenic heterogeneity is virtually impossible to accurately measure or quantify by traditional methods. A set of planar optical sensors designed to measure pH, pCO2, O2 , H2S, simultaneous H2S / O2, and Fe2+ at high resolution (~50 - 100 ìm) in single 2-D images over areas of ~ 100 - 300 cm2 were developed as part of recently funded research, and will be further optimized and applied. The ongoing development of new exoenzyme and Ca2+ sensors will be completed. These sensors will be used to directly investigate three-dimensional solute distributions produced by functionally distinct infauna in laboratory microcosms, and in natural communities in situ, using sediment profiling cameras designed for use with planar optodes. Building on previous microcosm experiments with Nephtys incisa, the effects of selected additional individual species and mixtures of functional types will be examined at multiple densities and constant biomass or biovolume. Biogenic structure and associated remineralization rate patterns will be quantified and hypotheses regarding scaling ? redox reaction relationships tested. Direct measures of microbial activity around biogenic structures will be guided by the optically sensed patterns. Diffusion-reaction cells designed to simulate the effect of irrigated burrows at multiple scales will be used together with optical sensors to examine transient and pseudo-steady redox reaction balances and microbial activity as a function of diffusive transport scale for comparison with natural structures of similar scale. The composition, structure, and degradation patterns of representative macrofaunal tube materials, which represent a significant but understudied pathway of sedimentary C, N, P, and metal cycling, will be examined in laboratory and field experiments. Experimental results will be incorporated into integrative conceptual and mathematical models. Broader Impacts: The present research will advance predictive, mechanistic-based understanding of interactions between benthic communities and sediment chemistry, their effect on biogeochemical cycles of societal importance, and the fate of pollutants. The further development and optimization of planar optical sensors integrated with biogeochemical applications will substantially improve the basis for conceptual and quantitative models of early diagenesis, aid experimental design, and extend capacity for practical in situ monitoring of biogeochemical processes for management purposes. Agricultural and soil research may also benefit from planar sensor applications. These capabilities will continue to be promoted and shared through interdisciplinary collaborations. Real time optical sensor images also provide an effective means to communicate the dynamics and importance of benthic biogeochemical processes, and to engage nonspecialists. Planar optode sensor images and in situ Chem-SPI systems will be incorporated as educational and research tools and will also be used as a way to raise general awareness about benthic processes in public forums. Graduate and undergraduate education and technical training will continue to be intimately integrated with laboratory and field research. Results will be presented at national and international meetings, and in peer-reviewed international scientific journals.