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

沉积矿床中的成岩作用在地球化学活性元素的循环和埋藏过程中起着重要作用。海洋底栖动物的活动极大地影响了早期成岩作用，改变了表层沉积物中的物质输运和反应分布以及大部分海底的沉积物-水交换。在这一项目中，斯托尼布鲁克的纽约州立大学的研究人员将继续利用新开发的光学传感器和模型，研究、概念化和量化这些生物对海洋地球化学循环的影响的具体方面，并将在底栖生物的共生和自生物学特征的范围内这样做。摄食、挖洞和生物结构的灌溉创造了复杂的、依赖时间的好氧和缺氧微环境网络。这些生源微环境的尺度和宏观几何模式决定了矿化途径的绝对和相对速率、微生物丰度和活动、反应之间的耦合，如硫酸盐还原/硫化物氧化或碳酸盐溶解-沉淀，以及元素埋藏。这种生物异质性几乎不可能通过传统方法准确测量或量化。作为最近资助的研究的一部分，开发了一套平面光学传感器，用于测量pH值，pCO2，O2，H2S，同时H2S/O2和Fe2+，在单个二维图像中的高分辨率（~50 - 100 μ m），面积约为100 - 300 cm 2，并将进一步优化和应用。新的胞外酶和Ca2+传感器的持续开发将完成。这些传感器将被用来直接调查三维溶质分布所产生的功能不同的底栖动物在实验室的微观世界，并在自然社区在原地，使用沉积物剖面设计与平面光电二极管使用的相机。在之前对Nevhtys incisa进行的微观实验的基础上，将在多种密度和恒定生物量或生物体积下检查选定的额外单个物种和功能类型混合物的影响。生物成因的结构和相关的矿化率模式将被量化和关于缩放的假设？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感测模式指导。扩散反应细胞，旨在模拟在多个尺度的灌溉洞穴的效果将与光学传感器一起使用，以检查瞬态和伪稳态氧化还原反应平衡和微生物活性作为扩散运输规模的函数，与类似规模的自然结构进行比较。将在实验室和现场实验中研究具有代表性的大型底栖动物管材料的组成、结构和降解模式，这些材料代表沉积C、N、P和金属循环的重要但未充分研究的途径。实验结果将被纳入综合概念和数学模型。 更广泛的影响：目前的研究将推进预测，基于机制的了解底栖生物群落和沉积物化学之间的相互作用，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。进一步发展和优化的平面光学传感器集成与地球化学应用将大大提高早期成岩作用的概念和定量模型的基础上，援助实验设计，并扩展能力的实际原位监测地球化学过程的管理目的。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分享。真实的实时光学传感器图像还提供了一种有效的手段，可用于交流底栖生物地球化学过程的动态和重要性，并吸引非专业人员参与。平面光电传感器图像和现场Chem-SPI系统将作为教育和研究工具，也将在公共论坛上作为提高对底栖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。研究结果将在国家和国际会议上以及同行评审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.