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

动物-沉积物相互作用对沉积物-水界面生物地球化学过程的影响

• 批准号: 0851207
• 负责人: Robert Aller
• 金额: $ 99.76万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0851207&HistoricalAwards=false
• 关键词: effects; animal; sediment; interactions; biogeochemical

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.

沉积矿床中的成岩作用在生物地球化学反应元素的循环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，改变了表层沉积物中的物质运输和反应分布以及海底大部分地区的沉积物-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继续使用新开发的光学传感器和模型来检查、概念化和量化这些对生物地球化学循环的生物成因影响的具体方面，并将在底栖动物的共生和自生特征的背景下这样做。对生物结构的取食、挖洞和灌溉创造了复杂的、依赖于时间的缺氧和缺氧微环境网络。这些生物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、微生物的丰度和活性、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。这种生物来源的异质性几乎不可能用传统方法准确地测量或量化。作为最近资助的研究的一部分，一套平面光学传感器被开发出来，用于在~100-300平方厘米的区域内以高分辨率(~50-100？m)测量单个二维图像中的pH、PCO_2、O2、H_2S、同时的H_2S/O_2和Fe2+。正在进行的新的胞外酶和钙离子传感器的开发将完成。这些传感器将被用来直接研究实验室微观世界和现场自然群落中功能不同的动物群产生的三维溶质分布，使用为平面光电二极管设计的沉积物剖面仪。在之前对灯心草进行的微观世界实验的基础上，将在多种密度和恒定生物量或生物量的情况下，检验选定的额外个体物种和功能类型的混合物的影响。生物成因结构和相关的再矿化率模式将被量化，以及关于比例的假设？测试了氧化还原反应关系。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。为模拟灌溉洞穴在多个尺度上的影响而设计的扩散反应池将与光学传感器一起使用，以检查瞬时和准稳定的氧化还原反应平衡和微生物活动作为扩散传输尺度的函数，以便与类似尺度的自然结构进行比较。具有代表性的大型动物管状物质的组成、结构和降解模式，代表了沉积C、N、P和金属循环的一个重要但未被研究的途径，将在实验室和野外实验中进行检验。实验结果将被纳入综合的概念和数学模型中。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的相互作用、它们对具有社会重要性的生物地球化学循环的影响以及污染物的去向的预测性、机械性的理解。进一步开发和优化与生物地球化学应用相结合的平面光学传感器，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现场监测的能力。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协作得到推广和共享。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力学和重要性，并与非专家接触。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海底过程的一般认识的一种方式。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。结果将在国家和国际会议上公布，并在同行评审的国际科学期刊上公布。