The Importance of Iron Complexation to Organic Matter Preservation in Suboxic Sediments

铁络合对含氧沉积物中有机物保存的重要性

基本信息

批准号：
9911364
负责人：
Bruce Frost
金额：
$ 6.96万
依托单位：
University of Washington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2000
资助国家：
美国
起止时间：
2000-03-01 至 2001-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9911364&HistoricalAwards=false
关键词：
Importance Iron Complexation Organic Matter

项目摘要

ABSTRACTOCE-9911364Unusually high organic carbon concentrations are found in sediments accumulating under suboxic water columns where the oxygen-deficient zone impinges on the continental shelf. Although several factors are believed to be responsible for these high concentrations and are a matter of ongoing debate, a mechanism to explain why a substantial fraction of sedimentary organic matter (OM) resists bacterial degradation only under suboxic water columns is still lacking. The PIs propose to study interactions between iron and OM in sediments from the Mexican coast to test their premise that the unusually high OM concentrations in sediments result from inner-sphere Fe-OM complexation and "refractorization" of the more labile OM. This scientific team believes that the complexation takes place because of the absence of significant amounts of kinetically faster competing species such as O2, NO3-, IO3-, Mn oxides and HS- in the sedimentary horizon where complexation takes place. Results from this study will prove or disprove whether this iron-complexation process indeed is a viable mechanism to explain the unusually high OM concentrations in sediments on the Mexican coast, as well as provide information on the kinetics of competing reactions (ie. O2, NO3-, IO3-, Mn oxides and HS-) leading to the speciation of Fe in oxic, suboxic and sulfidic sediments.

Abstractoce-9911364通常在亚氧化水柱下积聚的沉积物中发现了较高的有机碳浓度，在这些沉积物中，缺氧区域会影响大陆架上。尽管据信几个因素是对这些高浓度的原因，并且是持续争论的问题，但解释为什么大量沉积有机物（OM）的机制仅在亚氧化水柱下才能抵抗细菌降解。 PI提议研究墨西哥海岸沉积物中的铁和OM之间的相互作用，以测试其前提，即沉积物中的OM浓度异常高，是由pher-phere fe-om的浓度和更不稳定的OM的“折射率”引起的。这个科学团队认为，由于没有大量动力学竞争的物种，例如O2，NO3-，IO3-，MN氧化物和HS-在发生络合的沉积层中，因此进行了络合。 Results from this study will prove or disprove whether this iron-complexation process indeed is a viable mechanism to explain the unusually high OM concentrations in sediments on the Mexican coast, as well as provide information on the kinetics of competing reactions (ie. O2, NO3-, IO3-, Mn oxides and HS-) leading to the speciation of Fe in oxic, suboxic and sulfidic sediments.