Erosional Sorting of Fine Marine Sediments

细小海洋沉积物的侵蚀分选

• 批准号: 138535-2012
• 负责人: Hill, Paul
• 金额: $ 3.27万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569360
• 关键词: Erosional; Sorting; Fine; Marine; Sediments

The transport of fine sediment in intertidal waters affects the health and sustainable uses of the coastal zone in Canada. The response of the shoreline to sea level rise, navigability of coastal waters and exposure of humans and other organisms to sediment-bound contaminants all depend on fine sediment transport. To complicate matters, all of these effects are tied to the sortability of fine marine sediment, which is not well understood. The goal of this research is to improve understanding of the factors that affect the erosional sortability of fine marine sediment and ultimately to incorporate this understanding into models of fine sediment transport. Conceptually, erosional sortability simply describes how easy or difficult it is to separate particles of different sizes from one another during erosion of sediment from the seabed. "Fine sediment" is the term applied to sediments with mean particle diameters less than 63 micrometres. For decades, sedimentologists treated fine sediment particles as non-sortable, a hypothesis that led to poor predictions of fine sediment size distributions and concentrations in the seabed and in suspension. It also led to crude models for the mobility of particle-attached substances. Recent studies have shown, however, that fine sediments are sortable, but that the sortability depends on the interaction of biotic and abiotic factors. This research will focus on five factors that are likely to dominate the sortability of fine marine sediments: sediment texture, sediment water content, abundance of sediment-attached (epipelic) diatoms, abundance of bacteria, and concentration and properties of sediment exopolymeric substances (EPS). These factors will be examined with a combination of field studies, laboratory experiments, and modeling.

潮间带水域细小沉积物的输送影响加拿大沿海地区的健康和可持续利用。海岸线对海平面上升的响应、沿海水域的适航性以及人类和其他生物对沉积物污染物的暴露都取决于细沉积物的输送。更复杂的是，所有这些影响都与细小海洋沉积物的可分类性有关，而这一点尚不清楚。 这项研究的目的是提高对影响细小海洋沉积物侵蚀分选性的因素的理解，并最终将这种理解纳入细小沉积物迁移模型中。 从概念上讲，侵蚀分选性简单地描述了在海底沉积物侵蚀过程中将不同尺寸的颗粒彼此分离的难易程度。 “细沉积物”是指平均粒径小于 63 微米的沉积物。几十年来，沉积学家将细沉积物颗粒视为不可分类，这一假设导致对海底和悬浮液中细沉积物尺寸分布和浓度的预测不佳。它还产生了颗粒附着物质的流动性的原始模型。然而，最近的研究表明，细小的沉积物是可以分类的，但 可分类性取决于生物和非生物因素的相互作用。 这项研究将重点关注可能主导精细海洋沉积物分选性的五个因素：沉积物质地、沉积物含水量、沉积物附着（表层）硅藻的丰度、细菌的丰度以及沉积物胞外聚合物（EPS）的浓度和性质。这些因素将通过现场研究、实验室实验和建模相结合的方式进行检验。