Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA 95343, USA; National Life Science, Inc., Sacramento, CA 95660, USA; Kaiser Biotech, Inc., Sacramento, CA 95660, USA.
Bioengineering Program, School of Engineering, University of California at Merced, Merced, CA 95343, USA.
Sci Total Environ. 2019 Mar 20;657:1535-1542. doi: 10.1016/j.scitotenv.2018.12.147. Epub 2018 Dec 11.
Spilled oil treated with Corexit dispersant can cause unintended impacts on marine environment systems including altering marine organic matter dynamics; however, impacts on microgels and marine oil snow (MOS) formation are still debated and remain to be fully understood. Extracellular polymeric substances (EPS) are a major source of marine organic carbon for MOS and microgel formation. EPS initial aggregation plays key roles in the oil degrading process and various biogeochemical reactions. Here we used four types of EPS with water accommodated fraction (WAF), chemically-enhanced WAF (CEWAF) and Corexit, to represent potential situations during oil spills and post-application of Corexit. We found that Corexit alone can inhibit EPS aggregation and disperse pre-existing microgels. CEWAF can enhance EPS aggregation with efficiency by up to 80%-100% and more aggregates accumulated within the air-water interface. Additionally, more hydrophobic EPS aggregates showed high resistance to Corexit dispersion while hydrophilic EPS were more sensitive. Effects of oil spills on marine gel particle formation are primarily determined by chemical characteristics (hydrophobicity and protein content) of the constituent EPS. This study offers unique insights for organic particle dynamics and identifies controlling factors for MOS or gel particles associated with oil spills and Corexit dispersant used.
溢油用 Corexit 分散剂处理后可能会对海洋环境系统造成意外影响，包括改变海洋有机物动力学；然而，微凝胶和海洋油雪 (MOS) 形成的影响仍存在争议，仍有待充分了解。细胞外聚合物物质 (EPS) 是 MOS 和微凝胶形成的海洋有机碳的主要来源。EPS 的初始聚集在油降解过程和各种生物地球化学反应中起着关键作用。在这里，我们使用了四种类型的 EPS 及其水容纳分数 (WAF)、化学增强 WAF (CEWAF) 和 Corexit，以代表溢油期间和应用 Corexit 后的潜在情况。我们发现，Corexit 本身可以抑制 EPS 聚集并分散预先存在的微凝胶。CEWAF 可以提高 EPS 聚集的效率，最高可达 80%-100%，并且在气-水界面内积累更多的聚集物。此外，疏水性 EPS 聚集物表现出对 Corexit 分散的高抵抗力，而亲水性 EPS 则更敏感。溢油对海洋凝胶颗粒形成的影响主要取决于组成 EPS 的化学特性（疏水性和蛋白质含量）。本研究为有机颗粒动力学提供了独特的见解，并确定了与溢油和 Corexit 分散剂相关的 MOS 或凝胶颗粒的控制因素。
