The effect of oil and weathered oil along with nitrogen and carbon supplementation on natural phytoplankton community composition, growth and physiology

The Deepwater Horizon oil spill spilled 130 million gallons of oil into the Gulf of Mexico. This was followed by an application of 1.4 million gallons of chemical dispersants in an effort to disperse the oil into the water column and promote the biodegradation of oil. Photooxidation of oil is a natural process that causes oxygenation of an oil slick. Although the toxicity of oil on phytoplankton has been extensively studied, the effects of photo-oxidized oil, especially in combination with dispersants is virtually unknown. Phytoplankton vary in their sensitivities to oil and dispersant exposure. Here, we study the effects of photo-oxidized oil on the growth and photo-physiology of the natural phytoplankton community. We also looked at the effects of nutrient amendments as both C and N on the above-mentioned treatment. Several parameters such as EOE (estimated oil equivalent), ETRmax- maximum electron transport rate, and relative fluorescence (Fv/Fm) were measured.

深水地平线（Deepwater Horizon）原油泄漏事件向墨西哥湾倾泻了1.3亿加仑原油。事后相关方施用了140万加仑化学分散剂，以期将原油分散至水体中并促进原油的生物降解。原油光氧化是一种可使浮油发生氧化作用的自然过程。尽管学界已针对原油对浮游植物的毒性开展了大量研究，但光氧化原油（尤其是与分散剂联合暴露时）的生态效应仍几乎未被探明。不同浮游植物类群对原油与分散剂暴露的敏感性存在显著差异。本研究旨在探究光氧化原油对天然浮游植物群落生长及光生理特性的影响，同时还考察了以碳、氮形态添加的营养盐对前述各处理组的影响。本研究测定了多项关键参数，包括等效原油量（EOE，estimated oil equivalent）、最大电子传递速率（ETRmax，maximum electron transport rate）以及相对荧光（Fv/Fm，relative fluorescence）。