The Distribution and Fate of Microplastic Pollution in Polar Environments: From the Canadian Arctic to the South Pole

众多的并发压力对海洋生态系统/服务构成了有害的全球性威胁，了解这些环境扰动对海洋生物群的协同影响仍然是一个重大挑战。海洋酸化（OA）和微塑料对浮游动物功能和健康的负面影响已经被认识到（即Manno等人，2016年;科尔等人，2016年）。最近，有人假设浮游动物（及其粪便颗粒）可能在远洋生态系统中微塑料的垂直通量中发挥重要作用（Clark等人，2016年）。然而，这两种人为压力的协同影响仍然是未经探索的。南大洋（SO）预计将特别受到OA的影响，由于自然高CO2海洋吸收和低碳酸盐饱和度水平。此外，SO被强调为微塑料将与生物群有显著重叠的区域（Worm，2015）。在SO内，北方斯科舍海包含了迄今为止测得的最大的大气二氧化碳季节性吸收。在这一区域，浮游动物可以对深海碳输出（快速下沉的粪便颗粒的槽生产）和食物网（因为高营养级捕食者的主要猎物）做出重大贡献。人为多重压力源对浮游动物群落的负面影响可能反过来影响海洋生态系统和海洋地球化学循环。原理和资源：调查OA和微塑料对北方斯科舍海关键浮游动物类群（桡足类和翼足类）的多重压力源效应。还将调查对向深海输出碳的潜在影响。成功的候选人将在BAS的沉积物收集器样品档案室工作。候选人将参加一次高级船员抽样活动，为此，他/她将接受海上生存技能培训。在船上，学生将参与浮游动物网样采集和孵化实验。具体目标：1。为了评估对人为压力源的协同影响的生理反应：在采样活动期间，学生将在操纵海水中进行浮游动物的孵化，以检查它们对模拟OA和微塑料协同压力的反应。测量将包括死亡率、呼吸率、氨排泄率、粪便颗粒产生和产蛋量。将对样本进行稳定同位素分析，以确定压力源暴露对同位素特征的影响。为了量化浮游动物作为微塑料到深海的驱动因素的作用-博士候选人将通过调查从深锚沉积物捕集器（1500-2000米）收集的样本来评估“微塑料通量”到深海的季节和年际变化。他/她将量化沉降颗粒中的微塑料总量以及粪便颗粒和浮游动物尸体中的具体贡献。Worm，Silent spring in the ocean Boris Worm，PNSA，112，752-11753（2015）-J. R.克拉克，M。科尔，P. K林德克，J.布莱克福德，E. Fileman角刘易斯，T. M Lenton和T. S.海洋微塑料碎片：理解和量化的有针对性的计划

A multitude of concurrent stressors pose a pernicious, global threat to marine ecosystems /services and understanding the synergic impact of these environmental perturbations to marine biota remains a major challenge. The negative impact of Ocean Acidification (OA) and microplastics on zooplankton function and health has been already recognised (i.e. Manno et al. 2016; Cole et al. 2016). Recently, It has been hypothesised that zooplankton (and their faecal pellets) may play a significant role in the vertical flux of microplastics in pelagic ecosystems (Clark et al. 2016). However the synergistic impact of both anthropogenic stressors is still unexplored. The Southern Ocean (SO) is predicted to be particularly affected by OA due to naturally high CO2 ocean uptake and low carbonate saturation levels. Further, the SO has been highlighted as a region in which microplastics will have significant overlap with biota (Worm, 2015). Within the SO, the Northern Scotia Sea contains the largest seasonal uptake of atmospheric carbon dioxide measured yet. In this region, zooplankton can contribute significantly to the deep ocean carbon export (trough production of fast sinking faecal pellets) and to the food web (because key prey to high trophic level predators). A negative impact of the anthropogenic multi-stressors on the zooplankton community may in turn affect both marine ecosystem and biogeochemical cycles.Rationale and resources: to investigate the multi-stressors effect of OA and microplastics on key zooplankton taxa (copepods and pteropods) in the Northern Scotia Sea. The potential effect on the carbon export to the deep ocean will also be investigated. The successful candidate will work on the sediment trap samples archive at BAS. The candidate will participate in one SO sampling campaign for which he/she will receive training in sea-survival techniques. On board, the student will participate in collection of zooplankton net samples and run incubation experiments.Specific objectives:1. To assess physiological response to the synergic impact of anthropogenic stressors: During a sampling campaign, the student will undertake incubations of zooplankton in manipulated seawater to examine their response to the simulated OA and microplastic synergistic stress. The measurements will include mortality, respiration rates, ammonia excretion rates, faecal pellets production and egg production. Stable isotopes analysis will be performed on samples to identify the effect of stressors exposure on the isotopic signature.2. To quantify the role of zooplankton as drivers of microplastics to the deep ocean- The PhD candidate will assess the seasonal and interannual variability of "microplastic flux" to the deep ocean by investigating samples collected from deep moored sediment traps (1500-2000 m). He/she will quantify the total microplastic amount in the sinking particles and the specific contribution included in faecal pellets and zooplankton carcasses.References-B. Worm, Silent spring in the ocean Boris Worm, PNSA, 112, 752-11753 (2015)-J. R. Clark, M. Cole, P. K Lindeque, J. Blackford, E. Fileman, C. Lewis, T. M Lenton and T. S. Galloway, Marine microplastic debris: a targeted plan for understanding and quant