The Biological Carbon Pump in the Anthropocene

人类世的生物碳泵

• 批准号: RGPIN-2020-05103
• 负责人: Passow, Uta
• 金额: $ 4.44万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717526
• 关键词: Biological; Carbon; Pump; Anthropocene

The three main objectives of my DG proposal are central components to my larger goal to understand the Biological Carbon Pump (BCP), so that we may (a) evaluate its role in the distribution of pollutants and (b) determine how the ability of the ocean to sequester carbon may change. Since the industrial revolution the ocean has taken up 25-30% of anthropogenic carbon, yet it is unclear whether the ocean will continue to take up carbon as atmospheric pCO2 is increasing. Objective 1: Determine the strength of the gravitational settling particle flux pathway of the BCP in the North-West Atlantic: Although the Labrador Sea plays a central role in the global carbon cycle, as well as in the exchange of oxygen and CO2 between the surface and deep ocean, our knowledge of the role and variability of gravitational particle sinking and the loss rate of this flux with depths, is extremely limited for this region. Careful analysis of samples from moored, time-series sediment traps will provide information on seasonal variability of flux type and strength and of flux attenuation. Nutritional value of sinking matter, which provides the food source for organisms at depths will be investigated. Severe changes in nutritional value would impact food webs, including commercially valuable fish. Objective 2: Identify response patterns of phytoplankton to multiple stressors, e.g. shifts in temperature, light and carbonate chemistry. Recent research efforts have revealed that the response of phytoplankton to several simultaneous stressors is not additive, but complex, requiring targeted experiments to investigate interactive responses affecting growth, aggregation and sedimentation. Commonly only a single stressor and only the growth phase of phytoplankton are investigated. As phytoplankton primary production provides the maximum theoretical flux potential, changes in productivity, aggregation and sedimentation will drive shifts in the functioning of the BCP, and the potential for the ocean to sequester CO2. Loss of ice has the potential to alter sedimentation patterns, as ice algae and their exudates cause sinking ice edge blooms. These mechanisms will be investigated experimentally. Objective 3: Characterize the role of aggregation for the transport and fate of micro-plastics. Initial experiments show that small plastic particles may be incorporated into rapidly sinking aggregates, transporting them to the seafloor where benthic organisms and those feeding on them are exposed. As plastics are less dense than seawater, this pathway is unexpected and largely unexplored. A combination of detailed aggregation experiments and analysis of sinking material collected in sediment traps, will yield sedimentation patterns of plastic, and give insights to mechanisms driving their flux. Understanding these distribution pathways is a prerequisite for the mitigation and clean up of plastic pollution in the ocean, which Canada has pledged to in the “strategy on zero plastic waste”.

我的总干事提案的三个主要目标是我更大目标的核心组成部分，即了解生物碳泵（BCP），以便我们可以（a）评估其在污染物分布中的作用，（B）确定海洋固碳能力如何变化。自工业革命以来，海洋已经吸收了25-30%的人为碳，但目前还不清楚海洋是否会随着大气pCO 2的增加而继续吸收碳。 目标一：确定西北大西洋BCP的重力沉降粒子通量路径的强度：尽管拉布拉多海在全球碳循环以及表层和深海之间的氧气和CO2交换中发挥着核心作用，但我们对重力粒子沉降的作用和变化以及这种通量随深度的损失率的了解非常有限。仔细分析来自停泊的时间序列沉积物收集器的样本将提供有关通量类型和强度以及通量衰减的季节性变化的信息。将调查为深海生物提供食物来源的下沉物质的营养价值。营养价值的严重变化将影响食物网，包括具有商业价值的鱼类。目标2：确定浮游植物对多种压力源的反应模式，例如温度，光照和碳酸盐化学的变化。最近的研究工作表明，浮游植物对几个同时发生的压力的反应不是相加的，而是复杂的，需要有针对性的实验来调查影响生长、聚集和沉积的相互作用。通常只有一个单一的压力和浮游植物的生长阶段进行了调查。由于浮游植物初级生产提供了最大的理论通量潜力，生产力，聚集和沉积的变化将推动BCP功能的转变，以及海洋封存CO2的潜力。冰的损失有可能改变沉积模式，因为冰藻及其分泌物会导致下沉的冰缘水华。这些机制将进行实验研究。目标3：描述聚集对微塑料运输和归宿的作用。初步实验表明，小的塑料颗粒可能会融入快速下沉的聚集体中，将它们运送到海底，使底栖生物和以它们为食的生物暴露在外。由于塑料的密度低于海水，这一途径是意想不到的，而且在很大程度上未被探索。详细的聚集实验和沉降物收集在沉积物陷阱的分析相结合，将产生沉积模式的塑料，并提供见解的机制驱动其流量。了解这些分布途径是减轻和清理海洋塑料污染的先决条件，加拿大已在“零塑料废物战略”中承诺。