Quantifying kelp detrital pathways: what is potentially locked away as Blue Carbon?

海带林拥有全球最高的植物产量，在每单位面积每年460至3000克/平方米之间，对我们沿海系统的生物多样性很重要。据估计，海带系统产生的80%的生物量主要作为碎屑物质出口到浅水和深水系统。然而，对碎屑途径[3]的动力学知之甚少，特别是对物质分解成逐渐减小的颗粒的速率及其对颗粒运输和原位再矿化速率的影响知之甚少。这些信息在确定将被再矿化的碎屑碳的比例时非常重要，这些碎屑碳将向沿海水域释放二氧化碳，并可能以蓝碳的形式出口到沉积物中。这个跨学科博士的目的是确定在不同的环境条件下海藻生物量分解的速度，如流体动力学（波浪与流速）、温度和光，使用实验室和现场实验方法。此外，海带衰老和脱落的生物地球化学动力学将通过实地采样来阐明，以确定这些过程如何影响溶解有机碳的产生和组成，以及沿海和陆架海域无脊椎动物进一步分解颗粒有机碳库。博士候选人将在北爱尔兰Portaferry的女王海洋实验室（QML）工作，QML的设施由室内和室外水族馆设施组成，配有流动的海水，并且靠近实地地点。该候选人将与Louise Kregting博士（QUB）密切合作，Louise Kregting博士是一位专门研究生产力和生态生理学大型藻类与生物物理相互作用的生理学家，Jamie Dick教授（QUB）将提供生物分解过程的专业知识，例如草食性和营养性甲壳类动物，它们可以极大地促进转化为细颗粒有机物质，Ursula Witte教授（UoA）。一位生物海洋学家，他擅长用实验方法来阐明和追踪碳的早期成岩作用，这对理解海带衍生的有机物如何在海洋沉积物中保存至关重要；另一位是威廉·亨特博士（AFBI， NI），他擅长海洋生物地球化学，对环境变化如何影响碳和营养循环特别感兴趣。这项研究将提供广泛领域的培训，包括控制碎屑途径的化学、物理和生物过程。本课程将为学生提供全面的训练，但学生必须具备海洋生物学、定量生态学、数据分析和水化学的背景知识，并了解海岸流体动力学和生物物理相互作用。

Kelp forests have some of the highest plant production rates globally of between 460 g C m2 yr to 3000 g C m2 yr per unit area [1] and are important for the biodiversity of our coastal systems. It has been estimated that 80% of the biomass produced by kelp systems is exported to shallow- and deep-water systems primarily as detrital material [2]. Yet very little is known of the dynamics of the detrital pathway [3], in particular, the rate of breakdown of the material into decreasing size fractions and the effect of this on particle transport and remineralization rates in situ. This information is of significance when determining the proportion of the detrital carbon that will be remineralised, releasing CO2 into the coastal waters and what is potentially exported to the sediments to be locked away as blue-carbon. The aim of this interdisciplinary PhD is to determine the rate of kelp biomass breakdown under varying environmental conditions such as hydrodynamics (waves vs current velocity), temperature, and light using both laboratory and field experimental approaches. Additionally, the biogeochemical dynamics of kelp from senescence and shedding will be elucidated through field-based sampling to determine how these processes affect the production and composition of the dissolved organic carbon and particulate organic carbon pools are broken down further by invertebrates in coastal and shelf seas.The PhD candidate would be based at Queen's Marine Laboratory (QML) in Portaferry, Northern Ireland where QML's facilities are comprised of indoor and outdoor aquarium facilities with running seawater as well as being close to field locations. The candidate would work closely alongside Dr Louise Kregting (QUB), a phycologist with expertise in productivity and eco-physiology macroalgae merged with biophysical interactions, Prof Jamie Dick (QUB) who will provide expertise on biological breakdown processes by, for example, herbivorous and detritivorous crustaceans, which can contribute immensely to conversion of course to fine particulate organic matter, Prof Ursula Witte (UoA), a biological oceanographer with expertise on experimental methods to elucidate and trace the early diagenesis of carbon fundamental to understanding how kelp-derived organic matter is preserved in marine sediments and Dr William Hunter (AFBI, NI) who's expertise is in marine biogeochemistry, with a specific interest in how environmental changes affects carbon and nutrient cycling. The research would provide training in a wide range of areas including chemical, physical, and biological processes that govern the detrital pathway. Full training will be given to the student, however, a background in marine biology, quantitative ecology, data analysis, and water chemistry with an appreciation of coastal fluid dynamics and biophysical interactions will be desirable.