Volcanic fertilisation of tropical forest biomes

热带森林生物群落的火山施肥

• 批准号: 2886243
• 金额: --
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2886243
• 关键词: Volcanic; fertilisation; tropical; forest; biomes

Tropical rainforest biomes are some of the most diverse and productive ecosystems on the planet, but are also projected to be vulnerable to changing climatic and environmental conditions. These susceptibilities are exacerbated as tropical forest biomes often inhabit very nutrient limited soils. In most tropical soils phosphorus (P) is considered the key limiting nutrient and periods of high soil P concentration are linked to enhanced forest development. Recent research has hinted at the role that volcanism may play in fertilizing large areas of tropical forest with P-rich ash during volcanic events. However, these ashfalls have a complex temporal impact on soil P concentration and vegetation response. This relationship needs further investigation using a number of biological and geochemical tracers. One with great potential is phosphate oxygen isotopes, which can distinguish between soil P sources through the palaeorecord.This studentship will focus on the Dipterocarp forest of the Philippines, Southeast Asia, utilising modern soil and plant sampling, coupled with the development of paleoenvironmental records from Bulusan Lake spanning the last 1,500 years. A range of standard geochemical techniques including iTrax trace element mapping, tephra identification and radiocarbon chronology will be applied alongside more novel, phosphate oxygen stable isotopes and ancient DNA analysis. This combined proxy approach aims to 1. robustly characterise the timing and intensity of volcanic ash deposition events, 2. identify the role these events have played in changing availability of P to plants, and 3. identify the resultant impact on forest vegetation, including its composition, structure and mass flowering dynamics. Only by gaining a thorough understanding of these natural cycles of P addition can we begin to reveal the true vulnerability of these critical biomes in areas of intense volcanic activity and predict how they may develop and survive under ever changing climatic and anthropogenic pressures.

热带雨林生物群落是地球上最多样化、生产力最高的生态系统之一，但预计也容易受到气候和环境条件变化的影响。由于热带森林生物群落通常栖息在养分非常有限的土壤中，这些敏感性会加剧。在大多数热带土壤中，磷（P）被认为是关键的限制养分，土壤磷浓度高的时期与森林发展的加强有关。最近的研究暗示，火山活动可能在火山活动期间用富含磷的火山灰为大片热带森林施肥。然而，这些灰烬对土壤磷浓度和植被响应具有复杂的时间影响。这种关系需要使用许多生物和地球化学示踪剂进行进一步研究。具有巨大潜力的一个是磷酸氧同位素，它可以通过古记录区分土壤磷源。该学生项目将重点研究菲律宾和东南亚的龙脑香森林，利用现代土壤和植物采样，并结合 Bulusan 湖过去 1,500 年的古环境记录。一系列标准地球化学技术，包括 iTrax 微量元素测绘、火山灰鉴定和放射性碳年代学，将与更新颖的磷酸氧稳定同位素和古代 DNA 分析一起应用。这种组合代理方法旨在 1. 有力地描述火山灰沉积事件的时间和强度，2. 确定这些事件在改变植物磷利用率方面所发挥的作用，以及 3. 确定对森林植被的最终影响，包括其组成、结构和大规模开花动态。只有彻底了解这些磷添加的自然循环，我们才能开始揭示火山活动强烈地区这些关键生物群落的真正脆弱性，并预测它们在不断变化的气候和人为压力下如何发展和生存。