全新世以来北部湾海陆交错关键带的孢粉记录及其对气候变化和人类活动的响应

The Gulf of Beibuwan (Tonkin) situated in the south of China Guangxi Autonomous Region, is one of critical marine-terrestrial interlaced zones for Chinese natural resources. Study on the ecological evolution of the gulf environment is valuable for a better understanding of environmental change in this zone, providing important information to estimate the trajectory of climate change and work on strategies for sustainable development. Pollen records are considered significant information for geological region and chronic era on climate and vegetation variation. However, investigation into the relationships between modern pollen and plants should be a prior study on the gulf eco-geological project. In present study, we will perform a thorough investigation of the pollen assembles of different plant communities in the Gulf of Beibuwan, and built the modern pollen-plant relations accordingly. Meanwhile, a series of sediment cores will be collected and treated with high-resolution pollen analysis and AMS 14C dating, and reconstruct the plant and climate variations in different plant communities during the Holocene using the modern pollen-plant relations. Additionally, we will discuss and reveal the evolution histories of different plant communities, and their relations to the Holocene climate variations, providing a robust basis for the conservation and restoration of marine-terrestrial interlaced critical zone.

广西北部湾作为我国重要的海陆交错关键带，对其开展过去生态环境演化研究，有利于认识人类今天的生存环境，预测未来的气候变化，为制定可持续发展战略提供基础理论依据。孢粉是记录北部湾植物群落长期演化的良好信息载体，而充分了解现代孢粉-植被的关系，是利用钻孔孢粉资料准确重建古气候和古植被的基本前提。本项目拟在北部湾典型植物群落开展孢粉现代过程研究，揭示不同植物群落孢粉组合特征，并建立现代孢粉-植被关系。同时，采集典型钻孔样品，进行高分辨率的孢粉分析，在精确的AMS 14C 测年的支持下，结合现代花粉-植被关系的研究结果，利用钻孔孢粉资料来定量重建全新世典型植物群落的植被演替和气候演化序列，揭示出北部湾海陆交错关键带生态系统的长期演化规律，为丰富海陆生态系统长期演化理论以及在未来全球变化条件下制定海陆交错关键带的保护和恢复战略提供科学依据。

本项目旨在通过“古今结合”的思路将北部湾海陆交错关键带的典型植物花粉形态学、孢粉现代过程及孢粉沉积过程研究相结合，在精确的AMS 14C等测年的支持下，定量重建典型植物群落的植被演替和气候演化序列，全球变化背景下保护和恢复海陆交错关键带、制定可持续性发展战略提供科学指导和智力支持。研究结果表明，广西北部湾红树林典型植物和珍稀濒危植物-金花茶组植物的花粉形态学研究，为今后地层中准确鉴定红树林花粉和金花茶组植物的提供重要的基础数据。北部湾海域表层沉积物的孢粉现代过程研究显示，松属花粉和芒萁属孢子的高值均出现在钦州湾样品中，暗示其经茅尾海沉积后，仍然有向钦州湾汇集的趋势；草本植物花粉（主要为禾本科）的高值出现在河口近岸样品中，说明河流为其主要的传播动力，为接下来系统全方位开展广西北部湾孢粉传播机制及其现代花粉过程研究提供了重要的参考。但是，由于广西北部湾钻孔样品孢粉鉴定的工作量大，测年结果不是很理想，相关工作仍需后续开展才能完成。