Mangrove ecosystem services under pressure: the history and future of carbon sequestration hotspots

红树林生态系统服务面临压力：碳封存热点的历史和未来

• 批准号: NE/V012800/1
• 负责人: Barend Van Maanen
• 金额: $ 81.54万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV012800%2F1
• 关键词: Mangrove; ecosystem; services; under; pressure

Mangrove forests are often associated with the smell of rotten eggs and swarms of mosquitos. This may be true but at the same time these forests are unique and extremely valuable. Mangrove trees grow in challenging environments surviving hot, muddy and salty conditions as they thrive at the margin of land and sea in the tropics and subtropics. Mangrove ecosystems provide essential habitats for many animal species, they help filtering pollutants and protect the coast against erosion. Moreover, mangroves play a crucial role in combating climate change as they capture and store large amounts of carbon from the atmosphere. In fact, these forests store carbon faster than most land ecosystems. The trees store carbon not only in their wood and leaves, but also in those smelly muddy soils. Despite all these benefits, mangroves are heavily threatened as sea level rise may cause forest drowning and people are increasingly modifying coastal landscapes and interfering with the natural processes on which mangroves depend. The impacts of such pressures on mangrove forests are still unclear, but the consequences may be drastic mangrove loss and reductions in carbon storage.Mangrove trees flourish under very specific conditions. They grow well under regular inundation by tides, but they cannot survive prolonged flooding. Hence mangroves will need to keep raising the bed on which they grow to cope with rising sea levels. Mangroves may accomplish by trapping sediments from the land and the sea with their roots. In addition, dead roots, leaves and branches accumulate within the muddy soils. This helps mangroves to gain elevation and the build-up of dead plant material creates carbon-rich sediments. Now, essentially two possibilities emerge. If mangroves keep up with sea level rise by accumulating carbon-rich plant material in their soils, then carbon stocks can actually increase. However, if sea level rise outpaces mangrove soil buildup, then tree mortality will reduce carbon storage. Limits to the adaptability of mangrove forests to sea level rise exist and these limits are influenced by human activities. Building of river dams, for example, reduces the delivery of sediment to the coast, while this sediment is needed to help raising mangroves and enable continued carbon storage. Clearly, mangrove environments are highly complex and in order to protect these valuable environments, improved understanding and abilities to predict their future are urgently needed.In this project, we will unravel the processes that control how and how much carbon is stored in mangrove forests and develop new computer models to investigate the impacts of sea level rise and human activities on future carbon accumulation. We have selected three sites in Colombia (South America) where mangrove trees reach up to 40 meters (!) making these forests true carbon storage hotspots. First, we will obtain soil samples up to a depth of 2 meters. We will estimate their carbon content, how fast that carbon has accumulated during the past, and where the carbon is coming from. We will also use microscopic plant remains preserved in the soil to discover what mangrove species have grown there in the past and whether this has influenced carbon accumulation. Third, we will develop a model capable of simulating how entire deltas and estuaries with mangrove vegetation evolve over tens to hundreds of years. Finally, we will use this new model to investigate the fate of mangrove forests under rising sea levels and varying sediment supply, and impacts on future carbon accumulation. Colombian high-school students and teachers from will participate in fieldwork and will present their work in science fairs for the general public to increase the awareness of the values of mangrove forests. We will also work together with our project partners to use our findings to support the development of sustainable management strategies in order to safeguard mangrove environments.

红树林通常与腐烂的鸡蛋和大量蚊子的气味有关。这可能是正确的，但与此同时，这些森林是独特的，非常有价值。红树林在充满挑战的环境中生长，在热带和亚热带地区的陆地和海洋边缘繁衍生息，在炎热，泥泞和咸味的环境中生长。红树林生态系统为许多动物物种提供了重要的栖息地，它们有助于过滤污染物并保护海岸免受侵蚀。此外，红树林在捕捉和存储大气中的大量碳时，在对抗气候变化方面起着至关重要的作用。实际上，这些森林比大多数土地生态系统更快地存储碳。树木不仅将碳存储在木头和叶子中，还将碳存储在那些臭泥土中。尽管有所有这些好处，但由于海平面上升可能导致森林淹没，红树林受到了严重威胁，人们越来越多地改变沿海景观，并干扰了红树林所依赖的自然过程。这种压力对红树林的影响仍然不清楚，但后果可能是红树林的损失和碳储存的减少。在非常具体的条件下，曼格罗夫树繁荣起来。在潮汐的常规淹没下，它们生长得很好，但是他们无法在长时间的洪水中生存。因此，红树林将需要继续抬高它们生长的床，以应对海平面上升。红树林可能会通过扎根从土地和大海中捕获沉积物来完成。另外，死的根，叶子和树枝在泥土中积聚。这有助于红树林提高海拔高度，而死亡植物材料的积聚产生了富含碳的沉积物。现在，本质上出现了两种可能性。如果红树林通过在土壤中积累富含碳的植物材料来跟上海平面的上升，那么碳储量实际上可以增加。但是，如果海​​平面上升超过红树林的积累，那么树木死亡率将减少碳储存。限制了红树林对海平面上升的适应性，这些限制受人类活动的影响。例如，建造河水坝的建筑减少了向海岸的沉积物的传递，而这种沉积物则需要帮助饲养红树林并持续碳储存。显然，红树林环境非常复杂，为了保护这些有价值的环境，迫切需要理解和预测其未来的能力。在该项目中，我们将揭示控制如何以及在红树林森林中存储多少碳的过程，并开发新的计算机模型，以研究海平面上升和人类活动对未来碳积累的影响。我们在哥伦比亚（南美）选择了三个地点，在这里，红树林最多可达40米（！）使这些森林真正的碳储存热点。首先，我们将获得高达2米深度的土壤样品。我们将估计它们的碳含量，碳在过去积累的速度以及碳的来源。我们还将使用微观植物保存在土壤中，以发现过去在那里生长的红树林物种以及这是否影响碳积累。第三，我们将开发一种能够模拟带有红树林植被的整个三角洲和河口的模型如何发展到数十年到数百年的时间。最后，我们将使用这种新模型来调查海平面上升和变化的沉积物供应的红树林的命运，并对未来的碳积累产生影响。来自哥伦比亚的高中生和老师将参加现场工作，并将在科学展览会上为公众展示他们的工作，以提高对红树林的价值观的认识。我们还将与项目合作伙伴一起使用我们的发现来支持可持续管理策略的制定，以保护红树林环境。