CARBON TRANSFORMATIONS IN THE TROPICAL SILICATE-DOMINATED DEDURU OYA CATCHMENT, SRI LANKA (C-TROPIC-TRANS)

河流中的碳转移和转化是土地利用、风化和气候影响的重要反映。这样的碳系统同样完整地反映了河流生态系统和集水区的健康。在这一背景下，全球的不确定性包括河流的大量二氧化碳损失，而这些损失大多是在大型河流系统上预算的。然而，到目前为止，较小的河流和溪流几乎没有以这种方式进行调查。特别是，这种缺乏调查的情况适用于从小集水区直接排放到海洋的河流。在这里，我们提出了一个新的研究在热带Deduro Oya流域（斯里兰卡）的碳转化。这项研究将提供新的见解，热带功能方面的碳转化硅酸盐为主的岩性。此外，这项工作旨在调查典型的区域农业实践，例如可能影响河流内碳螺旋的稻田生长。其他因素，如水库和沿河的多个小型蓄水系统以及污水输入，也同样计划在这个季风驱动的系统中进行调查。计划中的地球化学工具包括对河流和地下水样品中的溶解碳和颗粒碳（DOC、DIC和POC）及其稳定同位素进行浓度分析。这将结合现场参数、水同位素以及主要和痕量元素分析。预期的数据将提供二氧化碳从水相脱气的模型。对其他水生系统的类似研究有助于概述自然和人为对重要生态因子（如光合作用和呼吸作用）之间水生碳平衡的影响。当转到Deduru Oya集水区时，这些技术可以帮助定义一个迄今为止鲜为人知的热带中型集水区的末端成员，该集水区直接向海洋排放，涉及河流在陆地碳循环中的作用。

Carbon transfer and transformations in rivers are important reflectors of land use, weathering and climate effects. Such carbon systematics equally reflect river ecosystem and catchment health in an integral manner. A global uncertainty in this context includes extensive losses of CO2 from rivers that have mostly been budgeted on large river systems. However, smaller rivers and streams have hardly been investigated in this way so far. In particular, this lack of investigations applies to rivers from small catchments that directly discharge to the oceans. Here we propose a new investigation of carbon transformations in the tropical Deduro Oya catchment (Sri Lanka). This study would offer new insights into tropical functioning with respect to carbon transformations of a silicate-dominated lithology. Moreover, the work aims to investigate typical regional agricultural practices such as rice paddy growth that likely influences carbon spiraling within the river. Other factors such as reservoirs and multiple small water retention systems along the river as well as sewage inputs are equally planned for investigation in this monsoon-driven system. Planned geochemical tools include concentration analyses of dissolved and particulate carbon (DOC, DIC and POC) together with their stable isotopes on river and groundwater samples. This will combine with field parameters, water isotopes and major- as well as trace element analyses. Expected data will offer modelling on CO2 degassing from the water phase. Similar approaches on other aquatic systems have helped to outline natural and anthropogenic influences on aquatic carbon balances between important ecological factors such as photosynthesis and respiration. When transposed to the Deduru Oya catchment, these techniques can help to define a so far hardly known endmember of a tropical medium-sized catchment that discharges directly to the ocean with respect to river functioning in the terrestrial carbon cycle.