Organic carbon export from the Icelandic glaciers: quantification, sources, and down-stream fluxes

冰川是有机碳(OC)的重要储存库，对陆地到海洋的碳通量具有潜在的影响。由于气候变化，这些通量预计将加速。尽管欧洲最大的非极地冰盖位于冰岛，但冰岛的冰川有机碳释放已被量化，但冰岛没有可供比较的数据。为了加强对冰川有机碳输出的全球预测，该试点项目旨在首次量化冰岛冰川的冰川溶解有机碳和颗粒有机碳(DOC，POC)的输出量，并与冰岛科学家就未来共同的研究项目建立新的合作关系。因此，将在不同季节开展总共4次实地考察活动，并与冰岛科学家举行面对面的会议。在每一次实地活动中，将采集Vatnajökull、Langjökull、Hofsjökull、Myrdalsjökull和SNæfellsjökull冰盖的23个冰川的冰样，以调查冰川有机质的生物地球化学多样性，并计算DOC和POC的平均出口量以及年度质量平衡。此外，将在冰川溪流中抽取水样本，以检测冰川末端的有机碳释放情况，并调查从冰川末端到海洋的6条河流从冰川末端到海洋的不同距离，从2公里到130公里的下游DOC的变化。通过重复和比较Gíslason教授1997年对大型无脊椎动物进行的调查，将评估冰川快速退缩对冰川供养的河流生态系统的长期影响。同时，为了开发一种更省时、更少侵入性的方法来监测未来冰川退缩对冰川供养的河流生态系统的影响，将在该河段采集水样进行EDNA条码。除了现场测量电导率、水温、pH值、氧气、浊度和叶绿素α外，还将应用创新的实验室设备(高效液相、DNA条码、Picarro、GC、TOC)来检测冰和水样中有机碳的组成(DOC、DIC、POC、光学性质(荧光、吸光度)、营养物质(P-PO4、N-NO3、N-NO2、N-NH4)、稳定同位素(18O，2H)、叶绿素α、二氧化碳和水生生物。基于激发发射矩阵的并行因子分析建模的应用将推进不同冰川输出有机碳来源的识别。将使用主成分分析来评估冰川冰和前冰川河流有机碳特征的空间多样性。所获得的知识将有助于加强对冰川有机碳输出的全球预测，并有助于加深对冰川环境的了解。对于早期职业申请者，该项目将导致与冰岛科学家在碳循环和通量的空间和时间方面以及冰川环境生态方面进行有希望的未来合作。

Glaciers are an important store of organic carbon (OC) with potential effects on the land-to-ocean carbon fluxes. Due to climate change these fluxes are expected to accelerate. The release of glacial OC has been quantified in several regions worldwide, but there is no comparable data available for Iceland, although the largest nonpolar ice cap of Europe is located there.To enhance the global prediction of glacial organic carbon export, this pilot project aims to quantify the export of glacial dissolved and particulate organic carbon (DOC, POC) of Icelandic glaciers for the first time and to establish new cooperation with Icelandic scientists for common future research projects.Thus, a total of 4 field campaign during different seasons will be carried out together with face-to-face meetings with the Icelandic scientists. At each field campaign ice samples of 23 glaciers of the ice caps Vatnajökull, Langjökull, Hofsjökull, Myrdalsjökull, and Snæfellsjökull will be taken to investigate the biogeochemical diversity of glacial organic matter and to calculate an average export of DOC and POC along with the annual mass balances. Further, water samples will be taken in proglacial streams to detect the release of OC at the glacier terminus and to investigate the downstream alteration of DOC at 6 rivers with different distances from the glacier terminus to the ocean ranging from 2 km to 130 km. The long-term impact of the rapid glacier retreat on a glacier-fed river ecosystem will be assessed by repeating and comparing the investigations on macroinvertebrates carried out in 1997 by Prof. Gíslason. At the same time, to develop a more time-saving and less invasive method for monitoring the future impact of the glacial retreat on the glacier-fed stream ecosystem, water samples will be taken for eDNA barcoding in this river section.Beside on-site measurement of electrical conductivity, water temperate, pH-value, oxygen, turbidity and chlorophyll α innovative lab devices will be applied (HPLC, DNA barcoding, Picarro, GC, TOC) to detect the composition of OC in ice and water samples (DOC, DIC, POC, optical properties (fluorescence, absorbance), nutrients (P-PO4, N-NO3, N-NO2, N-NH4), stable isotopes (18O, 2H), chlorophyll α, carbon dioxide and aquatic organisms.The application of parallel factor analysis modeling based on excitation emission matrices will advance the identification of sources of OC exported from the different glaciers. The spatial diversity of OC characteristics in the glacial ice and in the proglacial streams will be assessed using principal component analysis.The gained knowledge will contribute to an enhanced global prediction of glacial OC export and to a deeper understanding of glacial environments. For the early career applicants this project will lead to promising future collaborations focusing on the spatial and temporal aspects of carbon cycling and fluxes as well as the ecology of glacial environments with Icelandic scientists.