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

冰川是有机碳的重要储存库，对陆地-海洋碳通量具有潜在的影响。由于气候变化，预计这些通量将加速。全球多个地区的冰川有机碳释放量已得到量化，但冰岛没有可比数据，尽管欧洲最大的非极地冰帽位于那里。为了加强全球冰川有机碳输出的预测，本试点项目旨在量化冰川溶解和颗粒有机碳的输出（DOC，POC）的冰岛冰川的第一次，并建立新的合作与冰岛科学家共同未来的研究项目。因此，在不同的季节将进行总共4次实地考察，并与冰岛科学家进行面对面的会谈。在每次实地考察中，将采集23个冰帽冰川（瓦特纳冰川、朗冰川、霍夫斯冰盖、米达尔冰川和斯奈山冰川）的冰样，调查冰川有机物的地球化学多样性，并计算DOC和POC的平均输出量（沿着）以及年度质量平衡。此外，还将在冰前河流中采集水样，以检测冰川末端OC的释放，并调查从冰川末端到海洋的不同距离（2 km至130 km）的6条河流的DOC下游变化。将通过重复和比较Gíslason教授1997年对大型无脊椎动物进行的调查，评估冰川快速退缩对冰川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冰川退缩对冰川河流生态系统的未来影响，将在该河段采集水样进行eDNA条形码，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（HPLC、DNA条形码、Picarro、GC、TOC）检测冰和水样品中OC的组成（DOC、DIC、POC、光学特性（荧光、吸光度）、营养物质（P-PO 4、N-NO3、N-NO2、N-NH 4）、稳定同位素（18 O、2 H）、叶绿素α、基于激发-排放矩阵的平行因子分析模型的应用将促进对不同冰川输出的OC来源的识别。将利用主成分分析法评估冰川冰和冰前河流中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，并加深对冰川环境的了解。对于早期的职业申请人，该项目将导致有前途的未来合作，重点是碳循环和通量的空间和时间方面，以及与冰岛科学家的冰川环境生态。

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.