Determination of fluid sources in the Paleochori Bay hydrothermal system, Milos Island (Greece)

历史上，大多数关于海洋热液喷发的研究主要集中在深海、黑烟类型的地点，尽管记录了大约70个海洋浅水热液喷发系统(MSWHS)。MSWHs通常由气体喷口和热泉组成，排放到浅海海洋环境中，在那里它们可以通过释放还原的热液流体而对生物产生相当大的影响，这些热液流体往往含有潜在的有毒元素，如As和Hg。研究最好的MSWHs之一位于米洛斯岛南侧的古乔里湾，由于其独特的生物地球化学，一直是众多科学研究的焦点。然而，尽管我们进行了25年以上的研究，但我们没有关于热液和生物过程之间相互作用的可靠的生物地球化学模型，也没有可靠的单一地点的重复测量。这是因为没有为所研究的任何地点提供GPS坐标，因此，尽管大多数调查都有关于喷口地点一般位置和特征的描述，但实际上不可能返回这些特定地点。解决米洛斯火山的这一困境的一个可能的解决方案是借助航空摄影技术生成地理参考地图，因为由于其性质较浅，从地表可以辨别出热液特征。有了直接从地图获得GPS坐标的可能性，就有可能挑选样本收集的准确位置，包括温度和流量测量。此外，有可能将热液特征的实际出现情况与其在摄影地图上的表现联系起来，即通过直接观测确认其特征的数字航空地图的创建，这将是使用地理信息系统平台进行过去和正在进行的研究的基础，而所开发的技术将很容易转移到其他浅水热液喷口地点。绘制这样一张地图将第一次使人们能够前所未有地了解每个喷口所在地的位置和化学成分，并估计总的热液通量以及相关的汞和砷浓度。这项工作的意义超越了古曹里湾，因为这种方法可以很容易地转移到世界各地的MSWHS的其他地点。

Historically most research on marine hydrothermal venting focused primarily on deep-sea, black smoker-type locations, although approximately 70 locations of marine shallow-water hydrothermal vent systems (MSWHS) were documented. MSWHS usually consist of a combination of gas vents and hydrothermal springs, discharging into the shallow coastal marine environment where they can have a considerable impact on the biology by creating micro-environments due to the discharge of reduced, hot hydrothermal fluids often containing potentially toxic elements, such as, As and Hg.One of the best studied MSWHS is located in Paleochori Bay on the south side of Milos Island, which due to its peculiar biogeochemistry has been the focus of numerous scientific studies. However, despite more than 25 years of research we do not have a dependable biogeochemical model concerning the interaction between hydrothermal and biological processes, nor do we have reliable repeat measurements at single locations. This is owed to the fact there are no GPS coordinates given for any of the sites studied and thus, although descriptions of the general locations and characteristics of vent sites exist for most of the investigations, returning to those specific sites is virtually impossible.A likely solution to this quandary at Milos and a potential aide to many other studies of MSWHS could be the generation of geo-referenced maps with help of aerial photography, because due to their shallow nature, hydrothermal features are discernable from the surface. With the possibility to obtain GPS coordinates directly from the map it will be possible to pick exact locations for sample collection, including temperature and flux measurements. Furthermore, it is possible to correlate hydrothermal features between their actual occurrence and their representation on the photographic map, i.e., to ground-truth the aerial map.The creation of a digital aerial map whose features were confirmed by direct observation will be the basis for a GIS platform to be used for past and ongoing research in Paleochori Bay, while the developed techniques will be easily transferred to other sites of shallow-water hydrothermal venting. Generation of such a map would, for the first time, allow unprecedented understanding of locations and chemistry of each vent site, as well as to provide an estimate of overall total hydrothermal fluxes and the associated Hg and As concentrations. This work has significance beyond Paleochori Bay since this approach will be easily transferable to other sites of MSWHS worldwide.