Development of a laser-based sea-ice chlorophyll sensor

开发基于激光的海冰叶绿素传感器

• 批准号: NE/H002227/1
• 负责人: Andrew Brierley
• 金额: $ 23.01万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH002227%2F1
• 关键词: Development; laser; based; sea; ice

We want to build a scientific instrument that can measure the amount of algae growing on the underside of sea ice. Sea-ice algae form the base of many polar marine foodwebs, but data on the mesoscale (tens to hundreds of km) variability in the abundance of algae are lacking because of sampling difficulties. This is hampering efforts to understand sea-ice ecosystem function, and predictions of consequences that ongoing sea-ice melt (due to climatic warming) might have. At present the most reliable way to measure sea-ice algal abundance is to drill holes through the ice from above and collect the algae. This is labour intensive, time consuming and not without risk. In the past 10 years or so autonomous underwater vehicle (AUV; essentially an unmanned, remotely operated submarine) technology has matured to the extent that these vehicles can complete extended (tens to hundreds of km) missions under sea ice, collecting data underway as they do so: we have used AUVs to conduct echosounder surveys of krill under sea ice. We now want to use AUVs to survey sea ice algae, and propose here to build a laser-based instrument to make the algal measurements. The device will basically work by measuring the amount of light reflected back from the underside of sea ice. We expect a quantitative relationship to exist between the amount of algae present (actually the amount of the photosynthesis pigment 'chlorophyll') and the amount of light reflected. In preliminary measurements we have already seen that bare ice reflects laser light differently than ice colonized by algae, so have some practical evidence already that the approach should work. In addition, there is a wealth of published information on the reflectance of light at various wavelengths by algae. We will use this theory to guide instrument development. The instrument will be assembled by a team of talented engineers and technicians who have much experience developing lasers for applied use in hostile environments. Once a prototype instrument is built, we will test it on sea-ice algae grown on sea ice in an experimental facility in Germany (essentially a sea-ice aquarium). We will make measurements of reflectance of laser light of various wavelengths (different colours; blue, green etc) and construct curves showing relationships between chlorophyll concentration and % reflectance. If the prototype instrument works, we will write another grant application for funds to deploy a robustly-housed version on AUVs under sea ice in the Arctic and Antarctic to pursue ecological investigations.

我们想建造一种科学仪器，可以测量生长在海冰下面的藻类数量。海冰藻类是许多极地海洋食物网的基础，但由于取样困难，缺乏关于藻类丰度中尺度（数十至数百公里）变化的数据。这阻碍了对海冰生态系统功能的理解，也阻碍了对海冰融化（由于气候变暖）可能产生的后果的预测。目前，测量海冰藻类丰度最可靠的方法是从上面钻冰孔并收集藻类。这是劳动密集型的、耗时的并且并非没有风险。在过去的10年左右，自主水下航行器（AUV;基本上是一种无人驾驶的远程操作潜艇）技术已经成熟到这种程度，这些车辆可以在海冰下完成扩展（数十至数百公里）任务，收集正在进行的数据：我们已经使用AUV进行回声探测器调查海冰下的磷虾。我们现在想使用AUV来调查海冰藻类，并建议在这里建立一个基于激光的仪器来进行藻类测量。该设备的工作原理是测量从海冰底部反射回来的光量。我们期望存在于藻类数量（实际上是光合作用色素“叶绿素”的数量）和反射的光量之间的定量关系。在初步测量中，我们已经看到裸冰反射激光的方式与藻类定居的冰不同，因此已经有一些实际证据表明这种方法应该有效。此外，有大量关于藻类对各种波长的光的反射率的公开信息。我们将用这个理论来指导仪器的开发。该仪器将由一组才华横溢的工程师和技术人员组装，他们在开发用于恶劣环境的激光器方面经验丰富。一旦原型仪器建成，我们将在德国的一个实验设施（基本上是一个海冰水族馆）的海冰上生长的海冰藻类上进行测试。我们将测量不同波长（不同颜色;蓝色、绿色等）激光的反射率，并绘制曲线，显示叶绿素浓度与反射率%之间的关系。如果原型仪器有效，我们将编写另一份拨款申请，以获得资金，在北极和南极海冰下的AUV上部署坚固的封装版本，以进行生态调查。