Carbonate Chemistry Autonomous Sensor System (CarCASS)

人类每年向大气中释放大约10千斤的碳，主要是通过燃烧化石燃料，其中约一半被海洋吸收。当二氧化碳进入海洋时，它会溶解形成碳酸（H2CO3），这是一种弱酸，很容易解离成碳酸氢盐（HCO3-）和碳酸盐（CO32-）离子，以及降低海水pH值的氢离子。这一过程被定义为海洋酸化，已在几个海洋水库中通过时间序列观测得到记录，预计将对海洋生物，特别是海洋钙化动物（甲壳类动物、贝类动物、一些浮游生物、珊瑚等）产生不利影响，这些生物从CaCO3形成坚硬的结构。预计到2100年，海洋酸化对生态系统服务的负面影响将使世界经济每年损失1万亿美元。在英国，10种最有价值的海洋物种中有4种是钙化贝类或甲壳类动物，每年价值约2.5亿英镑。此外，贝类养殖业每年的产值约为3000万英镑。因此，需要对碳酸盐化学参数进行高空间和时间分辨率的测量，以同时表征空间和时间的变化，从而更好地了解生物耐受性和对海洋酸化的社会反应。尽管人们已经努力提高海洋中高分辨率碳酸盐化学观测的可用性，但由于缺乏自动化的高性能低成本碳酸盐传感器，仍然阻碍了使用自动驾驶汽车进行连续和空间广泛的碳酸盐化学测量。因此，开发能够实现未来海洋自主系统（MAS）部署目标的传感器，对于破解我们对全球海洋碳循环的理解中的知识空白和不确定性，以及优化全球海洋酸化及其影响模型，是一个紧迫的问题。在国家海洋学中心（NOC）的海洋技术和工程小组（OTEG），我们开发了用于海洋生物地球化学，物理和生物参数原位测量的传感器，包括溶解无机碳（DIC），总碱度（TA）和ph。目前这些传感器仍处于相对早期的发展阶段（技术准备水平（TRL） 4-6）。在这项提案中，我们请求资金来推进这些技术的TRL，并将它们集成到一个小型的自主设备中，我们称之为碳酸盐化学自主传感器系统（bone）。胴体还将采用由我们的合作伙伴ANB Sensors开发的屡获殊荣的快速测量pH传感器，作为这项工作的一部分，我们将从TRL 6推进到TRL 8。该机体积小，可以集成到大多数MAS上，包括Autosub Long Range （ALR）、Kongsberg滑翔机、C-Enduro ASV、Wave Glider和Argo浮筒。作为一个集成系统，屠体将是第一个能够自主完成海水碳酸盐化学特征从表面到整个海洋深度的设备。每个传感器组件都是完全自主的，能够独立部署。DIC和TA传感器将是第一批能够在整个海洋深度进行自主测量的设备，而pH传感器将首次在海洋的任何地方提供快速（0.1 Hz）自主校准的测量。该项目将提供工具，使海洋中的连续和空间广泛的碳酸盐化学测量能够破译我们对全球海洋碳循环的理解中的知识空白和不确定性。

Humans release approximately 10 petagrams of carbon per year into the atmosphere, mainly through combustion of fossil fuels, about half of which is absorbed by the ocean. As CO2 enters the ocean it dissolves to form carbonic acid (H2CO3), a weak acid which readily dissociates to bicarbonate (HCO3-) and carbonate (CO32-) ions, and H+ lowering the pH of seawater. This process, defined as Ocean Acidification, has been documented in several oceanic reservoirs through time series observations and is expected to have adverse consequences on marine life and especially marine calcifiers (crustaceans, shellfish, some plankton species, corals etc.) which form hard structures from CaCO3. Ocean acidification is expected to cost the world economy 1 trillion USD annually by 2100 through negative impacts on ecosystem services. In the UK, four of the ten most valuable marine species are calcifying shellfish or crustaceans with an annual worth around £250m. Furthermore, aquaculture of shellfish is worth annually about £30m. High spatial and temporal resolution measurements of carbonate chemistry parameters are therefore needed to concurrently characterise variability in space and time to better understand biological tolerances and societal responses to ocean acidification. Although efforts have been made to increase the availability of high resolution carbonate chemistry observations in the ocean, the lack of automated high performance low cost carbonate sensors continues to hold back continuous and spatially extensive carbonate chemistry measurements using autonomous vehicles. Developing sensors capable of fulfilling future Marine Autonomous System (MAS) deployment goals, is therefore a matter of urgency for deciphering knowledge gaps and uncertainties in our understanding of the global ocean carbon cycle and optimisation of global models of ocean acidification and its impacts. At the Ocean Technology and Engineering Group (OTEG) of the National Oceanography Centre (NOC) we develop sensors for in situ measurements of biogeochemical, physical and biological parameters in the ocean including Dissolved Inorganic Carbon (DIC), Total Alkalinity (TA) and pH. Currently these sensors are still at a relatively early developmental stage (Technology Readiness Level (TRL) 4-6). In this proposal we request funds to advance the TRL of these technologies and integrate them into a small autonomous device we call Carbonate Chemistry Autonomous Sensor System (CarCASS). The CarCASS will also incorporate an award winning fast measuring pH sensor, developed by our partners ANB Sensors, which as part of this work we will advance from TRL 6 to TRL 8. The CarCASS will be small enough for integration on most MAS including the Autosub Long Range (ALR), Kongsberg Seaglider, C-Enduro ASV, Wave Glider and Argo floats. As an integrated system, CarCASS will be the first device capable of autonomous complete characterisation of the seawater carbonate chemistry from surface to full ocean depth. Each sensor component will be fully autonomous and capable of being deployed independently. The DIC and TA sensors will be the first devices capable of autonomous measurements at full ocean depth while the pH sensors will provide for the first time fast (0.1 Hz) self-calibrated measurements autonomously anywhere in the ocean. This project will deliver tools which will enable continuous and spatially extensive carbonate chemistry measurements in the ocean deciphering knowledge gaps and uncertainties in our understanding of the global ocean carbon cycle.