Carbon chemistry observations in tropical coastal waters

The dataset reports field observations of the carbon composition of seawater at a coral reef lagoon and a mangrove tidal creek in Nusa Penida, Indonesia. Observations include high temporal resolution time series of radon, CO2, and ancillary parameters. Time series observations of radon (30 min intervals) and carbon dioxide (1 min) were performed using automated analysers powered with 12 V batteries. The calibrated radon (RAD-7 Durridge Company) and CO2 (Licor 840) analysers measure gas concentrations in a closed air loop in equilibrium with a stream of flowing water pumped at >3 L per minute into a shower head gas exchanger (Webb et al., 2016 and references therein). Water depths, salinity and temperature were measured using a conductivity-temperature-depth (CTD diver, Van Essen Instruments®) or a Hydrolab sonde (MS5) at time steps ranging from 5 to 30 min. Wind speeds were determined from local meteorological stations. Total alkalinity and dissolved inorganic carbon samples were immediately filtered using combusted 0.7 mm GF/F disposable filters and analysed using a VINDTA 3C (Versatile INstrument for the Determination of Total inorganic carbon and titration Alkalinity). The VINDTA measured TA via Gran titration with a Metrohm Titrino and DIC after sample CO2 extraction with phosphoric acid followed by coulometric titration (McMahon et al., 2018 and references therein). References McMahon, A., Santos, I.R., Schulz, K.G., Cyronak, T. and Maher, D.T. 2018. Determining coral reef calcification and primary production using automated alkalinity, pH and pCO2 measurements at high temporal resolution. Estuarine, Coastal and Shelf Science 209, 80-88. Webb, J.R., Maher, D.T. and Santos, I.R. 2016. Automated, in situ measurements of dissolved CO2, CH4, and δ13C values using cavity enhanced laser absorption spectrometry: Comparing response times of air-water equilibrators. Limnology and Oceanography: Methods 14(5), 323-337.本数据集记录了印度尼西亚努萨佩尼达岛一处珊瑚礁潟湖与红树林潮汐溪的海水碳组分野外观测数据。观测涵盖氡、二氧化碳及辅助参数的高时间分辨率时间序列。其中，氡（采样间隔30分钟）与二氧化碳（采样间隔1分钟）的时间序列观测采用12V电池供电的自动分析仪完成。经校准的氡分析仪（RAD-7，Durridge公司）与二氧化碳分析仪（Licor 840）采用闭合气路平衡法测量气体浓度：该气路与以每分钟>3升流速泵入淋浴头式气体交换器的水流达到平衡（Webb等，2016及参考文献）。水深、盐度及温度通过电导-温度-深度（CTD，conductivity-temperature-depth）潜水记录仪（Van Essen Instruments®）或Hydrolab探空仪（MS5）进行测量，采样间隔为5至30分钟。风速数据取自当地气象站。总碱度与溶解无机碳样品需立即使用经灼烧处理的0.7 mm GF/F一次性滤膜过滤，并通过VINDTA 3C型总无机碳与滴定碱度通用测定仪（其全称为Versatile INstrument for the Determination of Total inorganic carbon and titration Alkalinity）进行分析。该仪器通过Metrohm Titrino滴定仪采用Gran滴定法测量总碱度，溶解无机碳则先经磷酸萃取样品中的二氧化碳，再通过库仑滴定法完成测定（McMahon等，2018及参考文献）。 参考文献 McMahon, A.、Santos, I.R.、Schulz, K.G.、Cyronak, T.及Maher, D.T. 2018. 利用高时间分辨率自动碱度、pH及pCO₂测量确定珊瑚礁钙化与初级生产力. 《河口、海岸与陆架科学》209卷, 80-88页. Webb, J.R.、Maher, D.T.及Santos, I.R. 2016. 利用腔增强激光吸收光谱法自动原位测量溶解CO₂、CH₄及δ¹³C值：比较气-水平衡器的响应时间. 《湖沼学与海洋学方法》14(5), 323-337页.