UV climate over the Southern Ocean south of Australia, and its biological impact - Dissolved Organic Carbon (DOC) results

Minicosm design: Three successive experiments to a maximum incubation of 14 days were performed from mid November to early January in the summer of 2002/03 in a temperature controlled shipping container housing six 500 L polythene tanks or minicosms. Domes of UV transmissive PMMA in the roof of the container directly above the minicosms allowed ambient sunlight to be reflected to the tanks through tubes of anodised aluminium. These tubes reflected greater than 96% of the incident radiation irrespective of wavelength.Light perturbation to each minicosm was achieved by screening materials that attenuated UV wavelengths. UV stabilised polycarbonate removed wavelengths shorter than 400 nm, transmitting only photosynthetically active radiation (PAR) and provided the control treatment (PAR). In minicosm 2, a mylar screen removed UVB wavelengths (280 - 320 nm), providing a treatment (UVA) with PAR and UVA. Minicosms 3, 4 and 5 (UVB1, 2 and 3 respectively) were screened by borosilicate glass of 9, 5, and 3 mm thickness, transmitting ambient light (including UVR) at the equivalent water depths (ED, k=0.4) of 7.15, 5.38 and 4.97 meters respectively. Minicosm 6 (UVB4) was screened with PMMA that transmitted ambient light at an ED of 4.43 m.Light measurements: Measurements of downwelling UV and PAR were obtained using biometer and Licor sensors mounted on the roof of the minicosm container. A Macam, double grating spectroradiometer measured the spectral irradiance on the roof of the container. This was then weighted with the erythemal action spectrum and correlated to that obtained by the UV biometer. The Macam was used to measure the spectral irradiance at the cross of the UV biometer. The spectral intensity of light wavelengths were measured laterally and vertically in the minicosm screened only by UV-transmissive PMMA irradiance. These measurements were used to model the light field within the minicosm. In all other light treatments the Macam measured the spectral irradiance immediately below the water surface and in the centre of the minicosm. The model was then used to predict the spectral distribution and intensity of other light treatments. These measurements were repeated at interval throughout the season to determine whether solar elevation influenced transmission of ambient downwelling irradiance to the minicosms. UV and PAR sensors fixed to the outside of the minicosm container, together with the modelled light climates within each minicosm beneath each light treatment, predicted the quantify the light to which each experimental treatment was exposed.This work was conducted as part of ASAC project 2210.The download file contains three excel spreadsheets, plus three accompanying word documents which provide detailed methods used in the collection of these data, plus more information about the experiments.The fields in this dataset are:DayTreatmentUVAUVBPAR - photosynthetically active radiation

微型生态系统（minicosm）设计方案：2002/2003年夏季（11月中旬至次年1月初）开展了3组连续实验，培养周期最长为14天，实验在温控集装箱内进行，箱内设有6个500升聚乙烯水箱，即微型生态系统（minicosms）。
集装箱顶板位于微型生态系统正上方，其上安装有紫外线（UV）透射型聚甲基丙烯酸甲酯（PMMA）透光穹顶，自然光可通过阳极氧化铝管反射至水箱中。这类铝管对不同波长的入射辐射反射率均超过96%。

为实现对每个微型生态系统的光照调控，研究人员使用可衰减紫外线波长的遮蔽材料。其中，经紫外线稳定剂处理的聚碳酸酯可滤除400nm以下波长的光线，仅允许光合有效辐射（photosynthetically active radiation, PAR）透过，作为对照组（PAR组）。微型生态系统2使用聚酯薄膜（mylar）遮蔽屏滤除UVB波段（280~320nm）光线，形成仅保留光合有效辐射与UVA波段的处理组（UVA组）。微型生态系统3、4、5（依次对应UVB1、UVB2、UVB3组）分别使用厚度为9mm、5mm、3mm的硼硅酸盐玻璃进行遮蔽，其透过的自然光（含紫外线辐射UVR）等效于水深7.15m、5.38m、4.97m处的光照强度（等效水深ED，消光系数k=0.4）。微型生态系统6（UVB4组）使用聚甲基丙烯酸甲酯（PMMA）进行遮蔽，其透过的自然光等效水深为4.43m。

光照测量方案：研究人员通过安装在集装箱顶板上的紫外线生物计（biometer）与LI-COR传感器，采集下行紫外线与光合有效辐射数据。采用Macam双光栅光谱辐射计测量集装箱顶板处的光谱辐照度，随后依据红斑作用光谱对该数据进行加权处理，并与紫外线生物计的测量结果进行关联校准。同时使用Macam光谱辐射计测量紫外线生物计测点处的光谱辐照度。在仅使用紫外线透射型PMMA遮蔽的微型生态系统中，研究人员从横向与纵向两个维度测量各波长光线的光谱强度，基于上述测量结果构建微型生态系统内的光场模型。针对其余光照处理组，Macam光谱辐射计分别测量水面下方及微型生态系统中心处的光谱辐照度，随后利用该模型预测其余光照处理组的光谱分布与光强。实验季内定期重复上述测量，以探究太阳高度角是否会影响自然光下行辐照度向微型生态系统的传输效率。安装在集装箱外壁的紫外线与光合有效辐射传感器，结合各光照处理组下微型生态系统内的模拟光环境数据，可量化计算每组实验处理所受的光照条件。

本研究为ASAC项目2210的一部分。下载文件包含3个Excel电子表格与3份配套Word文档，其中详细记载了数据采集方法及实验相关补充信息。本数据集包含以下字段：Day（日期）、Treatment（处理组）、UVA、UVB、PAR - 光合有效辐射（photosynthetically active radiation）