Physiological effects of climate change and diuron on calcareous algae Halimeda opuntia (NESP TWQ 2.1.6, AIMS)

This dataset consists of two data files (spreadsheets) from a 15 days experiment simulating the combined effects of climate change (manipulated temperature and pCO2 from present days and predicted for 2050 and 2100) and diuron contamination. Photosynthetic parameters were used to evaluate the physiological responses of Halimeda opuntia.

Endpoints related to photosynthesis have high ecological relevance, once this physiological process is pivotal for algae health and survival. PAM fluorometry is reliable tool to evaluate toxicological effects of PSII herbicides and many other toxicants and stressors. Photochemistry parameters derived from PAM fluorometry and the direct measurement of photosynthesis by oxygen production will enable an evaluation of the species fitness in response to multiple stressors, and contribute to the knowledge regarding risks posed by herbicides, and how contaminants toxicity thresholds are affected by future climate change scenarios.

Methods:
Fragments of the calcareous green algae Halimeda opuntia were collected from SeaSim mesoscosm tanks (MOS system, Evolution 21 Project, more information on ). These organisms were kept, for at least 8 months, in tanks simulating three climate scenarios: ambient condition (average temperature of 28°C and pCO2 410 ppm), 2050 (average temperature of 29°C and pCO2 680 ppm) and 2100 (average temperature of 30°C and pCO2 940 ppm).

After this acclimatization period, fragments were transferred to 1.5L chambers kept in the same scenarios, but also receiving seawater with six levels of diuron. The nominal diuron concentrations were 0, 0.3, 1, 3, 10 and 30 µg,L-1. A total of 54 chambers were used, three for each climate scenario/diuron combination, containing six Halimeda fragments each.

After 15 days exposed to these combined stressors, the photosynthetic efficiency, expressed as the effective quantum yield (light adapted yields) was estimated from chlorophyll fluorescence measurements of three Halimeda fragments from each chamber (six for the ambient condition, to increase sample size at the reference/control condition). These measurements were taken with an Imaging-PAM chlorophyll fluorometer (I-PAM, Walz GmbH, Germany).

One fragment from chamber were used in incubations to assess oxygen production (two for the ambient condition, to increase sample size at the reference/control condition). One hour incubations under the experimental light levels were performed, using a manual OD meter to record oxygen concentration before and after the incubation. Blanks were run in parallel. Oxygen production was normalized by the volume of seawater used in incubations, time and fresh weight of the algae fragment.

Format:

This dataset consists of two csv spreadsheets, containing the climate change scenario (Ambient, 2050 and 2100), the diuron concentration and the respective responses of two endpoints, the photosynthetic efficiency (light adapted yields, “Light_Yields” column, on “dataPAM.csv” file) and photosynthesis (mg of oxygen produced per hour of incubation per fresh weight, “O2_prod” column, on “dataProd.csv” file).

Data Dictionary:

dataPAM.csv - Each row represents one Halimeda fragment.
CLIMATE_CONDITION: Ambient, 2050 and 2100.
DIURON_NUMERIC: Nominal diuron concentrations (0, 0.3, 1, 3, 10 and 30 µg.L-1).
CHAMBER: Identification of the chamber each fragment was kept in.
LIGHT_YIELDS: Effective quantum yield (light adapted yield) measured by an Imaging Pulse Amplitude Modulated (I-PAM) fluorometer. Three fragments from each chamber were used (six for the ambient condition, to increase sample size at the reference/control condition).

dataProd.csv - Each row represents one Halimeda fragment.
CLIMATE_CONDITION: Ambient, 2050 and 2100.
DIURON_NUMERIC: Nominal diuron concentrations (0, 0.3, 1, 3, 10 and 30 µg.L-1).
CHAMBER: Identification of the chamber each fragment was kept in.
O2_PROD: Photosynthetic rates measured as oxygen production after one hour of incubation under experimental treatment light level (units are ‘mg of oxygen produced per hour of incubation per fresh weight’), measured after 15 days of exposure. One fragment from each chamber was used because of logistical reasons related to time required to complete incubations for all treatments (two for the ambient condition, to increase sample size at the reference/control condition).

Data Location:

This dataset is filed in the eAtlas enduring data repository at: data\custodian\2016-18-NESP-TWQ-2\2.1.6_Cumulative-impacts\data\Halimeda

本数据集包含两份电子表格数据文件，源自一项为期15天的模拟实验，旨在探究气候变化（调控温度与当前及2050、2100年预测水平的二氧化碳分压（pCO2））与敌草隆（diuron）污染的复合效应。实验以仙人掌仙掌藻（Halimeda opuntia）为研究对象，通过光合参数评估其生理响应。

与光合作用相关的检测指标具有极高的生态学意义，因为该生理过程对藻类的健康与存活至关重要。脉冲振幅调制（Pulse Amplitude Modulated, PAM）荧光技术是评估光系统II（PSII）除草剂及多种其他有毒污染物与胁迫因子毒理效应的可靠手段。通过PAM荧光技术获取的光化学参数，以及通过产氧量直接测定的光合速率，可用于评估该物种应对多重胁迫的适应能力，同时有助于加深对除草剂风险，以及未来气候变化情景下污染物毒性阈值变化规律的认知。

### 实验方法
从SeaSim中宇宙实验 tank（MOS系统，Evolution 21项目，详见相关说明）采集了钙绿藻仙人掌仙掌藻（Halimeda opuntia）的片段，将其置于模拟三种气候变化情景的培养池中驯化至少8个月：当前环境情景（平均温度28℃，pCO₂ 410 ppm）、2050年情景（平均温度29℃，pCO₂ 680 ppm）以及2100年情景（平均温度30℃，pCO₂ 940 ppm）。

驯化期结束后，将藻片段转移至1.5L的培养舱中，这些舱体维持与驯化阶段相同的气候变化情景，同时添加含有六种不同浓度敌草隆（diuron）的海水，敌草隆的标称浓度分别为0、0.3、1、3、10和30 μg·L⁻¹。本实验共设置54个培养舱，每种气候变化情景与敌草隆浓度的组合对应3个重复舱，每个舱内放置6段仙人掌仙掌藻（Halimeda opuntia）。

经过15天的复合胁迫暴露后，通过对每个培养舱内的3段藻片段（当前环境情景的对照组设置6段片段以增加样本量）进行叶绿素荧光测定，估算得到以有效量子产率（光适应产率）表示的光合效率，本次测定使用成像式脉冲振幅调制（Imaging-PAM, I-PAM）叶绿素荧光仪（德国Walz GmbH公司生产）完成。

从每个培养舱中选取1段藻片段（当前环境情景的对照组选取2段片段以增加样本量）用于产氧量测定实验：在实验光照条件下开展为期1小时的孵育实验，使用手动OD仪记录孵育前后的溶氧浓度，同时同步设置空白对照。最终产氧量结果将根据孵育所用海水体积、孵育时长以及藻片段的鲜重进行归一化处理。

### 数据集格式
本数据集包含两份CSV格式电子表格，涵盖气候变化情景（当前环境、2050年及2100年）、敌草隆浓度，以及两项检测指标的响应结果：光合效率（光适应产率，对应`dataPAM.csv`文件中的"Light_Yields"列）与光合速率（每小时每克鲜重的产氧量，对应`dataProd.csv`文件中的"O2_prod"列）。

### 数据字典
#### dataPAM.csv
每一行对应一段仙人掌仙掌藻（Halimeda opuntia）片段：
- CLIMATE_CONDITION：气候变化情景，可选值为当前环境、2050年及2100年
- DIURON_NUMERIC：敌草隆标称浓度，取值为0、0.3、1、3、10和30 μg·L⁻¹
- CHAMBER：藻片段所在培养舱的编号标识
- LIGHT_YIELDS：通过成像式脉冲振幅调制（I-PAM）荧光仪测定的有效量子产率（光适应产率）。每个培养舱取3段藻片段进行测定（当前环境情景对照组取6段以增加样本量）

#### dataProd.csv
每一行对应一段仙人掌仙掌藻（Halimeda opuntia）片段：
- CLIMATE_CONDITION：气候变化情景，可选值为当前环境、2050年及2100年
- DIURON_NUMERIC：敌草隆标称浓度，取值为0、0.3、1、3、10和30 μg·L⁻¹
- CHAMBER：藻片段所在培养舱的编号标识
- O2_PROD：在实验光照条件下孵育1小时后测定的光合速率，以产氧量表示，单位为"每小时每克鲜重的产氧量毫克数"，测定于15天胁迫暴露结束后。由于所有处理组的孵育实验耗时限制，每个培养舱仅取1段藻片段进行测定（当前环境情景对照组取2段以增加样本量）

### 数据存储位置
本数据集存储于eAtlas长期数据仓储中，存储路径为：datacustodian2016-18-NESP-TWQ-22.1.6_Cumulative-impactsdataHalimeda