Combined Effects of near-future temperature increase and ocean acidification on coral reef foraminifera Marginopora vertebralis and Heterostegina depressa. (NERP TE 5.2, AIMS and MARUM)

This dataset measures 5 effects of temperature and pH stressors (individual and combined) on tropical Foraminifera. The effects measured are: respiration, survivorship, growth, chl-a content and photochemistry. The study was conducted in 2011 and the data is provided as 5 single sheet spreadsheets.

Warming and changes in ocean carbonate chemistry alter marine coastal ecosystems at an accelerating pace. Here we investigate the individual effects as well as the interaction of two stressors, temperature and pH on two species of benthic coral reef Foraminifera. This study consisted of a 7 week aquarium experiment manipulating temperature and pH changes and measuring survivorship, growth, photosynthesis, respiration and chl-a content in these benthic coral reef Foraminifera.

Method:

Specimens were collected from Orpheus Island in the central Great Barrier Reef in September 2011. H. depressa was collected at a depth of 8–12 m from coral rubble at Cattle Bay (18°34’08’’ S 146°28’55’’ E) and M. vertebralis at a depth of 0–1 m (below Lowest Astronomical Tide) from turf algae-covered rocks at Hazard Bay (18°38’58’’ S 146°29’11’’ E). Both species were acclimated to laboratory conditions in tanks with moderate flow-through conditions (same as used in experimental setup) under low-light conditions (10 µmol photons m-2 s-1) for a period of 3 weeks.
12 flow-through aquaria (working volume 17.5 L) were installed in a constant temperature room, and the experiment was carried out over a period of 53 d.

Specimens were kept inside custom made flow-through housings in each aquarium to achieve higher flow conditions more closely mimicking their habitat than in previous experiments. Flow-through housings contained two levels made from two standard 6-well cell culturing plates with flow-through lids. Twenty-four specimens (four specimens per well) of H. depressa were put in the lower level and the same number of M. vertebralis in the top level.

For each temperature (28 and 31 ºC) and pCO2 level (~790 µatm, pHNIST 7.9 and ~490 µatm, pHNIST 8.1), three replicate tanks were used; replicate tanks were randomly allocated to treatments. Seawater was pumped from the ocean into the laboratory, filtered to 5 µm, and stored in four header tanks where it was modified to the desired experimental conditions. Manual temperature and pH measurements were performed once to twice per day. Water samples for total alkalinity (AT) and dissolved inorganic carbon (DIC) determinations were taken weekly and analysed by AIMS Laboratory Services.

Flow rates into the individual wells were recorded before and after the experiment, ranging between 180 and 220 mL min-1. Velocity of the water flow varied from 4.2–5.2 9 10-1 m s-1 at the inlet (Ø 0.3 cm) to 3.1–3.8 9 10-3 m s-1 at the outlet (Ø 3.5 cm). The flow rates between inlet and outlet are in the same range as those measured in situ over dead coral rubble and sea grass.

Flow-through housings were made containing two levels so that one species could be kept in the top level exposed to higher light levels than the species in the lower level. Light levels were chosen for each species separately because of their known distributions and different light saturation points determined by pulse amplitude modulation (PAM) fluorometry. PAM fluorometry results for M. vertebralis indicated a maximum saturating irradiance (Ek) between 100 and 140 µmol photons m-2 s-1 and for H. depressa between 40 and 60 µmol photons m-2 s-1 (Ziegler and Uthicke 2011). The light levels used in the experiment were chosen to fall below the Ek values by Ziegler and Uthicke (2011) and P–I curve Pmax values determined by Vogel and Uthicke (2012) and were selected to correspond to levels which have shown no changes in mortality rates or chlorophyll a concentrations in previous experimental manipulations of the studied species.

Further detail can be found in this publication:
Schmidt, C., Kucera, M., & Uthicke, S. (2014). Combined effects of warming and ocean acidification on coral reef Foraminifera Marginopora vertebralis and Heterostegina depressa. Coral Reefs, 33(3), 805-818. DOI 10.1007/s00338-014-1151-4

Format:

5 text (csv) files are given, one for each measurement.

The 5 tables are listed below where:
Species: H=Heterostegina, M=Marginopora
Temperature: °C
Treatment: abbr. of Temp°C, and pH

1.) Foraminifera_survivorship.csv
Tank, Species, Real Temp (°C), Real pH, Treatment

2.) Foraminifera_PAM_data.csv
Tank, Well, MQY (Maximum Quantum Yield, Fv:Fm), EQY (Effective Quantum Yield), Ps (Apparent Photosynthetic Rate), Treatment, Species

3.) Foraminfera_Respiration_data.csv
Respiration [µg O2 h-1 mg-1], Production [µg O2 h-1 mg-1], Net production, Tank, Species, Absolute Respiration (Respiration given as positive), Treatment

4.) Foraminifera_growth.csv
Aquaria Number, Well, Area Inital (mm2), Area Final (mm2), Growth (%/day), Treatment, Real Temp, Real pH, Species (Averages given per Well in Marginopora, individual sizes per well in Heterostegina)

5.) Foraminifera_chla content-csv
Treatment, Chl a (µg pigment/ mg wet weight of the Foraminifera), Tank, Species

本数据集量化了温度与pH胁迫因子（单独及联合作用）对热带有孔虫（Foraminifera）的5项效应，所测定的效应包括：呼吸速率、存活率、生长速率、叶绿素a（chl-a）含量及光化学过程。本研究于2011年开展，数据集以5个单工作表电子表格形式提供。

随着海洋变暖与海洋碳酸盐化学改变，海洋沿岸生态系统正以加速的态势发生变化。本研究针对两种底栖珊瑚礁有孔虫，探究了温度与pH这两种胁迫因子的单独作用及其交互效应。本研究通过为期7周的水族箱实验，调控温度与pH条件，并测定了这些底栖珊瑚礁有孔虫的存活率、生长速率、光合作用、呼吸作用及叶绿素a含量。

方法：

实验样本于2011年9月采自大堡礁中部的奥费斯岛。异复球房有孔虫（Heterostegina depressa，简称H. depressa）采自牛湾（18°34′08″S，146°28′55″E）的珊瑚碎石生境，采集深度为8~12 m；脊椎边球房有孔虫（Marginopora vertebralis，简称M. vertebralis）采自危险湾（18°38′58″S，146°29′11″E）覆盖草皮藻类的岩石生境，采集深度为0~1 m（低于最低天文潮位）。两个物种均在中等流水条件（与实验装置一致）、弱光环境（10 μmol光子·m⁻²·s⁻¹）下的水族箱中驯化适应3周。

实验在恒温室内设置了12个流水水族箱（工作容积17.5 L），实验周期共计53天。

为获得比既往实验更贴近其自然生境的流水条件，每个水族箱内均放置定制的流水养殖舱。该养殖舱由两个带流水盖的标准6孔细胞培养板组成，分为上下两层。下层放置24个异复球房有孔虫样本（每孔4个），上层放置相同数量的脊椎边球房有孔虫样本。

针对28℃和31℃两个温度梯度，以及~790 μatm、pH_NIST 7.9和~490 μatm、pH_NIST 8.1两个二氧化碳分压（pH）水平，每个处理组设置3个重复水族箱，重复箱随机分配至各处理组。海水从海洋抽取至实验室，经5 μm过滤后储存于4个储水罐中，并调整至实验所需的条件。每日手动测定温度与pH值1~2次。每周采集总碱度（AT）与溶解无机碳（DIC）测定所需的水样，交由AIMS实验室服务部进行分析。

实验前后均记录了各孔的流水速率，范围为180~220 mL·min⁻¹。水流速度在进水口（直径0.3 cm）处为4.2~5.2×10⁻¹ m·s⁻¹，在出水口（直径3.5 cm）处为3.1~3.8×10⁻³ m·s⁻¹。进水口与出水口之间的流水速率范围，与在死亡珊瑚碎石及海草生境中原位测得的流速范围一致。

流水养殖舱分为上下两层，以便将一个物种置于上层以获得比下层物种更高的光照水平。光照水平根据两个物种的已知分布及通过脉冲振幅调制（PAM）荧光法测定的不同光饱和点分别设置。PAM荧光法测定结果显示，脊椎边球房有孔虫的最大饱和光强（Ek）为100~140 μmol光子·m⁻²·s⁻¹，异复球房有孔虫为40~60 μmol光子·m⁻²·s⁻¹（Ziegler & Uthicke, 2011）。本实验采用的光照水平低于Ziegler与Uthicke（2011）测定的Ek值，且符合Vogel与Uthicke（2012）测定的光响应曲线Pmax值，同时该光照水平在既往针对本研究物种的实验操作中，未导致死亡率或叶绿素a浓度发生变化。

更多详细信息可参阅以下文献：
Schmidt, C., Kucera, M. & Uthicke, S. (2014). 海洋变暖与酸化对珊瑚礁有孔虫脊椎边球房有孔虫及异复球房有孔虫的联合效应. 珊瑚礁, 33(3), 805-818. DOI: 10.1007/s00338-014-1151-4

数据格式：

本数据集包含5个文本（CSV）文件，每项测定对应一个文件。5个表格的说明如下：
物种（Species）：H代表异复球房有孔虫属（Heterostegina），M代表边球房有孔虫属（Marginopora）
温度（Temperature）：单位为摄氏度（°C）
处理组（Treatment）：温度（℃）与pH的缩写组合

1. Foraminifera_survivorship.csv
列依次为：水族箱编号（Tank）、物种（Species）、实际温度（Real Temp, °C）、实际pH值（Real pH）、处理组（Treatment）

2. Foraminifera_PAM_data.csv
列依次为：水族箱编号（Tank）、孔号（Well）、最大量子产率（MQY, Maximum Quantum Yield, Fv:Fm）、有效量子产率（EQY, Effective Quantum Yield）、表观光合速率（Ps, Apparent Photosynthetic Rate）、处理组（Treatment）、物种（Species）

3. Foraminfera_Respiration_data.csv
列依次为：呼吸速率（Respiration, μg O₂·h⁻¹·mg⁻¹）、总光合产氧量（Production, μg O₂·h⁻¹·mg⁻¹）、净光合产氧量（Net production）、水族箱编号（Tank）、物种（Species）、绝对呼吸速率（Absolute Respiration，呼吸速率以正值表示）、处理组（Treatment）

4. Foraminifera_growth.csv
列依次为：水族箱编号（Aquaria Number）、孔号（Well）、初始面积（Area Initial, mm²）、最终面积（Area Final, mm²）、日生长速率（Growth, %/day）、处理组（Treatment）、实际温度（Real Temp）、实际pH值（Real pH）、物种（Species）（注：边球房有孔虫数据按孔取平均值，异复球房有孔虫数据为孔内单个个体的尺寸）

5. Foraminifera_chla content-csv
列依次为：处理组（Treatment）、叶绿素a含量（Chl a, μg 色素·mg⁻¹ 有孔虫湿重）、水族箱编号（Tank）、物种（Species）