Abstract:
The Deepwater Horizon (DWH) blowout of 2010 exposed many coastal and marine ecosystems in the Gulf of Mexico (GoM) to the acute and chronic effects of crude oil. To date no studies have investigated the toxicity of DWH oil on shallow reef-building corals despite the relative proximity of some reef sites to the DWH (Flower Garden Banks, TX) and the potential for downstream oil transport to other more distant sites (Pulley Ridge and Florida Keys, FL). A novel 24-well optical fluorescence oxygen-sensing system (microplate respirometer) was used to measure respiration rates of individual polyps of the common Caribbean coral, Siderastrea siderea, in response to a 48 h exposure of a 4% dilution of surface oil from the DWH blowout at 25oC and 30oC, and used an Imaging Pulse Amplitude Modulated Fluorometer (I-PAM) to measure photochemical efficiency of algal symbionts (Symbiodinium spp.). This dataset reports oxygen concentrations that can be used to calculate the adult polyp oxygen consumption rates over the span of a two week period. Experimental polyps were first acclimated to the experimental chambers for 7 days until the baseline respiration rates stabilized. Temperatures in the heated treatment were then raised to 30oC over a 3-day period and all of the corals (including controls at 25oC) were exposed to oil on day 11. After 48 h of oil exposure corals were returned to clean seawater and maintained at 25oC or 30oC for 48h of respiration measurements during recovery and an additional two weeks of visual monitoring. Data for both the daily oxygen consumption rates as well as the IPAM data taken are provided.
Suggested Citation:
Jansen, Brittany; Pasparakis, Christina. 2017. Use of Microplate Respirometry to Measure Respiration of Individual Adult Coral Polyps Exposed to Deepwater Horizon Oil. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7HX19RB
Data Parameters and Units:
Control- The water temperature was held at 25 degC. Heated- The water temperature was heated to 30 degC. Control oil- Oil was added to the water, which kept at 25 degC. Heated oil- Oil was added to the water, which was kept at 30 degC. Control recovery- Corals were placed in oil-free saltwater and kept at 25 degC. Heated recovery- Corals were placed in oil-free saltwater and kept at 30 degC. There were four plates run each day each labeled with a different letter (w, x, y, z) to ensure that the polyps could be tracked. The coral polyps were randomly placed within the plate each day. The total number of polyps in each group: W- 20 polyps X- 19 polyps Y- 18 polyps Z- 19 polyps Oxygen Consumption (% air saturation and umol L-1)- data found in the folder labeled O2 Consumption. There were four different treatment groups that were tested each day and were labeled w, x, y, or z. This is followed by the type of treatment each group was exposed to “O2_Control”, “O2_Ambient”, or “O2_Heated. Data is presented as either % air saturation or umol L-1 by elapsed time (seconds). The microplate that was used for testing consisted of 4 rows and 6 columns of wells. For clarity the rows were labeled A, B, C, and D. The columns were labeled 1-6. So each well was labeled with a corresponding letter and number. For example well A1 was in the top left and A6 was the top right, while D1 was bottom left and D6 was bottom right. Each of these columns in the excel file corresponds to the data that was collected for that well and thus to an individual polyp. Date/Time (DD.MM.YY HH:MM:SS), Temperature (deg C) IPAM data which was measured in Fv/Fm, which is the standard measure of photochemical efficiency, can be found in the file labeled “IPAM.” F is the fluorescence yield, while Fm’1 is the maximum fluorescence yield that is measured after the saturation pulse of the IPAM and when you take (Fm’-F)/Fm = Y(II). So Y(II) is the Photosystem II quantum yield. The numbers each correspond to an individual polyp that was measured. Each file is labeled similarly as the Oxygen Consumption data. Each has the Day it was measured, the treatment group label (w, x, y, or z), and the treatment it was exposed to (“O2_Control”, “O2_Ambient”, or “O2_Heated). Date (DD.MM.YY), Time (HH:MM:SS) Sum PAH data- found in folder titled ‘Sum PAH data’. Raw data provided a long with break down and percentages of different ringed PAHs.
Methods:
Surface slick oil from the DWH spill was prepared as a high-energy-water-accommodated fraction (HEWAF) to generate environmentally relevant PAH concentrations and compositional profiles. Loligo Microplate was used to measure oxygen consumption of individual adult coral polyps. Photochemical efficiency of each polyp was measured using an Imaging Pulse Amplitude Modulated Fluorometer throughout the trial.
Instruments:
Oxygen Consumption- Loligo Microplate (24 well optical-fluorescence, oxygen-sensing system). Imaging Pulse Amplitude Modulated Fluorometer (I-PAM, Walz, Effeltrich, Germany) used to measure photochemical efficiency.
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