Quantifying the impact of ocean acidification on biofilms from rocky habitats.

• Main Author: Tait, Karen
• Format: Dataset
• Language: English
• Published: British Oceanographic Data Centre, Natural Environment Research Council 2017
• Subjects: biota; Ocean acidification
• Online Access: https://dx.doi.org/10.5285/5d531f60-a905-4dae-e053-6c86abc0c1fb; https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/5D531F60-A905-4DAE-E053-6C86ABC0C1FB/

Settlement panels that incorporate gas permeable membranes were designed to study the impact of increased CO 2 on biofilm formation and succession in the field. Each panel consisted of a 3 mm thick PVC backing panel, 5 mm gas space, 5 mm reinforced silicone polymer membrane and a 3 mm thick PVC gasket to seal the layers of the unit. The exact pressure required to produce a drop of 0.3 pH units was carefully calibrated in laboratory experiments under varying hydrodynamic regimes. The panels were immersed in a fully marine tidal embayment at a depth of 1 meter and randomly assigned one of three treatments: ambient pH (not supplied with gas), ambient pH (supplied with ambient atmospheric air) and 0.3 pH units below ambient (supplied with CO 2 at pressure). At 2, 4, 6, 8 and 12 weeks after deployment, 5 replicate panels of each treatment type were randomly selected and the microbial component analysed. Measurements of biofilm wet weight, biofilm coverage and 16S rDNA gene copies mm-2 were all made. For biofilm coverage, the proportion of the surface area covered by bacteria and by other organisms was determined with microscope image analysis, using an Image ProPlus imaging system (Media Cybernatics) attached to a Reichert Jung Polyvar microscope and a Optronics Magna Fire SP camera. For DNA extraction, biofilm material was scraped from the settlement panel using a sterile scalpel, placed into a sterile microtube and weighed. The MoBio PowerBiofilm™ DNA Isolation Kit (Carlsbad, USA) was used to extract DNA according to the manufacturer's instructions. For each biofilm sample, 10 ng DNA was used to determine the abundance of bacterial 16S rRNA genes using the primers Bact1369F (CGGTGAATACGTTCYCGG) and Prok1492R (GGWTACCTTGTTACGACTT) (Suzuki et al. 2000). An ABI 7000 sequence detection system (Applied Biosystems, Foster City, USA) and QuantiFast SYBR Green PCR Kit (Qiagen) was used. Reactions contained 300 nM of Bact1369F and 900 nM of Prok1492R and PCR conditions were 5 minutes at 95°C followed by 40 cycles of 95°C for 15 seconds and 60°C for 1 minute.