Plate Photos

During this step, high resolution photos will be taken for each plate side. Much like settlement plates, ARMS plate photo can be used to assess sessile taxa coverage, diversity, size of sessile colonies etc...

Because the sessile communities will be scraped off the plates and analyzed using next-gen sequencing, it is important to make sure that all the containers and tools used during the photo step have been bleached and rinsed between ARMS processing. Wear gloves at all times; do not touch the water or the plates with bare skin.

Materials:

  • Bleached photo tray (11”x14”)
  • 4 used nylon spacers glued to the photo tray to hold the plates
  • 1 camera with 60 mm lens
  • Camera tripod
  • 2 external strobes on gorilla pods
  • 18 plate tags labeled Site#-ARMS#-Plate#-T or -B for top or bottom
  • 1 pair of gloves

Procedures:

  1. Fill the photo tray with clean filtered seawater
  2. Place Plate#1 in the center of the tray on top of 4 nylon spacers
  3. Place the corresponding photo label on top of the plate and take a photo of the overall plate. Remove the label and take another photo.
  4. Photograph closely each corner and center several times to get detailed images of the organisms (4 to 9 or even 15 images per side of plate overlapping to make stitching possible). Make sure that the photos are taken on a horizontal plane, the use of a camera tripod helps with the consistency of photos
  5. If higher-resolution photos are needed, a grid of either 3x5 or 4x6 works well with 15%-20% overlap to allow image stitching into a single composite image.
  6. Repeat steps 2 to 4 for the bottom side of the plate using the corresponding label.
  7. Repeat for each plate. Change the water as needed when it gets dirty with sediment

Illustrations:

Plate photo set-up: The camera stands on a tripod and is connected to a computer

Schematic of the grid used to standardize the photos (pdf available at the top of this page). The photos can also be taken without this system but make sure they overlap so they can be stiched back together later on and are taken on the same plane.

The camera is connected to the computer and images are saved directly to the computer

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