Shelly’s Notebook: Fri. Oct. 18, Pt. Whitney Juvenile Geoduck var.low pH experiment

Steven and I took end point measurments and broke down the experiment. Steven’s post for the day is here

Water chem

  • Water level in header tanks look normal since the in-flow was adjusted last week.
  • took discrete measurments and poisoned water samples
  • did not run a tris curve
  • took Apex probes out around 10:30 to prep for final sampling

Survival and growth

  • Steven and I went through all silos by rinsing on 3000um mesh
    • we stacked screens in a tote with ambient water and submerged the silo within the 3000um screen to loosen the sand and animals to gently transfer them out of the silo on to the screen
  • Steven counted animals
    • count data here
      • need to compare counts from different size classes
        • need to use imageJ to measure animals from each image here. Maybe Hana can help with this.
        • Note about silo 2.4: 23 animals were removed (for sampling and respirometry) prior to the picture

Respirometry

Experiment breakdown

  • We preserved 5 individuals/silo and a pool of 10 individuals/silo in LN2. We also preserved 5 individuals/silo in glyoxyl
    • animals preserved in glyoxyl are in the wine cooler at point whitney and need to be brought back to UW (bring cooler and white boxes next time)
    • animals preserved in LN2 were brought back to the lab in the dry shipper and stored in Roberts lab -80C Rack 4 Column 3 Row 2
    • Because there were very few animals from low pH exposed parents, these individuals were preserved in LN2 (and in glyoxyl if possible). But no pool.
  • After sampling, all low pH exposed animals from ambient parents were discarded.
  • All animals exposed to ambient conditions were returned to the manifold to their corresponding rinsed silos with new sand (300mL)
  • pH treatment is still currently running in tote 1 although that seawater is no longer being pumped into any manifold
    • this needs to get turned off
  • Peristaltic pump ceased up. Matt noticed this in the morning when he went to fill the algae header and it was full from the previous day. The pump no longer shows rotation as it previously did, although it sounds like it’s turning. We disassembled the pumpheads but still see no rotation. Matt put a flathead screwdrived in the pump slot to see if it would turn assisted and it did, but it can’t turn on its own. This indicates a possible internal clog or build-up, but we didn’t open the pump up to look inside. Need to check if this pump is under warranty.
    • Matt plumbed in the oyster feed line into the B5 header tank (feeding the ambient silos) and into his new brood stock tank (B4).
    • Steven disassembled the H1 heath stack and moved the low pH exposed animals (T1) and their ambient exposed sibs (T2) to the breeze way. One heath tray containing manila clams was left floating in the B5 header tote.
  • all in all breakdown went really well and sampling was seamless

Conclusions

  • at first glance:
    • mortality is higher in low pH exposed juveniles from low pH exposed parents than in juveniles from ambient parents
    • there isn’t a difference in mortality between juveniles from low pH exposed parents and juveniles from ambient parents
    • juveniles from low pH exposed parents tended to have greater average shell length and wet weight than juveniles from ambient parents
  • need to run stats to confirm these observations

1.5-yr-old hatchery vs. Sequim reared juveniles

  • Steven photographed these animals for shell length measurments