Thur. Oct. 3, Pt. Whitney Juvenile Geoduck var.low pH experiment

  • Got to the hatchery at 12:30
  • Had lab meeting from 12:30-1:15

Water chem

  • Water level in header tanks look normal. Last couple weeks it must have been a fluke, or perhaps related to low tide?
    Low pH header: ambient header:
  • Took discrete measurements and TA at 3:40pm.
  • for TA, I took directly from the discrete measurment water after filtering it through 20uM. The discrete measurement water samples were directly from the headers and inside the silos (using clean TA cups). I poisoned samples to run at future time.
    • Discrete measurments looked as they should
    • I didn’t take measurments for volitional spawned low pH vs. ambient conditioned juveniles (from Sam’s summer experiment) because I was short on time.

animal check

Var.low pH treatment

ambient offspring:

  • 2.1:
  • 2.2:
  • 2.3:
  • 2.4:
  • 2.5:

var.low pH offspring:

  • 2.8:
  • 2.10:
  • 2.11:
  • 2.12:

Ambient pH treatment

ambient offspring:

  • 3.1:
  • 3.2:
  • 3.3:
  • 3.4:

var.low pH offspring:

  • 3.8:
  • 3.9:
  • 3.10:
  • 3.11:
  • 3.12:

Sequim bay animals

  • 3.7: 1 mort.

Volitional spawned low pH vs. ambient conditioned juveniles (from Sam’s summer experiment)

  • H1T1 (low pH):
  • H1T2 (amb):

System status

This is how things looked right before I left:

Low pH setup

Amb. pH setup

Respirometry

SDR plate order

Size photos

    • I accidentally smashed the third column first row animal when getting it out of the vial :(
  • more size photos are here

Data and analysis

  • I haven’t processed this yet, but will post soon.

Overall observations

  • Survival seems to be OK despite the empty shells on the surface. This is more obvious now that the animals are visibly growing.
  • Animals reared in the low pH condition show clear areas on their shells where perhaps calcium has been removed. Photos from the animal check and from the respirometry size photos show this.
  • Low pH conditioned animals appear larger than ambient conditioned, but many ambient animals are beneath the surface so this needs to be more thoroughly measured (which I’ll do in a couple weeks after 2 total months of conditioning). Besides the shell clearing, the low pH animals seem to look better than the ambient animals, but again that observation is disregarding animals that are buried.
  • It’s interesting that the low pH condition has more live animals hanging out on the surface compared to the ambient condition.
Written on October 3, 2019