What killed the amphipods?
I came into the office on Sunday to find hundreds of dead amphipods in the box of slugs. Because there is plenty of vegetable material and no predation, the amphipods had multiplied rapidly, but I was surprised at the sheer number of dead little bugs.
Naturally, I was anxious about the slugs, but they seemed unconcerned. In fact, none of the other inhabitants seemed at all bothered, including the corals.
Snails? Fine. They have been happily grazing away on the glass and other surfaces.
Isopods? Fine. If anything, they seemed more bold than usual. So, whatever it was did not affect all arthopods equally.
The sabellid worms that came in with the Bryopsis were also unaffected.
I learned later that there had been a power outage, which explains why the low-flow alarms for the fume hoods in the lab were ringing when I arrived Sunday. Perhaps the amphipods were more sensitive to the loss of circulation in the tank than were the other invertebrates. Maybe amphipods just don’t like big piles of Bryopsis. We may never know. Will the amphipod population rebound? We’ll see.