Zoo Tampa Stingray Deaths

[Belzelbub]

This was in the news here recently. Back in May, Zoo Tampa found that all 12 stingrays in their touch tank had died overnight. The results of the investigation just reported the cause. COD sound very similar to a condition that can affect divers.

ZooTampa stingray deaths blamed on 'supersaturation;' tank will be redesigned and rebuilt

Edit: ZooTampa, not Florida Aquarium.

 

[dlofting]

I'd be interested in how the water became supersaturated with oxygen. Any ideas?

 

[Marie13]

I'd be interested in how the water became supersaturated with oxygen. Any ideas?

Did you read the article? Some possibilities are mentioned.

 

[Belzelbub]

I'd be interested in how the water became supersaturated with oxygen. Any ideas?

Yeah, me too. They weren’t certain, as it had resolved when they tested the water, it had resolved. A guy the news interviewed speculated on possible sources, such as cracks in pipes, skimmers, etc. It didn’t sound like they knew.

 

[Jcp2]

Since it’s an aquarium with presumably fixed depth (pressure) and likely no plants for biotic changes, I’m guessing a change in temperature or salinity or both caused it, with the evidence being flushed away with the water change.

 

[ThatDogDontHunt]

How does "too much oxygen" get in the water?

Home aquariums can have a bubbler or a waterfall pump. I assume these both add some small trace amount of oxygen to the water.

Is adding oxygen necessary in a big aquarium and how is it done?

 

[Seaweed Doc]

Since it’s an aquarium with presumably fixed depth (pressure) and likely no plants for biotic changes, I’m guessing a change in temperature or salinity or both caused it, with the evidence being flushed away with the water change.

This.

I can't see how mixing with air would supersaturate. But a rise in temperature would do it.

(Or plants. You can see oxygen bubbles around the edges of floating eelgrass leaves on the surface in the summer.)

 

[uncfnp]

It seems “gas supersaturation” may have been interpreted by the writer as oxygen, just as they do with a diver’s “oxygen tank.” And as with divers, nitrogen is the more likely culprit with gas bubbles from supersaturation events.

Toledo Zoo Fish Health Q&A: Gas Bubble Disease

https://www.petplace.com/article/fish/general/supersaturation/

 

[Belzelbub]

Since it’s an aquarium with presumably fixed depth (pressure) and likely no plants for biotic changes, I’m guessing a change in temperature or salinity or both caused it, with the evidence being flushed away with the water change.

I don’t think it was mentioned in the article, but when the story first broke, they tested the water. I believe they pulled samples before the water change mentioned in the article. Initially, they tested it for toxins, but found nothing. If it happened over night, I could see that the dissolved air could have equalized by then.

It’s a touch tank, so fixed water depth, and only a couple feet deep.

I would be shocked if they didn’t have alarms for temperature and salinity.

This.

I can't see how mixing with air would supersaturate. But a rise in temperature would do it.

Wouldn’t a temperature rise result in less dissolved gas, not more? I could see a temperature rise leading to the water being supersaturated, but I would think that would need to be a pretty dramatic temperature spike.

 

[Seaweed Doc]

Wouldn’t a temperature rise result in less dissolved gas, not more? I could see a temperature rise leading to the water being supersaturated, but I would think that would need to be a pretty dramatic temperature spike.

Think of it from the tissue perspective. Gases aren't a problem when they're dissolved, but become a problem when they come out of solution and form bubbles. If the ray's tissue is nearly saturated to start with, a temperature rise could trigger bubble formation.