Why did my water fleas die?

[daggaz]

I've got water fleas and copepods in two different jars, both with an airstone.  The other day, I 

a) added a handful of dead beach leaves to each jar which quickly upped the tannins 

b) had to remove the airstones for about 12 hours

Now most of my critters are dead, floating around on the bottom.  There are still a number of survivors, especially the really tiny ones, but most of the adults are dead.  What did I do wrong? I'm gonna let it go for now and see how it evolves, I think there are enough survivors to get back to a strong, breeding population again, but I would like to understand what killed them off so I can avoid it in the future.  

[Tlindsey]

On 7/9/2024 at 12:23 PM, daggaz said:

I've got water fleas and copepods in two different jars, both with an airstone.  The other day, I 

a) added a handful of dead beach leaves to each jar which quickly upped the tannins 

b) had to remove the airstones for about 12 hours

Now most of my critters are dead, floating around on the bottom.  There are still a number of survivors, especially the really tiny ones, but most of the adults are dead.  What did I do wrong? I'm gonna let it go for now and see how it evolves, I think there are enough survivors to get back to a strong, breeding population again, but I would like to understand what killed them off so I can avoid it in the future.  

The scuds must have oxygenated water at all times because of how they were created to breathe. 

[daggaz]

The scuds seem ok (what few I still had left), its the daphnia and some of the larger swimmy critters that are all dead on the bottom, now.  

[jwcarlson]

Where did you get the leaves from?  In my experience, daphnia are really good at dying.

[daggaz]

From a forest.  No pesticides or anything like that.  I'm kind of leaning towards its the lack of oxygen that did them in, though honestly I am a bit surprised that the jars could get deprived so quickly, there's nothing big in there.  

[Tony s]

On 7/9/2024 at 2:29 PM, daggaz said:

From a forest

Any Idea what type of tree. Thinking of defensive chemicals like juglone

[Rube_Goldfish]

The two things that changed are the removal of the air and the addition of tannins (which bring down the pH, dependent on the starting KH, I guess).

If you get both cultures restarted, maybe try one variable in one culture and keep the other one however you were running it?

On 7/9/2024 at 3:27 PM, Tony s said:

Any Idea what type of tree.

@daggaz said beach tree but I'm assuming that was a typo for beech tree.

[Tony s]

On 7/9/2024 at 3:52 PM, Rube_Goldfish said:

aid beach tree but I'm assuming that was a typo for beech tree.

missed it, too busy fighting with machinery. that directly affects my reading skills. and typing apparently

[daggaz]

Yeah it's beech. My water is super hard tho so I doubt the pH swung very much, tho I could try and test that. 

[Tony s]

On 7/9/2024 at 9:11 PM, daggaz said:

Yeah it's beech

I’m still wondering if it’s not a toxin in the leaves. Beech contains saponin and oxalic acid. Not dangerous to humans but dangerous to grazing animals. Horses and cows. Possibly small critters as well?

[daggaz]

I think you need a LOT more of it to be harmful, Tony.  The local water ways are choked with beech, most of the water runs like coffee, and its still full of aquatic wildlife.  Oxalic acid binds calcium, but the water is completely saturated with leached calcium-carbonate already.  The micro-critters were all sourced from natural waterways in the first place, too.  

Honestly I am just a bit perplexed, but I think I will repeat the experiment once I get the colony up and running again (in separate jars).  

[Tony s]

Just a thought , what is harmful to livestock isn’t always harmful to micro critters. Sometimes they thrive in it.