A day in the life

(Notes: Don't forget to read Part 1 of my 3 part series on scientific misconduct.)

(Also, all the pictures below can be viewed much larger if you click on them.)

Many people have asked me, in the last few weeks, what I do down here on the Oklahoma-Texas border. Well, I’m going to tell you. Using pictures (so maybe people can read past the first paragraph!!).

I’m working on algae that cause fish kills. On Thursday, just down the road from us, some people started reporting dead fish on the lake behind their houses. So JE (the other postdoc), AE (his wife and the lab tech), and DH (the professor on this project) went down to investigate. Here are some pictures:

Notice that the water has a very murky appearance. This is probably due to the presence of a mixotrophic algal called Golden Algae. Mixotrophic just means that the algae acts like a plant and like a predator, using sunlight to produce energy, and eating bacteria and protists to get nutrients.

Usually, Golden Algae kill fish by causing hemorrhaging (bleeding) around the gills. This gizzard shad doesn’t seem to show any hemorrhaging, the gills look pretty normal. The fish had probably been dead for awhile, so this might not mean anything. The hemorrhaging isn’t as obvious if the fish has been dead awhile.

We checked several fish for bleeding around the gills, but none seemed to have it.

This white bass might have had some hemorrhaging, but it isn’t dead yet either.

You can see from this picture that the fish kill didn’t seem to be very species specific. We saw largemouth bass (shown here), green sunfish, bluegill, threadfin shad, gizzard shad, drum, bighead carp, and white bass. These are fish that feed on lots of different food sources and in different places in the lake.

This is a little hard to see, but this is a pool along the shore that had little fish (I can’t remember what they are called). As we stood here watching the fish in this little pool we realized they were dying as we watched. We decided to take some of the water from the lake back with us to see if it was still toxic. The number of Golden Algae in the water was really pretty low, so we wondered if the fish kill was being caused by low oxygen levels the previous night.

The next day we came back to measure oxygen again and to see if there were more dead fish. This is JE with an oxygen probe.

When fish kills happen, pelicans show up. There were some pelicans out this morning.

There were also lots of turkey vultures. These guys appeared to be eating stuff along the shore.

The day before we had brought water back into the lab. We then added fathead minnows to that water to see if it was still toxic. The bottom right tub is just plain water. The bottom left tub is ½ lake water and ½ regular water. And the top middle tub is all 100% lake water. As you can see, the lake water killed all the fish. That water definitely appeared to be toxic.

My wife and I decided to visit the part of the lake that has been having major fish kills three of the past four years. This is what we saw there:

This is a stretch of beach in Lebanon Pool. You can see here several dead gar and carp.

This gar was probably 5 feet long. The fish must have been amazingly beautiful when it was alive. Last year every single fish in Lebanon Pool was killed by the Golden Algae. Nobody could find a single fish in the entire pool in March of 2006. These are all fish that repopulated the area after last year’s wipeout.

We got pretty depressed looking at all the dead fish.

You can see that the pelicans were out in force. The Golden Algae toxins are broken down quickly by acid, so saliva or stomach acids in mammals, birds and most reptiles make them able to consume the dead and dying fish.

Pelicans are surprisingly beautiful birds.

This made us immensely sad. How did this turtle die, I wondered. The toxin needs a way to get into the body, and most turtles have an impermeable skin (soft-shelled turtles are an exception). Then we found this, still living turtle (this is a little disturbing):

This is difficult to see, but it is clear what’s happening. The Golden Algae toxin has gotten in through the turtle’s eyes. This turtle was alive, barely, but did not respond when we picked him up. He didn’t respond to sounds or visual cues. The poor animal was clearly on the verge of death. We didn’t think there was anything we could do to help him. JE later suggested that we might have been able to douse him in clean, pure, freshwater. I’m not sure that would have done any good.

This is what worries a lot of people. This is a striper, a cross between a white bass and a striped bass. The economic basis of recreational fishing in Lake Texoma is stripers. We didn’t see many of them dead along the shore, but they are definitely at risk when the Golden Algae is blooming.

We’re trying to learn more about how the Golden Algae kills fish, so we’re doing simple (and complex) experiments in the lab. Here we’re raising Golden Algae in flow-through containers known as chemostats:

We can then use that Golden Algae to conduct toxicity tests on fathead minnows.

On the right hand side of this picture you can just barely see a small fathead minnow baby.

We set up a lot of these babies in all different concentrations of Golden Algae.

Then we count to see how many Golden Algae cells it took to kill the fish.

There are lots of complications that I’m glossing over, but this is basically what’s driving my research. I hope you enjoyed my photoessay!