We’ve had a lot of blog posts recently on summer field work (we’ll resume our eclectic mix of posts soon – promise!) but I am going to add one more before we’re done. The last and final installment of the international research in China saga, namely, why the heck was I in China to begin with?!?

The main reason: cyanobacteria. Lots of cyanobacteria. And I’m not talking about the relatively benign cyanobacteria (essentially microcopic plant like creatures that live in the water, in this case freshwater). The cyanobacteria I’m talking about are little green monsters that produce toxins that are harmful to both humans and animals, and are known broadly as cyanoHAB’s (aka: cyanobacteria harmful algal blooms). These guys are incredibly abundant in Lake Taihu, China, a lake that supplies about 20 million people with drinking water. In 2007, these cyanobacteria effectively shut down the drinking water supply to these 20 million folks when green slime started poring out of the taps (similar to what happened in Toledo, Ohio last year). Something needed to change, and to figure out what needs to change they called in scientists from all over the world, including my adviser.

Can you imagine this coming out of the tap? And pictures don’t do it justice – the water is literally neon green, can accumulate so much it looks like jello, and smells like a combination of rotting trash and gasoline.

Which is where I come in (many years after the 2007 incident, of course). One of the main reasons for the rise of the cyanobacteria (not just in China, but worldwide), is the increase in nutrients (food for everything from cyanobacteria to you!) in our water systems. These nutrients come in a wide variety of forms, much like the way you can get all kinds of different types of food from the grocery store. The two main classes of nutrients are inorganic versus organic nutrients (if you’re interested: inorganics don’t contain any carbon, organics contain carbon). Most research up to this point has mainly dealt with inorganics (they’re easier to measure) with little research on the organic food sources. But I happen to like organics.

And so, I was in China to study if the cyanoHAB’s that are so abundant in Lake Taihu, can use organic nutrients as a food source (because if they can, then maybe by reducing some of these organics, in addition to several other things, we can actually control these harmful little critters). To do that, we conducted a bunch of experiments called bioassays. In bioassays, we take water from the lake, isolate it in big trash cans, and then manipulate different environmental factors to see how the cyanobacteria respond. In this case, we were testing how the harmful cyanoHABs would respond if we limited their inorganic nutrient supply. Would they use organic nutrients? Or did they have another trick up their sleeve (aka: nitrification, where some of the cyanobacteria can actually take un-reactive nutrients – in this case nitrogen – from the air and turn it into a food source)? Or did they just die?

The bioassay in all it’s glory!

By taking samples from these different experiments every other day, we’ll be able to see what types of nutrients the cyanobacteria are using and whether the lack of inorganic nutrients led to a decline in the health of the cyanobacteria (which is the goal, since we’re trying to figure out a way to control these blooms). Results pending (lots of samples to run first!).

Researching and traveling in China was an incredible experience, both scientifically and culturally. I not only have a million and one samples (not really, but it feels like it) to analyze, but I have a million and one memories to keep and a million and one people to thank for all the help and guidance a long the way. Stay tuned for more updates on the emerging importance of organic nutrients and new developments in the fight to control cyanoHAB’s! Summer field season is the best!!

And then sometimes there are goats in front of the biology lab. So many unforgettable memories!

For more information on the role of the Paerl lab in Lake Taihu, China, see the lab website.