My Plants are Pearling!

I'm pretty proud of myself - the plants in the 55 gallon tank in my office has started to pearl. What is pearling, you may ask? Simple - biology 101. Plants "breathe" in CO2 and breathe out oxygen during photosynthesis. That's no different for aquatic plants. Aquatic plants absorb CO2 that is dissolved in the water and release O2 gas.

The gas is released from little stomata on the bottom of their leaves, just like land plants. But, when the plants are underwater the O2 appears like little bubbles all over the bottoms of the leaves. As more and more oxygen is created the bubbles begin to break loose and rise up to the top of the tank.

It's called pearling because, on many types of plants, as the oxygen forms a bubble and prepares and break free from the plant it looks like a little pearl clinging to the plant. If you've never seen it is very cool, as is the look of many ultra tiny bubbles all across the aquarium rising to the top. In my tank, most of the bubbles range in size from the size of the tip of a pin to the size of a small pin head, so the overall effect is almost mystic as the bubbles rise.

I'm proud of myself because it's a pretty big breakthrough for me, a sign that the plants are beginning to thrive. I have them under pretty high light as freshwater aquariums go (190 watts, or about 3.5 watts per gallon) which is by design as several of the plants I've chosen for the tank require high light conditions. I also am injected CO2 via a homemade CO2 reactor to stimulate growth. I think they just started pearling because I recharged my CO2 bottle (I've been a little lax in that respect) on Monday and yesterday the pearling started.

It was kind of strange - I came back up to the office after lunch yesterday and was looking at the tank from across the room and noticed what appeared to be tiny particles of dust or other matter suspended in the water. As I watched I realized that they were all flowing upwards, telling me it was probably bubbles. My initial reaction was frustration, trying to figure out how enough air got down to the bottom of the tank to cause the gas release as it appeared upon first glance to be coming from the substrate. The only thing I could think of was that I had the power off over lunch while I installed a new light switch and when I turned it back on the filter had cavitated, resulting in an unusually high amount of air dissolved in the return flow. Upon further examination I realized that the bubbles weren't coming from the substrate and I started to get a little excited. I took a close look and, sure enough, all of the plants had a very fine sheen of bubbles glistening on the bottom of their leaves. A great sign for the overall health of the plants, and more oxygen in the water is always good for the fish. Fish are like humans, exactly the opposite of the plants - breathing in O2 dissolved in the water via their gills and breathing out CO2.

I'll get some pictures up eventually, hopefully I can get some good shots of the pearling. I actually took a quickie video with my phone yesterday and it came out pretty good, so maybe I'll work on trying to get a decent video up, too. In the meantime, do a google search for pearling aquarium plants and I'm sure you'll find a zillion cool pictures.