Last month was spring bloom and the tank had more algal biomass than ever before. The Sargassum muticum got really large. Most of my algae are fastened to relatively small rocks. The heavy pull from the pumps on the algal mass caused a small rockslide. So I decided to do some serious pruning, and to take out some rocks. Here is the result of that, almost 1.2 kilos of algae.
I have a number of these black brittle stars (Ophiocomina nigra), but it is usually very hard to get pictures of them because they are very shy of light. Usually they stay in the same spots under the rocks for long periods of time. But lately they have been wandering around somewhat. I wonder if they have mating season now in spring.
Here is one of the nice starfish (Henricia sp.) that I caught last month. It was great luck that I found them. I really thought I had found everything I would find in the tidal zone by now, but no. They seem to be doing all right. I see them quite often wandering around in the tank. Not only colorful, but probably quite safe with other animals too, unlike most larger starfish.
Rember my great spider crab (Hyas araneus) from the December update? Well it just molted again. The old shell is in the picture. And now it got really big. Something like 5 cm across the shell. It was like a troll sitting there. This time I decided to give it it's freedom back. I took it to a nice location not far from where I found it. So it got a one year vacation among the humans. I don't think many spider crabs in the wild can brag about that. The nice thing was that as soon as it was gone a new one turned up in the tank, about the same size as the old one was when I got it, 1.5 cm shell length.
This month I set up this plankton growth tank. It is basically the same experiment as with the bottles, except this time I use a 54 liters aquarium and 2x18 Watt plant lights. I filled it with about 45 liters of seawater. There was a bloom of Emiliania huxleyi at the time. It is a phytoplankton with calcium carbonate platelets that gives the water a milky turquoise color. As with the bottles the large zooplankton died within days. So now I know it is not the flow in the bottles that caused it. That was important knownledge. The water turned milky the first few days, and the walls and bottom got covered with some sticky white stuff, bacteria maybe. Then it cleared up. And then it got hazy again. Now, after two weeks it is turning green. The temperature is stable at 20.5C. The pH was a bit low at 7.4. I added some balling to get it up to 7.6. Now, with increased photosynthesis it is 8.0. And it will probably go higher.
Haven't found anything new lately, but it sure is nice just taking a walk and enjoying nature. On one trip I got the idea of dipping algae from the tidal zone in jars and just seeing what came out. I collected thousands if tiny critters. Hope I seeded my tank with something I haven't got from before. But that is not very likely. You can see the Emiliania huxleyi bloom on some of the pictures.
Male black grouse (Tetrao tetrix). Showing strange behaviour. Trying to trick me away from the nest maybe.