False Bay – Diatoms make a good floor

False Bay was amazing. The quietness was interrupted only by moonlight and the noises of feeding ducks. I didn’t even bring my camera (which explains the lack of pictures). And although I was stopping every twenty feet to monitor ecological changes in the mud, I was slowly beelining it to the water. After passing millions of worms and worm holes, a few dungeness crab, beached fish, and a pile of spluge;¬† I finally made it to the water’s edge with my trusty partner in crime, SE.

To summarize the mud, we did not see major shifts in the mud ecology until about 100 yards from the water. Here, we began to see patches of sea grass, and seaweed. We also saw increased brown stuff on the mud. Slimy, brown mats. After being told it was endless diatoms  (PS I LOVE DIATOMS), I scooped up some for microscope viewing back at the lab.

Continuing on our trek, we waded slowly through the water and over sand bars until we could wade no more and the seawater was coming over our boots. Unfortunately, our plans for seagrass domination were foiled when the water proved to be too deep at about an arm’s length away from the massive seagrass beds. Seagrass like being underwater, and therefore you will only see them at the very low intertidal and just beyond it.

Defeated, we slowly and curiously made our wet walk back to the flashing lights of our friends at the vans and passed more dungeness crab (Cancer magister) burrowing into the mud as well as some clam shells that did not want us to open them.

Back at the lab that night, I stayed up past a biologically reasonable time and enjoyed the wonders of the microalgae that I skimmed off the False Bay Flats. This is a picture of a Diatom, order Pennales, that I magnified at 400x power. pennate diatom

It is very difficult to classify diatoms under a light microscope because of the visual limitations and the diversity of the organisms. Diatoms are distinct in that they have 2-part silica (SiO2) frustules that encase what you may think of as a typical single alga cell–kind of like a glass petri dish covering an algae cell. Diatoms are classified into two orders, Pennales (elongated, pen-shaped) and Centrales (round). Pennales is further divided into Fragilariophyceae and Bacillariophyceae based on the presence of a raphe, a ridge in the organism’s cell wall. Other characteristics are even more difficult to distinguish (And this is only at the level of Order!). This demonstrates the difficulty of classifying diatoms based only on a light microscope picture without an algae expert. This particular one was about 90 micrometers in length and was amazing to see under the microscope.

Let me know if you have any cool algae or algae stories! I love to play with the microscope and look at these buggers move.

To close, this guy was quickly moving across the screen and I managed to quickly capture him.

moving fast

And— I thought these ones were interesting…

2 few diatoms





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