Field study at Ishigaki Island

3 years has passed since I last came to this island, though I used to come to this island 4 or 5 times per year before. But Ishigaki island was just Ishigaki island where I spent many days before.
This time the periods when I can stay was 2 weeks, irrespective of if typhoon comes or not. So I needed to move up my schedule if possible. On the first day and second day, I swam at several reefs to check the conditions of benthic macroalgae.
Some of anemone fishes, which had been disappeared due to poaching just after the release of Disney movie “Finding Nemo” (http://www.apple.com/trailers/disney/finding_nemo/trailer/), seemed to returned to their house, anemone.

Tomato Clownfish (Amphiprion frenatus) in Blue Ridge Coral (Heliopora coerulea)

They were not my targets. I collected several algae (Codium repens, Ceratodictyon spongiosum, Sargassum duplicatum, Galaxaura fastigiata) for pre-incubation at containers.

Pre-incubation

The day time radiation at Ishigaki Island in August is pretty severe.

My objectives this time was to grow several macroalgae with different morphology at different current-speed conditions, and check the species-dependent nitrate uptake ratio, and the extent of isotopic fractionation during nitrate uptakes. Though it was pretty hard to create this machine within limited budget, the system worked well, I think.

The apparatus to make different current flow conditions under the same radiation.

My friend, local fisherman, Sasaki, took me offshore to collect nutrient-free seawater. Because we have been working together since over ten years ago, he knows well about what I want to do.