Tom Iwanicki and Geir Johnsen, on sabbatical from NTNU in Norway, had a great time aboard the R/V Kilo Moana out to station ALOHA.
They caught plenty of the bioluminescent copepods, Pleuromamma, using plankton net tows (left) in the wee hours of night to depths of ca. 200m.
They tried measuring the bioluminescence on live animals. Nothing at sea comes easy… the bioluminescence, although really beautiful to watch in our "dark lord tent" as Geir liked to call it, was fleeting and lasted a grand total of 100 ms per emission.
They had to go old school and use techniques developed by Raphael Dubois's experiments from the 19 century. The copepods were ground up in distilled water (the “cold extract” containing luciferase) and then added this extract to coelenterazine (the luciferin) buffered in filtered sea water.
Tom getting work done in "the dark lord tent"
With this, beautiful spectral and kinetic recordings from individual copepods were obtained: plenty of Pleuromamma xiphias, P. abdominalis, and P. piseki/gracilis. They also have a few containers of live Pleuromamma (mostly P. xiphias) and hope to run some behavioural experiments in the coming weeks, so more to come!