Rachel Greene:

The Kiss Method for sizing krill!

The Kiss Method for sizing krill!

I would like to briefly explain the research I’m conducting onboard the N.B. Palmer.  The main piece of equipment I am using is the MOCNESS, which stands for multiple opening and closing net system, which does exactly what it sounds like.   There are a series of nine large nets held around a ring, and a marine scientist controls the deployment from inside while collaborating with the marine techs on the back deck.  The marine scientist is able to see the instrument go down on the computer screens and can ‘fire’ a net at any time, which will close a sample of organisms at a specific desired depth.  So when the MOCNESS returns, each of the 9 available nets has a sample from the desired depths.  This instrument is used to collect organisms only (a similar machine called the rosette is used to collect water in the same fashion).  The nets are then emptied into numbered buckets and quickly brought to the lab where I will take a random sample of around 200 individual krill per net.  I then use the very simple but effective KIS, which is the krill imaging sizing system I made (although Meng takes credit for the acronym).  I then preserve the krill in formalin and lay them on a board, take a picture, and upload it to my computer.  I mastered this process down to four minutes!  I then take the image and upload it to a ruler board, where I can size the 200 individuals in about 5 minutes instead of perhaps the hours it would take to do it individually.  I do this for 200 krill per net.  Eventually I will compare this data to the ADCP, which is the Acoustic Doppler Current Profiler.  This instrument sends out sound, which hits a solid thing and bounces back.  Ergo it uses backscattering to see what’s in the water by the sound it sends back.  I this works, krill size, distribution, and biomass can be more properly determined just from the ADCP feedback.  So far, it seems that the larger krill are in the middle of the aggregation and the smaller guys are left out and remain on the outside of the swarm.  However, it will take more data and more MOCNESS tows to tell for sure!

Categories: Life at Sea | 1 Comment

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One thought on “KISS

  1. Anita Blackman

    Thank you, Rachel, for your very thorough (and easy to understand) explanation of what you’re doing. I’m truly impressed by the system you invented! Great fun to be “involved” with a trip so far away and doing something I could never imagine doing. Keep up the good work! Aunt Nita (Bethany’s aunt)

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