data

Honey Badger is in its 61st mission day.  All is going pretty well.  The only issues that have come up are apparently linked to the software/computer interface with the systems.  When we average the data from Turner C3 that we can program on the fly, something in the glider's system is dividing by 2 (approximately).  We had this system (ID 32 on the data tab) running on single point measurements every 10 minutes for most of the mission.  However, we started taking 10 points at 1 Hz every 10 minutes and averaging them a few days ago to compare to the C3 (ID 3).  It is hardwired at this rate.  The reason for this is that starting around 10 June 2015, we started seeing extensive spiking in the C3-3.  We expected this and were interpreting the signal as phytoplankton aggregations or some other large organism with a chl signal (colonial radiolarians, for example).  The other C3 (32) was set on single point measurements and was giving us a different level of spiking. So, we decided to put them on the same frequency to see if they reported the same. This would eliminate fouling as a problem.
 

Turner C3-3 from the Honey Badger

Since starting this, they are looking the same. However, we have not found a low spiking area yet to confirm that the signal reduces simultaneously.  The data is in ERDDAP, so anyone can go replot this if they want to see more details (click on the window in that data page, it will take you to the server page).

This is all very good news.  We are excited by the geographic extent of this spiking.  A report by Karl et al (PNAS) indicated that a massive pulse of phytoplankton (probably symbiotic diatom/cyanobacteria)  occurs predictably at this time of year, and they are probably aggregated.  If this is what we are seeing, then this must be much larger than just of HOT (Hawai'i Ocean Time series station north of Oahu).  The thumbs of the camera pictures (looks downward from the bottom of the float) are not sufficient resolve anything unfortunately. The images are on the Honey Badger's computer awaiting it's (hopefully) triumphant return to Hawai'i.   The imaging system on the Sequioa LISST-Holo (holograms) should be capturing  detailed species data as well.  Again, we have to wait until Honey Badger returns  to extract it. Emily Anderson, the M.S. working on this, will have a LOT of images to look at. 

In the meantime, we are getting real-time physiological data on the phytoplankton from the Turner Phytoflash.  In between coffee breaks and dreamtime, it is recording data on two levels of fluorescence returned from different light flashes.  A manipulation of this data produces something we call Fv:Fm (technically variable fluorescence/maximum fluorescence).  The maximum value of this for this type of system is about 0.8 under perfect conditions (others max out at about 0.65 due to how this value is measured).  We are seeing consistent values at night of about 0.45. So, not in the best of shape, but there are number of factors likely reducing this number from its true value and we can try to correct for them.  However, the really interesting part is that we are seeing peaks at dawn and dusk that can be linked to nutrient limitation.  The dawn peaks seen in the figure below are what is predicted by a paper by M. Behernfeld et al (2006, Nature, doi:10.1038/nature05083).

These patterns indicated nitrogen limitation (red dots, 5 point running average).  If we find a bloom of the nitrogen-fixing symbioses we expect to, a reasonable expectation is that these patterns will shift to something else.  Iron limitation has a very distinctive signature in the Fm:Fv. It is not clear what other patterns look like (phosphorus or silicate), but we shall see what turns up.  The black dots are the Fm value (maximum fluorescence). It is akin to what the C3s are measuring and is the third chl fluorometer tracking spiking.  When plotted on the same scale, it shows much the same pattern as the C3s.  The oscillation seen in the data is the daily pattern.  High daytime solar radiation reduces the Fm and it rebounds at night.  This is the reason the Fm:Fv shows an oscillation as well. The daily fluorescence patterns are highly affected by daytime insolation.

This is all so cool.  I'm working at sea, and can go home tonight and make pizza.  Drink wine too, something a bit difficult to do on a UNOLS ship these days.  I attach an image of the most serious impediment to this type of work.