Bioluminescence and Biodiversity 2007
July 27 - August 1, 2007
July 28, 2007
Dan Swezey writes: My day started at 7:30 when I woke up to get ready for the morning's blue water dive at 9 am. The ROV had launched at 7 am, so after hopping out of my bunk and getting myself together, I made my way down to the ROV control room to see what the status of the blue water dive was. The boat had been rocking a lot throughout the night during our transit to the dive station Tiburon 3c so I was curious to see if conditions would permit a dive for the day. Unfortunately, the winds were still a bit high and surf a little too large for a safe dive, so I had time for breakfast then reported back to the control room to relieve Lynne and Meghan who were working the early shift for the day. We arrived at the bottom (~3,600m) and then began to gradually work our way up throughout the day to different depths of interest. The first thing we did when we arrived at the bottom was switch on the newly installed blue LEDs on Tiburon to observe the in-situ colorful fluorescence possessed by a handful of benthic animals including jellies, sea cucumbers and sea pens. The sea pens produced a beautiful yellow-green fluorescent color when they were illuminated by the powerful blue light. Steve and Lynne observed the results on a TV set we had setup which had the blue channel cut out, allowing the fluorescent signal to come through loud and clear. As we made our way further up the water column, we found representatives of several physonect siphonophore groups- including Erenna, Apolemia, and Bargmannia- all of which were quite deep. These specimens were eagerly collected and given to Phil Pugh, a visiting scientist from the UK and siphonophore taxonomy specialist. Specimens from these groups are generally quite rare at this depth, so they were an interesting find and will help scientists catalogue differences in the groups with increasing depth.
After lunch, I swapped out of the control room and went to take photos and make observations on a few fish I had collected in a trawl from the previous night. Among them were three fish from the Sternoptychidae (hatchet fish family). Two of the fish looked very much like typical hatchet fish (likely Sternoptyx sp.) and one fish was what we think is Valenciennellus sp. This fish produced a bright red fluorescent light when illuminated by blue light under the microscope (unlike other hatchets) and I added him to the growing list of fish that we're finding with prominent red fluorescent features.
A few hours later, we were graced by one of the kings of the fluorescent fish world: a Dragon Fish (which we believe was Photostomias sp.) These fish are known to produce and see red light which they emit from large bioluminescent structures located both behind and under their eyes. It is thought that these fish may have evolved a "secret channel" through which they are able to independently communicate, since the current thinking is that most deep sea fish and other invertebrates can't see longer wavelength red light. After spotting the fish with the camera, we quickly turned off all of the white lights and switched on the Blue LEDs to illuminate the fluorescent photophores possessed by the fish. When illuminated with blue, beautiful reds and greens shimmered from the fish back to our screens. Amazingly, we are probably among the first people to see fluorescent light emission from this animal in its native environment in the Monterey Bay. Sadly, the fish only hung around the ROV briefly, but we got great footage of its unique color ability in situ, which is a very rare thing to see.
The science crew is now busily organizing and beginning to work on the samples that have just come up with the ROV. You can see the ROV Tiburon coming up to the surface in the photo to the right. The trawl is also being readied for deployment to 450m. Hopefully we'll get some more cool stuff tonight! Below are a couple of images from our dive today - the bottom sea floor and a jelly floating by in the midwater.