Research Cruise

Last night’s dive was very productive!  We managed to collect some great biological samples, from undescribed soft corals to black corals with ophyroid symbionts, to deep-sea bivalves…It’s really been quite exciting.  The previous watch tried to collect one of these bivalves, but cracked it, and within seconds there were stars of all sizes descending on it, trying to get a piece of the flesh inside.  It’s amazing that in the dark, these creatures can sense such an event and respond so quickly, whether it be through chemosensing or some sort of conductivity sensing like on sharks, or maybe even slight vibrations in the water.  On my watch, we were able to capture on film a currently undescribed deep-sea octopus known as a benth octopus – It doesn’t have any color-changing capabilities, and also lacks an ink sac.  It has no other defense mechanisms that we know of; perhaps it just relies on its ability to slide away in the face of danger.  We caught it fairly unawares, and it was probably stunned by the bright lights on Jason; none of these creatures are built to handle such large amounts of light; their world is pitch black, save a few flashes of bioluminescence here and there.  It is thought that some corals, especially the Isidids, are bioluminescent, and some animals do use luminescence as a predatory or anti-predatory mechanism.

Surprisingly, on this dive, we harvested much more Caryophillia than on the last, although they are just as useful for radiocarbon analysis.

We also conducted 3 CTD profiles today, in the hopes to elucidate the characteristics of the first 1,000 meters or so; we’re going to be diving in this area today, so it will be helpful to pair collection data with ocean profiles.  We also want to collect fossil corals from a region of low depth; the summit of this Sister is around 850 meters, so hopefully we’ll be able to pair our low-depth CTDs with fossil samples.

Tonight’s dive is in a different location than the previous two; we’re moving North to the Sisters, starting at the northernmost of the bunch.  This area has been severely impacted by trawling; in particular the orange roughy has been overfished in this area to the point of almost completely obliterating the population, with no real recovery in sight.  Unfortunately, the reef itself has also taken hits from the trawling, so one of our goals is to get a sense of the damage done to the area – and therefore the fishery – and take some footage of an impacted area here.  We will be doing a photo mosaic of two sites: an impacted site and a “healthy” site.  The mosaics will consist of two 80m transects forming an X, and a 20x20m square centered on the vertex of the X.  These mosaics will serve as the “time zero” mark for future ecological studies on the area; we want to see how the seamount’s community recovers over time.