May 16 2008
May 16 2008
Some of the solitary corals brought up by the dredge.
Scientists look in happy amazement at a handful of the material brought up by the box dredge.
We had a very successful dredging day today! Our first few attempts at using the box dredge (one of the smaller, more lightweight dredges) mainly yielded rocks, with a few coral holdfasts attached to them. We knew corals were down there, but were they the right type? And how could we bring them up intact? We suspected that the corals were breaking into small pieces and washing out through the coarse mesh of the dredge – but how could we prove this, and improve our dredge to collect the samples?
The winds died down enough (from 40 knots to 25 knots!) to allow us to use the Towcam. The swell was large, so we had to wait until a suitable gap in the waves to get the TowCam in the water safely. The photographs from Towcam were wonderful. Unlike our previous sites we had sandy sediment interspersed with ferromanganese pavements and a few boulders. There was life in every picture, clustered around the boulders and on the flat surfaces. More important to our project - there were also dead corals scattered on the seafloor too! Using an improved box dredge (heavy steel plates welded on by Greg Buikema, and a new, fine-mesh dredge bag expertly sewn by Daniel Wagner and Taryn Noble), allowed us to bring up several dredges full of fossil corals, live corals, sponges, brachiopods and an assortment of echinoderms – just what we wanted!
We’re now heading west, transiting for about 24 hours, to another seamount in Drake Passage. The seas have been remarkably calm for the middle of the Southern Ocean in May and we’re taking advantage of our luck to catch up on packing and cleaning.
KRH
MT’s Zim Zimmerman and Josef Kuehnast bring in the new and improved box dredge.
The box dredge coming up from the water.
The seafloor on this tow looked almost exactly like seamounts in the North Atlantic.
A close up taken by the ROV Hercules during a cruise in the North Atlantic.
This is a fossil coral (Desmophyllum dianthus) we collected earlier in the cruise.