Mission Blog: August 30, 2009
Beautiful Underwater Scenery, Magnificent Islands
Daniel Wagner, PhD student, Department of Oceanography, University of Hawaii at Manoa
Branching Black Coral at Laysan Island. (Photo credit: Greg McFall/NOAA)
Today we are back in the water, diving the waters of Mokumanana. This is a really nice change after two full days in transit from our previous station. There are quite a few amenities aboard our vessel R/V Hi'ialikai that keep us busy on days we do not dive, including a movie collection paralleling Blockbuster's as well as a full gym, which really comes in handy with all the fabulous meals prepared by our incredibly talented and hard-working kitchen staff.
On today's first dive I joined the fish collection team. Upon my descent I had a pair of eagle rays, a sea turtle, a Hawaiian monk seal as well as a group of white tip reef sharks welcome me to the waters of Mokumanana. It was a friendly welcome and a remainder that we are only foreign but fortunate visitors to these beautiful Northwestern Hawaiian Islands. The fish collection went well, in spite of a rather low visibility.
Yannis Papastamatiou collects black coral at 200 feet at Laysan Island. (Photo credit: Kelly Gleason/NOAA)
In the afternoon I joined the technical diving team and acted as a safety diver on a couple of dives to 230feet to collect black coral. Sending divers down to these deeper depths takes a few more precautionary measures than conventional SCUBA diving. A dive supervisor and a team of two safety divers stays at the surface ready to go down to assist the bottom divers if an emergency were to arise. Continuous communication between the surface and bottom teams is maintained via a fancy text messaging device that relates messages between the two parties. "OK," the first message reads shortly after the diver's descent. We patiently wait at the surface. Approximately quarter of an hour later the text messager beeps announcing another message: "Coming up." My safety dive buddy Kelly Gleason and me hit the water and descent following the trail of bubbles of the bottom divers. At about 100 feet I see them below and they serenely signal that they are OK. I stay just above them and accompany them on their slow ascent back to the surface. It takes us about an hour to get back the surface; the ascent needs to be slow enough to allow the divers to decompress. Approximately an hour later we repeat the exercise for a second dive team.
Dan Wagner processing coral samples before heading back to the ship and into the lab. (Photo credit: Kelly Gleason/NOAA)
We return to the ship in the late afternoon and processing of samples collected on today's dives is on the agenda. A couple of dozen colonies of black corals were sampled by our deep divers: a respectable collection considering that these corals have previously not been sampled in these remote islands. What species are they? Are they genetically related to black coral species found on the Main Hawaiian Islands? How do these black corals reproduce at these depths? Are there any differences between black coral populations in these pristine northwestern Hawaiian waters and those surrounding the Main Hawaiian Islands where black coral has been harvested for decades? These are some of the questions that I hope to address in the upcoming months as part of my dissertation research. But for now, I will keep enjoying the beautiful underwater scenery of my visit to these magnificent Islands...