Finding Nemo 3: Ancient White Shark
Finding Nemo 3
Ancient White Shark
|Norfanz vessel, see full image slide show|
As Harvard professor of evolutionary biology, Andrew Knoll, remarked: "[For astrobiology] everything we know about life in the universe comes from life on Earth. In a sense, putting current diversity at peril for those who would like to understand biology as a planetary phenomenon is like burning a library."
To explore deep sea habitats and biodiversity in the Tasman Sea, a joint Australian-New Zealand research voyage carried leading Australian, New Zealand and other international scientists to uncover new marine species and habitats. The NORFANZ research voyage explored deep sea habitats around seamounts and abyssal plains around Lord Howe and Norfolk Islands through to northern New Zealand. The voyage collected biodiversity samples, DNA tissue samples, seabed habitat data, photographs and video on seamounts at depths between 200 meters and 1.2 kilometers, and surveyed free-swimming animals that live in the water masses above and around these seamounts. Australia’s National Oceans Office – the body responsible for developing and implementing Australia’s Oceans Policy – and the New Zealand Ministry of Fisheries supported the four-week voyage between 10 May and 8 June.
With cooperation from the National Oceans Office , the NASA-sponsored Astrobiology Magazine chronicles the scientific notes written by the researchers onboard. As the director of the Hayden Planetarium, Neil Tyson, wrote about the marvels of biodiversity: "I do not know whether biologists walk around every day awestruck by the diversity of life. I certainly do. On this single planet called Earth, there co-exist (among countless other life forms), algae, beetles, sponges, jellyfish, snakes, condors, and giant sequoias. Imagine these seven living organisms lined up next to each other in size-place. If you didn’t know better, you would be hard-pressed to believe that they all came from the same universe, much less the same planet".
The main goal of the summer expedition mirrored that sentiment: to provide baseline information on the, nature and potential vulnerability of these unique habitats and their biodiversity. The results will give scientists interested in biodiversity a much better understanding of the species that live on and around the deep seamounts and ridges throughout the Tasman Sea, many of which were new to science. The information will also enhance and contribute to international collaboration in oceans management.
Day 6: 06.00hrs, 15 May 2003.
By Clive Roberts, Te Papa scientist
Wind SE 21 knots; sea moderate, SW swell 2-3m. Air temp 20.5 C, sea surface temp 22.0 C.
As I write this I can see Norfolk Island through my porthole. The wind is blowing strongly, whipping the tops off the waves, the sky is overcast, and although it is not cold, the area does not have the feel of a tropical paradise. It is almost bleak and certainly very isolated.
|Gorgonians, see full image slide show|
Overnight we had success with the beam trawl which came up from 350m with some good samples of both invertebrates and fishes. The last night station shot was with the mid-water trawl targeting the deep pelagic fishes that rise up in the water column during the hours of darkness. On the first attempt the net became tangled due to several broken floats getting caught in the meshes. So it was hauled, untangled and repaired quick time, in order to be re-shot just on our watch change over at 03.00hrs.
The net is just about up, having run at 1200m depth for 2 hours, and taken another 30 minutes to shoot and haul. The mid-water trawl sampled a variety of fishes, prawns, and squids, with even a few jellyfish remaining intact. Judging from the 5kg of lanternfishes, dragonfishes, anglerfishes, loosejaws, lighthousefishes, hatchetfishes, and others we shall be busy sorting and identifying right through to the next site.
I have just finished a 12-hour watch, working on two sample stations for 10-hours. I am exhausted, but thrilled that our gear has worked so well. The mid-water trawl contained over 00 fish species, several of which are not identifiable and are probably new.
The beam trawl contained mostly invertebrates, but the 10 fish species it caught were spectacular, being multi-coloured and in very good condition. The fish sample included two new species, some rare ones, and a few that represent range extensions.
Currently we are swath mapping this area to locate a safe route for the trawls and dredges over the coming night and next day Having learned the hard way about the dangerous nature of the seabed from the last site, we are being very cautious about where we shoot the bottom sampling gear. We need to get it back intact and complete with its sample of scientifically valuable the marine life.
Day 7: 16.00hrs, 16 May 2003.
By Robin Wilson, Museum Victoria scientist
Wind S 33 knots; sea rough, S swell 2-3m. Air temp 21.1 C, sea surface temp 22.0 C.
For the last day and half now, the invertebrate specialists on board RV Tangaroa have been busy sorting and trying to identify a major sample of animals that live on the sea floor. Since invertebrates are the most abundant kinds of marine life, they are very important in a biodiversity survey such as the NORFANZ voyage.
If we were able to collect and identify every animal inhabiting even a small section of the sea floor (say the size of a coffee table), we would find several hundred species of invertebrates. But it would take several specialists many months with a microscope to study and identify most of them.
|Fangtooth, see full image slide show|
Studies of seamounts elsewhere in the world suggest that the sea floor where we are working harbour a good variety of corals, crabs, sea stars and a myriad of smaller invertebrate animals. But we are finding that the seamounts of the Tasman Sea are so rocky and steep that it is difficult to get the battered sledge and trawls back on board with the samples intact.
At last, however, our persistence is paying off. We have found some areas flat enough to use the fine-meshed beam trawl and with this have been able to sample a great diversity of corals, gorgonians, and sponges. Also sampled are many shrimps, crabs, shells, worms and other creatures that live among this marine forest. Many will be new to science.
One of the major goals of this research voyage is to investigate whether or not each seamount has its own unique fauna of marine life. Seamounts are isolated rocky peaks, truly islands in the deep sea, because many creatures that live on them cannot survive in the deep muddy sea floor in between.
Some invertebrates like crabs, shrimps, sea stars, sea urchins and some corals have planktonic larvae that can be carried great distances by the ocean currents. As a consequence these are often widely distributed. Other kinds of invertebrates, such as smaller crustaceans and some kinds of worms, cannot disperse so far, even as larvae. It is study of these later groups of invertebrates that, through investigation of their diversity and evolutionary relationships, may ultimately tell us most about the seamounts that they live on.
Day 8: 10.00hrs, 17 May 2003.
Wind NE 33 knots; sea rough, NE swell 2-3m. Air temp 21.7 C, sea surface temp 22.0 C.
We had quite a busy night finishing off the samples collected from our last two stations before steaming towards our next site 150 n miles to the north. ETA is 14.00hrs so we have several hours to go yet. Sea state is rough with strong NE wind, so our passage is rather lumpy. Some scientists are not feeling well and have retired to their bunks.
|Ancient shark tooth, see full image slide show|
Last night both the orange roughy bottom trawl and the beam trawl were badly ripped and took several hours to be repaired by our crew. Replacing broken meshes in the net is a boring but important job that requires good sowing skills. Luckily we have a great crew with both the skills and perseverance to get the repair job done in time for shooting at the next station.
Our next sampling site is the most northerly that we shall be working. This is a subtropical location, not far from the New Caledonian seamounts of the northern Norfolk Ridge. It will be most interesting comparing our samples from this site with those reported by French surveys carried out about 100 n miles to the north.
The last sample station earlier today was carried out with Sherman, our armoured sledge. Among the invertebrates collected were some rather rare and special finds that will be described by our Australian voyage leader below.
In certain conditions, the hard parts of dead marine animals may become fossils on the seafloor. These are usually only collected by luck when scientific sampling equipment happens to be in the right place. This is what happened last night off Norfolk Island.
We were sampling animals on a sloping rocky seabed over one kilometre deep. We used a sled, which bumps across the seabed surface scooping up marine life and samples of the bottom. After the sled had been landed safely back on deck, a group of us were busy sorting through the samples when someone suddenly yelled "check this out!"
It was a huge tooth (see photo) that once belonged to a giant marine predator, the monstrous, ancient white shark Procarcharodon megalodon. This species lived about 30-40 million years ago and is now extinct. It was related to the ancestors of the great white shark that roams our oceans today, but was many times larger. Now, by chance, after all that time in the cold dark depths, the tooth of this ancient fish was being passed around for close inspection by a group of excited scientists and deck crew.
|Norfanz deck filled with a catch, see full image slide show|
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the New Zealand National Institute of Water and Atmospheric Research Ltd (NIWA) are providing scientific support for the voyage. The NORFANZ voyage will use NIWA deep-sea research vessel, the R.V. Tangaroa (NORFANZ).
The expedition received considerable interest from scientists worldwide. Twenty four scientists from more than eleven research organisations will be represented onboard, including staff of CSIRO, Hobart; Museum Victoria; the University of Tasmania; Australian Museum; Queensland Museum; Northern Territory Museum; NSW State Fisheries; Te Papa, Wellington; National Institute of Water and Atmospheric Research, New Zealand; Institute de Recherche pour le Développement, Noumea; Natural History Museum, Paris; and California Academy of Sciences, San Francisco.