Finding Nemo 10: Weird Adaptations
|Norfanz vessel, see full image slide show|
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 27, 5 June 2003.
Mark Norman, Museum Victoria
Low swell (1-2 m), 10 knot NW wind, 17 ° C
Last day of trawling today before the long steam towards Wellington . Overnight we’ve been on very rocky ground at around 800 m, so have had limited success in getting samples. The Sherman bounced around and didn’t catch much. The first orange roughy trawl snagged up immediately, the second came up with one shark, one silver roughy and three sea urchins. The last had little more, with a few rattails, a couple of sharks, slickheads and an orange roughy. We are now heading towards a much deeper site.
As time is running out, I am frustrated that there are still too many interesting stories of the deep-sea animals we’ve been coming across and their weird adaptations and behaviours. So I thought I’d briefly cover some of the more interesting ones.
The front ends of many deep-sea fishes are fascinating. The viperfish (Chauliodus sloani) has great wide jaws with huge teeth. They coax in their fish prey with a glowing lure on their head. When it comes to swallowing, their whole head is hinged: they have a flip-top head. They lift the head like the nose cone of a front-loading cargo plane and shunt the fish straight into the stomach. These fish hang in the water halfway between the depth limits of night migrating fishes and wait twice a day to ambush the passing traffic.
Many deep-sea fish will try to eat anything irrelevant of size. The Loosejaw (Malacosteus niger) can dislocate its long jaws to fit anything in, resetting them once the meal is inside. The Hammerjaw ( Omosudis lowei ) has a big solid lower jaw with strong teeth. It uses these to make fast strikes on passing squid.
The jaws of snipe eels (family Nemichthyidae) seem ridiculous. They are long and thin with small fine teeth, and both curve outwards. So they don’t even join up. It’s only when you look at their diet that you get some clues, they feed on shrimp. Some researchers have suggested that these fast eels thrash about and use their long beaks to tangle the long antennae of fast shrimps, which then can be easily grabbed.
Many deep-sea ambush predators have hinged teeth that can be flattened down when prey is going in and stand up when resisting. The deep-sea lizardfish has these sort of teeth, they don’t even need to actively swallow, the struggling prey just ratchets itself inside.
Some oreo dories have adaptations for eating stinging jellyfish. At the back of their throat the gill arches and gill rakers are modified to form a second set of grinding jaws, known as a pharyngeal mill". These break up the jellyfish and help discharge the stinging cells. As the bits are swallowed, the last of the stinging cells do no harm as the throat and oesophagus are lined with thick leathery skin.
Just like crows to a road kill, many animals of the deep sea are attracted to dead animals. Carcasses sinking from the surface is one of the ways energy flows from surface waters to the nutrient-poor deep sea. Of these carrion feeders, the most voracious are the large fast-swimming amphipods" (relatives of the springtails you find under rotting seaweed on the beach). Some get to 18 cm long. They cruise like buzzards up to 20 m above the seafloor waiting to detect the smell of a fresh sinker (stinker?). They then swarm to the carcass and can strip a large animal in under 24 hours. These animals can eat more than 60% of their body weight in half an hour (the equivalent of us eating a whole sheep in half an hour!).
|Leathery Barnacle see full image slide show|
Swarms of smaller amphipods and other crustaceans (isopods and ostracods) also converge on carcasses. They end up being the desired food of some small jelly-like sluggish fishes like the snailfish (Psednos sp.) we caught several days ago. The jelly-like flesh gives buoyancy so these animals probably float around smelling for carcasses and then bob in and feast on the swarms of small crustaceans. Nobody knows how they avoid being eaten themselves at these feeding frenzies.
We just brought up the ratcatcher from 1700 metres with a fairly small catch but an amazing array of creatures, many seen for the first time on this voyage. In the invertebrates there were fluorescent orange lobsters new for the trip, large jelly-like finned octopuses, jewel squid, a jelly-like free-swimming octopus without fins (called Japetella ), collapsible sea urchins, three large sea spiders (over 30 cm across) and a range of prawns. The fishes included a large blobfish, a large white skate that is at least a new species and may even be a new genus, chimaeras, deep-sea lizardfishes, an anglerfish, a halosaur, slickheads, a Schmidt’s cod ( Lepidion schmidti ) that only come in one size (big), and some rattail species new for the trip. There was also a weary fish, the first record of the genus Ahliesaurus from New Zealand waters, much further south than previously reported. It was clear that there was a very different fauna at these depths compared with our shallower trawls in the region.
The mid-water trawl has just gone out in deep water..
Day 28, 6 June 2003.
Mark Norman, Museum Victoria
Increasing swell (2-3 m), 20 knot SW wind, 16 ° C
Today everybody was able to sleep and wake at a more reasonable hour. As all sampling finished yesterday, everybody was able to get a solid night’s sleep. The Tangaroa crew and the scientific staff have all changed back to day shift. We are now on the long steam back to the ship’s home port, Wellington .
Yesterday’s mid-water trawl was very successful. The mid-water net is used for sampling the marine life of open water and is very different in set-up to the other nets we have been using. It still uses the doors (otter boards) to hold the net mouth open but has different wings and ground rope arrangement. The wings contain very little net, mainly consisting of long lengths of rope joined to make a large grid. Vibrations from these ropes are enough to flush corral fish and invertebrates into the net mouth. Floats hold up the head line of the net mouth while two large tangles of chains act as corner weights to hold open the bottom edge of the net mouth. The cod end of the net is fine mesh, good for sampling some of the smaller animals.
We deployed the net at 1700 m deep. As marine life is not very abundant in mid-water at these depths, this net was towed for more than an hour. It bought up only a small catch but contained fantastic animals. These included gulper eels, viperfish, several anglerfish species including Johnston’s anglerfish, lancetfishes ( Alepisaurus brevirostris ) with their upright sail fin, several small firefly squids (genus Abralia ), two vampire squids, small transparent shrimp, twelve species of lanternfishes, two species of bristlemouths (genus Sigmops ) and several species of scaleless dragonfish. We have caught some of these species in our other stations, as the bottom nets continue to catch animals as they are hauled back to the surface, but not in such good condition.
There are many confusing terms used for different groups of animals in the deep sea. As discussed in earlier diary entries, the mid-water animals at depths of around 200 to 800 metres migrate up into shallower waters every night to feed. These are known as vertical migrations" and happen all over the world on a massive scale every night. The animals from these depths are known as "mesopelagic", meaning "middle" (as in mid-depth) and "free-swimming". The animals in yesterday’s mid-water trawl live much deeper (>1000 m) and do not make the treks up and down every night. These animals are known as "bathypelagic", meaning "deep" and "free-swimming". They hang mid-water, typically a long way from the seafloor. Other groups of animals also hang in the water but close to the seafloor, feeding on animals associated with the seafloor. These are known as "benthopelagic", meaning "bottom" and "free-swimming" (the term demersal" is also used to describe such animals). The animals that live on (or in) the seafloor are known as "benthic", meaning "bottom-living". Those that live on the surface are called "epifauna", those that are buried in the sand or mud are known as "infauna". Enough terms!
|Black-lip rat fish see full image slide show|
Bruce Barker from CSIRO has just developed another series of drop camera films taken yesterday on the top of a seamount at around 750 m deep. Most of the shots were of barren rocky seabed. One shot however had snapped three rattail fishes over a rippled seafloor. It is difficult to tell if the ripples are in sand or part of the rocky seabed. Most people think that there is no water movement in the deep sea, that it is a still, static sink. Deep-sea currents do occur, strong enough in areas to form regular ripples in the sand or mud. It is these currents that carry the smells of food to foraging animals. These are also the currents that strike the seamounts sticking up out of the deep-sea plains to form eddies that concentrate nutrients and result in the rich communities found on seamounts.
As we steam for Wellington, it is appropriate to describe the driving force of the Tangaroa , its engine room and the engineers, John and Geoff, that keep the system running smoothly. The Tangaroa has a single large 3,000 kW diesel engine. It has eight cylinders with each huge piston being 32 cm across. When under way, the electricity for the ship is produced by a large alternator that runs off the drive shaft. Separate refrigerator plants power the large onboard freezers used on this trip to store specimens. The Tangaroa makes its own fresh water using two "evaporators", which heat seawater under a vacuum so that it boils at around 50 ° C. The steam is then drawn off and cooled to make pure water. These units can produce 16 tonnes of fresh water per day.
People have spent most of today on the big clean up and preparation for unloading all the specimens collected over the past four weeks. We should hit Wellington tomorrow morning. Everybody is keen to see land.
Day 29, 7 June 2003.
Mark Norman, Museum Victoria
Moderate swell (2-3 m), 20 knot SW wind, 16 ° C
Well, at 7 am this morning we woke to find a beautiful sunny day and the Tangaroa steaming inside Cook Strait in the last few miles to Wellington .
It is the end of an amazing voyage. It has been a ground-breaking survey – the most complex and multi-faceted marine research expedition ever conducted in Australasia. This unique trans-Tasman collaboration involved diverse organizations and more than 20 scientists from Australia, New Zealand, France and the USA. Their combined expertise covered geology, seafloor mapping, water characteristics and marine life of the deep sea.
The statistics for the NORFANZ voyage are impressive. The ship has covered more than 5000 nautical miles, sampled 14 seamount systems and 168 stations (almost twice the planned number of stations), down to a depth of 2000 metres. A huge diversity of animals was encountered, in every shape and size: from blobfish to prickly sharks, and miniature brittle stars to giant sea spiders. The adaptations of these animals to their dark cold homes were just as diverse.
A total of over 500 fish species and 1300 invertebrate species were sampled. Many species new to science were recognised including new sharks and rays, redfish, rattails and a range of invertebrates. More than 100 species could not be recognised and may yet constitute new species. The final tallies are likely to rise further, once the appropriate experts examine all the material in detail. One of the regular themes of this voyage was the discovery of animals rarely caught in the past. These included the Ballina Angelfish, the Leopard Chimaera, several anglerfish species and various invertebrates such as deep-sea Sponge Shrimps.
|Blue skates see full image slide show|
The technological revolutions on this trip were the accuracy of the seafloor mapping and the generation of the onboard species reference folders. The detailed maps generated by multibeam scanning made it possible to place the nets precisely. Without these maps we would have snagged, damaged or lost most of our gear. The four fat fish folders and 11 invertebrate reference folders were invaluable in getting an immediate handle on the biodiversity encountered on this voyage. This enabled preliminary sorting and much more targeted distribution of the material on return to Wellington. The onboard digital photography captured fresh animal colours and form before preservation, a first for many of the species encountered. The sophisticated onboard databasing was also excellent for recording all aspects of voyage, station and specimen data.
Where does all this stuff go now? Collected material is now being distributed to the various research collections and world experts for further detailed examination. The ensuing analyses will allow assessments of the composition, diversity, unique nature and isolation of these amazing deep-sea and seamount communities. This material will be the subject of detailed research for years to come.
As this is the last entry I’d like to finish by thanking all the people that helped me so much with production of this daily diary, in particular Andrew Stewart, Bernard Seret, Karen Gowlett-Holmes, Martin Gomon, Tomio Iwamoto, Peter Davie, Penny Berentz, Tim O’Hara, Rick Webber, Ken Graham and all the subjects of individual stories in the diary entries. It has been fantastic to work with such an experienced, knowledgeable and enthusiastic group of people. I’d also like to thank the captain, Andrew Leachman, and all his wonderful crew for making the voyage such a success. We wouldn’t have caught a single animal without them. Thanks also to all the team at National Oceans Office, particularly Katrina Haig and Alicja Mosbauer. Most of all I’d like to thank Karen Zipkas for all her encouragement and support.
It is important to stress that the NORFANZ voyage has only skimmed the surface of the rich diversity of marine life found in the deep waters between Australia and New Zealand. There is still so much to learn.
|Collin Fish 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.