Scleractinian or stony cup coral Desmophyllum dianthus. (Credit: Alan Blacklock, NIWA)
Scleractinian or stony cup coral Desmophyllum dianthus. (Credit: Alan Blacklock, NIWA)
Gorgonian bubblegum coral, Paragorgia_arborea. (Credit: Julian Finn, NIWA)
A video image of Scleractinian corals, taken by NIWA’s Deep Towed Imaging System (DTIS). (Credit: NIWA)
26 November 2008
The world’s top 200 leading deepsea coral scientists do – and they are due in town next week to share their knowledge and insights on these rare beauties.
Deepsea, cold-water corals were first discovered in the 18th century, but it is only recently with technological advances like deepwater trawling, deep-towed imaging systems, submersibles, and advanced underwater acoustics, that the extent of deepsea corals has been realised.
And because they are so hard to reach – more than 200 metres below the surface – there’s still a lot to learn about them.
The 4th International Deepsea Coral Symposium, hosted by the National Institute of Water & Atmospheric Research (NIWA), will bring together scientists, resource managers, students, and policy-makers to help provide an understanding of the critical factors for conserving deepsea corals.
Understanding the ecosystem role, function, and value of deepsea corals and associated fauna has become a priority for many national governments and international regional resource management bodies, to ensure deepsea coral protection.
In conjunction with the symposium, Te Papa and NIWA will also be launching “Corals – hidden beauties of the deep” – a new display of deepsea corals owned by Te Papa, NIWA, Ministry of Fisheries, and the Department of Conservation. More than 40 species of coral will be on display, showing the diversity of these unique beauties that can be found in New Zealand waters.
Details:
4th International Deepsea Coral Symposium
1-5 December, 2008
Victoria University of Wellington
Rutherford House, Pipitea Campus
Bunny Street, Wellington
Media are welcome to attend any of the sessions at the Forum. For a copy of the programme, or for more information, go to: http://coral2008.niwa.co.nz/programme.php
For more information contact:
Di Tracey
NIWA
Tel: +64 4 386 0866
Mob: +64 274 951 287
d.tracey@niwa.co.nz
Dr Helen Neil
NIWA
Tel: +64 4 386 0375
Mob: +64 21 0233 1320
h.neil@niwa.co.nz
Scientists are available for interviews prior to, and at the conference. Please contact: Greta Shirley – +64 21 455 922, g.shirley@niwa.co.nz
More than 10 000 described species of deepsea corals are known worldwide, with more than 1100 found in New Zealand. Identifying deepsea corals requires specialist taxonomists and species new to science are constantly being found. There is a global shortage of trained scientists to undertake this work. Most of these experts will be at the symposium.
Using the skeletons of these long-living creatures, scientists have reconstructed the palaeo-climatic history of our oceans over the last 100 years, including a recent large scale study in the Southern Ocean. Changing ocean chemistry (ocean acidicification) can threaten the survival of marine life. The scientific community is becoming increasingly worried about this development.
Very little is known about how deepsea corals live (e.g. how fast they grow, what they eat, how they reproduce). A unique experiment recreating deepsea conditions in the laboratory to better understand the behaviours of the deepsea coral Lophelia pertusa will be presented at the symposium. New Zealand work on bamboo corals indicates the corals may be more than 400 years old.
Deepsea corals provide a home for many other deepsea animals. Some corals form large reefs. (e.g. Lophelia Reef off Northern Norway is 100 km2 with some parts reaching 30 m off the seabed). Several research projects have been developed to map these structures, and investigate the various fish and invertebrate fauna associated with them. Often several hundreds of species are found hidden in the branching structures. Working in the deepsea drives fast-paced technological and methodological advances (e.g. remotely operated underwater advanced camera systems) to meet the challenges of understanding these hidden ecosystems.
Deepsea corals may be impacted by a number of human activities. The symposium will bring together scientists and managers to consider management decisions and policy (national and international) to conserve and protect deepsea corals from human impacts.
Awareness of deepsea corals and their ecological importance is growing rapidly. Continuing with the tradition of the 1st Symposium in Halifax, Canada (2000), the 2nd Symposium in Erlangen, Germany (2003), the 3rd Symposium in Miami, USA (2005), this 4th International Deepsea Coral Symposium will facilitate global exchange of the current scientific knowledge of deepsea corals and associated fauna and discuss management measures and options to conserve and protect deepsea habitat.
This is the first time the symposium has been held in the Southern Hemisphere. The Symposium is being hosted by NIWA, with major sponsors – NOAA (the National Oceanic and Atmospheric Association). Other sponsors include CSIRO, MMS, Ministry of Fisheries, Department of Conservation, Te Papa, UNEP, USGS, Neptune Minerals, DeepWater Group, and the Royal Society of New Zealand.
What are deepsea corals?
Deepsea corals were first discovered in the 18th century but it is only recently, with technological advances such as deepwater trawling, imaging systems, submersibles and advanced acoustic seafloor mapping systems, that the extent of deepsea corals has been known.
The first records of corals being found in New Zealand waters date back to 1833.
Deepsea corals, also known as cold water corals, are distinct from tropical coral. Deepsea coral lives in depths greater than 200 metres, in cold, dark water.
Corals feed by snatching food (often zooplankton, crustaceans, and krill) from the water using tentacles that stun their prey. Corals are sedentary organisms (i.e. they do not move) so they must live near nutrient-rich water currents for their food.
Deepsea corals belong to the Cnidaria grouping of animals, and are related to animals like sea anemones and jellyfish.
They come in many forms, ranging in size from 2 millimetres individual corals to large colonies of corals that form reefs.
Deepsea corals grow very slowly – some as slow as between 4–25 millimetres per year – compared to tropical corals that can grow up to 100–200 millimetres per year.
Where are deepsea corals found?
Deepsea corals are found in the Atlantic, Mediterranean, Indian and Pacific Oceans, in waters with temperatures between 4°c and 12°c degrees.
Most deepsea coral are found between 200 and 1500 metres deep but some species have been found more than 3000 metres deep. Corals require a hard surface to attach to which is why they are often found growing on seamounts (undersea mountains) and other rock surfaces.
The largest known deepsea coral reef is the Sula Rodge complex off the Norwegian coast. It is 14 kilometres long and grows up to 35 metres in height.
How many species of deepsea corals exist?
Globally two-thirds of all known coral species are deepsea corals.
There are more than 10 000 documented species of deepsea corals internationally but scientists believe many more exist.
The majority of deepsea coral research takes place in the north-east Atlantic Ocean where more than 1300 species have been recorded.
More than 1100 species of deepsea coral have been identified so far in the New Zealand Exclusive Economic Zone.
Types of deepsea corals
Black corals: sea trees of the deep
Black corals (Antipatharia) are named for the dark colour of their skeletons. Although some species are found at depths of up to 3000 metres, New Zealand’s Antipathes fiordensis occurs in cold Fiordland waters at only 15–50 metres below the surface. Colonies of black coral can look like trees with branches, whips, fans, or feathers. Some live for hundreds of years, and may grow over three metres tall.
Overseas, some species are harvested and polished to make jewellery. New Zealand’s black corals, however, are strictly protected.
Stony corals: chalices of the deep
Stony corals (Scleractinia) are usually associated with the tropics, but they are also common in the cold deepsea. Over 120 species live in the New Zealand region. Several of the branching stony corals are important reef builders, creating complex 3-D structures – up to 40 metres high and 700 metres wide – that provide habitat for hundreds of animals, such as the squat lobsters, carnivorous sponges, and brittle stars.
Cup corals do not build reefs; they live alone or in ‘clumps’ instead. Their beautiful forms include an internal carbonate skeleton shaped like a cup or a cone into which they can retract and hide.
Bamboo corals: candelabra of the deep
Bamboo corals (Gorgonacea) are often branched, and can form dense thickets several metres high. Their branches are made of alternating black and white jointed segments, which give them their bamboo-like appearance.
Like several other coral groups, bamboo corals develop prominent growth rings, which can be used to determine their age. Counts of zones of a cross section of a bamboo coral showed ages of at least 400 years old.
Readable growth rings make bamboo corals extremely useful to scientists researching past oceanic conditions. These rings, like those of trees, enable them to establish when any crucial physical or chemical changes occurred.
Hydrocorals: lace of the deep
Hydrocorals are delicate and tiny, with a ‘lacy’ skeleton, and several genera are covered with pinhole-sized pores where polyps live. Colonies are usually small and slow growing, and have fragile branches that are easily damaged.
New Zealand’s hydrocoral fauna is one of the most diverse in the world, and of the more than 50 species that live here, 80% are endemic. The protected, red-coloured species Errina spp. occurs widely in our seas.
The biology and ecology of New Zealand hydrocorals is largely unknown. However, studies of the protected species Errina novaezelandiae have highlighted its vulnerability to human impacts.
Bubblegum corals: kauri of the deep
New Zealand’s deepsea region is thought to have the most diverse range of bubblegum coral (Gorgonacea) species in the world.
Known as ‘kauri of the deep’ after its large tree-like colonies, this coral can grow up to 7 metres tall and live for more than 500 years.
‘Bubblegum’ refers to the distinctive bright pink colour and knobbly surface of the colony. This spectacular coral offers food and habitat to vast numbers of animals, and could soon be classed as a protected species.
Gorgonians: fans of the deep
Sea fans (Gorgonacea) are often fan-like in form, but can also appear as whip, bottlebrush, or tree-like structures. The branches of golden corals are especially beautiful with their lustrous metallic sheen.
The New Zealand deepsea region is home to almost 250 species of sea fans – possibly the largest number worldwide – and many of them are endemic. Several of the largest species, however, are yet to be identified and more research about their habitats and protection is needed.
Sea fans attach to rocky areas swept by strong currents, and have been seen to provide shelter for small fish and other invertebrates.
Why are deepsea corals important?
Deepsea corals have a critical ecological role and are extremely important to the biodiversity and sustainability of fisheries. They provide shelter, food, and breeding grounds for many species of fish and invertebrates, including commercially important fisheries species.
Because some deepsea corals can live for many hundreds of years they also provide important information about past climates, and are helping scientist to understand and mitigate the effects of global climate change.
Some deepsea corals are also being used by pharmaceutical industries to develop new drugs that may help fight cancer, Alzheimer’s disease, asthma, pain, and viral infections.
Threats to deepsea corals
Because deepsea corals are long-lived but slow-growing they are particularly susceptible to physical disturbances by human activities – particularly bottom trawling, and mining.
Deepsea corals are also at risk from ocean acidification. Deepsea corals are likely to be one of the first ecosystems affected. As oceans move towards increasing acidity, the corals structures will grow slower, become weaker and even dissolve.
In New Zealand black and red corals are protected under the Wildlife Act 1953.