Exploring Australia’s ‘other reefs’ south of Tasmania

File 20181217 27779 1tg4cyr.jpg?ixlib=rb 1.1
Solenosmilia coral reef with unidentified solitary yellow corals.

Nic Bax, CSIRO and Alan Williams, CSIRO

Off southern Tasmania, at depths between 700 and 1,500 metres, more than 100 undersea mountains provide rocky pedestals for deep-sea coral reefs.

Unlike shallow tropical corals, deep-sea corals live in a cold environment without sunlight or symbiotic algae. They feed on tiny organisms filtered from passing currents, and protect an assortment of other animals in their intricate structures.

Deep-sea corals are fragile and slow-growing, and vulnerable to human activities such as fishing, mining and climate-related changes in ocean temperatures and acidity.

This week we returned from a month-long research voyage on CSIRO vessel Investigator, part of Australia’s Marine National Facility. We criss-crossed many seamounts in and near the Huon and Tasman Fracture marine parks, which are home to both pristine and previously fished coral reefs. These two parks are part of a larger network of Australian Marine Parks that surround Australia’s coastline and protect our offshore marine environment.

The RV Investigator criss-crossed the Huon and Tasman Fracture marine parks.

The data we collected will answer our two key research questions: what grows where in these environments, and are corals regrowing after more than 20 years of protection?

Read more:
Explainer: the RV Investigator’s role in marine science

Our eyes on the seafloor

Conducting research in rugged, remote deep-sea environments is expensive and technically challenging. It’s been a test of patience and ingenuity for the 40 ecologists, technicians and marine park managers on board, and the crew who provide electronics, computing and mechanical support.

But now, after four weeks of working around-the-clock shifts, we’re back in the port of Hobart. We have completed 147 transects covering more 200 kilometres in length and amassed more than 60,000 stereo images and some 300 hours of video for analysis.

The deep tow camera system weighs 350 kilos and has four cameras, four lights and a control unit encased in high-strength aluminium housings.

A deep-tow camera system designed and built by CSIRO was our eye on the seafloor. This 350 kilogram system has four cameras, four lights and a control unit encased in high-strength aluminium housings.

An operations planner plots “flight-paths” down the seamounts, adding a one-kilometre run up for the vessel skipper to land the camera on each peak. The skipper navigates swell, wind and current to ensure a steady course for each one-hour transect.

An armoured fibre optic tow cable relays high-quality, real-time video back to the ship. This enables the camera “pilot” in the operations room to manoeuvre the camera system using a small joystick, and keep the view in focus, a mere two metres off the seafloor.

This is an often challenging job, as obstacles like large boulders or sheer rock walls loom out of the darkness with little warning. The greatest rapid ascent, a near-vertical cliff 45m in height, resulted in highly elevated blood pressure and one broken camera light!

Reaching into their world

Live imagery from the camera system was compelling. As well as the main reef-building stony coral Solenosmilia variabilis, we saw hundreds of other animals including feathery solitary soft corals, tulip-shaped glass sponges and crinoids. Their colours ranged from delicate creams and pinks to striking purples, bright yellows and golds.

To understand the make-up of coral communities glimpsed by our cameras, we also used a small net to sample the seafloor animals for identification. For several of the museum taxonomists onboard, this was their first contact with coral and mollusc species they had known, and even named, only from preserved specimens.

A deepwater hippolytid shrimp with large hooked claw, which it uses to clean coral and get food.

We found a raft of undescribed species, as expected in such remote environments. In many cases this is likely to be the only time these species are ever collected. We also found animals living among the corals, hinting at their complex interdependencies. This included brittlestars curled around corals, polychaete worms tunnelling inside corals, and corals growing on shells.

We used an oceanographic profiler to sample the chemical properties of the water to 2,000m. Although further analysis is required, our aim here is to see whether long-term climate change is impacting the living conditions at these depths.

A curious feature of one of the southern seamounts is that it hosts the world’s only known aggregation of deep-water eels. We have sampled these eels twice before and were keen to learn more about this rare phenomenon.

Using an electric big-game fishing rig we landed two egg-laden female eels from a depth of 1,100 metres: a possible first for the record books.

Dave Logan of Parks Australia with an eel landed from more than a kilometre under the sea.
Fraser Johnston/CSIRO

In a side-project, a team of observers recorded 42 seabird species and eight whale and dolphin species. They have one more set of data towards completing the first circum-Australia survey of marine birds and mammals.

More coral pedestals than we realise

An important finding was that living S. variabilis reefs extended between the seamounts on raised ridges down to about 1,450m. This means there is more of this important coral matrix in the Huon and Tasman Fracture marine parks than we previously realised.

In areas that were revisited to assess the regrowth of corals after two decades of protection from fishing, we saw no evidence that the coral communities are recovering. But there were signs that some individual species of corals, featherstars and urchins have re-established a foothold.

Read more:
Sludge, snags, and surreal animals: life aboard a voyage to study the abyss

In coming months we will work through a sub-sample of our deep-sea image library to identify the number and type of organisms in certain areas. This will give us a clear, quantitative picture of where and at what depth different species and communities live in these marine parks, and a foundation for predicting their likely occurrence both in Australia and around the world.

The seamount corals survey involved 10 organisations: CSIRO, the National Environmental Science Program Marine Biodiversity Hub, Australian Museum, Museums Victoria, Tasmanian Museum and Art Gallery, NIWA (NZ), three Australian universities and Parks Australia.The Conversation

Nic Bax, Director, NERP Marine Biodiversity Hub, CSIRO and Alan Williams, Researcher, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Exploring the solar system: the best of what you can look out for in 2016

Alan Duffy, Swinburne University of Technology

This year is shaping up to be another exciting one for space after a bonanza of discoveries and celestial events in 2015.

One of my hoped-for highlights of 2016, NASA’s Insight mission, has unfortunately been scrubbed due to a serious leak in last stage testing. But here are three of my particular favourite space missions to watch out for as well as some key night sky events to try and experience throughout 2016.

1. ExoMars

One of the next big missions to Mars will be the European Space Agency’s ExoMars programme, a two-stage mission.

The first stage is a joint Trace Gas Orbiter (TGO) and Schiaparelli lander which will launch in March (to arrive by October). The technologies demonstrated by Schiaparelli will then be used for a rover to land in any interesting sites identified by TGO as the next stage in ExoMars.

The orbiter will spend five years attempting to “sniff” out those gases in the Martian atmosphere such as methane that break down over time, with any trace amounts indicating a process of creation on Mars. Whether biological (that is, expelled by microbial life) or geological in nature will be investigated throughout the ExoMars programme.

2. Juno

A key story for 2016 will be the investigation of Jupiter by NASA’s Juno mission. As the enormous gravity of Jupiter pulls the spacecraft to ever higher speeds, ultimately travelling at more than 70km per second, Juno will become the fastest craft in human history.

It will fire its rockets to slow down and then enter one of the most challenging orbits ever attempted, skimming as low as just 5,000km above the cloud tops, ducking below the intense – and damaging – radiation belts of Jupiter to study the gas giant as never before. To put that in perspective, if Jupiter were a soccer ball, Juno would be skimming less than a centimetre off the surface.

The aim is to see if there’s water in the atmosphere (revealing the conditions from which the gas giants formed), to study the gas giant’s magnetic and gravitational field and the nature of the interior.

Thousands of kilometres of clouds crush the core to extraordinary pressures that might form a planet-sized diamond (as Arthur C. Clarke once wrote) or more likely a core of superconducting metallic hydrogen that powers the enormous magnetic field of the planet.

It will be deorbited in Februrary 2018 after 37 death-defying orbits threading through the incredibly dangerous radiation belts.


The latest telescope on Earth could hardly look more different to those that use light (be it visible or radio waves) but LIGO is searching the skies for colliding black holes, with the telltale signals as ripples in the very fabric of spacetime itself. These gravitational waves are Einstein’s final prediction and are yet to be verified.

As a gravitational wave passes through you, you’d be stretched one way becoming thinner and then as the wave continues through you are squashed and fattened. Since this doesn’t visibly appear to happen we can guess that the stretching and squashing is tiny. The expected change is less than the thickness of an atom in a ruler a million kilometres long.

To measure this incomprehensibly tiny change we use lasers (technically an interferometer bouncing two lasers back and forth) in different locations on Earth to triangulate the position to a few degrees on the sky (the width of a few full moons).

The LIGO observatory at Livingston, Louisiana.

Discovering these waves will allow us to see the universe with an entirely new sense, as distinct from hearing to seeing. In 2016, humanity will gaze with entirely new eyes into the cosmos.

Celestial events

There are also some fantastic sights in the sky to watch out for in 2016.

Southeast Asia and Africa will get to enjoy the more visually impressive solar eclipses, with Australia, Europe and the United States missing out (although everyone can enjoy the stunning meteor showers).

These are selected from a more exhaustive list of all the motions of the planets and other celestial highlights. If not mentioned, all times and viewing directions are from an Australian perspective.

Planetary alignment

January 20 to February 20

All five planets visible to naked eye – Mercury, Venus, Mars, Jupiter and Saturn – will appear in morning sky. This is the first time since 2005 and should be something we can all manage to see without telescopes.

Stand in line: the five planets visible to the naked eye.
Alan Duffy, created with Sky Safari, Author provided

Jupiter at opposition

March 8

This the best time to see the gas giant as it forms a direct line with the sun – Earth – Jupiter. Similar to a full moon, Jupiter will be entirely illuminated by the sun making it appear brighter than any other time this year.

With binoculars you should easily discern the four largest (Galilean) moons sitting in a line either side of the planet.

Total solar eclipse

March 9

The total solar eclipse will be visible from central Indonesia and some Pacific Islands. Neighbouring regions, such as Northern Australia and Southeast Asia, will see a partial eclipse but protective eyewear should be used at all times. Check the NASA predicted track.

Eta Aquarids meteor shower

May 6 to 7

Eta Aquarids is a particularly good meteor shower with up to 60 meteors per hour at its peak in the southern hemisphere (the northern hemisphere might see half this). This meteor shower is from the Earth running through the dust tail of Halley’s comet.

The new moon will mean even more of the faintest shooting stars are visible. Look towards the constellation Aquarius after midnight.

Transit of Mercury across the sun

May 9

Mercury will pass between the Earth and the sun, with the dark disk of the planet visible across the face of the sun. There will not be another transit of Mercury until 2019 and then the next one will be in 2039.

This can only be seen with specialised protective eyewear and a telescope, including a pinhole camera. Unfortunately, this will not be visible from Australia but will be seen in most of the rest of the world, in particular the eastern United States and eastern South America.

Blue moon

May 21

As the third of four full moons in this season, it is known as a blue moon. This is a relatively rare occurrence, hence the term “once in a blue moon”.

Each season you could expect three full moons but the lunar cycle is every 29.53 days meaning on average every 2.7 years you can squeeze in a fourth full moon in a season, nothing to do with the colour changing!

Don’t expect the blue moon to be coloured blue.
Flickr/Ed Dunens, CC BY

Mars at opposition

May 22

The sun and Mars sit directly opposite one another as seen from the Earth ensuring the planet is fully illuminated by the sun.

Mars will be a clear red point of light in the night sky. Using an eight- to ten-inch telescope you can see darker regions amid the orange/rust coloured planet.

Saturn at opposition

June 3

Saturn is in a direct line between the Earth and sun meaning that it rises in the east just as the sun sets in the west.

Saturn will be a bright diamond coloured point of light, at its brightest for the entire year. A medium-sized telescope will be needed to see the famous rings.

Perseids meteor shower

August 12 to 13

With up to 60 meteors per hours the Perseids is a reliably good meteor shower as the Earth ploughs through the debris of the comet Swift-Tuttle.

There is only a minimal amount of moonshine (a waxing gibbous moon setting just after midnight) ensuring that the majority of shooting stars will be seen after midnight.

The shooting stars will radiate from the constellation Perseus.

Conjunction of Venus and Jupiter

August 27

Two of the brightest planets in the night sky will appear to move towards each other throughout August. They reach their closest point (a conjunction) just after sunset in the western sky (just seven arcminutes apart, or less than the nail of your little finger held at arm’s length) on August 27.

Annular solar eclipse

September 1

The moon is a little further from the Earth than the March 9 eclipse meaning that it will not completely cover the sun, revealing a burning bright ring (or annulus) around the moon.

The eclipse path will pass through Congo, Tanzania and Madagascar before ending in the Indian Ocean. A partial eclipse will be visible in the neighbouring African nations. Check the NASA predicted track.

1st Supermoon

October 16

First of this year’s three supermoons, when the moon is closest to the Earth in its orbit. This means it is bigger in the sky and hence brighter when fully illuminated by the sun (a full moon) on the opposite side of us from the sun.

2nd Supermoon

November 14

Second of three supermoons for 2016.

Geminids meteor shower

December 13 to 14

The Geminids are usually the best meteor shower of the year with up to 120 meteors per hour, but unfortunately there is nearly a full moon this year (a supermoon no less) that will outshine all but the brightest shooting stars.

All other meteor showers this year are from the Earth ploughing through a debris tail from a comet, but the Geminids are unique in being from an asteroid (3200 Phaethon). The radiant is in the constellation Gemini (the Twins).

3rd Supermoon

December 14

Third and final supermoon of 2016. What a great way to end the year, but a shame about the Geminids meteor shower.

The Conversation

Alan Duffy, Research Fellow, Swinburne University of Technology

This article was originally published on The Conversation. Read the original article.

Oceans: Exploring the Deep

The article below includes a short video of a short talk by marine biologist Dave Gallo on the world’s oceans, including footage of some strange creatures.

See also: