Who lives in a pineapple under the sea?

 

Welcome back! We are now on day 5 since arriving in the Bonaparte Archipelago (Tuesday 8 December) and this is where we are.

SolanderLocation101215
Solander location 10/12/2015
Today  we are working north of Maret Island, in much deeper water (45+ metres deep) than yesterday. We have photographed sea floor habitats and critters along eight different 1.5 km transects with the AIMS towed video system, and collected 2 sled loads of critters from the sea floor to study.

 

A highlight for the day was getting a close-up look at several large sponges (see below) before we headed northward. So, today’s blog is all about sponges!

 

MaretIslandSponges
Sponges collected from the sea floor by AIMS at north-west Maret Island in the Bonaparte Archipelago, Western Australia.
Yes, sponges do indeed live under the sea. But of course they do not live in a pineapple, and in fact, they are only sometimes yellow like SpongeBob SquarePants.

  
What is a sponge?

A sponge is an animal with no muscles, heart or lungs! A sponge’s body is basically a U-shape – often like a barrel or a glass (see below). Spongebob Squarepants (and other kitchen sponges you may have seen or used) are actually just small pieces of the real sponge they would have come from.

 

 

 

SpongeMorphology
An diagram showing the main parts of a sponge’s body (left) compared to an example of a real sponge filmed by AIMS towed video system (right). It is easy to see the central cavity (2) but you have to look closely to see the pores.
Even though it has no bones, a sponge keeps its shape because it is filled with a jelly-like substance called mesohyl within a skeleton made of fibers rather than bones. Water comes in and out of the sponge’s body through holes in its body walls called pores (see above). The water brings food (tiny bits of debris and plankton) to every part of the sponge, and the water takes away wastes. All the pieces that fit together to make the sponge can work together to squirt water out quickly, such as to prevent burial under sand.

What shapes can a sponge be?

Sponges can form into many interesting shapes. Some common ones include:

  • Barrel

This type of sponge can grow up to 1.5 metres long – big enough for a person to stand inside it! The surface of these sponges often have deep ridges. 95% of all sponge species are of this type.

 

BarrelSponge
Examples of medium sized barrel sponges collected by AIMS near the Maret Islands in the Bonaparte Archipelago of Western Australia. They are upside down in the photo. See the ridges on the outside of the sponges?

 

  • Fan

This type of sponge can grow up to 1 meter long. They form a fan shape.

FanSponge
An example of a small fan sponge collected by AIMS near the Maret Islands in the Bonaparte Archipelago of Western Australia.
  • Tube

Tube sponges are made up of thick tube-like structures that join at the base. They can grow up to 1 metre in length. They can chase away predators by squirting out toxic chemicals.

 

TubeSponge
An example of a small tube shaped sponge collected by AIMS near the Maret Islands in the Bonaparte Archipelago of Western Australia

Watch this video of sponges near Maret Island

 

  • How many barrel sponges do you see? Are they all the same kind? 
  • Look closely to find the tube sponge towards the end of the video.
  • Do you see any fish or other creatures near or on the sponges?

 

Sponges are home to many small critters

You most likely saw fish swimming near some of the sponges in the video. And if you looked very closely, you may have seen little animals crawling on them. In fact, sponges are a very important part of the sea floor as they provide food and homes to many different types of animals like fish, starfish, brittle stars, feather stars, crabs, and more. In fact, some microscopic organisms even live inside the tissues that make the sponge’s body walls and give the sponges their colour.

Look at the picture of a sponge below.  Can you see the crab living on it?  Can you see the pores?

SpongeWithCrab
A sponge collected by AIMS from the sea floor. Can you see the crab living on this sponge? Look closely to see the pores
 
Look at the sponge below closely.  This time can you see the pores? What about the central cavity? How many critters can you spot living on it?

SpongeWithAnimals
A barrel sponge collected by AIMS from the sea floor. How many critters can you spot on this sponge? On this sponge, it is very easy to see the central cavity but hard to see the pores.

Did you know…

  • New medicines for treating HIV and breast cancer have been discovered from sponges.
  • Sponges are common in Western Australia. 275 species of sponges have been found in the Damper Archipelago and 500+ at Ningaloo ReefNingaloo Reef.  
  • This expedition is helping to figure out how many are found in the Kimberly region of Western Australia.
  • Many types of fish, nudibranchs, star fish, turtles and other animals depend on sponges for food and shelter.
  • Sponges are under threat from heavy fishing gear which drags along the sea floor and damages or kills them.

 

I hope you enjoyed this blog! See you next time.

 

A sea star with body armour…

 

Welcome back! We are now on day 6 since arriving in the study area, see where we are . It is Wednesday 9 December 2015, and we’ve completed nearly half of our journey.

So far, we’ve seen many sea stars of all shapes and sizes (see some examples below).

starfish
Four examples of sea stars collected by WA Museum staff and photographed by John Keesing of CSIRO during this expedition.

 

Sea stars are marine animals that live throughout the world’s oceans. They have been found as deep as 6,000 metres below the surface.

They usually have 5 arms (as in the photos above), but some types have many more. If one of their arms gets chewed off or otherwise damaged, they can grow a new one! But it might take months to years to do so.
They have tube feet, but usually move quite slowly – a typical speed is just 16 cm per minute!
Sea stars normally eat tiny animals that live on the sea floor. But Tritons , crabs , fish, seagulls and sea otters like to eat them. Some sea stars try to stop other animals eating them by making chemicals to give themselves a yucky taste, or by oozing mucous (the slime star ), or by squirting poison, or by growing body armour!
Today we confirmed that the AIMS towed video system (see previous post) detected a special kind of sea star – a crown-of-thorns starfish on the fringing reef at the north-west corner of Maret Island. This is important because this type of sea star – called COTS for short – prefers to eat corals and can destroy entire reefs under certain conditions.

 

What is a crown-of-thorns starfish?
These sea stars, called COTS for short, prefer to eat corals – specifically the soft fleshy polyps that combine to form coral colonies. They get their name from the long sharp spikes that stick up all over their bodies which look like thorns (see below).

CrownOfThorns
Crown-of-thorns starfish feeding on a reef. Photo courtesy of Rore bzh 

Watch the video of the COTS we found at Maret Island


Look closely and see if you can spot it

Watch a video created by AIMS about COTS to learn more.

Look closely and see if you can spot it.

Did you know that the crown-of-thorns starfish…
• Is one of the largest types of sea stars in the world?
• Squeezes its stomach out through its mouth to put it directly on the coral it is eating?
• Can have up to 21 arms?
• Can give you a painful sting with the long, sharp spines?
• Under certain conditions, can destroy entire reefs in an ‘outbreak’?

cotoncoral-p1050803

Adult COTS feeding on coral. It pushes its stomach part way out of its mouth and digests the coral while sitting on it.

How do COTS outbreaks threat reefs?
Under normal conditions, COTS exist on reefs in small enough numbers that damage to coral is minimal. Every now and then, however, conditions are just right to favour the survival and growth of COTS and their numbers reach plague proportions (see picture below). When this happens, it is called an outbreak and entire reefs over many kilometres can be stripped bare of live coral.

CotsOutbreak
Multiple adult COTS feasting on corals during an outbreak.

Four outbreaks of COTS have happened over the past 30 or more years on the Great Barrier Reef : the 1960s, late 1970s, early 1990s, and the current outbreak which began in 2010.
For example:
• Watch a map of how outbreaks of COTS have spread across the Great Barrier Reef over the past 30 years.

• The Great Barrier Reef lost half its coral from 1985-2011 due to a combination of cyclone wave damage and COTS 

Recently COTS have been found in Western Australian waters around the Montebello Islands  and some scientists worry that they may move southward and damage Ningaloo Reef

Because of this, it is very important to know that COTS also exist as far north as Maret Island so scientists can investigate whether they could pose a threat to the reefs of the Kimberly coast.
The COTS in the AIMS video above from Maret Island was clearly visible which means that it was an adult. Baby COTS tend to hide and are even hard to spot for divers looking closely to try to find them. This implies that more COTS might be present at Maret Island than just the one that we saw.

Thanks for reading – see you next time!

 

 

Sea turtle far from home…

Welcome back! We are now on day 4 since arriving in the study area.

Today (Monday 7 December 2015) we are busy surveying around Maret Island, Berthier Island, Albert Island and Suffren Island (see map below).

 

pic1
RV Solander is surveying near the Maret Islands and vicinity today and tonight using multibeam sonar, towed video and sleds. The white X shows where we saw a turtle. The black dot on the map of Australia shows where the Maret Islands are along the West Australian coast.

 

We found a turtle!

The AIMS towed video system (see previous post) found a hawksbill sea turtle lazing on the sea floor between Albert Islands and Berthier Island (white X on map above).

pic2
Hawksbill sea turtle observed by AIMS in the Bonaparte Archipelago, Western Australia. Can you see the barnacles growing on its shell?

 

Why is it called a ‘hawksbill’ turtle?

Hawksbill turtles have a mouth that look like a hawk’s beak. The narrow and curved shape of their mouth helps them search for food near coral reefs. Dr Scott Whiting from the Western Australian Department of Parks and Wildlife says that Hawksbill turtles in this region mainly eat sponges and sometimes seaweed.

Did you know that hawksbill turtles…

  • Spend the first 5 to 10 years of life drifting on ocean currents?
  • Hatch from eggs buried in the sand?
  • Are reptiles that need to breathe air?
  • Can hold their breath underwater for up to 7 hours if they are sleeping?

Why did we find it so far from home?

The size of the turtle we found means that it may be an adult. For this part of the world, that means it would be at least 30 years old. Over those 30 or so years, it has travelled a great distance from the beach where it most likely hatched from one of its mother’s hundreds of eggs. Dr. Whiting says that Hawksbills in Western Australia primarily nest at beaches on the Lowendal Islands, Montebello Islands and the Dampier Archipelago. These beaches are more than 1,100 km away from where we spotted the turtle today (see map below).

pic3
AIMS scientists observed the turtle (today’s location) more than 1,100 km from where it likely hatched (nesting beaches).

Amazingly, it is quite common for Hawksbill turtles to move to feeding grounds even farther away from the beach where they were born! Scientists have attached tags to turtles and found them moving as far as 2,400 km away from their home beaches. Some studies show that once turtles select a preferred feeding location, they sometimes remain in the area for years – surely by the time they travel that far, they need a bit of a rest!

Perhaps because they travel so widely, scientists have seen hawksbill turtles throughout the world’s tropical and sub-tropical oceans (see map below).

pic4
Locations where Hawksbill turtles have been seen (source)

Why are hawksbill turtles in danger?

Hawksbill turtles are identified as ‘critically endangered’ by the International Union for the Conservation of Nature (IUCN) and Natural Resources.

Threats to their survival in Australia occur when:

  • Hatchlings leaving the nest don’t reach the sea because they are led astray by artificial lights
  • Turtles are injured or killed when struck by vessels
  • Turtles are killed accidentally caught by commercial fishermen, especially trawlers
  • Turtles are killed or made ill by eating plastic or getting tangled in trash in the ocean
  • Turtles are killed or made ill by polluted waters
  • Fewer turtles hatch as beach temperatures getting too hot
  • Less space for nests as beaches get washed away by storms and sea level rise
  • People hunt turtles for their shells.

 

Thanks for reading – see you next time!

 

A hands on look at what lives on the Kimberly sea floor

Welcome back! We are now on day 3 since arriving in the study area (Sunday 6 Dec 2015).  See where we are right now.

In my last blog, I showed you how we can see live video footage of creatures and habitat on the sea floor without even getting wet (using the Tow-vid system).

Sometimes, though, scientists need to see creatures first hand in order to understand more about them and where they live. For that reason, on this expedition we are also collecting samples of sea floor creatures for scientists from the Western Australian Museum and elsewhere to study.

To do this, we are using a large metal frame with a mesh bag attached to it called a sled (see below). The RV Solander crew lower the sled carefully into the water using a strong steel cable until it hits the sea floor. The RV Solander then slowly moves forward for 50 to 100 metres as the sled drags along the sea bottom, collecting sand, mud and critters in the mesh bag. Then the crew then slowly pull up the sled using one of the several heavy duty winches mounted from the upper deck.

RetreavingASledOntheSoander
RV Solander crew carefully raise the sled, secure it on deck, lift the mesh bag over the sorting table, and release the contents

Once the sled is securely anchored to the deck, the crew use the winch to raise the mesh bag above a sorting table and empty the bag.

Sorting sled contents

The next step is to sort everything that came out of the mesh bag into groups based on what kind of animals and plants they are (see below).

SortingSamples
WA Museum and CSIRO scientists sort samples into groups on the back deck of the RV Solander

Measurements, photos and preservation

Samples are then weighed, assigned a unique ID number and bar code and then recorded in a computer database (see below). A series of photos is taken of each specimen with its bar code for later use by scientists on land in the laboratory.

CatalogSamples
WA Museum scientists carefully weigh, catalog and photograph each specimen.

Caption: WA Museum and CSIRO scientists carefully weigh, catalog and photograph each specimen.

Finally, the specimens are then carefully stored in a liquid that keeps them from decaying or are frozen. This keeps them fresh until they can be analysed back on dry land in the lab.

Sample sled hauls

A few examples of the types of creatures we’ve found so far are:

StarFish
Examples of starfish. Most have 5 arms, but some have 8 or more. An arm can regrow if lost to a predator.
CoralCrab
Example of a coral crab.
Nudibranchs
Nudibranchs (sea slugs) eat sponges and leave a ‘slime trail’ where-ever they go to avoid getting lost
SeaCumbers
Sea cucumbers are so named because some people consider them a delicacy. Don’t eat the ones shown here though because they are poisonous!
FeatherStarts
Examples of feather stars. The one on the left is broken and you are seeing the top of it. The one on the right is intact and you are seeing the bottom of it. It has nearly 100 arms!
AssortedCreatures
Examples of creatures collected. Clockwise from top left: sea whips, sponge, sea urchin, soft corals, sponge, sponge.

Now that I’ve given you an idea of the ways we are exploring the Bonaparte Archipelago, the rest of my posts will focus on interesting creatures or habitats we find along the way.

MarjiWhips
Sea whips look just like their name.

Thanks for reading – see you next time!

 

Exploring the sea floor with video

 

When most people think of marine scientists discovering underwater habitats and creatures, they assume those scientists will be swimming underwater using SCUBA.

But Western Australia’s Kimberly coast has extremely high tides that create treacherous currents that make it too dangerous for divers.Watch a video about how the tides work. Not to mention the tiger sharks   and crocodiles that infest these waters!

CrocAndShark
Salt water crocodiles and sharks make it dangerous to SCUBA dive offshore from northern Western Australia.

Plus, we are interested in parts of the sea floor that are too deep for divers (40-100 metres deep).

How do you see what is on the sea floor when it is too deep or too dangerous for divers?

AIMS have developed a solution – attaching a camera and a video camera protected in waterproof cases to an aluminium sled that can be towed behind the ship using a long strong cable. This is called the tow-vid system (see below). A powerful strobe light illuminates the sea floor for the video.

TowedVideo
RV Solander crew prepare tow-vid

 

The ship’s powerful winch lifts the tow-vid system into the air and the crew carefully guide it into the water. Note how everyone involved is wearing hard hats, life jackets and steel toed boots!

 

TowvidWinch
RV Solander crew lower the AIMS tow-vid into the water.

Once the tow-vid is submerged and lowered to the sea floor, the ship slowly moves along a predetermined 1.5 km long transect line at a constant slow speed. The video camera continually records and transmits to a computer on deck.

Watch a sample of what the tow-vid saw today near Augereau Island.

TowvidStills
Examples of still photos from tow-vid on this trip: top = sea cucumber, middle = sponge, bottom = feather star.

Still photos of the sea floor are taken at regular intervals and downloaded once the tow-vid is back on deck. Later, back on land, scientists analyse these to identify the species of animals and plants they contain.

Examples of still photos from tow-vid on this trip are on the left : top = sea cucumber, middle = sponge, bottom = feather star.

While the ship is moving along the tow transect, two scientists are responsible for keeping the tow-vid on track, and recording data as it operates.

First, a tow vid technical expert (in our case, Neill), watches a computer screen which shows live footage from the underwater video camera. He uses this as a guide to change the speed and direction of the tow-vid via the winch so that it doesn’t hit the bottom, and also so that it is close enough to the bottom to be able to see the habitats and creatures there as clearly as possible.

TowVidTec
Tow vid technician Neill steering the tow-vid using the joystick in his hand.

 

Second, a marine scientist (in our case Marcus) watches the live video footage and regularly clicks a button on the smaller computer screen to record what type of habitat he sees on the sea floor in a computer database. This can be used to create maps of the study area.

 

 

 

 

 

CollectingTowedVideo
Live video footage from the towed video as viewed on deck, and Marcus recording what he sees as Neill drives the tow-vid.

Back on dry land, spatial scientists then use this data to map where various habitats were found. The first step is to colour code each location where Marcus made an observation as a point along the track the ship towed the tow-video system.

 

 

TowvidWormPlot
An example of ‘Worms’ map

To end for today, below is a map of where we are working today. The red line shows the path followed by the RV Solander. The blue numbers show were we plan to run tow video transects.

TripProgress051205

I hope you are enjoying this blog! Leave a comment and let me know what you think. I will post again in a day or so.

Mapping the sea floor…

Last night we finally arrived at our destination (See where we are) while the sun sank into the Indian Ocean!

 

Spatial scientist and blogger (Marji) soaking up the serenity.
Now that we’ve arrived, we plan to:

  • Map the sea floor.
  • Examine the habitats and creatures that live there.
  • Measure how much light is in the water, how hot it is, and how salty it is.
  • Measure how much the water level changes with the tides.

In today’s blog, I’ll explain a bit about how we map the sea floor.

You may think that the sea floor is flat, but it can have seamounts (underwater mountains) and canyons and everything in between, just like dry land (see example below).

 

An example of a 3d map of the ocean floor.
How can we tell what the sea floor is like when it is hidden under 10s to 100s of metres of water?

In the past, ships dropped long ropes with heavy weights on them to measure the distance from the surface to the sea floor.

Today we use sound waves to measure this distance – it is much more cost effective.  This is called sonar (watch a video of how it works).

We attach a high-tech instrument (a multi-beam sonar) underneath the ship (see below).

 

Installing the multibeam sonar on the RV Solander

It sends sound pulses downward. The time it takes for the sounds to hit the bottom and bounce back to the ship tells us how deep the sea floor is and whether it is made of sand, rock or mud (see picture below).

 

An example of how sonar works.
We have two scientists on board in charge of our sonar.  Nick operates the sonar and Iain (below) analyses the data to create 3D models of the sea floor.

Sonar data processing in the ‘dry laboratory’ on the RV Solander
For example, here is data from a test run completed on our way to the study area. Blue areas are deepest and red areas are shallowest.

 

Example of sonar data recorded in a test run.

And here is a map of the route the ship will take (blue lines) through the study area to map the sea floor with sonar. Where possible, we run sonar at night to free up the days for other work.

Sonar survey plan (blue lines). RV Solander shown in red.
In my next post, I’ll explain how we use a towed video system to take photos and record video deep under water.

See you then!

And we’re on our way…

map
Map of our journey along the West Australian coast.

The RV Solander has left Broome (See where we are), steaming northwards to our study area in the Bonaparte Archipelago!

It will take us more than a day and a night (about 30 hours) to get here – Western Australia is bigger than you may think.  The red line on the map above shows you our entire journey.

 

karen
Cruise Leader Karen en route to the RV Solander

Safety at sea is very important. Our Cruise Leader (Karen) makes sure everyone on board is prepared for the journey ahead. Here she is riding in an a zodiac (small inflatible boat) from the dock  in Broome to the ship.

 

rob.jpg
Skipper Rob steers the ship

Our Skipper (Rob) makes sure the ship gets us where we need to be safely. Here he is in the wheelhouse, steering the ship.

And we all learn the safety rules of the ship-

liferaft.jpg
All science staff attend the safety induction before we get underway.

including how to use the life raft.

In my next post, I’ll explain some of the ways we plan to explore the study area!