Scientific Scribbles

The voice of UniMelb Science Communication students

Victoria’s Cultural Cornerstone – Literally!

 

Melbourne is a beautiful city, anyone can tell you that. And not just due to its elegant skyline; one could easily spend a day only touring the laneways and historical buildings of the city. And if that person was paying close attention, they may have noticed a common thread in many of these sites: they are constructed from the same material.

This, of course, is Victoria’s famous “Bluestone,” so called after its steely blue veneer. It is a stone that has been a prized for its hardness and durability since the 19th century, when the Victorian gold rush saw a huge influx of fortune seekers. With the colonies rapidly expanding, building material was in great demand, and so bluestone was quarried from huge deposits in the surrounding areas.

Some of the most famous of Victoria’s historical buildings are constructed from bluestone. Going clockwise: Melbourne Grammar School (credit: Donaldytong via Wikimedia), Saint Paul’s Anglican Church in Kyneton (credit: Diverman via Wikimedia), Old Melbourne Gaol (credit: Bidgee via Wikimedia), St Patrick’s Cathedral (credit: Donaldytong via Wikimedia).

 

 

What Melbourne was built upon.

In Melbourne, and many other Victorian towns, Bluestone was used as the foundation of many buildings and was extensively used as cobblestone. It has proved itself to be extremely robust: take the Old Melbourne Gaol for example. Constructed in the 1850s, only an occasional light wash is needed in order to maintain it. Even today, bluestone remains ever popular: next time you’re in the CBD, look down. Chances are you’re treading on bluestone pavement!

 

But what is bluestone exactly?

Well, as it turns out, Victorian bluestone is actually basalt; a volcanic rock that spewed forth as lava millions of years ago, then subsequently cooled. These eruptions occurred remarkably recently: beginning a mere 4.5 million years ago and continuing intermittently until around 4000BC. While these time periods may seem unimaginable from a human perspective, in geological timescales they are a blink of the eye. Even so, this series of volcanic activity managed to produce a huge amount of lava and ash, creating what is now known as the Newer Volcanics Province. It is the cooled lava from the province, now basalt, that is bluestone.

 

Wait a minute: Australia has volcanoes?

Indeed, it does! While Australia has the deserved reputation for being flat and tectonically inert, there are hundreds of extinct volcanoes dotted across the South-Eastern region. These are the volcanoes that created the Province and are also responsible for some of the area’s most recognisable natural landmarks!

Mostly flat and featureless, driving through the Victorian countryside can be a bit of a drag. However, occasionally conspicuous mounds will appear, rising comparatively high into the air to offer a refreshing change in scenery. These are scoria cones, often optimistically called mountains. They can rise to be several hundred metres high and are actually mounds of ash and volcanic rock created by brief, violent eruptions. The most well-known of these include Mt Sugarloaf, Mt Elephant and Red Rock Lookout.

When creating these scoria cones, lava can sometimes overflow and spill out over the landscape. In some places these lava flows accumulate into massive deposits of basalt, forming the bluestone quarries throughout south Victoria.

These scoria cones are found throughout south-eastern Australia, and in Victoria especially. At Red Rock Lookout, maar lakes can be seen as well. Going clockwise: Mt Sugarloaf (credit: denisbin via Flickr), Mt Elephant (credit: Mattinbgn via Wikimedia), Red Rock Lookout (credit: Sean O’Brien via Wikimedia)

 

Crater lakes leave an explosive impression!

Often occurring close to these scoria cones are maar crater lakes. They form when magma rising from within the earth encounters groundwater, causing enormous explosive eruptions of steam and lava. The huge hole left behind forms the lake, and the ejecta rains down and forms scoria cones. Famous maars that are a part of the Newer Volcanics Province include Lake Bullen-Merri, Lake Gnotuk and Lake Purrumbete.

 

Surviving through cultural memory

The most famous maar lake in Australia is also a part of the Province. The Blue Lake of Mt Gambier, in South Australia, erupted as little as 6000 years ago. This is so recent that many believe that the actual event is still remembered today.

There are several aboriginal stories from the region that bear remarkable similarities to the events that must have transpired. The stories have been passed down orally for thousands of years. They detail the earth rumbling, cracking and heating, the air filling with dust, and ear-shattering shrieks. Interpreted by them to be the works of the Rainbow Serpent and other folkloric characters, it could also very well be an eyewitness account of the end of Australian volcanism.

 

Future volcanic eruptions: should I be worried?

After all this talk about volcanoes and explosions, some of you may be worried. If these eruptions have been occurring for millions of years, and only stopped a couple of thousand years ago, what’s the guarantee that they won’t resume in the future? Well, the short answer is: there isn’t one. But reassuringly, volcanism in Victoria seems to only occur cyclically every 25000 years or so.  So if the volcanoes were to return, it definitely wouldn’t be our (or even our great-great-grandchildren’s) problem.

 

The Newer Volcanics Province has shaped Victoria in uncountable ways: literally in the formation of our landscape, historically in the bluestone of our buildings, and culturally in the Aboriginal mythos.  So the next time you visit an aboriginal cultural centre, or any of Melbourne’s historical sites or even if you decide to take a break from the city to explore the surrounding countryside, keep on the lookout for these links to Victoria’s past.


DNA size to scale, the biggest instruction set ever written

Let’s say we can print your DNA in a book, how many pages should it have? Fortunately for us, The Human Code Foundation literally printed a human genome, which is the entire collection of DNA a living thing has, and this resulted in 175 volumes of 1,600 pages each! The enormous amount of information that defines a living organism is stored in these DNA molecules.

Not surprised? Well now consider this, that collection of books is the amount of information we can find in a single cell when it contains a unique copy of the code, also most of our cells include twice this amount and we are made of trillions of cells!

An even more interesting question might be: How cells manage to store so much in such a small space?
Instead of just giving you numbers like the length of DNA molecules inside a single cell, or the diameter of the nucleus, which is the inner compartment in which cells store DNA, allow me to picture the proportion between the size of both, DNA molecules and the nucleus, in terms of objects we are more familiar with.
First, consider that we are about to use as reference the equivalent of two copies of the entire Human Code books collection mentioned above because this is the amount of information present in most of our cells. Actually, if we could put all these 46 DNA molecules one next to each other as a stretched line it should reach 2 meters in length! On the other hand, the diameter of a nucleus is equivalent to 0.00001 meters, see where we are going?

Now let’s use our imagination:
If a mandarin orange represents the nucleus of a cell and the 46 DNA molecules inside it are represented as silk fibres, then the resulting length of putting the 46 fibres next to each other as a stretched line should reach 16 kilometres, which is longer than the depth of the Mariana Trench, the deepest spot on Earth’s oceans. Take a moment to picture that in your mind, you swimming at that point, and all the distance between you and the bottom of the ocean … inside a delicious mandarin orange!

 

Location of the Mariana Trench. Image by Kmusser on Wikimedia Commons.

To be fair the width of the fibres are also important and above we represented them as silk fibres following the same proportion considering the mandarin orange as a reference to a human cell nucleus. Also, the width of a silk fibre is slightly below the smallest object visible to the naked eye but still, I am sure you can better feel the dimension of the question we did before: How cells manage to store so much in such a small space?
As you might expect, a complex packaging system is part of the answer and the key idea behind it is that it shows several levels of folding. A group of auxiliary proteins called histones play a central role and the resulting DNA-protein structure is known as chromatin. Let’s take a closer look.

Electron micrograph of loosened chromatin. Image by Chris Woodcock, derivative work made by Gouttegd on Wikimedia Commons.

In the image only the first packaging level is visible: the nucleosome. These units, seen as black dots (black arrowheads), are made by histones and the DNA, seen as lines between the dots (white arrowheads), wraps around each unit almost two times. From here some sections of chromatin get more tightened as the fibre made of nucleosomes coils in the second level of packaging: the 30-nano meter fibre. Yes, most of the names in biology are as original as this one.
Additional levels of packaging arise when the cell enters division, but that is a story for another day. More research is needed, as new discoveries always come up with more questions.


You are what you eat

The link between diet and overall health is obvious, but have you ever wondered how your diet can affect your mental health?  Well, recent evidence suggests that a person’s diet can do just that.

Nutritional psychiatry is aimed to help target mental health problems. It does this by looking at the relationship between mental health and food. While it seems obvious that food could impact all aspects of health, nutritional psychiatry is a new field.

How are food and mental health related? 

Research has shown that the gut is linked to mental health and mood. Serotonin, a molecule used to regulate mood, has 95% of its production in the human gastrointestinal tract. This means serotonin effects both food digestion and absorption but can also affect a person’s mood.

Studies have shown that specific food groups can have a negative effect on mental health. For example, diets high in carbohydrates can lead to depression as well as diets with a lot of processed sugar.

Why do we care? 

According to the World Health Organization, depression is the most common cause of disability around the world. What is even more surprising is that depression is predicted to be the second most common cause of death by 2020.

Depression and mental health problems are on the rise. Image by Ian Espinosa on Unsplash.

Treatment should be the main focus, but medications used to treat depression are often not effective. A professor named David Healy found that in 29 clinical trials using antidepressant medications in young people, drugs were often ineffective or subjects continued to feel suicidal.

Another issue is that antidepressant medications can create dependency. If a patient stops taking them, they can experience symptoms of withdrawal. And without medication, behaviors that were decreased by medication can come back.

Because medication can sometimes be unreliable, treating the body with a better diet might be an additional therapy to consider. Eating lots of fruit, vegetables and protein foods can help reduce depression symptoms.

Improving mood with healthy food. Image by VIBE 105 on Flickr.

Nutritional supplements could be more advantageous for improving mental health than medication. For example, a study using magnesium citrate in depressed patients alleviated depressive and anxiety symptoms. There is also evidence for omega-3 fatty acids in treating mood disorders. However, research suggests that these supplements can’t be used alone for treatment. So, there needs to be a focus on if taking supplements in combination with other therapies can help.

Hope for the future?

There is so much research about the negative effects of food on a person’s overall health. Sometimes it seems that there is less focus on how food improves our health. This is what makes nutritional psychiatry exciting. It is looking at how food can change mental health for the better.

But there is more work to be done. Studies should be looking at whether changing a person’s diet could completely replace the effects of medication. Or whether diet and medication when together are better at treating mental health problems. These questions need to be asked.

Food and pills to better health. Image from Justin Doyle on Flickr.

We should also develop studies to examine diet and age. Based on their age, people could have different responses to diet-based interventions.

The field could be a real game changer in mental health. It would be great if we could not have to take pills to feel better. We could just change what we eat.

 

 

 


UNPOPULAR OPINION: Coffee isn’t all it’s cracked up to be.

 

Coffee – is it all that great? Image Credit: Nathan Dumlao, Unsplash 

Now, I understand from the headline alone that I’ve already got most of you offside. Recent studies show 33% of young Australians need a coffee to survive the day, and 84% buy at least one coffee a week.

But the truth? I just can’t stand the stuff. No amount of sugar, milk or weird-hipster-influenced flavour combinations will make me like these cups of scalding, bitter liquid.

People look at me like I’m crazy when I say this. Who knows, maybe I am. But I’ve got science on my side – caffeine (and, by extension, coffee) isn’t all its cracked up to be.

The science:

Throughout the day, our most basic body functions are fuelled by a molecule called ATP (adenosine tri-phosphate, for those playing along at home). I like to think of this little guy as the petrol of the body, providing the energy for pretty much everything we do – from large scale movement down to chemical reactions that even the most powerful microscopes can’t see.

After we use ATP it gets broken down, and one of the things we get left with is a chemical called adenosine. By binding to specialised sensors in the brain, adenosine gradually increases our level of tiredness as the day goes on, until eventually, we fall asleep. The process is beautiful in its simplicity: the more energy you use throughout the day, the more tired you get.

That is, until caffeine comes along. 

You see, caffeine’s a bit of a sneaky operator. It binds to the same sensors in the brain as adenosine, but has the complete opposite effect. It keeps you awake – wide awake – for the 8 hours until it gets broken down.

But sleep isn’t that important, right?

Wrong.

Look, I’m not going to pretend that because I don’t drink coffee I have a functional sleep pattern. I too am a perpetrator of the “just one more episode/video/anything-except-sleep” culture that’s rendered many of us uni students more nocturnal than diurnal.

But the fact of the matter is, as humans, we need 7-9 hours of sleep to function at our peak. Whether or not we get that by choice is one thing, but for those who drink coffee in the afternoon or evening, that amount of sleep is often a physiological impossibility.

Plus, there’s that whole coffee-hangover thing.

Don’t get me wrong: I get why people drink coffee (at least, I think I do). Sometimes you just need something to make you feel awake. The trade-off, however, is the ‘hangover’ you get when it wears off.

You see, the whole time caffeine is bound to the sensors in your brain, adenosine sits there waiting for it to leave. And when it does, all the adenosine you’ve accumulated throughout the day floods the receptors in the brain. The result? A tsunami of fatigue that hits you right when you need it least.

So, you’ve made it to the end of my manifesto against coffee.

To those like me who can’t stand the stuff: congratulations! We’ve had our voices heard.

To the coffee-drinkers: I don’t expect you to stop drinking it on the basis of anything I’ve had to say (really, I don’t). Spend your $5 on a broccoli latte if you want. Just know that my $5 is going towards some smashed-avo instead.


Cane Toads: a Toxic Relationship with Australian Fauna

Ahh the cane toad, a name that strikes horror in the hearts of Northern Queensland locals and environmentalists alike. This pest species has been a troublesome addition to the Australian landscape, causing the dramatic decline of several native species. Many share the general feelings of distaste for these annoying amphibians, but how did this invasive species arrive in Australia in the first place? And what’s all the fuss really about?

Due to the high abundance of cane toads up north, Port Douglas locals have established creative uses for these toads within their community. Image credit: author’s own

A Horrible History

Local to South and Central America, cane toads (Rhinella marina) were thought to be the miraculous answer to an economic crisis in the sugar cane industry. Many believed that the cane toad was the perfect biological control against agricultural pests (namely beetles) ravaging through plantations.

After hearing of the cane toad’s great success in reducing beetle populations in Puerto Rico in the early 20th century, Australia’s interest was piqued. After all, Australia had already seen just how effective biological controls can be, having introduced Cactoblastis cactorum, a moth native to Argentina, to prey upon the wildly out of control prickly-pear cactus, a resounding victory. In short, using biological controls was very on-trend at this point in history.

In 1935, 102 toads were delivered from Hawaii to Far North Queensland, where they were bred in captivity. Two months later, 2,400 were released into the cane fields. With the toads on the loose, it was only a matter of time before the beetle crisis was a thing of the past… or so the would-be saviours of the plantations thought.

The only trouble: they were terrible at their job! The cane toads were released to target greyback cane beetles. However, in hindsight, this was a poor solution for a couple of reasons. Let’s count those reasons, shall we?

  1. Greyback cane beetles feed in the top canopy of the sugar cane stalks, while cane toads tend to dwell on the ground below, not particularly known for their climbing or flying abilities.
  2. Greyback beetles are typically diurnal, meaning they like to be out and about during the day, whilst Cane toads are nocturnal, active at night.

These two species seem to have very different ecological niches; they were just never supposed to meet!

The Situation Toaday

Fast-forward 83 years: Cane toads have spread approximately 1 million km2 across parts of Queensland, New South Wales, and the Northern Territory, continuing their invasion West at approximately 40-60 km per year. From those 2,400 toads released back in the thirties, there is now a whopping 200 million! Yes, you read that right! It is safe to say they have well and truly settled in here in Australia. So why is this an issue again?

Rhinella marina: a particular pesky pest species. Image credit: Geoff Gallice via Wikimedia Commons

A Worthy Competitor

Firstly, these guys are incredible generalists; they aren’t fussy at all. They can occupy a HUGE range of habitat types as seen from their wide distribution, as long as they have enough moisture to keep themselves happy.

In addition to their habitat adaptability, cane toads will eat pretty much ANYTHING (as long as it can fit in their mouths). From other amphibians and tadpoles, to reptiles, small mammals, snails, insects, and even human food! Many pet owners have also caught toads red-handed stealing their pets’ food! Sadly, many native (and sometimes threatened) species become the cane toad’s dinner – toads just don’t seem to be as concerned about protecting endangered species as we are!

The generalistic nature of their lifestyle means cane toads are fierce competitors in the wild, out-competing many native species for food and breeding sites. Speaking of breeding, the females can lay up to 30,000 eggs in one brood, leaving native frogs wanting. Try out-competing that!

Oh, and did I mention that they’re poisonous? These tough toads produce poison not only in their adult form, but across the entire lifespan;  from egg to tadpole to toadlet to fully fledged adult toad. Adults exude their bufo toxins from glands on their shoulders when threatened, so that any hopeful predators quickly learn not to mess with this toad. These toxins are a death sentence for many native animals, acting on cardiac tissue and the nervous system, causing paralysis and death.

Hope is on the way!

Happily, there is new research surfacing, indicating that many animals are now adapting to having cane toads as their neighbours. Some are learning not to eat them, others have learned to flip them over and only eat their bellies, avoiding the poison glands. One study has discovered a correlation between snakes that are vulnerable to cane toads, and a reduction in gape size. This phenomenon has been suggested to be a result of natural selection favouring snakes that don’t have large enough mouths to swallow these poisonous pests.

Thankfully, many ecologists are concentrating their efforts on controlling the cane toad situation in Australia, mapping future distributions and forming plans of attack. But that doesn’t mean the cause doesn’t need more help! If you want to take part in citizen surveillance next time you find yourself up north, you can map your toad spottings on ToadScan, a sub-program of FeralScan, an organisation backed by the NSW government to combine government, research and community efforts to addressing Australia’s pest issues. This resource also has some great information on how to spot a cane toad and more about their fascinating biology.

Better hop to it!


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