A century of destruction: the death of the Murray Darling basin

In the 1870s, Victoria's second largest Port was not where most would place it today if asked to pinpoint it on a map. It was not Geelong, or Portland, nor was it in the sheltered Westernport Bay, or Port Welshpool on the Gippsland coast. It was 96 metres above sea level, and over 200 kilometres to the nearest sea at Port Phillip Bay. It was Echuca, on the Murray River, where a fleet of over a hundred paddle steamers navigated the river on a daily basis transporting wool and other agricultural produce, as well as manufactured goods between inland towns along the Murray and Darling rivers, and many of their tributaries.

By the dawn of the 20th century, much of this transport load had moved on to the railways, and though it had begun in the 1880s, irrigation with water drawn from both these rivers began in earnest. This opened up huge areas of the inland to farming, particularly for water hungry crops, orchards, and vineyards. And the flow of the largest river system in the country was gradually, but consistently reduced to a trickle. The once navigable river has all but dried up, and in most summers would be difficult to travel along in more than a kayak.

The effect of this drastically reduced water flow on the natural environment has obviously been immeasurable. And now, it seems that concerned scientists have given the river less than six months to live, before it becomes little more than a drain, carrying the run-off effluent from the farms that have profited from it for over a century.

It seems almost incomprehensible that such a dramatic tragedy could take place before the eyes of a population so supposedly concerned with the environment. But there it is. For once, the government is faced with a decision which is as straight forward as it has always been, though in this case probably much more obvious: economy vs environment.

In this particular case, at this time, the choice is either/or. The time for compromise has clearly passed, and if the river is to be saved, then massive amounts of water need to be released from facilities upstream. This water will cost money, and in no way do I expect the farmers who rely on it will wish to go without compensation.

But the clock is audibly ticking, and a lack of decision will ultimately be the final nail in the coffin for this once mighty river system.

Just the facts #3

Today's questions:

What is the line between artificial and natural?

and, in relation to tomato sauce:

At what point does a tomato cease to be a fruit?

In response to the first question, i would contend that "artificial" means that it has been constructed or manufactured by human beings, while natural means it may be found already existing in nature without human interference. What this means in actual fact is really a question of context. For example, a food product may claim it contains "no artificial colours or flavours", but obviously, it may be coloured or flavoured with "natural" agents. The same goes for artificial sweeteners, preservatives, and so on.

In this context, it usually means the difference between a naturally occurring chemical, which is extracted directly from a plant or animal, and a synthetic chemical, which is obtained by chemical reaction in a laboratory or factory. There is no guarantee that a naturally occurring chemical is any safer than a synthetic one, and some of the most toxic substances known to science come directly from natural sources. In fact, in certain cases, synthetic versions of chemicals may be safer than their "natural" alternatives, having potentially toxic, carcinogenic or mutagenic compounds removed or converted into harmless forms.

As for the second question, this requires a brief foray into botanical terminology. In botanical terms, a fruit is the seed of a plant, together with the ripened ovary. So, a grain of wheat is a fruit, as is a coconut, and at least part of what we call a Tomato. The tomato is formed when the ovules in a tomato flower are fertilised by pollen. The ovules are contained within an ovary, which swells after fertilisation to become the flesh of the tomato fruit. However, tomato sauce is usually made with only the fleshy parts of a tomato, known as the carpel, excluding the seeds. So in my opinion, a tomato ceases to be a fruit when it is de-seeded, as the seed is the defining characteristic of a fruit.

However, while this is a botanical explanation of when a tomato ceases to be a fruit, legally, in the United States at least, it ceased to be a fruit in 1893, as a result of a court ruling on tariffs covering fruit and vegetables. According to the US supreme court, the tomato is a vegetable.

Cerebrity of the Week #1: Andrew Merchant

These days it seems that much of the media is saturated with "celebrity news". Reports of births, deaths, marriages, affairs, and general gossip about people who, were they not so spotlighted by the media, would be otherwise relatively unimportant to the world at large. Actors, musicians, models, and people who are just obscenely rich may have no actual influence on the lives of anyone but for media reports flooding our senses on a daily basis. That politicians and increasingly other actual professions are now compelled by necessity to "market" themselves, their ideas, or their organisations in order to "compete" for attention is somewhat disturbing.

So, in my own small way, I have decided to award a weekly prize to the person who I feel has the most to offer the world on account of who they are, what they think, and what they have achieved. It is the reverse of celebrity in a way, as these faces may not be known to the masses, but in their own way, they have contributed more to the world than all the hotel heiresses, former game show hosts, reformed child actors, celebrity brothel keepers and other miscellaneous media spakfilla combined.

This week, in order to highlight the cumbersome-but-descriptively named (the Department of Agriculture, Fisheries and Forestry don't like acronyms, because it makes them look daffy) Science and Innovation Awards for Young People in Agriculture, Fisheries and Forestry entries for which close on July 14th, I wanted to name one of last years winners as cerebrity of the week. Please, put your virtual hands together for Andrew Merchant!



Andrew's project involved trying to figure out what cellular processes allow Australian tree species greater tolerance of their harsh environmental conditions. He hopes to use this information in order to breed tougher trees, more capable of withstanding future climatic extremes, and current marginal environments.

Congratulations, Andrew, for being the Survival of the Fittest Cerebrity of the Week, Number 1.

The benefits of climate change?

I was reading the other day on Science Daily about the positive effect of climate change on the range and population of a species of butterfly in Great Britain, the Brown Argus (left). The article stated that the butterfly had increased it's range over the last thirty years much further north than it had been previously known, all the way into Scotland.

The article then went on to explain how this extension of range had allowed the caterpillars of the butterfly to escape their usual parasites, which were not present in the more northerly habitat. Now obviously for the Brown Argus butterfly, this is largely a beneficial outcome, and as the geographic shift was allowed by warmer temperatures, at least in part due to climate change then surely this is a "benefit of climate change"?

I can't say I agree with the assessment of Science Daily that "some species benefit". If all species are affected by climate change, the likelihood of predicting the ecological impact of the changes is minimal. In this case, for example, removal of the natural predators of the butterfly also removes the selection pressure on the butterfly to resist them. This means that if interbreeding occurs between individuals from the new range and those from the old, those in the old range have an increased risk of being less fit for their environment. This kind of genetic pollution is at least possible, and at worst could result in the species becoming endangered, or even extinct in it's original range.

More disturbing a prospect, though, is the effect of the caterpillars in their new environments. With no predation, caterpillar numbers could reach much larger numbers than in their old feeding grounds, and could have adverse effects on natural vegetation, or even agricultural crops. The caterpillars may out-compete the local species of larvae, which could lead to their predators being reduced in number. This in turn could lead to serious implications in boom and bust cycles of caterpillars, and their effects on local vegetation.

There is simply no way anyone can claim that an increase in population of any single species is a benefit, no matter what it's cause. All change may be either good or bad, but without appropriate analysis, there is no way to predict which.

Just the facts #2

Okay, so, in response to elaine's question from two days ago, when she asked

"can you please tell me if there are cells that do not contain DNA? If yes, please give me some examples. Also if yes, what is the difference between DNA-less cells and cells with DNA as it what do they do differently and why do some have it and some don't (if it is known)."

The short answer is yes... and no.

In mammals, the red blood cells contain no nucleus or organelles, so contain no DNA. Red Blood cells are primarily for carrying oxygen throughout the body, and removing carbon dioxide from tissues, and are specialised for this function by having little in the way of cellular "baggage" in order to optimise their efficiency for the task. This also ensures the cell itself uses none of the oxygen it carries. This means they are incapable of self repair or cell division. Red blood cells are constructed in specialised regions of an animal body, for example, in the bone marrow, or in the liver in embryos. They may be stored to some extent in the spleen for periods when rapid physical activity requires larger volumes of oxygen to be delivered rapidly to muscle tissues.


Human Red Blood Cells

In plant tissues, the xylem cells, those carrying water and nutrients from the roots to other tissues, completely lack a protoplast at maturity. They also contain no DNA, but are effectively non-living tissues, and comprise the woody parts of plants. Again, this is to increase the efficiency of their primary function, that of conducting water through the plant. They are also incapable of self repair or cell division as a result.

Bacteria contain DNA, but unlike the linear chromosomes of multi-cellular organisms, it is arranged in a ring like structure. Certain organelles of plants, such as chloroplasts; and animals, such as mitochondria; contain their own DNA. Because such organelles are usually inherited directly form the female parent, and because their rate of mutation is very low, this allows certain genetic testing to gauge the rate of evolution between different species.


Bacteria

Viruses are complex organic entities, and though not classified as living, may also contain DNA, or in some cases RNA. They differ from living organisms in that they lack the ability to reproduce on their own, and require a host in order to multiply. Viral infections cause the most trouble to other organisms when they reduce the rate of cellular processes by hijacking the machinery and energy of a cell to make copies of the virus.


An "artificial" bacteriophage virus (electron micrograph)

Just the facts #1

I suppose this will be an ongoing series, but it was precipitated by a query from a friend via Facebook the other day, his question was as follows:

Is DNA a physical thing? For example, those double-helix pictures you see, is DNA a physical thing that actually looks like that, or is that just a representation of DNA?

If DNA is a physical, tangible object, where does it exist? Does it exist IN cells? Around cells? Between cells?

It surprised me that such basic understanding of the foundation of biology was lacking in a relatively well educated adult, but I answered, nonetheless. And as an attempt to make people sound more informed in public debate (that is, debate in public bars of hotels) on topics such as "Genetic Engineering" and such topics, I will repeat and expand my answer here.

First of all, yes, DNA is a physical structure. It denotes the molecule Deoxyribo-Nucleic Acid, a very scientific sounding name which describes its

a) chemical components and structure: deoxyribo = deoxygenated ribose (a type of sugar)

b) location: nucleic = from the nucleus

c) chemical properties: acid = pH below 7.0

The molecule itself consists of a phosphate/sugar "backbone" with a series of bases attached, of which there are four: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). Due to difference in electrical charge between the bases, they pair up, A with T, and G with C. This pairing means the molecule rarely exists as a single strand, but is bound in a double helix a spiral shape, a section of which is shown at the top of this post. The backbone forms the sides of the ladder, while the basepairs form the rungs.

DNA is not visible to the naked eye, though if unravelled and laid in a straight line, a single stand of human DNA would be around three metres long. That's a lot of information to fit into every single cell of your body, so it is wound and twisted into an extremely compact form, known as a chromosome, so it can do so. This is how every cell is able to contain all the information required to replicate an entire organism, and is what makes cloning possible, not to mention basic ongoing maintenance that keeps the organism functioning.

Any questions?

It's the brain drain all over again

Submissions to the latest Australian Biosecurity and Quarantine review have lamented the continuing decline in qualified technical staff in important posts win the Australian Quarantine and Inspection Service (AQIS), and Biosecurity Australia (BA). The Australian Plant Pathology Society submission claims that both organisations have been guilty of appointing "customer service" oriented managers rather than candidates with technical know-how, and this may be impacting on effective decision and policy making in scientific matters.

This reflects a wider trend to customer focus in many local science, education and research organisations, that ultimately changes their direction, either subtly or drastically. An understanding of the science behind policy decisions is absolutely crucial in maintaining efficient Quarantine measures, and biosecurity protocols. But it is also necessary in fields such as education and general scientific research capacities. The people who can best interpret the guidelines for policy decisions are those who fully understand the science which sets their parameters, and the changes in scientific knowledge, or environmental conditions which may predict required alterations in those policies.

In the case of science, it may be that the customer is best served by someone qualified in the area of technical service, rather than just being possessed of people skills. This is compounded by the lack of young people training for these positions. CSIRO estimates 50% of Australia's diagnostic expertise will be lost in the next twenty years, due to the advancing age of current scientists in the workforce. The lack of trained pathologists and taxonomists in itself is actually dangerous, as an unidentified or mis-identified threat could spread to non-eradicable levels very rapidly, especially in the case of micro-organisms and invertebrates. At present, protection is often in the hands of unpaid, volunteer retirees called in for their expert advice.

Obviously this is tied in to the promotion of technical science as an educational pathway for young students, which should obviously be a priority for both State and Federal governments to pursue, and budget for. The cost of funding university places or creating scholarships and other incentives to attract and keep young scientists in technical positions in this country is a drop in the ocean compared to the potential loss of entire export industries due to a lack of local expertise.