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Wednesday, February 10, 2016

Our homing muscovy duck

I find this hard to believe and completely unexplainable.  We have a female Muscovy duck who was hatched on our property.  She can just about fly well enough to go over a fence and land on our little pond in front of the house.  She laid 14 eggs under an old three wheeler motor cycle and hatched out all three of them.  Unfortunately she and her ducklings took to roosting at night (is roosting the right word for ducks??)  on our front porch.  What a mess in the morning.

Finally, when the babies were only a few weeks old we decided we had had enough.  We found a friendly farmer who raises ducks himself and has a nice big pond.  He lives 6km away across our main highway.  We crated up the ducks and he  came and got them in his pick up truck.  Two days later they were all back on the pond.

We phoned him and asked him if he had changed his mind.  Not at all, he said.  The ducks just disappeared.  Somehow, she had led her small ducklings on a 6km walk.  Somehow she knew where we were in relation to where she was and what direction to go to get home.  Somehow she didn't loose a single duckling.  I'm in awe of her.

Friday, January 1, 2016

The Greenhouse Effect

Much has been written about the green house effect without really explaining what it is and how it works.  I thought I would chip in my two cents worth and hopefully make it make more sense.  I'll start with the Sun which has the mother of all green house effects.  I use the sun because it is pure physics with no emotion involved.

So, the sun started out as a cloud of elements with by far the greatest part being hydrogen.  It collapsed under its own gravity and if you have every pumped up a bicycle tire, you know that the end where the hose is, warms up.  A diesel engine works on the same principle.  You compress the charge of air about 20 times and it becomes so hot that when you spray in the mist of diesel oil, the oil ignites.  Of course, with a cloud of gas heavy enough to produce the sun, the compression was far greater and the hydrogen at the middle was very hot and very compressed.  It was so hot and so compressed that the hydrogen atoms began to fuse together and produce Helium, releasing large quantities of energy as photons.

This heated up the nearby hydrogen which was hot enough to fuse but not compressed enough.  What is interesting for our example is that very hot hydrogen absorbs and re-emits the photons produced by the nuclear furnace.  And it reemits them  in all directions.  Some are sent back toward the core, some sideways and some toward the surface.  All are reabsorbed and reemitted over and over again.  It is variously estimated that for the energy of a photon to reach the surface of the sun it takes thousands of years.

Compare this to what the situation would be if each photon created in the centre of the sun was not absorbed by the overlying hydrogen.  As quickly as the energy was produced it would travel through the overlying hydrogen as leave the sun.  Remember that it only takes 8 minutes for the energy of the sun to reach us once it has reached the surface.  Instead of staying in the sun, the energy would leave the sun in about 1/2 X 8minutes / 93 X 60 = about three seconds.  The sun would cool down and probably the thermo-nuclear reaction at the centre would stop.

This what the green house effect is.  If you have the energy being radiated from the surface of a body travelling through its atmosphere into outer space with no restriction, the planet cools rapidly.  If on the other hand, some of the gasses in the atmosphere absorb and re-emit the energy coming from the planetary surface, the planet warms up.

On earth we have the same phenomenon but vastly reduced.  Green House gasses in the atmosphere including Carbon dioxide, water vapour and Methane absorb photons in the infra-red part of the spectrum and re-emit them in every direction.  More of these molecules then do the same.  This delays the escape of heat from the atmosphere and causes it to warm.  The greater the proportion of green house gasses in the atmosphere, the slower the energy absorbed from the sun is emitted.

Oh I forgot to mention something.  You probably know it anyway.  Except for a small portion of the UV radiation from the sun, the atmosphere, including the green house gasses is transparent to the wave lengths of electromagnetic radiation (light etc) that comes from the sun.  All this energy travels through the atmosphere to be absorbed or reflected by the surface it shines on.  The emission from the land is in the infra red which is absorbed and re-emitted by the green house gasses.

Sunday, December 27, 2015

How to get the beaver back

OK, so you have finally realized that at least a partial solution to your water problems is to get the beaver back in every stream or seep where he can possibly build a dam.  As you have realized, this will shift water from winter to summer (just as snow packs and glaciers used to do), recharge your water table, clean your water of sediment and nutrients, extend the life and effectiveness of your hydro-electric dams, allow these dams to provide more water and more electricity than they are doing now and so forth and so on.  So how do you get the beaver back in your catchments.

First, beavers need trees to build their dams.  Willows are great but any deciduous tree will do.  If you have such areas, capture and transfer some beavers to the area.  release them in lakes, artificially dammed ponds in streams or naturally deep parts of the stream. This will keep them happy as they explore the area and find a suitable location to build a dam.  However, the problem is, that much of the catchment will have been degraded and will be lacking a riparian zone of trees. Let's fix that and spend very little money doing it.

Tools you will need are a chain saw (If you don't like the noise, get an electric one that plugs directly into your specially installed alternator on your pick up truck) a pair of secheters (pruning sheers), a lopper (optional), an axe, a sledge hammer and 5 foot  steel bar sharpened on one end for each member of the crew.

Find a suitable deciduous tree such as a willow, poplar, aspen, cotton wood etc. Cut it down about waste height.  You want to leave a stump to coppice (grow from the stump).  Cut the entire tree all the way from the trunk to the small twigs into fore-arm length pieces.  The pruning sheers will come in handy for the smallest branches.

The larger logs you can leave as-is or split into four.  Sharpen the bottom end of all the larger pieces with your axe.  The thinner branches don't need sharpening.  Bundle all this into your pick up truck, cover with some wet sacks and head for your site.  You must do this when there is some moisture in the soil where you want to establish a beaver friendly riparian* zone.  This might be following a rain which has zoomed down to the sea, taking your top soil with it.  Nothing like watching your top soil disappear to inspire action.

*A a zone of trees and bushes on the side of a stream or river.

At the site, take the sharpened logs and quarter logs and pound them into the ground with your sledge hammer.  For the smaller branches, use your steel bar to punch a hole into the ground.  Try to make the hole about a third as deep as the length of your pieces of branch.  Drop in the branch and heel in.

For the intermediate diameter branches, if the ground is too hard to pound them in, the bar is also useful.  Punch a hole with your bar by ramming it a few times into the same hole,  rotating the top around to widen the hole at each punch.  It is now much easier to pound the medium diameter pieces into the ground.

If you have deer around the place and no wolves to keep them moving, you will have to find some way to keep them off of your new forest at least until it has a couple of years to grow.  Many of the deciduous trees grow at phenomenal rates if protected and soon will be too high for the dear to destroy.

Have fun and make sure to take 'before' and 'after' pictures and maybe write a blog with an article for each site you do.

And what happens if your introduced beavers threaten to flood your house or wash away a road.  Simple. You install a beaver deceiver.   Look them up on the net.  Here is how you make and install one model.

At a convenient place on the dam, remove branches.  Make a depression deep enough so that if the water only gets to that level, it won't cause damage to whatever you are trying to protect.

Get a piece of that corrugated pipe and lay it over the dam.  It must be long enough to reach the bottom of the pond and  to reach the stream on the down side of the dam.

Make up a U of scrap wood and pound it down into the beaver dam, upside down to hold the pipe in place.  The beavers will come and patch up the leak that evening and you don't want them to accidentally shift the pipe.

And the last step. Get some wire weld mesh of the type they use to reinforce concrete.  The bigger the holes the better but not large enough to let an adult beaver through.  Bend this mesh in a circle to make a cylinder and attach the ends together.  On one end, clip out a couple of cross ties all around.  A bolt cutter will do nicely.  You are going to pound this cylinder into the bottom of the pond with the clipped end down and removing the cross ties will allow you to push or pound the cylinder into the bottom of the pond.  The cylinder should extend above the level of the water or you could even put a top on it of mesh* and have it totally under water.  You, of course, are going to place this cylinder over the inner end of the pipe (almost forgot to mention that).

Now no matter what the beavers do, the water will remain at the level you have determined.

* Unprotected steel which is always immersed in water corrodes (rusts) very very slowly so putting a mesh lid on the cylinder and making sure it is completely submersed is not a bad idea.  Besides if you are in an area where the water freezes in the winter, if the top of the cylinder is below the bottom of the ice, it won't be shifted by ice movement.  A bit more work but worth the effort.  Iron corrodes most quickly just at the surface of the water.

Friday, October 9, 2015

The Chernoble Nature Reserve

Much surprise is exhibited by people when they realize that the no-go area around Chernobyl is turning into a wild life sanctuary.  We see such comments as "People are worse than nuclear fall out", referring to  the ever increasing richness and abundance of the flora and fauna in the area since people were excluded.  No argument there but it misses the basic biological point.

It is, of course true that if there is sufficient radiation, such as you might find inside one of the damaged Fukushima reactors and you stay in there long enough (not all that long), you will have your insides sun tanned and you will die.  Expressing it a bit more scientifically, the ionizing radiation wizzing through your body will disrupt so much of your physiology that your organism will cease to work.

Less radiation than a fatal dose will cause an increase in mutations and as we all know, most mutations decrease an organisms fitness to survive in his environment.  The effect on an individual organism, being hit with increased radiation is something of a lottery.  One individual may be made less fit, another not effected. A very very small proportion will have a mutation that will be advantageous.   And remember that we all live with a background level of radiation.  We get it from the sky as cosmic rays (heavy nuclei travelling at near relativistic speeds) and from radioactive elements in our soil.  To some extent our genetics is adapted to this radiation and there are mechanisms in our bodies that repair at least a portion of the copying errors.

Let's jump sideways for a moment.  Think of a pair of wolves.  The mother can easily have three pups (often many more) each  year and a wolf can easily live for 10 years.  Let's say 30 pups born to the couple over their life time.  Why are we not overrun by wolves.  A sparrow even more so.  A successful pair of sparrows can have 5 clutches with 5 young in each clutch in a single season.  Why are we not overrun by sparrows.  Even Humans are in this category.  A female human can have 10 babies in her lifetime and it wasn't so long ago that this was not unusual.  Thank heaven for contraception.  Without it, there would be standing room only.  Actually, the result would be starvation and pestilence.   

Most of the young of any animal  you care to mention die and in fact, in a stable population, on average, only two young from each pair of adults survive to carry on the species and they themselves give rise to two survivors.  Natural selection involves a lot of death.

So how does this relate to animals living in an area of increased radiation.  As long as the radiation isn't of such a level to "cook" any organism in the area, some offspring will be dealt a poor genetic hand, some not and natural selection will winnow out the ones with no aces.  The winnowing will simply occur a little earlier in a population with higher radiation  levels.  In the case of our wolf, in a "normal" radiation area, all the pups could well survive during the summer with most of them starving in the winter if their food source is not sufficient*.  In the high radiation area, it is likely that less of  the litter will survive initially and by and large, the same number of wolves will survive into the next spring in both cases.

*Which will  eventually occur at some point, if the wolf population is increasing.

Part of the reason we are so shocked is that if we humans were exposed to increased radiation, many of our children would be effected and we don't just shrug this off and let the maimed children die.  In the animal  world, without human interference, many young would die before they are born  We never see this.  Following hatching, many little sparrows fall. It may or may not meet his tender view but that is life (or rather natural selection).  The radiation has to be pretty severe to cause an actual decrease in population.  All animals produce a  massive excess of young, surplus to what what is needed to keep the population in a steady state.  As long as each pair leave more than two offspring who in turn produce more than two, the population grows.

This is clearly what has happened in Chernobyl.  The radiation is not sufficient to kill off enough young to decrease the population.  Quite the contrary. The animals have left more young than enough to grow the population 

We get tied up in misunderstanding when we try to apply a human perspective of the acceptableness of having many wonky children to the Animal situation in which only a very few of the progeny of any animal survive even without increased radiation.  Short of massive radiation levels, natural selection simply occurs a little earlier and as long as a few survive, the population will rise until it encounters the usual limiting factors, such as food supply at which point, the population will level out.

Note that in certain extreme areas with simplified assemblages of flora and fauna such as the Arctic, population boom and bust but still remain over all around the carrying capacity of their area.

Saturday, September 5, 2015

The Arctic Hurricane

The following is a hypothesis of why we have hurricanes in the Arctic and what lies in the future.  It is written as if it is well established fact.  It is not.  The reason I write it this way is that it is simply too annoying to read something that full of might be's and could be's.  Remember too, that while much of it is well established science, you only need one broken link in  a chain of argument to wreck the whole.  With that in mind, here goes.

Does it ever strike you as odd that we have hurricanes in the Arctic.  The one in 2012 was right on the border between a category 2 and 3, quite a powerful beast.  That was also the year of the greatest ice melt we have yet seen (up to 2015*). 

* 2016 could well be a different story all together with the massive El Nino we are experiencing.  We will see. (written Jan, 2016)

In the tropics the surface water must be at least 25 or 26C to create a hurricane. This is because, in the tropics, all the pressure gradient needed to create a hurricane is supplied by the "suck" in the middle.  Warm humid air rises, reaches the dew point, and the water vapour begins to condense, releasing latent heat of vaporization*.  This keeps the air buoyant and powers it upward.  Air is sucked along the surface of the ocean from all around to be sucked up and continue the process.  Only with the sea above about 26 degrees C is there enough water vapour in the air to sustain this process.

* It takes 2260 kj (kilojoules) of heat to vaporize one kg (kilogram) of water.  When water vapour condenses, it gives out this heat.

In the Arctic the surface water never gets this warm (so far) so to achieve the pressure gradient necessary to create a hurricane.  We need the suck in the middle to be augmented by a "blow" from outside.  This is created, especially in the fall when the land begins to rapidly cool down, cooling the air above it.  The ever more open Arctic ocean has accumulated heat in the top tens of meters while the land rapidly cools off. And in the Arctic, the land is all around the sea.  We have a push from almost all sides from this cooling, sinking air toward an ocean that  each year is accumulating more and more heat.

This is further exacerbated by Coriolis.  In the Northern hemisphere, Coriolis causes anything that is moving to veer to the right.  Since it is a function of how rapidly something moves closer to the centre of rotation (the earth's axis) it is more powerful in the Arctic than in the tropics.  Near the North Pole, a km of motion across the sea is nearly a km toward the centre.  However, just like water going down a plug hole, once the rotation starts it is powered by the gradient between the outside and the centre.

So what can we expect.  The Arctic ocean, as more of it becomes open ocean, is absorbing more and more heat from the sun.  Snow over top of ice is said to reflect about 90% of the incoming radiation back into space while open water absorbs 90% of the radiation.  Don't take the exact figures too seriously.  There are a number of whichever's involved but the basic principle holds.  At present, melting ice helps to keep the water cold as it absorbs latent heat of crystallization.*  We are seeing another one of these positive feed back mechanisms.  As the ice melts, it sets up the situation to melt even more ice.

* To melt a kg of ice takes 334kj.  Water, when it freezes gives out the same amount of heat per kg.  This will become important below.  Incidentally, to get a feel for how much heat this is, it is approximately enough heat to raise the same mass of water by 80 degrees.

So as the ocean becomes more an more ice free, we can expect more hurricanes, especially in the fall.  And we might, in the future, even see them following Sept 15 when the freeze up starts again.  Remember it is the gradient that creates hurricanes.  If we have got to the point where most of the Arctic is ice free then a lot of latent heat is released as the water freezes.  If this freeze doesn't start until the surrounding land is really cold and snow covered, a serious pressure gradient could be created.  Of course, as it freezes, sublimation replaces evaporation which is less vigorous.  If the land has really cooled down and air is falling over the land,  the gradient could still be enough to create a hurricane.  Other effects occur.

In the historical situation with the Arctic Ocean is pretty well covered with ice and snow, the air doesn't get heated from below as it does everywhere else on earth due to the absorption of heat from the sun.  It is an area of falling air which gives rise to a clockwise, high pressure weather system.  This clockwise rotating air pushes the water in the same direction giving rise to the clockwise rotating Beaufort Gyre to the North of Alaska.  Coriolis comes into play again as surface water rotating in this gyre veers toward the centre.  Fresh water is pouring into the ocean from surrounding rivers and this floating fresh water (and ice) accumulates in the gyre. The gyre is actually a little higher in the middle than on the outside.  The fresher water layer is a couple of hundred meters deep and holds an amount of fresh water equivalent to a couple of years  flow from the surrounding rivers. 

Now what happens if we start to have anti-clockwise (storm) patterns over the Arctic.  If sufficiently long and strong, the Beaufort gyre should reverse direction, flinging ice and surface fresher water outwards (Coriolis again) to be expelled through the Bering and Fram straights.  This creates  another positive feed back loop.

The surface water in the Arctic is colder than the deeper water.  It is only kept on the surface because of its lower salinity.  If we start to expel this surface layer, the deeper warmer water comes closer and closer to the surface.  The very storms which expel this fresher water from the arctic, create large waves which mix the layers.  This is especially so when the waves come into shallower water and internal waves between the layers break.

It would appear that in the coming years we should expect more and more hurricanes occurring in the arctic.  As the melting of the ice progresses, these hurricanes should occur earlier and earlier in the melt season.  It is also possible that they will continue into the beginning of the re-freezing season.  If their effect is to send more ice and fresh water into the Atlantic and Pacific, this will exacerbate the melting.

I wouldn't want to live in a coastal community on the shores of the Arctic Ocean.  I would be moving to higher ground.Increased storms with an increased fetch for the waves to build up will cause severe erosion of the coast.