Honestly!, You cant trust anybody with your valuables these days!
It seems that lake Atitlan has had enough of the terrible treatment that it gets by the people that live around it. Just six months ago, I swam across the lake. It took me a couple of hours and I swallowed my share of water but it was no problem then. Likewise, every day there were dozens of local women washing their clothes, children and them selves in the lake, every day.
But, not now... There is not a single person swimming or washing, and the lake is full of a stinking green slimy filamentous algae (actually, its a cyanobacteria... but algae is near enough).
But this has been coming for a long time, and it was obvious to me when I first saw the lake two years ago... I just didnt expect to see such a dramatic change so quickly.
... Refer back to my blog post of "A Lake with Problems" from April this year.
What happened?
Which is to say, Why has it changed suddenly... Why is it full of algae now, in a way that has never happened before but the people have not changed what they are doing for many years?
Some people say its because there was not very much rain in the wet season this year.
Some say its due to Global warming and the lake temperature has risen just enough.
Some say the lake pH has changed
Some say, God has decided it should happen...
etc. etc. etc.
Well, in my opinion, it is without doubt because of a combination of many things, but I am sure there has been a combined change in the lake environment of about 10% or more over the last year.
I believe that the most likely candidates are Light, Temperature, and Nutrients.
Before I go further, Ill justify my qualifications for my opinions and predictions.
They are amature qualifications but I think they are highly relevant.
Over the past ten years , I have personally spent somewhere between 10 and 20 thousand dollars on experimenting with a bio-system with a volume of about 500 litres of water...
In layman's terms, I have been keeping a marine aquarium!
Further; I was keeping a miniature version of one of the most complex bio-sytems on the planet, and I kept it in a unique way. It was a "reef system" which means that it had many many live corals and shrimp and crabs and fish... and basically everything in it.
Now, lots of people keep these systems and lots of them are far prettier and nicer and more densely populated than mine was... But, I was the only person I know that kept the system in such a "low-tech" and low maintenance way. Most people keep their systems going by feeding their tanks lots and lots of specialist foods and chemicals... and consequently they also have lots of specialist filtering equipment to get all the waste products from the food and chemicals back out of the tank.
My system however had No filtering, and I put almost no food into the tank... and it worked very well. But it took me ten years to be able to do it, and I had plenty of failures and lessons along the way, and lots of them looked EXACTLY like what is happening with this lake!!!.
So, I believe I know roughly what is going on, and I believe I know what happens next, and I believe I know how to fix it... Sadly, I also believe that even though things here can actually be fixed quite quickly....They wont be!
What we have here is a classic "algae bloom".
The alge in question are not new to the lake... Its been there for many years, but the conditions for it to "bloom" have not been right. The algae are single celled critters that can "breed " (by cell division) extremely quickly given the right conditions but if conditions are less "opportune", they breed only slowly and no one notices that they are there at all.
Once conditions are right however, and they start breeding fast, you get an avalanche effect and before you know it youve got more algae than you know what to do with - and then people notice!
The main things that the algae need to breed, are nutrients, light, and warmth... The more of each, the faster they breed.
So, this is why I say that there has been a change of about 10% (Though it may be as little as 2%).
Now, the nutrients in the lake have been there for years, Im sure of that... Though Im also sure that every year there are more, and I suspect that there is a a new and significant contributor somewhere in the lake catchement. The most likely candidates are a new and significant user of chemical fertilisers in the area, and the direct dumping of a significantly large supply of human waste into the lake (Like say from a town sewer system that they just decided to stop processing because the old plant was small and old and didnt make any difference anyway...etc)
Light... Well, this year there was apparently far less rain in the rainy season (climate change or whatever). This probably also means that there was far more sunlight for the last couple of months and that can make a huge difference. On my aquarium, I had experiences where the system was healthy and stable, and I just replaced an aging light bulb with a new one. Two weeks later I had a bloom like you would not believe... The new light was producing about 10% more light and it was enough to tip the scales!
Warmth... Well, the lake is always quite warm, so I dont think this one is a big change, but...
The rains that fall here are very cold. And the deep water in the lake is very cold. If there has been less cold rain, causing less river flow that mixes the surface and deeper waters then I can see that we may have a degree C or more of temperature difference than is usual in the top layer of the lake... and that could definitely do the damage.
So, thats what I think is happening. Now, for what I think will happen next!
With my aquarium, Algae blooms are almost always "a very bad experience". Once thay start, there is not much you can do till the system has got its self back under control.
First the algae starts to show up. Then it starts to smother the corals... Takes the light and grows on the rock... Then the corals die and release nutrients and toxins in the water... which kills the shrimp and crabs... which releases more nutrients and toxins... which kills the fish... which all releases more nutrients into the water and grows more algae.... In my experience, you lose the "weaker" elements throughout the entire system ... between 30% and 70% of them!!!
And it matters little if you try getting as much of the algae out of the system as possible as soon as you see it... Once its happening, you are just "along for the ride" so to speak.
Now, for the lake, I actually dont see this as being too terribly bad.
Thats because its been a corrupted system for many years. Any native fish have long since been replaced by introduced Perch and Black Bass (Maybe there are still a few natives in there but if so they are really quite tough critters). These introduced fish are very hardy, fast breeders, and easily reintroduced if you have to. There are some mid-sized crabs here, and they may be native, but I suspect if they have survived in the pollution for this long, that they will be OK.
So, for the moment, we have algae... And there is a lot of it... And it stinks and is not nice to swim or wash in .... and I suspect (though am not sure) that soon there could well be a "die-off" of a bunch of the fish in the lake, but not all... but its really probably only going to badly effect the Humans on the lake..... And very well deserved that is too !!
What I dont know is if this bloom will remain long term, or if it will dissipate in the next month or so as the seasons of the lake change and conditions change in an annual cycle.
But, I'll make this prediction...
The lake will continue to turn green (or will stay green) until the people living around the lake "turn green" instead!
Which is to say, that this problem will absolutely not go away until all the people that live within the lake catchment change the way they live to being significantly more environmentally responsible!
Next post I will describe how I think the "problem" can be solved - quite quickly actually.
But, not now... There is not a single person swimming or washing, and the lake is full of a stinking green slimy filamentous algae (actually, its a cyanobacteria... but algae is near enough).
But this has been coming for a long time, and it was obvious to me when I first saw the lake two years ago... I just didnt expect to see such a dramatic change so quickly.
... Refer back to my blog post of "A Lake with Problems" from April this year.
What happened?
Which is to say, Why has it changed suddenly... Why is it full of algae now, in a way that has never happened before but the people have not changed what they are doing for many years?
Some people say its because there was not very much rain in the wet season this year.
Some say its due to Global warming and the lake temperature has risen just enough.
Some say the lake pH has changed
Some say, God has decided it should happen...
etc. etc. etc.
Well, in my opinion, it is without doubt because of a combination of many things, but I am sure there has been a combined change in the lake environment of about 10% or more over the last year.
I believe that the most likely candidates are Light, Temperature, and Nutrients.
Before I go further, Ill justify my qualifications for my opinions and predictions.
They are amature qualifications but I think they are highly relevant.
Over the past ten years , I have personally spent somewhere between 10 and 20 thousand dollars on experimenting with a bio-system with a volume of about 500 litres of water...
In layman's terms, I have been keeping a marine aquarium!
Further; I was keeping a miniature version of one of the most complex bio-sytems on the planet, and I kept it in a unique way. It was a "reef system" which means that it had many many live corals and shrimp and crabs and fish... and basically everything in it.
Now, lots of people keep these systems and lots of them are far prettier and nicer and more densely populated than mine was... But, I was the only person I know that kept the system in such a "low-tech" and low maintenance way. Most people keep their systems going by feeding their tanks lots and lots of specialist foods and chemicals... and consequently they also have lots of specialist filtering equipment to get all the waste products from the food and chemicals back out of the tank.
My system however had No filtering, and I put almost no food into the tank... and it worked very well. But it took me ten years to be able to do it, and I had plenty of failures and lessons along the way, and lots of them looked EXACTLY like what is happening with this lake!!!.
So, I believe I know roughly what is going on, and I believe I know what happens next, and I believe I know how to fix it... Sadly, I also believe that even though things here can actually be fixed quite quickly....They wont be!
What we have here is a classic "algae bloom".
The alge in question are not new to the lake... Its been there for many years, but the conditions for it to "bloom" have not been right. The algae are single celled critters that can "breed " (by cell division) extremely quickly given the right conditions but if conditions are less "opportune", they breed only slowly and no one notices that they are there at all.
Once conditions are right however, and they start breeding fast, you get an avalanche effect and before you know it youve got more algae than you know what to do with - and then people notice!
The main things that the algae need to breed, are nutrients, light, and warmth... The more of each, the faster they breed.
So, this is why I say that there has been a change of about 10% (Though it may be as little as 2%).
Now, the nutrients in the lake have been there for years, Im sure of that... Though Im also sure that every year there are more, and I suspect that there is a a new and significant contributor somewhere in the lake catchement. The most likely candidates are a new and significant user of chemical fertilisers in the area, and the direct dumping of a significantly large supply of human waste into the lake (Like say from a town sewer system that they just decided to stop processing because the old plant was small and old and didnt make any difference anyway...etc)
Light... Well, this year there was apparently far less rain in the rainy season (climate change or whatever). This probably also means that there was far more sunlight for the last couple of months and that can make a huge difference. On my aquarium, I had experiences where the system was healthy and stable, and I just replaced an aging light bulb with a new one. Two weeks later I had a bloom like you would not believe... The new light was producing about 10% more light and it was enough to tip the scales!
Warmth... Well, the lake is always quite warm, so I dont think this one is a big change, but...
The rains that fall here are very cold. And the deep water in the lake is very cold. If there has been less cold rain, causing less river flow that mixes the surface and deeper waters then I can see that we may have a degree C or more of temperature difference than is usual in the top layer of the lake... and that could definitely do the damage.
So, thats what I think is happening. Now, for what I think will happen next!
With my aquarium, Algae blooms are almost always "a very bad experience". Once thay start, there is not much you can do till the system has got its self back under control.
First the algae starts to show up. Then it starts to smother the corals... Takes the light and grows on the rock... Then the corals die and release nutrients and toxins in the water... which kills the shrimp and crabs... which releases more nutrients and toxins... which kills the fish... which all releases more nutrients into the water and grows more algae.... In my experience, you lose the "weaker" elements throughout the entire system ... between 30% and 70% of them!!!
And it matters little if you try getting as much of the algae out of the system as possible as soon as you see it... Once its happening, you are just "along for the ride" so to speak.
Now, for the lake, I actually dont see this as being too terribly bad.
Thats because its been a corrupted system for many years. Any native fish have long since been replaced by introduced Perch and Black Bass (Maybe there are still a few natives in there but if so they are really quite tough critters). These introduced fish are very hardy, fast breeders, and easily reintroduced if you have to. There are some mid-sized crabs here, and they may be native, but I suspect if they have survived in the pollution for this long, that they will be OK.
So, for the moment, we have algae... And there is a lot of it... And it stinks and is not nice to swim or wash in .... and I suspect (though am not sure) that soon there could well be a "die-off" of a bunch of the fish in the lake, but not all... but its really probably only going to badly effect the Humans on the lake..... And very well deserved that is too !!
What I dont know is if this bloom will remain long term, or if it will dissipate in the next month or so as the seasons of the lake change and conditions change in an annual cycle.
But, I'll make this prediction...
The lake will continue to turn green (or will stay green) until the people living around the lake "turn green" instead!
Which is to say, that this problem will absolutely not go away until all the people that live within the lake catchment change the way they live to being significantly more environmentally responsible!
Next post I will describe how I think the "problem" can be solved - quite quickly actually.
