Q&A: Yogas aquatic microbiology class 101
Hello Dr.Kevin,
Hope everything is going well for you. I must say, your post on
October 11th further enlightened me on how the eradicate
cyanobacteria in the pond. I admit it wasn’t an easy read for me, and to help
myself to better understand, I tried to break down the points you were
delivering (according to my understanding and limitations) and see the relation
between each point. Within some of the points I made, lead to some questions,
which I hope you can help me out with. The points are as follow:
1. Cyanobacteria will happen in certain times in ponds due to high
levels of nutrients within the bulk water. The problem will be difficult to
overcome when intervention is late.
2. Late intervention enables cyanobacteria to become independent
from nutrients from the bulk water.
3. The hobbyist is to blame for the high level of nutrients.
4. Cyanobacteria start to develop on surfaces where the bulk water
is high in nutrients.
5. Cyanobacteria spores end up where the flow is the slowest.
6. The Anoxic Filter’s first function is as a settlement chamber,
it is here where the spores and detritus should settle down.
7. The Biocenosis baskets within the anoxic filter function as
nutrient magnets/absorbers. Cyanobacteria will develop here and keep developing
until there are not enough nutrients left, and then they will start to die off.
8. To ensure spores do not settle in the pond, a good circulation
must be created
9. Good circulation within the pond, a good pre filter and
the taking out of nutrients by the BB’s would increase the pond’s ORP.
10. Limiting dissolved organic carbon by proper gas off and
avoid using alkalinity controllers.
11. Frequently rinse prefilter to reduce organics and
carbons.
Questions:
1.
Related to point No.2, if our pond has already become
infested by cyanobacteria, will an AFS still be able to solve the problem? If
yes, is it mainly because of the settling of spores in the AFS or a combination
of point No’s. 9,10 and11?
There is no way to stop cyanobacteria from infiltrating ones pond
because the spores can be brought in by many different ways, eventually every
pond will have a plague of it sooner or later and that’s just the way it is.
Containment is the key word here and without containment then everything in
your pond will get covered with it. The Anoxic Filtration System (AFS) does
just that; it will contain it to one location by design. The diffusion of water
going into the AFS serves many purposes and one of them is holding
cyanobacteria at bay until the filters bacteria can use the available foodstuff
that also feeds the cyanobacteria too. That’s why I recommend a good prefilter
to stop any organics that could become another foodsource for cyanobacteria to
feast on. Your AFS is still considered to be new or an immature filtration
system right now and the chemical and biological processes are still not
complete. There is a lot more going on than just the nitrogen cycle inside a
Biocenosis Baskets (BB) unlike other filters; ion exchange is one of them.
Other filters do this to some degree but then those processes are slowed down
or blocked altogether as time goes on but not so the AFS. AFS do not clog so
those ion exchange mediators never shutdown like conventional filtration
systems do. You will get more to this question as you read on to the next
questions.
2.
Related to point No.7, what causes
the depletion of nutrients? Is it the development of facultative bacteria
within the BB’s outnumbering the cyanobacteria for nutrients, proper gas off
(point No.10), competition between cyanobacteria, frequent rinsing (point No.11)
or do all the mentioned contribute and have roughly the same level of
contribution?
The nutrients you speak of are in organic and
nonorganic ion form and the BB’ s are trying to use whatever ions that come
their way inside the BB’s. But diffusion is slow and cyanobacteria growth is
very fast comparatively speaking. Once the AFS bacteria catch up to the amount
of available foodstuffs or insults that enters the baskets and pond then you
will have more efficient nutrient users that then will use the available carbon dioxide, nitrates, and phosphates. All these ions
unfortunately are a food for cyanobacteria too but now the bacteria inside the
BB’s are too competitive and the cyanobacteria dies out form the overabundance
of heterotrophic bacteria. Remember, we are talking about trillions of cells
that have to establish a BB and that will take time for those nutrient users to
compete with such a fast growing bacteria like cyanobacteria or purple
photosynthetic bacteria. Think of it this way: How can you compete with
something that can make its own food supply, to something that has to wait for
its food to come to them first.
When the weather gets cold like it does here in the
US, the heterotrophic bacteria go dormant until temperatures and food
availability gets back to normal once again. However, in early springtime when
temperatures start increasing very slowly and late autumn when the temperature
begins to drop once again the heterotrophic bacterium slows down, the cyanobacteria
now becomes more competitive and growth supersedes that of the heterotrophic
bacteria. It seem that the cyanobacteria is not affected by temperatures as
much as autotrophic and heterotrophic bacteria are. Better utilization of
available foodstuff! Forget about
autotrophic bacteria altogether because now it is almost useless because of
slower reproduction times becoming slower yet or stopping altogether. The BB’s
are making N2 and carbon dioxide still and that is what feeds the officious
cyanobacteria.
In your pond with the old filtration system like you
had also made carbon dioxide (CO2), nitrates, and phosphates. But the
bacteria’s utilization of such was not that good or made it as a byproduct and
all went back into solution once again without containment. These available
ions in solution now made everything in the pond an accessible holding ground
for the cyanobacteria to live, multiply and feed on.
Heterotrophic bacteria will have a shorter
reproduction time compared to autotrophic bacteria and therefore will out
compete that of the cyanobacteria if given the right environment to live on.
The AFS now provides that for then and since both bacteria use the same
foodstuff the competition is too great for the cyanobacteria and the
bacteria/cells eventually die or go dormant once again. This change of events
will keep happening year after year with the change of seasons.
If however
you maintain a 70F˚ temp all year-round in your pond and the cyanobacteria
comes back…then you’re doing something wrong with pond husbandry or overfeeding
to the point that your AFS is too small for your pollution input and you are
now overwhelming the filtration system with particulate organic carbon, organic
and inorganic constituents.
3.
Related to point No.10, from what I
recall, within the biocenosis baskets CO2 is produced, but carbons are also
produced in prefilter. So where is it best to gas off these carbons? Is it after
the prefilter but prior to the Anoxic Filter, after the anoxic filter but prior
to the prefilter (meaning waterfall and aeration in the pond) or both? For my
case where there are biocenosis baskets in chambers where the flow has not yet
been diffused, would it be okay to add aerations in those chambers to gas off
carbons? Would aeration have any effect on the anoxic zone within the
biocenosis baskets?
Carbon availability along with oxygen in the form of
ions is there in the BB’s and is used as an electron acceptor by the
heterotrophic bacteria. However, any excess is best to be gassed off in the
main pond by air, waterfalls or agitation the ponds surface.
Prefilter is
just that: Mechanical filters that need to be cleaned before bacteria can break
down the organic compounds and make more carbon to go back into solution. In
your case, adding air inside any chamber/s without the BB’s would gas off any
CO2 before the AFS, but this is not mandatory to do so. Once again this is also
a two edges sword and gassing off too much CO2 can affect pH and drive it up to
unacceptable levels without the CO2 buffering.
The AFS would not excise the available oxygen either
and all available oxygen or most of it would go to the main pond for your
animals. Cation: Do not use aeration in the AFS itself with the BB’s; you will
upset the diffusion process of slow water movement in a wider mass and will
disrupt the layering effect that's inside the AFS.
I look forward to your reply. One more thing, I’ve finally
decided to buy an ORP Monitor, “American Marine Pinpoint ORP Monitor”, it
should arrive by the first week of next month.
The Pinpoint ORP monitor is a good monitor; it’s too
bad you didn’t have one before your conversion to the AFS it would be nice to
see the comparison of the two filters.
Thank you Dr.Novak,
Best regards,
Yogas
To read more about cyanobacteria:
No comments:
Post a Comment