Excellent artiucle on decomposition of aquatic plant leaves in relation to bacteria

Tom Barr

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"Influence of Macrophyte Decomposition on Growth Rate and Community Structure of Okefenokee Swamp Bacterioplankton
Robert E. Murray,* and Robert E. Hodson
Institute of Ecology and Department of Microbiology, University of Georgia, Athens, Georgia 30602


ABSTRACT

Dissolved substances released during decomposition of the white water lily (Nymphaea odorata) can alter the growth rate of Okefenokee Swamp bacterioplankton. In microcosm experiments dissolved compounds released from senescent Nymphaea leaves caused a transient reduction in the abundance and activity of water column bacterioplankton, followed by a period of intense bacterial growth. Rates of [3H]thymidine incorporation and turnover of dissolved D-glucose were depressed by over 85%, 3 h after the addition of Nymphaea leachates to microcosms containing Okefenokee Swamp water. Bacterial activity subsequently recovered; after 20 h [3H]thymidine incorporation in leachate-treated microcosms was 10-fold greater than that in control microcosms. The recovery of activity was due to a shift in the composition of the bacterial population toward resistance to the inhibitory compounds present in Nymphaea leachates. Inhibitory compounds released during the decomposition of aquatic macrophytes thus act as selective agents which alter the community structure of the bacterial population with respect to leachate resistance. Soluble compounds derived from macrophyte decomposition influence the rate of bacterial secondary production and the availability of microbial biomass to microconsumers. "

click on the pdf for the full article:

Influence of Macrophyte Decomposition on Growth Rate and Community Structure of Okefenokee Swamp Bacterioplankton -- Murray and Hodson 51 (2): 293 -- Applied and Environmental Microbiology
 

Zain

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Apr 7, 2007
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Global Warming Impact?

Nymphaea leachates are known for possessing inhibitory compounds which serve as a source of resistance for the bacteria population. It may be fathomable that the leachates can be placed in other parts of the swamp, not necessarily just in habitat where a water-lily thrives, but additionally where other types of flora may reside and want to be protected. This may lead to an increase in microbial biomass to microconsumers, but after some time, this relationship may become mutually exclusive and independent of the other party involved.
 

Zain

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Apr 7, 2007
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How might the introduction of baceteriophages, such as pathogenic control agents, be possibly harmful to the root nodulation of other plants, which are necessary for normal growth? It is aware that in general such agents would help to improve the health of the plants, but are the risks of possibly destroying the foundation of a range of plants based on the layout of Okefenokee Swamp, worth the rewards of seeing a select group of plants grow and flourish, in terms of the addition of bacteria fighting substances, regardless of potency?
 

Evan DeFilippis

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Apr 9, 2007
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I was under the impression that there were different types of bacterioplankton-- such as autotrophic or saprotrophic-- what species are most effected by the decomposition of the lillies and what ecological consequences does this have?

Another question; after the intense period of growth by the bacterioplankton, is the increase ever offset by periods of decrease? Or will the bacterioplankton continue to grow in population until the sheer amount is overwhelming?

If the increase is never offset by a decrease will increases in bacterioplankton have adverse consequences?

Finally, what is the significance of the bacterioplankton in context of the swamp? Is the swamp the site of this scientific phenomena or have the findings been replicated elsewhere-- in areas that are not swamps?

-Evan.

P.S. Gatsby gets shot.
 

Tom Barr

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I've walked in it, swam in it as have many a grad student and researcher...........we ain't dead.

This is about decaying plant material, not limbs rotting off from some tropical fungus. Cameroon has some good diseases there.


Regards,
Tom Barr
 

Evan DeFilippis

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Apr 9, 2007
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I've walked in it, swam in it as have many a grad student and researcher...........we ain't dead.

This is about decaying plant material, not limbs rotting off from some tropical fungus. Cameroon has some good diseases there.

Perhaps the decaying plant material has consequences... I think ecological abstracts such as this are very interesting and are insightful for learning about procedures to deal with excessive bacteria in swamps.
 

2nd Period - 12

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Apr 10, 2007
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Nymphaea leachates are known for possessing inhibitory compounds which serve as a souce of resistance for the bacteria population. It may be fathomable that the leachates can be placed in other parts of the swamp, not necessarily just in habitat where a water-lily thrives, but additionally where other types of flora may reside and want to be protected. This may lead to an increase in microbrial biomass to microconsumers, but after some time, this relationship may become mutually exclusive and independent of the other party involved.
 

Austin

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Apr 10, 2007
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Global Warming?

Perhaps maybe global warming could be an issue with the Okefenokee Swamp. I mean put aside the issues of the polar ice caps melting, but instead consider the real effect that pollution and the "green house effect" is having on not just swamps, but the entire environment. It's likely that the pollution could be contributing to this issue?
 

Austin

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Apr 10, 2007
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Is it a single issue?

I agree that the dissolved substances released during the decomposition of the white water lily is altering the growth rate of the Okefenokee Swamp bacterioplankton. However, I see it more likely that this alteration is more of a result of a handful of chained together that result in a chain reaction, thus altering the swamp bacterioplankton. One cause for instance could be acid rain, as a result from the smog and pollution in the air. I don't know, it's just a theory, but what are your thoughts on this idea?
 

Tom Barr

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There is little population from smog etc in the area generally, farther north, this is the case. The acids are plenty low in the region due to tannins, pH's of 4-5 ranges are not uncommon.

Bacteria and fungi generally process waste faster if you increase the temps.
But in general, we will have more production/growth from wetland plants as the temps increase due to Global warming + more CO2. They are one of the few winners most likely if that was all that happened to them.

A trophic chain or a decompositional chain is a good way to think about it.
Each player has their role.

Regards,
Tom Barr
 
M

Michelle

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solution?

I think that we use pesticides to control this problem. There will be various factors that we need to consider before attempting to solve it, and I understand that there will be both pros and cons in dealing with this issue. However, this is something that will affect us all both directly and indirectly and thus we should carefully consider its effects and ways in which we can solve the problem.
 
M

Michelle

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What are some possible factors that the readers should take into account (other than the dissolved substances) that affect the growth of the Okefenokee Swamp? How will this affect each one of us personally?
 

2nd period-c

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Apr 11, 2007
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What are some possible factors that the readers should take into account (other than the dissolved substances) that affect the growth of the Okefenokee Swamp? How will this affect each one of us personally?


I think that we use pesticides to control this problem. There will be various factors that we need to consider before attempting to solve it, and I understand that there will be both pros and cons in dealing with this issue. However, this is something that will affect us all both directly and indirectly and thus we should carefully consider its effects and ways in which we can solve the problem.
 

Tom Barr

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2nd period-c;15897 said:
What are some possible factors that the readers should take into account (other than the dissolved substances) that affect the growth of the Okefenokee Swamp? How will this affect each one of us personally?

The role of carbon in the cycling, export/import/rates of growth.
Everything in wetlands is determined by the carbon.
Increased rates of nutrient cycling will affect different species at different rates, I think for now, the swamp is going to be pretty hard to alter, but if you switch the hydrology, then you will have massive issues that cannot be rectified.
and that's often what the humans like to do...........

I think that we use pesticides to control this problem. There will be various factors that we need to consider before attempting to solve it, and I understand that there will be both pros and cons in dealing with this issue. However, this is something that will affect us all both directly and indirectly and thus we should carefully consider its effects and ways in which we can solve the problem.

I'm not so sure pesticides are really that large of an issue in this system. Out here in CA, we have far far more pesticides in the wetlands/water due to massive agriculture year round+ very little remaining wetlands(4% left since 1850).

I've suggested adding wetland type buffer zones that mitigate agricultural run off, this reduces the levels of nutrients by about 40-80% with minimal land use, public funding for it, public support, increased biodiversity and reclaimation.

Farmers have less issues dealing with their runoff obligations, get better yields as they now have a source of natural pollinators and pest, so the selection is not as great (so you get less resistance to herbicides/pesticides with proper management) and have nicer areas around their land which increases land values, reduces dust, and saves soil(a lot), reduces erosion, reduces aquatic weeds, recreational value.

This can be done at the massive scale, one study modeled the Mississippi River and conservatively estimated a 40% reduction if such buffer zones where added. This would cost about 4 Billions dollars and take 10-12 years. Not cheap, but given the lost in Gulf fishing, a drop in the bucket............and it would improve many things up and down the river, remember that 1993 flood?

It would not have been remotely close to that bad if these same buffers where added. Wetlands buffer flooding and soil lost.

I think better management of the environment and horticulture interface is the way to go here.

That way we nab back some of those lost wetlands, improve the water quality and keep the farmers/industry happier.

Using the rates of decomposition as an indicator of system health is a good predictor for most wetlands.


Regards,
Tom Barr
 

rahim

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Apr 11, 2007
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Although pesticides may be a desirable way to control, we must also evaluate the consequences such action might have before we take any sort of action. As it already is, the inhibitory compounds released during the decomposition of aquatic macrophytes act as selective agents which alter the structure of the bacterial population, with regards to resistance. If pesticides were used to control the situation, then that could alter the rate at which this decompisition happens, thus altering the bacterial population, with regards to resistance, at a faster rate. Such possibilities need to be taken into consideration before any action is taken.
 

rahim

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Apr 11, 2007
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Does the natural temperature of Georgia and Florida have anything to do with the rate at which the decomposition of the bacteria occurs? Think about it. If something phenomenal is occurring here that is producing a different outcome than in other places, there has to be a reason for it other than simply the things that are present in that site. There has to be an external factor that is altering the rate at which the process occurring. I believe that this external factor might be the higher temperatures that are present throughout these regions, which speed up the process of the bacterial decomposition.
 

spencehud

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Apr 15, 2007
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Global Warming

It is a subject that can not easily be put aside. It is obvious that global warming is present through weather fluctuations and o-zone depletion. Could pollution and the green house effect be contributing to destruction of swamps in America such as the Okefenokee swamp?