Vegetables FAQ

PLANTS ARE NOT OXYGENATORS

Question:

After reading several  posts, and a long absense from making any posts, I felt the need to clarify some things.  First, shading a pond to prevent an algae bloom is a band- aid approach.  The correct control for planktonic algae involves a properly designed bio filter that allows the proliferation of the many kinds of bacteria that work on both organic and inorganic waste.  Because alga spores blow in with the wind and replicate quickly, (6 hours) the use of some shading or better yet a uv sterilizer will eliminate a light green tinge which may come over your pond in the spring.  In my experience, I only get algae blooms in the spring if my pond is overstocked, regardless if my filter is seeded.  Proper water movement and aeration inhibit the growth of algae.  Keeping Nitrates below 50 ppm and not feeding foods high in phosphourus will also help. As for plants, they are not oxygenators in terms of a fish pond.  They consume oxygen at night thereby stressing the fish population and causing death to the larger fish first.(if not balanced)  Sure in the day they may add some oxygen through photosythesis. However, this can lead to other problems like super saturation and potential death to the fish through gas bubble disease.  This can also happen with nitrogen.  The use of a powerful blower, running 24 hours a day will not only raise the ambient d.o. level but lower it  as well if the water happens to become supersaturated. There is the art of keeping fish and the science.  To me, without the fundamentals being correct it is just a matter of time before your fish pay the price.  For example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   This post is not intended to insult anyone, please don’t infer it as such.  Instead, anyone who is going to build a pond should think twice, plan thrice  and please be nice, to the fish.  Thanks. randall, Clarke Koi Company, toronto

Response:

>After reading several  posts, and a long absense from making any posts, I felt the >need to clarify some things.  First, shading a pond to prevent an algae bloom is a >band- aid approach.

The use of shading is not, as you put it, a band aid approach. It is a viable and legitimate means of controlling the photo-period your pond is exposed to, which despite what you may think, is a primary factor in algae blooms. Balance is important, but other means are still necessary. >and replicate quickly, (6 hours) the use of some shading or better yet a uv >sterilizer will eliminate a light green tinge which may come over your pond in the >spring.

UV sterilizers are nice, and right after I pay my insurance, property taxes and two car payments, I’ll just go right out and purchase one. Why do you people think it’s all that complicated, skip the UV sterilizer, add more plants and use a little extra particulate filtration during blooms, the use of a good flocculant works wonders also, just make sure you don’t let the resultant film collect on the bottom and set there till it decomposes. >spring.  In my experience, I only get algae blooms in the spring if my pond is >overstocked, regardless if my filter is seeded.  Proper water movement and aeration >inhibit the growth of algae.  Keeping Nitrates below 50 ppm and not feeding foods >high in phosphourus will also help.

Good advice, and the best way to keep nitrates at a minimum is plants whether they oxygenate or not. However the stress you refer to in the average pond is non-existent. Most stressed is caused by trying to control water quality too tightly. It’s better to have stable less than ideal water than to constantly try to keep it within narrow parameters. Water in nature has wild fluctuations, during rain, fast climatic changes etc, fish are far more adaptable than we give them credit for, don’t abuse them, but don’t sweat too much if something isn’t exactly right. >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks.

Was slightly snobbish though, maybe you should read it again. And if you ever get down to Webster County, Iowa, I can show you at least 30 or so ponds where fish thrive in less than three feet of water (yes, natural ponds) many species do just that in nature. Granted there are some ideas that are slightly askew, but there is no one correct way, and some of the best ponds I have seen to date have been simple affairs, no big commercial filters, no aerators, sterilizers or such, just beautiful ponds. There are rules of thumb of course, but please don’t be so narrow minded. – Hide quoted text — Show quoted text ->randall, Clarke Koi Company, toronto

Response:

Randall is probably well meaning but a bit holier than thou. I suggest he take the time to lighten up and just enjoy!

Response:

ahh the inferences made from the written word.  Very interesting.  I’m not holier than thou but when I read a recommendation of floating ping pond balls on a pond, well….   Additionally I don’t own a uv sterilizer.  they are for people who are overstocked or, in the case of an area (ie. California) that has a lot of sunlight and no shade cloth over the pond.  If you can’t tolerate the slightest green tinge in your water then get one.  Obviously sunlight is imperative to alga blooms, never said otherwise. I have had no plants in my pond and no alga blooms many springs. Keeping a nice layer of string alage on the side of your pond will do more for algae control in the spring then plants will.  Mainly because it is already established. Since the sun does shine most places, it is more a function of nutrients added and systems added to rid the pond of said nutrients. ie. foam fractioner, aeration, proper circulation etc. The use of flocculants is the epitimy of a bandaid approach.  Aside from being quite costly, they have to be applied properly.  If the system is not fundamentaly rectified, they will have to be applied again.  Also, depending on which flocculant you chose, there can be ramifications to the ph.  Gypsum ( calcium hydroxide ) will not lower ph which can be deadly.  It is not as effective a flocculant as  aluminum sulfate, but this can  crash your ph  (kh should be high before application).  Additionally as you mentioned the mulm will form on the bottom, can become anaerobic, add to the inorganic and organic loads, etc.etc. However, with a properly designed pond ie bowled with a 4 inch bottom drain, the pond is self cleaning.  Of course once in the filter it has to be flushed out of there or it is still in the system. Good point about keeping the water within the levels of your tap water.  However, this only pertains to the ph, other factors should be tested for and adjusted to optimum levels. particularily kh, also gh, nitrate maybe, etc. etc. etc.  I never said narrow paratmeters, optimal parameters are desired.  I do also sweat it on occaision, having lost enough fish in the past 15 years through my own stupidy and that very additude.  Not only are they expensive, they are pets we love and they deserve to be kept properly.  The fact that carp are probably the toughest fish out there ( outside of tilapia) does not give us the license to be uninformed fish keepers.  99.9 % of koi (my guess) die not of old age, but rather through our actions or lack thereof. In closing in dealing with certain fundamentals, there is only one correct way. We really aren’t fish keepers, we are water keepers.  I’m not narrow minded, my mind is always open, there  is much more for me to learn. I’ll repeat for the "touchies" this post is not intended to be condescending or pseudo flammatory, (enter any additional small print you desire here )  Apply what you think you can. Thanks for your post, next time e-mail me directly regards, Randall Randall, Clarke Koi Company, Toronto ps. I’m interested to know what species of fish live in these shallow ponds in your area and if they were introduced by man. thanks pps.  Your right, I do need to lighten up, I’ve gained about 10 pounds this winter!!!

Response:

>ahh the inferences made from the written word.  Very interesting.  I’m not holier >than thou but when I read a recommendation of floating ping pond balls on a pond, >well….

Man you really are the quintessential pond snob aren’t you. However unorthodox things may seem to you (and you obviously feel yourself an expert) it may work and sometimes, that’s what it takes. >Additionally I don’t own a uv sterilizer.  they are for people who are overstocked >or, in the case of an area (ie. California) that has a lot of sunlight and no shade >cloth over the pond.  If you can’t tolerate the slightest green tinge in your water >then get one.  Obviously sunlight is imperative to alga blooms, never said otherwise. >I have had no plants in my pond and no alga blooms many springs. Keeping a nice layer >of string alage on the side of your pond will do more for algae control in the spring >then plants will.  Mainly because it is already established. Since the sun does shine >most places, it is more a function of nutrients added and systems added to rid the >pond of said nutrients. ie. foam fractioner, aeration, proper circulation etc. >The use of flocculants is the epitimy of a bandaid approach. Aside from being quite

There you go again, flocculants are something you use to take care of minor cloudiness perhaps due to the sand storm that just blew through or it helps to remove suspended algae, again shit happens and your way is not the the only nor the best. Christ you really are full of yourself aren’t you. I use Accu-Clear ocaasionally and never concern myself with minute water chemistry measurements, not wishing to shell out stupid amounts of wasted money on twenty million test kits. My are fish are thriving, growing and show no signs what so ever of stress, never had a disease and never had one die yet. >Good point about keeping the water within the levels of your tap water.  However, >this only pertains to the ph, other factors should be tested for and adjusted to >optimum levels. particularily kh, also gh, nitrate maybe, etc. etc. etc.  I never >said narrow paratmeters, optimal parameters are desired.  I do also sweat it on >occaision, having lost enough fish in the past 15 years through my own stupidy and >that very additude.  Not only are they expensive, they are pets we love and they >deserve to be kept properly.  The fact that carp are probably the toughest fish out

Sorry don’t keep carp, don’t like em, find them boring but tothers probably don’t. Suppose that makes a lesser pond keeper to eh. >there ( outside of tilapia) does not give us the license to be uninformed fish >keepers.  99.9 % of koi (my guess) die not of old age, but rather through our actions >or lack thereof.

Perhaps you should re-read that. If your way is the best, how come your fish are dying ??? >In closing in dealing with certain fundamentals, there is only one correct way. >We really aren’t fish keepers, we are water keepers.  I’m not narrow minded, my mind >is always open, there  is much more for me to learn. I’ll repeat for the "touchies" >this post is not intended to be condescending or pseudo flammatory, (enter any >additional small print you desire here )  Apply what you think you can. Thanks for >your post, next time e-mail me directly

What you intend and what you achieve are two different things, you did offend people, pissed them off even. Go watch your fish die. – Hide quoted text — Show quoted text ->regards, Randall >Randall, Clarke Koi Company, Toronto >ps. I’m interested to know what species of fish live in these shallow ponds in your >area and if they were introduced by man. thanks >pps.  Your right, I do need to lighten up, I’ve gained about 10 pounds this winter!!!

Response:

- Hide quoted text — Show quoted text – >ahh the inferences made from the written word.  Very interesting.  I’m not holier >than thou but when I read a recommendation of floating ping pond balls on a pond, >well….   >Additionally I don’t own a uv sterilizer.  they are for people who are overstocked >or, in the case of an area (ie. California) that has a lot of sunlight and no shade >cloth over the pond.  If you can’t tolerate the slightest green tinge in your water >then get one.  Obviously sunlight is imperative to alga blooms, never said otherwise. >I have had no plants in my pond and no alga blooms many springs. Keeping a nice layer >of string alage on the side of your pond will do more for algae control in the spring >then plants will.  Mainly because it is already established. Since the sun does shine >most places, it is more a function of nutrients added and systems added to rid the >pond of said nutrients. ie. foam fractioner, aeration, proper circulation etc. >The use of flocculants is the epitimy of a bandaid approach.  Aside from being quite >costly, they have to be applied properly.  If the system is not >fundamentaly rectified, they will have to be applied again.  Also, depending on which >flocculant you chose, there can be ramifications to the ph.  Gypsum ( calcium >hydroxide ) will not lower ph which can be deadly.  It is not as effective a >flocculant as  aluminum sulfate, but this can  crash your ph  (kh should be high >before application).  Additionally as you mentioned the mulm will form on the bottom, >can become anaerobic, add to the inorganic and organic loads, etc.etc. >However, with a properly designed pond ie bowled with a 4 inch bottom drain, the pond >is self cleaning.  Of course once in the filter it has to be flushed out of there or >it is still in the system. >Good point about keeping the water within the levels of your tap water.  However, >this only pertains to the ph, other factors should be tested for and adjusted to >optimum levels. particularily kh, also gh, nitrate maybe, etc. etc. etc.  I never >said narrow paratmeters, optimal parameters are desired.  I do also sweat it on >occaision, having lost enough fish in the past 15 years through my own stupidy and >that very additude.  Not only are they expensive, they are pets we love and they >deserve to be kept properly.  The fact that carp are probably the toughest fish out >there ( outside of tilapia) does not give us the license to be uninformed fish >keepers.  99.9 % of koi (my guess) die not of old age, but rather through our actions >or lack thereof. >In closing in dealing with certain fundamentals, there is only one correct way. >We really aren’t fish keepers, we are water keepers.  I’m not narrow minded, my mind >is always open, there  is much more for me to learn. I’ll repeat for the "touchies" >this post is not intended to be condescending or pseudo flammatory, (enter any >additional small print you desire here )  Apply what you think you can. Thanks for >your post, next time e-mail me directly >regards, Randall >Randall, Clarke Koi Company, Toronto >ps. I’m interested to know what species of fish live in these shallow ponds in your >area and if they were introduced by man. thanks >pps.  Your right, I do need to lighten up, I’ve gained about 10 pounds this winter!!!

Wow!  I just want to see my fish since I went to the trouble to go to Wal Mart and buy them!  If they die; I’ll go back to Wal Mart and get more.  I just want to get rid of the green look of my water for little or no money.  

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Please tell me this isn’t developing into another flame war! – Trying to keep track of her 16 year old and failing miserably!!!!!

Response:

Texas Howdy,   I’m inclined to agree with the posts that say fish are tougher that we give them credit for.  Here in Houston, I know of several areas around town where you can find wild guppies in drainage ditches that sometimes contain no more than a couple inches of water.  Yes, I know they were ditched by someone, but it shows the hardiness of some species to adapt to their new environments.   Mark

stuff deleted here: – Hide quoted text — Show quoted text ->There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks. >randall, Clarke Koi Company, toronto

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<snip> >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks.

I agree with most of what you wrote, though I don’t think deoxygenation by submerged plants is a common problem. Rates of gas exchange are usually sufficient. Also, the function of biofilters is not the prevention of algal growth. Oxidation of ammonia to nitrate is their primary function. Algae can use nitrate as a nitrogen source too. Algal growth can be inhibited by lowering levels of N and P, most easily achieved by wise planting, or more efficiently by use of a vegetable/reed bed type filter. The other options are to reduce the availability of light or to use a uv system to kill and flocculate the algae. The only other thing I’d disagree with is the assertion that we don’t find fish in the wild in ponds 2-3 feet deep. Obviously this depends on the local climate, in particular freezing depth, but I’d like to borrow our portable electrofishing kit from work and demonstrate just what can be found in shallow ponds. I remember the first time I saw it used, in a stream about 8 inches deep. Flick the switch, and suddenly half a dozen small trout appear from nowhere! Cheers, Steve. From where I’m sitting, you lot don’t all pass the Turing test.

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– Hide quoted text — Show quoted text – > As for plants, they are not oxygenators in terms of a fish pond.  They consume oxygen > at night thereby stressing the fish population and causing death to the larger fish > first.(if not balanced)  Sure in the day they may add some oxygen through > photosythesis. However, this can lead to other problems like super saturation and > potential death to the fish through gas bubble disease.  This can also happen with > nitrogen.  The use of a powerful blower, running 24 hours a day will not only raise > the ambient d.o. level but lower it  as well if the water happens to become > supersaturated. > There is the art of keeping fish and the science.  To me, without the>

randall, Clarke Koi Company, toronto Really now Randall, what proportion of the pond would have to be full of plants to cause the wild swings in oxygen level that you suggest are a potential problem of submerged plants? I suspect that for most pondkeepers, the value of submerged plants for consuming nitrates far outweighs any dangers from either supersaturation or oxygen depletion (or presumably elevated CO2 levels at night). Not only that but if you’re keeping koi in the pond the chances of reaching a high concentration of submerged plants is almost nil, given my experience with plant-munching koi. — Fran Groeters

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– Hide quoted text — Show quoted text – ><snip> >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks. >I agree with most of what you wrote, though I don’t think deoxygenation by >submerged plants is a common problem. Rates of gas exchange are usually >sufficient. >Also, the function of biofilters is not the prevention of algal growth. >Oxidation of ammonia to nitrate is their primary function. Algae can use >nitrate as a nitrogen source too. >Algal growth can be inhibited by lowering levels of N and P, most easily >achieved by wise planting, or more efficiently by use of a vegetable/reed bed >type filter. >The other options are to reduce the availability of light or to use a uv >system to kill and flocculate the algae. >The only other thing I’d disagree with is the assertion that we don’t find >fish in the wild in ponds 2-3 feet deep. Obviously this depends on the local >climate, in particular freezing depth, but I’d like to borrow our portable >electrofishing kit from work and demonstrate just what can be found in shallow >ponds. >I remember the first time I saw it used, in a stream about 8 inches deep. >Flick the switch, and suddenly half a dozen small trout appear from nowhere! >Cheers, >Steve. >From where I’m sitting, you lot don’t all pass the Turing test.

To clear up a few points on photosynthesis.  Under lighted conditions, plants use carbon dioxide (CO2) in photosynthesis to produce glucose. Oxygen is produced from spliting a water molecule and useing the free electons produced to power the photosynthesis cycle.   Respiration uses oxygen and produces carbon dioxide in the reverse reaction.  Normally there is less respiration than photosynthes.   Therefore, plants are normally oxygenators.  The ammount of oxygen transfered to the water varies with the type of plant (floating vs. submerged, species, etc.) In areas where there is a great deal of free nutrients (nitrogen, phosphorous, etc.) plants can grow to their (and everyone elses) detriment.  This is refered to eutrophication.  If photosynthsis is stoped (cloudy day or night) respiration can run out of control and reduce the avaliable oxygen to dangerously low levels. It can drop to zero. To sum up, plants can be oxygenators or deoxygenators depending on the circumstances provided. These processes can be looked up in any biology textbook. Hope this clears up a few things.   NOTE:  This is not an attempt to insult anyone, only to inform.  This information comes from my wife (College Biology Professor) and myself (Marine Biologist / Aquaculturlist)

Response:

Sorry if I offended anyone.  That was not my intention.  I won’t get involved in any insult exchange, didn’t even read your post after the first comment.  Looking to spark some conversation and interesting debate, if you like, and sharing some of my personal experiences.  If you want to judge me and call me names after a post, you think you know me or what I’m about? (ie snob???) No further posts from me on the subject. Sorry to the people who have to read this childish bantor. randall, Clarke Koi Company, Toronto

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><snip> >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.   Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we

know the answer. RE: Now wait a second! Down home on the south-east Kansas farm I grew up on, I fished a small pond about 3" foot deep every summer and could count on catching Large-Mouth Bass up to and including one of about 3 pounds, over and over again. (Catch and release in 1959! ALL-RIGHT!) How do I know how deep it was? Well, for one thing, I often had to walk across it to get a fish loose from the green weed cover that reached from one side to the other during the summer months. I stand 5′6" in my stocking feet, and usually took my shoes off before wading in after "old faithful", the 3# Bass! During dry winters I have seen the pond almost dry, and frozen solid with fish in the ice, yet there were still good sized fish in the pond the next spring. How do you explane that?

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- Hide quoted text — Show quoted text -> As for plants, they are not oxygenators in terms of a fish pond.  They > consume oxygen > at night thereby stressing the fish population and causing death to the > larger fish > first.(if not balanced)  Sure in the day they may add some oxygen through > photosythesis. However, this can lead to other problems like super > saturation and > potential death to the fish through gas bubble disease.  This can also > happen with > nitrogen.  The use of a powerful blower, running 24 hours a day will not > only raise > the ambient d.o. level but lower it  as well if the water happens to become > supersaturated. > There is the art of keeping fish and the science.  To me, without the> > randall, Clarke Koi Company, toronto

I would _almost_ call this post idiotic  Even in my aquaria with CO2 injection and hundreds of plants, I have _never_ had problems with supersaturation of oxygen affecting fish.  Perhaps anyone who _thinks_ they have had this problem really had green water that used up all of the 02 at night, but I really doubt that there is a possibility of fish mortality due to the number of plants in a pond! — Eric Schoville http://FTPhome1.gte.net/rschovil/index.htm A member of EPAPB – Educated People Against Pat Buchanan Visit the EPAPB Home Page – http://FTPhome1.gte.net/rschovil/epapb.htm

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– Hide quoted text — Show quoted text -> > As for plants, they are not oxygenators in terms of a fish pond. They > consume oxygen > > at night thereby stressing the fish population and causing death to the > larger fish > > first.(if not balanced)  Sure in the day they may add some oxygen through > > photosythesis. However, this can lead to other problems like super > saturation and > > potential death to the fish through gas bubble disease.  This can also > happen with > > nitrogen.  The use of a powerful blower, running 24 hours a day will not > only raise > > the ambient d.o. level but lower it  as well if the water happens to become > > supersaturated. > > There is the art of keeping fish and the science.  To me, without the> > randall, Clarke Koi Company, toronto >I would _almost_ call this post idiotic  Even in my aquaria with

CO2 injection and hundreds of >plants, I have _never_ had problems with supersaturation of oxygen

affecting fish.  Perhaps anyone >who _thinks_ they have had this problem really had green water that

used up all of the 02 at night, >but I really doubt that there is a possibility of fish mortality due

to the number of plants in a >pond! >– >Eric Schoville >http://FTPhome1.gte.net/rschovil/index.htm >A member of EPAPB – Educated People Against Pat Buchanan >Visit the EPAPB Home Page – http://FTPhome1.gte.net/rschovil/epapb.htm

Eric, and group, I’ve had supersaturation in aquaculture ponds of oxygen and never had trouble during the supersaturation phase.  Supersaturation of oxygen (up to 20 ppm) can occur during the afternoon in intense sunlight onto phytoplankton rich ponds.  This is usually a pretty good indication of a rapid oxygen crash and resulting depletion after dark on the same day/next morning.  I’ve also seen high carbon dioxide levels (above 60 ppm) in similar situations in the early morning hours which combined with depleted oxygen will kill fish.   The other thing, in ponds with lots of higher aquatic plants, oxygen can be depleted to zero or less (oxygen debt) during the night.  This results in dead fish.  Happens all the time in many sizes of ponds and lakes.  We had the situation in a 100 acre lake two years ago.  During the day, you could find oxygen levels near to saturation, by 2 am, you could not get a reading above 0.2 ppm anywhere in the lake.  Water was crystal clear, but full of coontail grass, bushy pondweed, and filamentous algae.  We had to run large tractor powered and electric aerators as well as oxygen injection combined with big pumps (36" 8000 gallons per minute) to keep the fish alive during the night for over 3 months.  At best, we could create safety zones of relatively high DO (above 2 ppm) which the fish learned to come to at night.  As soon as the sun was up, we could shut down till dark and start all over again. Several lakes in our neighborhood lost all thier fish to similar conditions, resulting from abundant aquatic plant growth. For a good explanation, see post #8642 PLANTS ARE NOT OXYGENATORS. Brett Rowley Fisheries Biologist Great Lakes Sportfishing Resort and Koi Breeding Farm West columbia, Texas http://home.cdsnet.net/~dearlix/index.html

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Gee Randall, did you get offended ???

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>To clear up a few points on photosynthesis.  Under lighted conditions, >plants use carbon dioxide (CO2) in photosynthesis to produce glucose. >Oxygen is produced from spliting a water molecule and useing the free >electons produced to power the photosynthesis cycle.   >Respiration uses oxygen and produces carbon dioxide in the reverse >reaction.  Normally there is less respiration than photosynthes.   >Therefore, plants are normally oxygenators.  The ammount of oxygen >transfered to the water varies with the type of plant (floating vs. >submerged, species, etc.)

This is a good synopsis. >In areas where there is a great deal of free nutrients (nitrogen, >phosphorous, etc.) plants can grow to their (and everyone elses) >detriment.  This is refered to eutrophication.  If photosynthsis is >stoped (cloudy day or night) respiration can run out of control and >reduce the avaliable oxygen to dangerously low levels. It can drop >to zero.

This is also true, however highly eutrophic lakes are often devoid of submerged higher plants. The reason for this is that algae tend to dominate this system, and block out the light. Deoxygenation in eutrophic lakes is more likely to be caused by the decay of dead algae than the respiration of living algae. It isn’t impossible, though. It is also worth mentioning that the respiration of plants at night can lead to a noticeable fall in pH, due to their production of CO2. >To sum up, plants can be oxygenators or deoxygenators depending on the >circumstances provided.

True. I’m not a big fan of submerged plants anyway, as they tend to get completely rampant. Steve From where I’m sitting, you lot don’t all pass the Turing test.

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After reading several  posts, and a long absense from making any posts, I felt the need to clarify some things.  First, shading a pond to prevent an algae bloom is a band- aid approach.  The correct control for planktonic algae involves a properly designed bio filter that allows the proliferation of the many kinds of bacteria that work on both organic and inorganic waste.  Because alga spores blow in with the wind and replicate quickly, (6 hours) the use of some shading or better yet a uv sterilizer will eliminate a light green tinge which may come over your pond in the spring.  In my experience, I only get algae blooms in the spring if my pond is overstocked, regardless if my filter is seeded.  Proper water movement and aeration inhibit the growth of algae.  Keeping Nitrates below 50 ppm and not feeding foods high in phosphourus will also help. As for plants, they are not oxygenators in terms of a fish pond.  They consume oxygen at night thereby stressing the fish population and causing death to the larger fish first.(if not balanced)  Sure in the day they may add some oxygen through photosythesis. However, this can lead to other problems like super saturation and potential death to the fish through gas bubble disease.  This can also happen with nitrogen.  The use of a powerful blower, running 24 hours a day will not only raise the ambient d.o. level but lower it  as well if the water happens to become supersaturated. There is the art of keeping fish and the science.  To me, without the fundamentals being correct it is just a matter of time before your fish pay the price.  For example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   This post is not intended to insult anyone, please don’t infer it as such.  Instead, anyone who is going to build a pond should think twice, plan thrice  and please be nice, to the fish.  Thanks. randall, Clarke Koi Company, toronto

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>After reading several  posts, and a long absense from making any posts, I felt the >need to clarify some things.  First, shading a pond to prevent an algae bloom is a >band- aid approach.

The use of shading is not, as you put it, a band aid approach. It is a viable and legitimate means of controlling the photo-period your pond is exposed to, which despite what you may think, is a primary factor in algae blooms. Balance is important, but other means are still necessary. >and replicate quickly, (6 hours) the use of some shading or better yet a uv >sterilizer will eliminate a light green tinge which may come over your pond in the >spring.

UV sterilizers are nice, and right after I pay my insurance, property taxes and two car payments, I’ll just go right out and purchase one. Why do you people think it’s all that complicated, skip the UV sterilizer, add more plants and use a little extra particulate filtration during blooms, the use of a good flocculant works wonders also, just make sure you don’t let the resultant film collect on the bottom and set there till it decomposes. >spring.  In my experience, I only get algae blooms in the spring if my pond is >overstocked, regardless if my filter is seeded.  Proper water movement and aeration >inhibit the growth of algae.  Keeping Nitrates below 50 ppm and not feeding foods >high in phosphourus will also help.

Good advice, and the best way to keep nitrates at a minimum is plants whether they oxygenate or not. However the stress you refer to in the average pond is non-existent. Most stressed is caused by trying to control water quality too tightly. It’s better to have stable less than ideal water than to constantly try to keep it within narrow parameters. Water in nature has wild fluctuations, during rain, fast climatic changes etc, fish are far more adaptable than we give them credit for, don’t abuse them, but don’t sweat too much if something isn’t exactly right. >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks.

Was slightly snobbish though, maybe you should read it again. And if you ever get down to Webster County, Iowa, I can show you at least 30 or so ponds where fish thrive in less than three feet of water (yes, natural ponds) many species do just that in nature. Granted there are some ideas that are slightly askew, but there is no one correct way, and some of the best ponds I have seen to date have been simple affairs, no big commercial filters, no aerators, sterilizers or such, just beautiful ponds. There are rules of thumb of course, but please don’t be so narrow minded. – Hide quoted text — Show quoted text ->randall, Clarke Koi Company, toronto

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Randall is probably well meaning but a bit holier than thou. I suggest he take the time to lighten up and just enjoy!

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ahh the inferences made from the written word.  Very interesting.  I’m not holier than thou but when I read a recommendation of floating ping pond balls on a pond, well….   Additionally I don’t own a uv sterilizer.  they are for people who are overstocked or, in the case of an area (ie. California) that has a lot of sunlight and no shade cloth over the pond.  If you can’t tolerate the slightest green tinge in your water then get one.  Obviously sunlight is imperative to alga blooms, never said otherwise. I have had no plants in my pond and no alga blooms many springs. Keeping a nice layer of string alage on the side of your pond will do more for algae control in the spring then plants will.  Mainly because it is already established. Since the sun does shine most places, it is more a function of nutrients added and systems added to rid the pond of said nutrients. ie. foam fractioner, aeration, proper circulation etc. The use of flocculants is the epitimy of a bandaid approach.  Aside from being quite costly, they have to be applied properly.  If the system is not fundamentaly rectified, they will have to be applied again.  Also, depending on which flocculant you chose, there can be ramifications to the ph.  Gypsum ( calcium hydroxide ) will not lower ph which can be deadly.  It is not as effective a flocculant as  aluminum sulfate, but this can  crash your ph  (kh should be high before application).  Additionally as you mentioned the mulm will form on the bottom, can become anaerobic, add to the inorganic and organic loads, etc.etc. However, with a properly designed pond ie bowled with a 4 inch bottom drain, the pond is self cleaning.  Of course once in the filter it has to be flushed out of there or it is still in the system. Good point about keeping the water within the levels of your tap water.  However, this only pertains to the ph, other factors should be tested for and adjusted to optimum levels. particularily kh, also gh, nitrate maybe, etc. etc. etc.  I never said narrow paratmeters, optimal parameters are desired.  I do also sweat it on occaision, having lost enough fish in the past 15 years through my own stupidy and that very additude.  Not only are they expensive, they are pets we love and they deserve to be kept properly.  The fact that carp are probably the toughest fish out there ( outside of tilapia) does not give us the license to be uninformed fish keepers.  99.9 % of koi (my guess) die not of old age, but rather through our actions or lack thereof. In closing in dealing with certain fundamentals, there is only one correct way. We really aren’t fish keepers, we are water keepers.  I’m not narrow minded, my mind is always open, there  is much more for me to learn. I’ll repeat for the "touchies" this post is not intended to be condescending or pseudo flammatory, (enter any additional small print you desire here )  Apply what you think you can. Thanks for your post, next time e-mail me directly regards, Randall Randall, Clarke Koi Company, Toronto ps. I’m interested to know what species of fish live in these shallow ponds in your area and if they were introduced by man. thanks pps.  Your right, I do need to lighten up, I’ve gained about 10 pounds this winter!!!

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>ahh the inferences made from the written word.  Very interesting.  I’m not holier >than thou but when I read a recommendation of floating ping pond balls on a pond, >well….

Man you really are the quintessential pond snob aren’t you. However unorthodox things may seem to you (and you obviously feel yourself an expert) it may work and sometimes, that’s what it takes. >Additionally I don’t own a uv sterilizer.  they are for people who are overstocked >or, in the case of an area (ie. California) that has a lot of sunlight and no shade >cloth over the pond.  If you can’t tolerate the slightest green tinge in your water >then get one.  Obviously sunlight is imperative to alga blooms, never said otherwise. >I have had no plants in my pond and no alga blooms many springs. Keeping a nice layer >of string alage on the side of your pond will do more for algae control in the spring >then plants will.  Mainly because it is already established. Since the sun does shine >most places, it is more a function of nutrients added and systems added to rid the >pond of said nutrients. ie. foam fractioner, aeration, proper circulation etc. >The use of flocculants is the epitimy of a bandaid approach. Aside from being quite

There you go again, flocculants are something you use to take care of minor cloudiness perhaps due to the sand storm that just blew through or it helps to remove suspended algae, again shit happens and your way is not the the only nor the best. Christ you really are full of yourself aren’t you. I use Accu-Clear ocaasionally and never concern myself with minute water chemistry measurements, not wishing to shell out stupid amounts of wasted money on twenty million test kits. My are fish are thriving, growing and show no signs what so ever of stress, never had a disease and never had one die yet. >Good point about keeping the water within the levels of your tap water.  However, >this only pertains to the ph, other factors should be tested for and adjusted to >optimum levels. particularily kh, also gh, nitrate maybe, etc. etc. etc.  I never >said narrow paratmeters, optimal parameters are desired.  I do also sweat it on >occaision, having lost enough fish in the past 15 years through my own stupidy and >that very additude.  Not only are they expensive, they are pets we love and they >deserve to be kept properly.  The fact that carp are probably the toughest fish out

Sorry don’t keep carp, don’t like em, find them boring but tothers probably don’t. Suppose that makes a lesser pond keeper to eh. >there ( outside of tilapia) does not give us the license to be uninformed fish >keepers.  99.9 % of koi (my guess) die not of old age, but rather through our actions >or lack thereof.

Perhaps you should re-read that. If your way is the best, how come your fish are dying ??? >In closing in dealing with certain fundamentals, there is only one correct way. >We really aren’t fish keepers, we are water keepers.  I’m not narrow minded, my mind >is always open, there  is much more for me to learn. I’ll repeat for the "touchies" >this post is not intended to be condescending or pseudo flammatory, (enter any >additional small print you desire here )  Apply what you think you can. Thanks for >your post, next time e-mail me directly

What you intend and what you achieve are two different things, you did offend people, pissed them off even. Go watch your fish die. – Hide quoted text — Show quoted text ->regards, Randall >Randall, Clarke Koi Company, Toronto >ps. I’m interested to know what species of fish live in these shallow ponds in your >area and if they were introduced by man. thanks >pps.  Your right, I do need to lighten up, I’ve gained about 10 pounds this winter!!!

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- Hide quoted text — Show quoted text – >ahh the inferences made from the written word.  Very interesting.  I’m not holier >than thou but when I read a recommendation of floating ping pond balls on a pond, >well….   >Additionally I don’t own a uv sterilizer.  they are for people who are overstocked >or, in the case of an area (ie. California) that has a lot of sunlight and no shade >cloth over the pond.  If you can’t tolerate the slightest green tinge in your water >then get one.  Obviously sunlight is imperative to alga blooms, never said otherwise. >I have had no plants in my pond and no alga blooms many springs. Keeping a nice layer >of string alage on the side of your pond will do more for algae control in the spring >then plants will.  Mainly because it is already established. Since the sun does shine >most places, it is more a function of nutrients added and systems added to rid the >pond of said nutrients. ie. foam fractioner, aeration, proper circulation etc. >The use of flocculants is the epitimy of a bandaid approach.  Aside from being quite >costly, they have to be applied properly.  If the system is not >fundamentaly rectified, they will have to be applied again.  Also, depending on which >flocculant you chose, there can be ramifications to the ph.  Gypsum ( calcium >hydroxide ) will not lower ph which can be deadly.  It is not as effective a >flocculant as  aluminum sulfate, but this can  crash your ph  (kh should be high >before application).  Additionally as you mentioned the mulm will form on the bottom, >can become anaerobic, add to the inorganic and organic loads, etc.etc. >However, with a properly designed pond ie bowled with a 4 inch bottom drain, the pond >is self cleaning.  Of course once in the filter it has to be flushed out of there or >it is still in the system. >Good point about keeping the water within the levels of your tap water.  However, >this only pertains to the ph, other factors should be tested for and adjusted to >optimum levels. particularily kh, also gh, nitrate maybe, etc. etc. etc.  I never >said narrow paratmeters, optimal parameters are desired.  I do also sweat it on >occaision, having lost enough fish in the past 15 years through my own stupidy and >that very additude.  Not only are they expensive, they are pets we love and they >deserve to be kept properly.  The fact that carp are probably the toughest fish out >there ( outside of tilapia) does not give us the license to be uninformed fish >keepers.  99.9 % of koi (my guess) die not of old age, but rather through our actions >or lack thereof. >In closing in dealing with certain fundamentals, there is only one correct way. >We really aren’t fish keepers, we are water keepers.  I’m not narrow minded, my mind >is always open, there  is much more for me to learn. I’ll repeat for the "touchies" >this post is not intended to be condescending or pseudo flammatory, (enter any >additional small print you desire here )  Apply what you think you can. Thanks for >your post, next time e-mail me directly >regards, Randall >Randall, Clarke Koi Company, Toronto >ps. I’m interested to know what species of fish live in these shallow ponds in your >area and if they were introduced by man. thanks >pps.  Your right, I do need to lighten up, I’ve gained about 10 pounds this winter!!!

Wow!  I just want to see my fish since I went to the trouble to go to Wal Mart and buy them!  If they die; I’ll go back to Wal Mart and get more.  I just want to get rid of the green look of my water for little or no money.  

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Please tell me this isn’t developing into another flame war! – Trying to keep track of her 16 year old and failing miserably!!!!!

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Texas Howdy,   I’m inclined to agree with the posts that say fish are tougher that we give them credit for.  Here in Houston, I know of several areas around town where you can find wild guppies in drainage ditches that sometimes contain no more than a couple inches of water.  Yes, I know they were ditched by someone, but it shows the hardiness of some species to adapt to their new environments.   Mark

stuff deleted here: – Hide quoted text — Show quoted text ->There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks. >randall, Clarke Koi Company, toronto

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<snip> >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks.

I agree with most of what you wrote, though I don’t think deoxygenation by submerged plants is a common problem. Rates of gas exchange are usually sufficient. Also, the function of biofilters is not the prevention of algal growth. Oxidation of ammonia to nitrate is their primary function. Algae can use nitrate as a nitrogen source too. Algal growth can be inhibited by lowering levels of N and P, most easily achieved by wise planting, or more efficiently by use of a vegetable/reed bed type filter. The other options are to reduce the availability of light or to use a uv system to kill and flocculate the algae. The only other thing I’d disagree with is the assertion that we don’t find fish in the wild in ponds 2-3 feet deep. Obviously this depends on the local climate, in particular freezing depth, but I’d like to borrow our portable electrofishing kit from work and demonstrate just what can be found in shallow ponds. I remember the first time I saw it used, in a stream about 8 inches deep. Flick the switch, and suddenly half a dozen small trout appear from nowhere! Cheers, Steve. From where I’m sitting, you lot don’t all pass the Turing test.

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– Hide quoted text — Show quoted text – > As for plants, they are not oxygenators in terms of a fish pond.  They consume oxygen > at night thereby stressing the fish population and causing death to the larger fish > first.(if not balanced)  Sure in the day they may add some oxygen through > photosythesis. However, this can lead to other problems like super saturation and > potential death to the fish through gas bubble disease.  This can also happen with > nitrogen.  The use of a powerful blower, running 24 hours a day will not only raise > the ambient d.o. level but lower it  as well if the water happens to become > supersaturated. > There is the art of keeping fish and the science.  To me, without the>

randall, Clarke Koi Company, toronto Really now Randall, what proportion of the pond would have to be full of plants to cause the wild swings in oxygen level that you suggest are a potential problem of submerged plants? I suspect that for most pondkeepers, the value of submerged plants for consuming nitrates far outweighs any dangers from either supersaturation or oxygen depletion (or presumably elevated CO2 levels at night). Not only that but if you’re keeping koi in the pond the chances of reaching a high concentration of submerged plants is almost nil, given my experience with plant-munching koi. — Fran Groeters

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– Hide quoted text — Show quoted text – ><snip> >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.  Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we know the answer. >Shortcuts, shortsightedness and poor plannning lead to ridiculous measures such as >floating styrophoam and ping pong balls on a pond.  I thought I had heard it all.   >This post is not intended to insult anyone, please don’t infer it as such.  Instead, >anyone who is going to build a pond should think twice, plan thrice  and please be >nice, to the fish.  Thanks. >I agree with most of what you wrote, though I don’t think deoxygenation by >submerged plants is a common problem. Rates of gas exchange are usually >sufficient. >Also, the function of biofilters is not the prevention of algal growth. >Oxidation of ammonia to nitrate is their primary function. Algae can use >nitrate as a nitrogen source too. >Algal growth can be inhibited by lowering levels of N and P, most easily >achieved by wise planting, or more efficiently by use of a vegetable/reed bed >type filter. >The other options are to reduce the availability of light or to use a uv >system to kill and flocculate the algae. >The only other thing I’d disagree with is the assertion that we don’t find >fish in the wild in ponds 2-3 feet deep. Obviously this depends on the local >climate, in particular freezing depth, but I’d like to borrow our portable >electrofishing kit from work and demonstrate just what can be found in shallow >ponds. >I remember the first time I saw it used, in a stream about 8 inches deep. >Flick the switch, and suddenly half a dozen small trout appear from nowhere! >Cheers, >Steve. >From where I’m sitting, you lot don’t all pass the Turing test.

To clear up a few points on photosynthesis.  Under lighted conditions, plants use carbon dioxide (CO2) in photosynthesis to produce glucose. Oxygen is produced from spliting a water molecule and useing the free electons produced to power the photosynthesis cycle.   Respiration uses oxygen and produces carbon dioxide in the reverse reaction.  Normally there is less respiration than photosynthes.   Therefore, plants are normally oxygenators.  The ammount of oxygen transfered to the water varies with the type of plant (floating vs. submerged, species, etc.) In areas where there is a great deal of free nutrients (nitrogen, phosphorous, etc.) plants can grow to their (and everyone elses) detriment.  This is refered to eutrophication.  If photosynthsis is stoped (cloudy day or night) respiration can run out of control and reduce the avaliable oxygen to dangerously low levels. It can drop to zero. To sum up, plants can be oxygenators or deoxygenators depending on the circumstances provided. These processes can be looked up in any biology textbook. Hope this clears up a few things.   NOTE:  This is not an attempt to insult anyone, only to inform.  This information comes from my wife (College Biology Professor) and myself (Marine Biologist / Aquaculturlist)

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Sorry if I offended anyone.  That was not my intention.  I won’t get involved in any insult exchange, didn’t even read your post after the first comment.  Looking to spark some conversation and interesting debate, if you like, and sharing some of my personal experiences.  If you want to judge me and call me names after a post, you think you know me or what I’m about? (ie snob???) No further posts from me on the subject. Sorry to the people who have to read this childish bantor. randall, Clarke Koi Company, Toronto

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><snip> >There is the art of keeping fish and the science.  To me, without the fundamentals >being correct it is just a matter of time before your fish pay the price.  For >example do you find fish in the wild in ponds 2 -3 feet deep? No.   Do we find fish in >ponds 2 -3 feet deep ( and less ) in peoples backyards? I think we

know the answer. RE: Now wait a second! Down home on the south-east Kansas farm I grew up on, I fished a small pond about 3" foot deep every summer and could count on catching Large-Mouth Bass up to and including one of about 3 pounds, over and over again. (Catch and release in 1959! ALL-RIGHT!) How do I know how deep it was? Well, for one thing, I often had to walk across it to get a fish loose from the green weed cover that reached from one side to the other during the summer months. I stand 5′6" in my stocking feet, and usually took my shoes off before wading in after "old faithful", the 3# Bass! During dry winters I have seen the pond almost dry, and frozen solid with fish in the ice, yet there were still good sized fish in the pond the next spring. How do you explane that?

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- Hide quoted text — Show quoted text -> As for plants, they are not oxygenators in terms of a fish pond.  They > consume oxygen > at night thereby stressing the fish population and causing death to the > larger fish > first.(if not balanced)  Sure in the day they may add some oxygen through > photosythesis. However, this can lead to other problems like super > saturation and > potential death to the fish through gas bubble disease.  This can also > happen with > nitrogen.  The use of a powerful blower, running 24 hours a day will not > only raise > the ambient d.o. level but lower it  as well if the water happens to become > supersaturated. > There is the art of keeping fish and the science.  To me, without the> > randall, Clarke Koi Company, toronto

I would _almost_ call this post idiotic  Even in my aquaria with CO2 injection and hundreds of plants, I have _never_ had problems with supersaturation of oxygen affecting fish.  Perhaps anyone who _thinks_ they have had this problem really had green water that used up all of the 02 at night, but I really doubt that there is a possibility of fish mortality due to the number of plants in a pond! — Eric Schoville http://FTPhome1.gte.net/rschovil/index.htm A member of EPAPB – Educated People Against Pat Buchanan Visit the EPAPB Home Page – http://FTPhome1.gte.net/rschovil/epapb.htm

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– Hide quoted text — Show quoted text -> > As for plants, they are not oxygenators in terms of a fish pond. They > consume oxygen > > at night thereby stressing the fish population and causing death to the > larger fish > > first.(if not balanced)  Sure in the day they may add some oxygen through > > photosythesis. However, this can lead to other problems like super > saturation and > > potential death to the fish through gas bubble disease.  This can also > happen with > > nitrogen.  The use of a powerful blower, running 24 hours a day will not > only raise > > the ambient d.o. level but lower it  as well if the water happens to become > > supersaturated. > > There is the art of keeping fish and the science.  To me, without the> > randall, Clarke Koi Company, toronto >I would _almost_ call this post idiotic  Even in my aquaria with

CO2 injection and hundreds of >plants, I have _never_ had problems with supersaturation of oxygen

affecting fish.  Perhaps anyone >who _thinks_ they have had this problem really had green water that

used up all of the 02 at night, >but I really doubt that there is a possibility of fish mortality due

to the number of plants in a >pond! >– >Eric Schoville >http://FTPhome1.gte.net/rschovil/index.htm >A member of EPAPB – Educated People Against Pat Buchanan >Visit the EPAPB Home Page – http://FTPhome1.gte.net/rschovil/epapb.htm

Eric, and group, I’ve had supersaturation in aquaculture ponds of oxygen and never had trouble during the supersaturation phase.  Supersaturation of oxygen (up to 20 ppm) can occur during the afternoon in intense sunlight onto phytoplankton rich ponds.  This is usually a pretty good indication of a rapid oxygen crash and resulting depletion after dark on the same day/next morning.  I’ve also seen high carbon dioxide levels (above 60 ppm) in similar situations in the early morning hours which combined with depleted oxygen will kill fish.   The other thing, in ponds with lots of higher aquatic plants, oxygen can be depleted to zero or less (oxygen debt) during the night.  This results in dead fish.  Happens all the time in many sizes of ponds and lakes.  We had the situation in a 100 acre lake two years ago.  During the day, you could find oxygen levels near to saturation, by 2 am, you could not get a reading above 0.2 ppm anywhere in the lake.  Water was crystal clear, but full of coontail grass, bushy pondweed, and filamentous algae.  We had to run large tractor powered and electric aerators as well as oxygen injection combined with big pumps (36" 8000 gallons per minute) to keep the fish alive during the night for over 3 months.  At best, we could create safety zones of relatively high DO (above 2 ppm) which the fish learned to come to at night.  As soon as the sun was up, we could shut down till dark and start all over again. Several lakes in our neighborhood lost all thier fish to similar conditions, resulting from abundant aquatic plant growth. For a good explanation, see post #8642 PLANTS ARE NOT OXYGENATORS. Brett Rowley Fisheries Biologist Great Lakes Sportfishing Resort and Koi Breeding Farm West columbia, Texas http://home.cdsnet.net/~dearlix/index.html

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Gee Randall, did you get offended ???

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>To clear up a few points on photosynthesis.  Under lighted conditions, >plants use carbon dioxide (CO2) in photosynthesis to produce glucose. >Oxygen is produced from spliting a water molecule and useing the free >electons produced to power the photosynthesis cycle.   >Respiration uses oxygen and produces carbon dioxide in the reverse >reaction.  Normally there is less respiration than photosynthes.   >Therefore, plants are normally oxygenators.  The ammount of oxygen >transfered to the water varies with the type of plant (floating vs. >submerged, species, etc.)

This is a good synopsis. >In areas where there is a great deal of free nutrients (nitrogen, >phosphorous, etc.) plants can grow to their (and everyone elses) >detriment.  This is refered to eutrophication.  If photosynthsis is >stoped (cloudy day or night) respiration can run out of control and >reduce the avaliable oxygen to dangerously low levels. It can drop >to zero.

This is also true, however highly eutrophic lakes are often devoid of submerged higher plants. The reason for this is that algae tend to dominate this system, and block out the light. Deoxygenation in eutrophic lakes is more likely to be caused by the decay of dead algae than the respiration of living algae. It isn’t impossible, though. It is also worth mentioning that the respiration of plants at night can lead to a noticeable fall in pH, due to their production of CO2. >To sum up, plants can be oxygenators or deoxygenators depending on the >circumstances provided.

True. I’m not a big fan of submerged plants anyway, as they tend to get completely rampant. Steve From where I’m sitting, you lot don’t all pass the Turing test.

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