Pond Boss Forums STOCKING A NEW POND Creating the food chain Plankton

Trying to figure out a few simple ( I hope) answers. I have been reading about plankton, and there are a lot of good past threads on it that get very detailed. So, I know it can get complicated, but didn't notice any references to my questions. I am not really planning on doing anything to create a bloom, but want to know what to expect and look for. It does seem crucial that one at least exists.

1) IF you have FA, does that mean there should be enough nutrients/fertilizer in the water for a plankton bloom?

2) Will the FA compete, suppress, or eliminate a plankton bloom?

3) What temp range does plankton blooms occur? or the ideal temp?

4) Most pond managers seem to like a long bloom. But when temps get to that certain point, isn't it impossible to keep it going? Otherwise, I shouldn't be disappointed and consider it a failure cuz it's out of my control?

Thank you, Jim

Fish in Chip I am by no means a specialest on Plankton. I have however have done research & been some what educated a little on the subject in the past. Plankton blooms have been a interest to me because of my love for ocean fishing and understanding why fishing around them is so good.

The Green looking plankton you see is from Chlorophyll in the Phtyoplankton. Zooplankton that alot of our freshwater fish feed on may be present and not visable since they are an animal plankton.

1> Yes for Phytoplankton (aka Plant plankton) phosphorus, and nitrogen also play a key role in growing plants (FA INCLUDED). However high N & P have been known to produce a bloom that is less productive (because Aphanizomenon is often present) and tends to make phytoplankton less grazeable for the more desireable Zooplankton (AKA animal plankton like BG eat).

2> Some FA present can be an alternate food source for the Zooplankton (animal plankton and BG food) while it also takes vital N & P from Phytoplankton.

3> Phytoplankton (food for zooplankton) needs longer sunny days, Nutrients & a substainable water temperature for growth. Most places I would say have there best production during late spring with water temps between 70 to 75 degrees. After this alot of the nutrients tend to be used up for the larger phytoplankton blooms. The zooplanton also generally have some other form of algea to feed off of other than the Phytoplankton.

4> Longer blooms provide visable food for the much sought after Zooplankton. Extending more production of grazable phytoplankton helps increase the biomass of the zooplankton. However physical enviroment can also influence the length of time a larger Phytoplankton bloom can exist. Often you will have a late Spring early summer bloom. As the nutrients are used up the phytoplankton bloom dies down or the zooplankton reaches the typing point of more consuming than what is being produced. Warmer water temps often then supress the reproduction of Phytoplankton in my area until near fall when the water temps again cool enough to allow another bloom (with enough sunlight, nutrients and more viable water temperature all come together at the same time).

Just a side note I often fertilize and use some pond dye at the same time to prevent nutrients being used for lower growing algea to provide more for top growing phytoplankton.

When building a pond I also take notes from the ocean that if your pond is designed where upwelling (slight underwater currents that will bring nutrients from depths to the surface) can take place your phytoplankton bloom will also last longer. This can be done by elavation changes when building instead of a flat bottom. Often spring thunderstorms will provide the wind power for currents. I got this idea from fishing a placxe called the Midnight lump off of the coast of Louisiana. It is underwater dome that causes an upwelling of rich oceans currents that makes for plankton rich waters in the winter. This in turn draws bait fish that bring in the yellow fin tuna.

Hope this kind of helps answer some of the questions you are asking.

Alternative answers.
1. Filamentous algae (FA), Chara, or submerged plants are typically nutrient hogs and if present in fair amounts, they will overpower and out grow the ability of phytoplankton to bloom. If a pond has about 5%-15% coverage of FA then it is my opinion the FA should be first killed and a day or two later add fertilizer to feed the current phytoplankton so it can bloom and shade the return of the FA. Sometimes killing the FA will kill the competition, relese sme nutrients from the FA and stimulate the phytoplankton to grow & start a bloom which without more nutrients the bloom will die out or gradually decrease not too much later. You typically need to 'feed' the bloom to keep it going long term. Phytoplankton can create a bloom relatively quickly - it has fasterer reproductive growth than FA or submerged plants including Chara.
2. FA typically outcompetes the phytoplankton if the FA has a good head start. It can depend on the percent abundance of each. It wouldn't suprise me if some species of FA exert a chemical inhibitor to phytoplankton. Research has shown rooted submerged plants produce chemical inhibitors to phytoplankton.
3. When fish hatcheries fertilize to produce a plankton bloom the most common temperature for the bloom to get going strong is 60F +-5F. In spring you want to watch the weather forcasts and fertilize prior to an upcoming warming trend. There are exceptions; see below, as usual, it all depends.
4. Typically when water temps gradually cool to below 60F then the activity and rapid reproduction of the plankton slows down significantly. HOwever this applies to those species that thrive in water above 60F. I have seen water stay green all winter in manure ponds with rich phosphorus concentrations. There are phytoplankton that will thrive and bloom in cool and cold water depending on the specie of phytoplankton. Thus the algae species in the plankton will be different as daylength and water temperatures change seasonally. Normally most zooplankton species do not bloom in cold water due to most of them are cold blooded and they are warm water species in the normal warmwater pond and they are not well adapted to reproduce in cool-cold water. They can typically survive but don't do much reproducing in late fall-winter, very early spring below 55-60F. There are a few cold water adapted zooplankton species but most warmwater ponds do not have them because the cold water species get eliminated in summer either due to too warm of water or too low of DO. Most cold water zooplankton require high DO similar to the reqirements of trout. When the trout die in a pond the cold water zooplankton and other stenotherm invertebrates also are eliminated.

Thank you TUMS for your time to give so much info. I was mainly talking about the Phytoplankton. I am sorry I forgot to include that the first time.

The FA questions arise from my past observations of the pond. This will be the first year since renovating. Prior, I never noticed a phytoplankton bloom, but might have had them not realizing what it was. Now I am gaining some knowledge to recognize the difference. All I noticed over the last 20 years was how bad the FA got. I am wondering if the FA was keeping the phytoplankton bloom suppressed. Yes, it could have been many other things too. This year I am seeing FA again, and I just don't want it to interfere with a bloom, like using all the nutrients that it needs,if that can even be the case.

Sources never seem to say an actual temperature that phytoplankton starts. You are the first that I have seen to say a temp range. Most will be vague, and say that when it gets to warm it dies back, global warming, yada, yada. It must have to do with so many verities that grow in different temps?

I must have had some bloom in the old pond, otherwise all new life would have come to a halt ( if I underatand it correctly). I just want to make sure that I will get something going this year with the new fish stocked. I don't want something simple to get in the way of a bloom.

Thank you BILL. Those are some of the concerns that I have had, especially in #1 & #2.

5 - 15 percent doesn't seem like much, so I bet that was some of the problem in the past. I am very leery about fertilizing after killing off the FA, because it seems like a lot of the info here says not to fertilize for a bloom unless the pond has a track record. This will be the first year full pool with stocked fish. Should I let it go naturally and see what happens, or interfere if the FA gets more than 15% ??

I do not have aeration yet, but if I am understanding it correctly, a nice slow but steady bloom would actual produce O2 and be beneficial because of no aeration. I would need to make sure that it all doesn't come to a screeching halt, creating a O2 depletion. Can a bloom be slowly dissipated with management, or is it always growing bigger and bigger and the bottom falls out?

It doesn't take much established FA to overpower the phytoplankton. A narrow band of FA around the perimeter of a pond is enough FA to be problematic for producing a bloom. Add some extra nutrients manually or with runoff and the FA blooms quickly. The more it grows, the clearer the water gets and the deeper and more the FA grows. It can get "out of hand" quickly. You will always have some phytoplankton even in a thick massive FA bloom. It is just the phytoplankton is suppressed from forming a dense bloom. Actually if truth be known it is probably the ratio of N:P that has a lot to do with causing the FA vs phytoplankton to bloom. More research needs to be done with this topic. Most just eliminate the FA or weed competitative factor to play it safe, then fertilize. A fish hatchery guy just told me today that he was going to kill the FA in his pond with Curtine and then fertilize to produce a bloom.

In northern ponds it is usually suggested to not fertilize to get a bloom unless you are a fish hatchery who can usually monitor the bloom and are expereined with blooms. Blooms are hard and troublessome to maintain at corrrect densities in northern ponds. If you keep the FA suppressed reasonably,, very adequate phyto and zooplankton occur naturally in our more limestone based Ohio soils. Do you know your total hardness or alkalinity of the current pond water? Usually if you feed pellets to the fish this will grow big fish and compensate for not having a dense fertilized bloom. Actually feeding fish will help create a nominal ongoing bloom due to the added nutrients from the pellet feeding. For the first year I would feed pellets, and use some manual methods to stiffle early growths of FA.

Phytoplankton is responsible for creating most of the DO in the oxygen budget for the pond ecosystem. Obvious lack of a plankton bloom then transfers the majority of the DO production to the FA or submerged plants.

Blooms typically grow and increase until the nutrients are depleated due to some limiting factor or the nutrient ratio shifts and the bloom changes species composition or size. Blooms can be managed by monitoring the nutrient compositon and concentrations but this is only practical or doable by academic types. Definately not by hatcheries or pond owners. More practically blooms can be slowed or 'trimmed' with partial herbicide applications. IMO best way to trim a blooom is with Sodium carbonate peroxyhydrate, aka peroxyhydrate (Green Clean, Phycomycin) or secondarly Cutrine-Plus (buffered copper based products).

Thanks BC
FNC sorry I didnt understand exactly what you where looking for. I think I may have an old reproduction temp curve chart for phytoplankton I can upload when I get back to my office tommorow. seems like I remember it basically has production starting just above freezing for cold water all the way up to 100 for the warm water type got to hot for reproduction.

Thanks again guys. This is the basic info I was searching for, especially in relation to a pond scenario. Basic enough for a beginner like myself to understand and yet complete enough to get a good feel for the situation as a whole.

I have a PH tester that does soil. It's reads 7PH and a few spots are 8. Interestingly those 8's are in the areas I placed concrete slabs up the edge for habitat. I have not had the water tested itself. Anyone know of a place to test pond water in the Ohio area?

Bill said -"Phytoplankton is responsible for creating most of the DO in the oxygen budget for the pond ecosystem. Obvious lack of a plankton bloom then transfers the majority of the DO production to the FA or submerged plants." ---- To add a trivia tidbit to this, one source I was reading said that phytoplankton was responsible for half of the O2 produced in the world. wow...

I imagine that tilapia would not be a feasible solution to the control of FA in regards to a phytoplankton bloom. My reasoning is that the FA comes on earlier than that what the water temps would allow tilapia to be stocked. Sound right?


thank you, Jim

There's 2 ways to utilize Tilapia for FA. 1) stock a higher rate to let them catch up to the FA that is already in the pond or 2) whack back the FA with chemicals and then stock the Tilapia. 49#/surface acre won't catch up to the FA if Tilapia are stocked in a nutrient rich pond when water temps are in the low '70's.

I've found that FA needs to be treated about once every 5-6 weeks in fertile ponds if a bloom doesn't get established to cut down on sunlight penetration and there aren't Tilapia in the pond.

You can whack back the FA, then a couple days later fertilize to get a bloom going quickly. Monitor the bloom with a secchi disc and like Bill said treat if necessary. FA will outcompete the bloom.

Phytoplankton produces O2 during the day, but uses it an night. That's where the aeration system comes into play.

The attached file is from a book released in 1972 (Fishery Volume 70, NO 4, 1972.)

FNC I kill any FA back with Cutrine. The process I use in my 3ac pond is to Kill back FA and then Fertilize with adding pond dye. The Pond dye keeps stuff from growing at depths for me. I curreently have 5 grass carp per acre to help combat any other growth the pond dye does not halt. I will remove some bigger grass carp when FA is not a problem as the year goes along. I then add small grass carp back in the winter to replace what I remove. I use pond dye thru most of the year as a management tool. If I see a spot of FA coming on pretty strong I will mix in a gallon sprayer a little of Cutrine and treat that small area also. Pretty much every year here I have to do things a little different because of the changes in annual climates. I take a more proactive approach.

One has to be careful when genralizing from graphs or a conclusion. The graph of phytoplankton growth curve above can be misleading because it does not provide what species were present as the temperature increases. Often in freshwater (FW) systems, it is the less than beneficial bluegreen algae (Cyanobacteria) are the most heat tolerant species. For most "wild" FW plankton communities normally as the temperature increases there is a shift in species composition which occurs at various points based on several variables such as day length & nutrient composition.
The graph alone also leads one to believe or asume that phytoplankton is a simple system comprised of one, a couple or a few species creating the nice 'smooth' data set. Rarely is that the case. What happens in my experience is as the temperature increases the species present change and above certain temperature levels or plateaus many drop out and at the end only a few or one specie is present at the highest temperatures on the graph - heat tolerant types. Sometimes those graphs are adapted from laboratory studies (growth cultures) where only one or two optimum species are used to create the data points and the graph nicely displayed the author's point.

Bill I thought you may find this copy of a Journal on plankton research in 2001 interesting.
http://plankt.oxfordjournals.org/content/23/2/165.full.pdf+html

Interesting and informative study. It is another one that shows the importance of N:P ratio for maintaining good plankton bloooms.

Bill As I said to begin with I am not a specialest on Plankton and I am glad people that know more than I do are around. In the Book it said that Figure was derived from over 130 different species or clones at different temperaturs (the way I read it). Anyway I found the online PDF version of where I got that Chart from for you. Thanks
http://lgmacweb.env.uea.ac.uk/green_ocean/publications/Nano/Eppley72.pdf

Thanks for sharing that information. It does have some value.
My comments from my perspective about phytoplankton are:
Data points from that phytoplankton growth curve have IMO some characters or features that make comparison of them to "wild" freshwater phytoplankton highly questionable as far as predictable similarity. 1. They were all lab cultures. Lab algae cultures can behave differently compared to regular species out in nature, because some of the lab species have been in culture for decades and they have "lost" some of the wild traits. 2. They are all marine species. Marine species can to my knowledge behave differently than many of the species found in freshwater ponds. They are considered different species for reasons. Comparing marine and freshwater organisms is always suspect from my experience and IMO . 3. all of the data in Figs 1 & 2 were from studies using continuous light. Again not natural conditions. Many of these points would be overlooked by most laymen and even some scientists.
It is interesting that many of the species dropped out when the temperature got above 78.8F. This suggests to me that the species growing in the higher temps were fewer in number and adapted to warmest waters. The chart does not indicate what species were growing at each temperature range, for example those present at every 5 degrees C increment. There were some species also growing at 3-10 C (37-50F). But we do not know if those were the same species that were growing at 60, 70 or 80F.

I don't put much importance or value to information in that chart as to how it applies to our wild freshwater algae phytoplankton populations. The research paper was a paper about phytoplankton modeling where the authors were looking for trends to create a model. The authors were careful to always state the data were for algae in the marine, ocean or sea habitats. The figures 1 & 2 do have some merit for freshwater phytoplankon. The figures 1&2 were created to make a point, but one has to be careful that the information is not naively extrapolated to apply to all phytoplankton or other points/topics, concepts. The data apply to the types or species of algae that were used to create the data and we don't know what those species were. To me it is similar to saying that 300 meat samples from agriculture farms had red color. Then the trend is all meat will likely be red meat. What I am basically saying is - be careful how one interprets published data. I'm sure that similar cautions apply to many other professions.

I am a specialist in phytoplankton and algae, so it stands to reason that I would be overly opinionated or would critically evaluate these topics. Do not take my opinions as a personal attack. Tums posts and FnC's questions generated some good discussion and maybe were helpful to a few others. Thanks to all for participating.

Bill being educated should never be offensive to anyone. We all have something to share that someone else does not know. The only way to share that is by a useful means of communication (IE posting in this case). Thanks for volunteering your specialization for our benefit and the benefit of others. I consider this thread a prime example of how useful communication in a proper forum can benefit others. Fish N Chips thanks for starting such a discussion.