Pond Boss Forums INTRO Questions & Observations Where'd the algae bloom go?

Yesterday in my small pond (25' X 50' X 4' deep) the water was green (planktonic algae I presume), visibility about 20". Pondgrass covers about 50% of the surface (will be thinning out this week) and very little filamentous algae. Today the water is clear, visibility 4'. What happened?

In the bigger pond (1/2 acre, 6' deep) the water is still green, visibility about 22".

Since I have LMB, BG, CC and mosquito fish in both, I would like to maintain some bloom. In the larger pond I have an ongoing duckweed problem and black layer muck. I've been told adding microbes may help. I'll do that later this week. I add aerated well water at least every other day although haven't done so for a week. How will the microbes effect the aglae bloom? Should I still add them to the little pond that has cleared up?

I can't answer your question reguarding the bloom but if you add microbes to get rid of the muck it would be helpful if you could post what you are doing & what results you get here:
http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=14;t=000153

Now the 1/2 acre pond has cleared the same way.

I'm just curious if it is normal to have the visibility go from 20" to more than 48" overnight without any external changes that I know of.

I know nothing about Ca water but it sounds like you are asking about what has happened to your phytoplankton base. I don't think it is normal. You may have a weather or climate condition that has occurred but? In general it sounds like you have a phytoplankton die off. Why? Maybe Bill Cody will chime in.

Could be other types of plants are uptaking your nutrients. In my warmwater pond that had an algae bloom of about 2 feet clarity last year it became clear and has stayed clear starting in late summer when after I took out about 100 lbs. of bass for harvest. At the same time filamentous algae took off last fall and now chara is dominant.

Have you seen an increase in macrophytes (leaved and rooted plants)?

I went from a 20" or so bloom to a tea brown color in a few days and was concerned. A few days later I had CRYSTAL clear water and 4'-5' visibility. I have not seen any unusual plant growth. This is the first year for me using diffused aeration instead of surface aeration. I also used sonar to combat the heavy growth of duckweed and watermeal this year. My fish seem to be alot more lively after the clear water onset. I don't mean to ramble on on the subject but thought maybe you might have used or done one or a few of the same things I did to cause the clear water. Maybe someone will jump in and tell us both. I am on the other side of the country from you but may be experiencing the same problems. Good luck

Aaron,

I do know what you describe is a symptom of an algae crash. Sounds like your's was not severe enough to cause a fish kill.

Clear water is nice but there is a downside to it. You may see an increase in nusiance weeds or filamentous algae. Most likey this time of year nuisance weeds.

Some rooted plants (looks like Sago pondweed) have been growing rapidly. Duckweed continues but manage with skimming and spot treat with Reward. No other chemicals or agents have been put in either ponds.

I have seen gradual changes in both ponds over time but never this dramatic. The fish are still very active and feeding. After the water cleared in the small pond I removed a lot of pondgrass (and stirred up the bottom layer in the process), I now have what almost looks like a light oil slick and lots of greenish bubbles on top.

Weather has been mostly sunny; night, 47-56 and day, 77-85 . Water temperature 68 deg.

Last night I added some microbes/enzymes and aerated well water to both ponds. We'll see what happens.

Techman and AhomeIN both experienced rapid decreases or crashes of the phytoplankton community. Both phytoplankton decreases were due to lower nutrients in the water column. Techman's reduction of nutrients was due to rooted vegetation absorbing nutrients whereas AhomeIN's reduction of nutrients was probably due to the phytoplankton bloom itself absorbing available nutrients in the water column and starving itself out. Phytoplankton blooms can crash due to decreases in only one limiting nutrient. AhomeIN's brown water was due to one of the numerous algae species that when very abundant can cause a brownish tint to the water. Note other things besides phytoplankton can also impart a brown tint in water.

I am now seeing my green tint come back. Before my pond crashed we had a few days of heavy cloud cover. Could this have been the culprit. This is also the first year for my pond with no duck weed and heavy aeration. Thanks for the help guys, I was also worried when I read the post so I had to jump in.

Yes, thank you all for the info. I'm still wondering what the "light oil slick and lots of greenish bubbles on top" are in the small pond and...is it is anything to be concerned with or do anything about.

tecman = I think the slight oil slick is from stirring the bottom sediments which usually contain oils from dead plants including phytoplankton. Stirring or mixing the sediments during raking or removing pondgrass usually disrupts sediments and releases nutrient reserves trapped in the sediments. Nutrient reserves can stimulate a rapid growth of microalgae. I think the green film on the surface and associated bubbles is a microalgae growth. Bubbles are from either oxygen from plants or gases from sediments and they get temporarily caught in the algae surface film.

AHomeIN - Several days of cloudy weather can in certain conditions help suppress phytolankton blooms. Numerous combinations of variables can affect phytoplankton blooms.