Algae in lakes

JoshP12

Member
Joined
8 Dec 2019
Messages
406
Location
Canada
Hi all,

I mentioned in a few other posts that < I went snorkeling > in a lake the other day.

In that lake, the only algae I saw was brown diatoms and the random bloom of green hair (which was only in very shallow areas near the shore line. Also, the prominence of diatoms decreased as I went further away from the shore (I mean, I could only see down to the drop off, so I can't comment for anything lower). When I pulled out a hair grass to look at it (I felt bad to ruin the ecosystem :arghh:) and scrubbed off the diatoms, I noticed the plant was really healthy - nice and green, sturdy, strong.

So, why the algae?

If unhealthy plants are spawning grounds for algae and I pulled out a healthy plant which had algae, then what is going on? Also, and I will add, I have seen some diatoms on perfectly healthy plants in my tank and after I give a little scrub it doesn't come back - perhaps what I saw was just "dirt" and not algae at all?

Josh
 

tiger15

Member
Joined
14 Mar 2018
Messages
449
Location
USA
If unhealthy plants are spawning grounds for algae and I pulled out a healthy plant which had algae, then what is going on? Also, and I will add, I have seen some diatoms on perfectly healthy plants in my tank and after I give a little scrub it doesn't come back - perhaps what I saw was just "dirt" and not algae at all?

Josh
There are as many algae types as causes for algae. Not all types of algae are harmful to plants or sign of unhealthy plants. Cause and effect is murky as unhealthy plants will invite BBA, blue green, and matting algae which in turn can block off light and harm plants. Even healthy plants apparently free of algae have micro algae if examined by a microscope. Green thread/hair algae are hard to get rid of as they thrive under the same conditions as healthy plants, as you noticed the present of diatom and green hair algae in apparently healthy plants in a healthy lake.
 

dw1305

Expert
Joined
7 Apr 2008
Messages
10,188
Location
nr Bath
Hi all,
Even healthy plants apparently free of algae have micro algae if examined by a microscope.
They certainly do. Any lit surface underwater <"has a green biofilm patina">.
Green thread/hair algae are hard to get rid of as they thrive under the same conditions as healthy plants, as you noticed the present of diatom and green hair algae in apparently healthy plants in a healthy lake.
Same for me, they have the <"same photosystems and basic physiology">.

One thing that will happen is that the algal assemblage will alter with <"changes in nutrient levels">.

cheers Darrel
 
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