answer this

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we often see algae floating during day and they sink during night in a pond
why does this happen?????????????? Cool

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Quite Interesting Wait for A few Seconds I am searching The Answer
Very Happy

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The Reason Why They Float is Here : bounce

Some blue-green algae can float to the surface under these
conditions having access to all the light in the top waters (photic region) and
nutrients in the top and bottom waters. This allows the
algae to flourish and bloom. Some other algae are motile
and can swim to the photic region under these conditions.

Many other factors play a role in the formation of blue-green algal blooms
including temperature, salinity, zooplankton grazing, pH and turbidity.
Algae vary considerably in size, shape, and growth form.

They can be:

Single celled
Many celled - either colonially or as filaments of cells; or
Elaborate plant bodies with differentiated cell types

Main habitat preferences are:

Free floating in the water column (planktonic). These comprise the
microscopic unicellular algae and colonial and filamentous algae,
known as "phytoplankton".
Growing as a film on rocks on the bottom (benthic) or on plants
growing in the water (epiphytic). These may be single celled or
small colonial and filamentous species.
Growing out into the water column but attached to a substrate at one
point. These comprise the larger filamentous algae, and macroalgae
(eg. seaweeds).

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THI IS A 2 MARK QUES
I WANT 2 POINTS only
please be specific

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even we had the same question....i think it's like this:

during daytime, photosynthesis occurs, releasing O2 and filling up aerenchyma and thus, increasing the buoyancy?

at night no photosynthesis so, it sinks....

well..its a guess!!! i dunno whether its ryt or wrong!! Razz

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i think during day time O2 IS GIVEN OUT , O2 IS LIGHT SO THEY RISE
during night CO2is produced which is heavy bounce

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so...wats the ryt answer?

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hey wait...is this topic related to our syllabus Question

if yes...someone plzz explain it in a simple 2 lines.

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yeah it is there...thts y i'm scratching my head for it Suspect

wait till we figure out an answer...then we ll explain in 1 simple line only cat

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hey anu...u still scratching ur head?? confused

plzz explain this in 2 lines..

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still dont know the answer....ask your intelligent frnd and get an answer!!! the answers will be out by monday or tuesday..i'll ask my teacher, as i had got this question in preparatory

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hey..stop harrasing my 'intelligent' friend.just kidding lol!

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not harrasing...make use of intelligence!! Twisted Evil

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my answer is correct...i verified with maam

so, john, read my answer again...its just two lines.

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what kind of sense is that??
o2 is given out and because it is light the algae rises ???????

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vallabh....check out my answer...not nish's...he just guessed like me.....so, there is nothing compulsory that guesses should be sensible na!! scratch

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pls give the final ans..........

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arre....ambili...i told na....my answer is correct ...check it....i have given it here only in previous comment

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"during daytime, photosynthesis occurs, releasing O2 and filling up aerenchyma and thus, increasing the buoyancy

at night no photosynthesis so, it sinks...."

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but which chap of our syll is this topic related??

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mm...good question...though i dont know the answer for it!! Very Happy

but, i gt this ques in the pre board....but, i cant rely on my teacher,,she is good for irrelevant things only!!

maybe this is related to photosynthesis in aquatic plants? its not in syll!!

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Hello,
I think I have d ans.... Wink

this is coz of sum property of plants known as phototropism...
it exists for unicellular organisms as well...
if you remember that when plant is kept in a dark room with one window from where it recieves sunlight ...it bends/grows in that direction ...
in the same way algae (rather all unicellular organisms) not only have the property of growing in that direction but even moving in that direction... hence they rise up... Exclamation

same relative terms exists:
-> chemotropism .....towards water
->thermotropism.....towards heat eg: folding of mimosa leaves..[Note: 2 reasons for folding of mimosa: turgidity or thermotropism]

Best Of Luck! What a Face

---$@% Jigar %@$--- bounce

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thankyou....but this isnt in syllabus...but still, helpful

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uh...if the ans about phototropism is rite...den i think it is in our syllabus...cuz we hav turgor...and phototropism is a type of turgor

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i haven't read about phototropism in the text(it is there?)