Sea temp on surface and deep down

Discussion in 'General Discussions and Advice' started by neo, 18 Jun 2010.

  1. neo


    25 Jun 2009
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    with one or two threads on heaters and water temp and my own experience the last 2 weeks I was thinking:
    What is the sea temp at 20 - 100m ?
    Why do we want our tanks at 24deg ?
    Maybe the temp at depth where our livestock normally occurs is lower than 24deg ??

    So I GOOGLED, found some info, still no straight answer for me, I will share what I have found and ask for your opinion.

    First, we have easy access to the surface temp measured by satellite, here's an example:


    [FONT=&quot]but what happens lower down cause the above measures the top micro meter of the water.

    water temp in the sea looses temp according to the following graph:

    [FONT=&quot]The thermocline region is where the sharpest decrease in temp occurs and is typically the top 50 - 250m according to some sources.[/FONT]
    [FONT=&quot]There are other sources which uses the following graph:[/FONT]
    [FONT=&quot] 20424c1b581cc266e.png

    but from this, how close to the surface temp will it be at say 50m, only 1 degree less ? or more ?

    So my questions to the MASA community and especially the marine biologists and divers.
    What is the typical underwater temp where our livestock occurs for winter and summer?
    Do we have to run our tanks at 24 - 26 degrees ?
    Do we have to keep this temp up during winter time?[/FONT]
  2. Guest

  3. jacquesb

    jacquesb Retired Moderator

    29 May 2007
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    Cape Town
    Thanks for sharing Neo. Any SCUBA diver can attest - the water temp in SOME areas of our seas, deeper down, does sometime drop with up to 6 to 8 degrees celsius (my dive computer clearly shows it).....

    The water temp does vary somewhat, over the reefs where most (not all) our lifestock comes from - but the variance is +-4 to 6 degrees, between summer and winter. Where the summertime temps of the water over the reefs, can go up to ie. 34 degrees celsius (this is personal experience of diving the reefs of the Seychelles)... and the wintertime temps be around 26 to 28 degrees celsius...

    Wintertime water temps over the reefs of Southern Mozambique for example (where a lot of the same types of fish and corals live, that we keep), can be so low as 20 degrees celsius (on the reefs itself)....

    The reefs at ie. Sordies also share those temps of that of Southern Moz.

    The reefs at the Aliwal Shoal, suffer from winter temps down to 18 degrees celsius, as does the reefs at Protea Banks....

    This is just from personal diving experience, though.

    We tend to try and keep our tank temps stable - but if you do want to try and have a natural cycle (as long as the change is NOT sudden, but gradual over the period of a few days), then you can decrease the water temp in your tank slightly (but slowly), to simulate water temp changes between summer/winter....
  4. clinton stanford

    clinton stanford

    11 Mar 2009
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    East London
    very interesting thread;)
  5. JD167


    5 Apr 2008
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    Cape Town
    I was in Bali in January this year and did some diving. The locals refuse to go diving if the water temperature drops below 26 degrees. :)
  6. brentv


    4 Jun 2009
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    Cape Town
    This is a great Topic...
    I was a Scuba Diving instructor for 10 years, and diving many countries... different reefs different conditions and I have had many dives where the surface is say 20 and at the bottom 24!!! (reverse) Thermoclines only really happen when the Specific Gravity of 2 water masses are different. This can be caused by temp. , current, sediment and a pile of other stuff.... But generally where most of our corals grow... and most tropical reef fish live 1-20M the water due to current is normally the same top and bottom (if there is no thermocline!)
    Like Jaques said Temp in tropical island type environments can go way up especially in confined areas at a low tide.
    I have honestly seen anemones and clownfish in ponds of water over 36!!! and thats the truth!!!
    I think we use the 24-26 degree area for our tanks, because it allows for the greatest range of biodiversity to survive from fish to corals and everything in between!
  7. Reef Maniac

    Reef Maniac

    15 May 2007
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    Interesting topic :thumbup:

    As Brentv stated: "we use the 24-26 degree area for our tanks, because it allows for the greatest range of biodiversity to survive from fish to corals and everything in between!"

    Fish in the ocean can swim/dive to whatever depth / temperature they prefer, but in our tanks they cannot swim to warmer or colder zones, so it is best to keep the temperature within a "good" range, which is a compromise between high metabolism and high dissolved oxygen content, and that temperature just happen to be in the 24°C - 27°C range for our tropical marine fish.

  8. MistaOrange


    20 Jan 2010
    Likes Received:
    Somewhere in Cape Town
    lol they are a bunch of moffies send them to the cape to have a lekker brain freeze:lol::lol::lol::lol:
  9. deadmeat2016

    deadmeat2016 Wouter

    19 Jul 2009
    Likes Received:
    Gordons bay
    very intelligent answerson this here thread :thumbup: but temps do indeed go down the deeper u go except in some cases, Brent :p, thermoclines and haloclines dramatically affect the temps but the key to a perfect reef is stability, if you measured the temp stability of the most beautiful reefs you will find that they are fairly stable, fluctuation by about 6 degrees+/-. Although most life can withstand the extremes for a while, without adaptation, the stress will most likely take them to the great reef in the sky.
    Whats really interesting is the exploration done on depths deeper than 2Km, the marine snow and sediments are very mysterious

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