Does ocean PH change at night?

[seth the wine guy]

If it does, then Im reconsidering running my fuge light the opposite my tank.

 

[lilrobb]

It does,
But nowhere close to our tank swings - just consider the billions of gallons that are unaffected by light changes and that in our tank almost all water is "lit"...

 

[mvm]

Seth The Wine Guy;724870 wrote: If it does, then Im reconsidering running my fuge light the opposite my tank.

That's the way most do it, but I found it to have little effect on the swing. I found that dosing kalk when the lights are off keeps things more stable.

 

[tangaray]

+1 I dose Kalk for 1 min of every hour that my lights are off in my 90 and my PH remains consistent.

MvM;724910 wrote: That's the way most do it, but I found it to have little effect on the swing. I found that dosing kalk when the lights are off keeps things more stable.

 

[seth the wine guy]

LilRobb;724880 wrote: It does,
But nowhere close to our tank swings - just consider the billions of gallons that are unaffected by light changes and that in our tank almost all water is "lit"...

Sure but how much of that "dark" water is exchanging with the water of the reef? Especially a reef like the great barrier reef. It's more than a hundred thousand square miles of very shallow water. Pretty much all of it shallow enough that photosynthetic organisms can exist right down to the very bottom. So, you actually have a concentrated area of billions of gallons experiencing something similar to our tank. Then there are so many lagoonal reefs and coves that have very little "dark" water exchange if any at all.

 

[tangaray]

Then I would place the responsibility on Tides to exchange the deep water. Even though the water is shallow at these points there is still water transfer by passing water from high and low tides. For example if there is 10 feet of beach at low tide and 3 feet of beach at high there is 7 feet of water plus depth plus length that gets replaced approximately every 12 hours or so. So you take that volume and pull it into deeper water churn it up and mix it with deeper water and then you bring that same volume back in with all new nutrients. Even though the water depth at reefs does not change, the water volume passing by on these events does replace the water. So effectively there is a water change performed every 12 hours or so at these reefs.

 

[ichthyoid]

Seth The Wine Guy;724870 wrote: If it does, then Im reconsidering running my fuge light the opposite my tank.

According to Scripps Institute, in open ocean no, less than 0.1 day/night on coral reefs (but that change does appear to be regular/periodic).

http://wattsupwiththat.com/2012/01/09/scripps-paper-ocean-acidification-fears-overhyped/">http://wattsupwiththat.com/2012/01/09/scripps-paper-ocean-acidification-fears-overhyped/</a>



[IMG]http://www.plosone.org/article/showImageLarge.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0028983.g002">[IMG]http://jonova.s3.amazonaws.com/graphs/ocean/ocean-ph-changes-graph-journal.pone.0028983.g002.png alt="" /></a>

 

[seth the wine guy]

Tangaray;724932 wrote: Then I would place the responsibility on Tides to exchange the deep water. Even though the water is shallow at these points there is still water transfer by passing water from high and low tides. For example if there is 10 feet of beach at low tide and 3 feet of beach at high there is 7 feet of water plus depth plus length that gets replaced approximately every 12 hours or so. So you take that volume and pull it into deeper water churn it up and mix it with deeper water and then you bring that same volume back in with all new nutrients. Even though the water depth at reefs does not change, the water volume passing by on these events does replace the water. So effectively there is a water change performed every 12 hours or so at these reefs.

There is a water change yes. But, the origin of the vast majority of the water coming in at tide change is water from the top 100 meters of ocean (where photosynthetic organisms can live.) A tide is an ocean swell. The ocean as a whole rises.

Example: Fill the bath tub with water. Take an empty five gallon bucket and push it down in the water right side up. What happens? Water level goes up. That action won't be an effective one for an exchange of water from different depths to take place. It just causes all existing water to rise.

 

[ichthyoid]

Seth The Wine Guy;724966 wrote: There is a water change yes. But, the origin of the vast majority of the water coming in at tide change is water from the top 100 meters of ocean (where photosynthetic organisms can live.) A tide is an ocean swell. The ocean as a whole rises.

Example: Fill the bath tub with water. Take an empty five gallon bucket and push it down in the water right side up. What happens? Water level goes up. That action won't be an effective one for an exchange of water from different depths to take place. It just causes all existing water to rise.

I agree ^.

Upwelling currents are responsible for deep water turnover. These happen in late winter/early spring and late summer/early fall. They are due to temperature differences in the water (essentially convection currents in the oceans). Cold water sinks, warm water rises, just like in air. Wind contributes, but it is superficial when compared to the above currents.

Part of the problem we have is perception. The oceans are so vast they tend to boggle the mind, IMO. Few of us have ever been beyond sight of land in a small boat.

Being at sea in the Navy, on what I HAD perceived to be a big ship (400+ feet), and then seeing how really small it seemed in 35 foot seas changed my perspective. You really have to be there to 'get that'. -JMHO