Help - What do you say when:

Marty · Post by **Marty** » Sat Mar 12, 2011 9:25 am

Someone asks you a question about a statement you made that is hard to defend?

This is what happen – was at work talking with a few of my fellow workers that don’t fish and could not understand my passion for fishing for Bass. I was telling them it is not just putting a worm on a hook and hanging it over the boat. You have to know the habits of the Bass, the food they eat, the territory they live in, and the elements that effect them. That is about the time I start telling them about “Convection of the Water” and I made a statement from a book that I was reading. I said, that ““The trapped water beneath the thermocline may become virtually devoid of dissolved oxygen”! (from the book “Advanced Bass Techniques” by Rich Zaleski – given to me by one of our fellow poster on Western Bass).

Well one of the fellow works was this young very lovely lady! She looks me in the eye and bats her eye lashes two or three times and asks me, “how can the water beneath the thermocline be devoid of oxygen when water is made up of H2O, two hydrogen and one oxygen atom, it would not be water anymore? She had me by my manhood and was not going to let me go! Was I glad that the phone just rang and I said I had to get this call.

Ok, how do I answer the Convection question and does water under the thermocline is actually “virtually devoid of dissolved oxygen? How do we answer that?

mac (Doyle McEwen) · Post by **mac (Doyle McEwen)** » Sat Mar 12, 2011 9:56 am

Marty, not being a chemist it might be a difficult question to answer..But the dissolved oxygen you are talking about is free bubbles of oxygen rather than oxygen that has bonded molecularly to the molecules of water..If they were bonded with the water molecules then you would have hydrogen peroxide or some other molecular compound..

mac

sTony · Post by **sTony** » Sat Mar 12, 2011 10:46 am

Tell Miss Smarty pants this:

Thermoclines can be observed in lakes. In colder climates, this leads to a phenomenon called stratification. During the summer, warm water, which is less dense, will sit on top of colder, denser deeper water, with a thermocline separating them. The warm layer is called the epilimnion and the cold layer is called the hypolimnion. Because the warm water is exposed to the sun during the day, a stable system exists, and very little mixing of warm water and cold water occurs, particularly in calm weather.

One result of this stability is that as the summer wears on, there is less and less oxygen below the thermocline, as the water below the thermocline never circulates to the surface, and organisms in the water deplete the available oxygen. As winter approaches, the temperature of the surface water will drop as nighttime cooling dominates heat transfer. A point is reached where the density of the cooling surface water becomes greater than the density of the deep water, and overturning begins as the dense surface water moves down under the influence of gravity. This process is aided by wind or any other process (currents for example) that agitates the water. This effect also occurs in Arctic and Antarctic waters, bringing water to the surface which, although low in oxygen, is higher in nutrients than the original surface water. This enriching of surface nutrients may produce blooms of phytoplankton, making these areas productive.

mrobinett · Post by **mrobinett** » Sat Mar 12, 2011 6:35 pm

I think Tony's explanation is dead on. I just wish I understood what he said!

swordfish · Post by **swordfish** » Sat Mar 12, 2011 6:59 pm

Just think of shallow water mixed up by wind and waves it gets oxegenated in the mix, he lower levels are less affected especially if statified, when all else fails go with common sense and not so many book smarts, overthinking the seasonal patterns of those greeen fish can drive you nuts. At least she had a good come back,

offduty · Post by **offduty** » Sat Mar 12, 2011 7:45 pm

mac (Doyle McEwen) wrote:Marty, not being a chemist it might be a difficult question to answer..But the dissolved oxygen you are talking about is free bubbles of oxygen rather than oxygen that has bonded molecularly to the molecules of water..If they were bonded with the water molecules then you would have hydrogen peroxide or some other molecular compound..

mac

+1 not to mention the fact that both hydrogen and oxygen support combustion yet together water puts out the majority of fires. Amazing world we live in. fish dont breathe the water to survive they breathe the oxygen in it.

DAKINE198 · Post by **DAKINE198** » Sat Mar 12, 2011 10:49 pm

sTony is correct and the term you are looking for is "Dissolved Oxygen" or DO.
Dissolved Oxygen

Why Is It Important?

Like terrestrial animals, fish and other aquatic organisms need oxygen to live. As water moves past their gills (or other breathing apparatus), microscopic bubbles of oxygen gas in the water, called dissolved oxygen (DO), are transferred from the water to their blood. Like any other gas diffusion process, the transfer is efficient only above certain concentrations. In other words, oxygen can be present in the water, but at too low a concentration to sustain aquatic life. Oxygen also is needed by virtually all algae and all macrophytes, and for many chemical reactions that are important to lake functioning.

Reasons for Natural Variation

Oxygen is produced during photosynthesis and consumed during respiration and decomposition.

Because it requires light, photosynthesis occurs only during daylight hours. Respiration and decomposition, on the other hand, occur 24 hours a day. This difference alone can account for large daily variations in DO concentrations. During the night, when photosynthesis cannot counterbalance the loss of oxygen through respiration and decomposition, DO concentration may steadily decline. It is lowest just before dawn, when photosynthesis resumes.

Other sources of oxygen include the air and inflowing streams. Oxygen concentrations are much higher in air, which is about 21% oxygen, than in water, which is a tiny fraction of 1 percent oxygen. Where the air and water meet, this tremendous difference in concentration causes oxygen molecules in the air to dissolve into the water. More oxygen dissolves into water when wind stirs the water; as the waves create more surface area, more diffusion can occur. A similar process happens when you add sugar to a cup of coffee - the sugar dissolves. It dissolves more quickly, however, when you stir the coffee.

Another physical process that affects DO concentrations is the relationship between water temperature and gas saturation. Cold water can hold more of any gas, in this case oxygen, than warmer water. Warmer water becomes "saturated" more easily with oxygen. As water becomes warmer it can hold less and less DO. So, during the summer months in the warmer top portion of a lake, the total amount of oxygen present may be limited by temperature. If the water becomes too warm, even if 100% saturated, O2 levels may be suboptimal for many species of trout.

FinesseKid · Post by **FinesseKid** » Sun Mar 13, 2011 3:01 pm

Oxygen cannot exist as a solitary atom in nature (its simply too unstable). It must be attached to another atom in order to be stable. (such as H2O and CO2 etc..) Dissolved oxygen simply means two oxygen atoms bound together. (O2 or Oxygen gas) Explain to your buddy that O2 is the only usable type of oxygen by fish and water with no dissolved oxygen (O2) technically means the water is devoid of oxygen.

In theory, usable oxygen can be acquired from water by running an electrical current through it. Just as a side note.

So tell her that....

Then slap her.

LOLOLOL

DanWarme · Post by **DanWarme** » Sun Mar 13, 2011 5:10 pm

The previous answers pretty much cover it. Fish don't breathe the "O" in H2O. They breathe the additional disolved "O2" that is present to varying degrees in water.

My only advice I can add is that you not try to argue with an idiot.
They will beat you with experience!

fish_food · Post by **fish_food** » Sun Mar 13, 2011 5:58 pm

DanWarme wrote:My only advice I can add is that you not try to argue with an idiot.

He wasn't arguing with an idiot. The gal who asked him about oxygen knew he couldn't provide an adequate response, hence this post asking for the correct answer to her question.

barse41 · Post by **barse41** » Mon Mar 14, 2011 12:06 pm

Marty, just give her my number. I'll straiten her out.

davet. · Post by **davet.** » Tue Mar 15, 2011 6:31 pm

How did she have enough time to ask this between fetching you coffee, running errands and fixin yer lunch?

acm95301 · Post by **acm95301** » Wed Mar 16, 2011 3:33 am

I think the best, most accurate answer is that concerning the difference between an atom of oxygen versus usable dissolved oxygen.

That said,is consider an airtight vault. As you use up your oxygen you suffocate. The air still has oxygen, but it has less oxygen. You need something like 16 percent oxygen to survive, below that and your going to decline. The thermocline creates a situation where the water isnt inclined to hold dissolved oxygen, and because it lacks it the are area is devoid of life.

thukidad · Post by **thukidad** » Wed Mar 16, 2011 6:55 am

davet. wrote:How did she have enough time to ask this between fetching you coffee, running errands and fixin yer lunch?

wondering that myself?!?!?! lol

Riplip · Post by **Riplip** » Wed Mar 16, 2011 9:51 am

Just think of what happens in your livewell...The fish metabolize the dissolved O2 and without recirculating (areating) the water, the fish will "suffocate" even though they are still wet.

Smee Again · Post by **Smee Again** » Wed Mar 16, 2011 11:48 am

FinesseKid wrote:Oxygen cannot exist as a solitary atom in nature (its simply too unstable). It must be attached to another atom in order to be stable. (such as H2O and CO2 etc..) Dissolved oxygen simply means two oxygen atoms bound together. (O2 or Oxygen gas) Explain to your buddy that O2 is the only usable type of oxygen by fish and water with no dissolved oxygen (O2) technically means the water is devoid of oxygen.

In theory, usable oxygen can be acquired from water by running an electrical current through it. Just as a side note.

So tell her that....

Then slap her.

LOLOLOL

Correct! You might want to ask her if she's ever heard of a little thing called carbon monoxide poisoning. There is obviously an oxygen atom in the CO molecule, but it is completely unusable for aerobic respiration, hence people/animals dying in an overly rich CO environment (actually called competitive inhibition, but that's the long version). All oxygen is not created equally...

SA

DanWarme · Post by **DanWarme** » Wed Mar 16, 2011 8:19 pm

Wanted to add one additional item you had asked about, regarding Oxygen below the thermocline.
Yes, the area of the lake below the thermocline (it is called the hypolimnion) can be devoid of oxygen by mid to late summer. But not always. The determining factors include how much decaying matter is in the lake, and how much water there is below the thremocline.
Shallow lakes with lots of vegitation are great candidates to have zero oxygen below the thermocline. The decaying matter consumes the O2 very quickly and there is not a huge amount of water available in the first place.
Contrast that to a lake like Mead what has a huge amount of water below the thermocline. It is far harder to use up the available O2 because there is a huge amount of it. Combined with the fact that there is little vegitation. The lake is gererally clear and far less fertile than say a farm pond.
Like everything else in bass fishing, the answer will be , "it depends". On lakes like Mead, or even Castaic, I have no problem fishing below the thermocline all summer long. The fish do just fine and there is plenty of O2 for them. A farm pond or shallow weedy lake, I wouldn't waste my time fishing deep by mid summer. The fish couldn't survive there due to O2 depleation. Fish the thermocline and above.

KPalmer · Post by **KPalmer** » Fri Mar 18, 2011 10:50 am

You guys have once again made something very simple into a complicated scenario....you are way over thinking this thing...The most important thing to keep in mind is:
"How big was her rack?"