Water Quality B/C

FlyingMonkey85
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Re: Water Quality B/C

Postby FlyingMonkey85 » April 14th, 2012, 5:29 am

Patar:
--I believe that high pressure too increases dissolved oxygen (http://www.elmhurst.edu/~chm/vchembook/174temppres.html)

--The ideal pH range for aquatic animals is around 6.5-8.5 (http://www.ncsu.edu/sciencejunction/dep ... fects.html). The answer varies online, but generally aquatic organisms prefer alkaline waters.

--I am not sure about this, but I would think that plant and animal diversity would affect the dissolved oxygen levels because of photosynthesis and respiration, respectively. In would be hesitant to pick "C" because it says "green plants" because I think plant of other colors also perform photosynthesis. (No Source Here...)
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Re: Water Quality B/C

Postby quizbowl » April 14th, 2012, 7:25 am

...One of the question asked the water in which scenario has more dissolved oxygen and the answer on the key stated that high pressure and low temperature is correct. But I thought lower pressure and lower temperature meant higher DO?... and also another question asked what was the pH range of most aquatic organisms. The answer on the key was 7-9 but I thought many organisms can tolerate below pH of 7?
You're right that low temperatures correlate to higher Dissolved Oxygen levels. However, it is true that as one increases the pressure of a liquid, the amount of gas that can be dissolved will increase. That's why lakes at high elevations often have surprisingly low DO levels - the decrease in atmospheric pressure is to blame for that. As for the pH range, I've always remembered that the true range for most aquatic organisms is 6.5 to 8.2. I'd understand a pH of 7 being the minimum for the answer (rounded up and such) but 9 does seem a bit high - I'm sure that the incredibly basic environment would be detrimental to some organisms.
...one of the questions asks: what does the amount of oxygen in any body of water depend on? and the options were:

A: the amount of animals species diversity
B: the amount of plant species diversity
C: Water temperature, number of green plants, and sunlight
D: All of the above

I put C since the quality of water does not depend on species diversity, rather the species diversity represents the quality of the water. The answer on the answer key was D... can anyone clarify this?
Well, think of it this way - high species diversity means high water quality, right? And usually with high water quality, one sees a strong correlation with DO levels. I know the question sounds poorly worded, but it is clear that species diversity plays an important role in establishing these levels.
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Re: Water Quality B/C

Postby hpfananu » April 14th, 2012, 9:53 pm

We took our state test today and it had mostly Dynamic Planet stuff with Base Levels, flow rate, stream gradients and sediment patterns etc.
Has anyone found this on any other test or was it just this weird test? The events are slightly related but I think it's slightly wild to expect us to know all about Dynamic Planet and general Water Quality...
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Re: Water Quality B/C

Postby Infinity Flat » April 15th, 2012, 1:27 am

...One of the question asked the water in which scenario has more dissolved oxygen and the answer on the key stated that high pressure and low temperature is correct. But I thought lower pressure and lower temperature meant higher DO?... and also another question asked what was the pH range of most aquatic organisms. The answer on the key was 7-9 but I thought many organisms can tolerate below pH of 7?
You're right that low temperatures correlate to higher Dissolved Oxygen levels. However, it is true that as one increases the pressure of a liquid, the amount of gas that can be dissolved will increase. That's why lakes at high elevations often have surprisingly low DO levels - the decrease in atmospheric pressure is to blame for that. As for the pH range, I've always remembered that the true range for most aquatic organisms is 6.5 to 8.2. I'd understand a pH of 7 being the minimum for the answer (rounded up and such) but 9 does seem a bit high - I'm sure that the incredibly basic environment would be detrimental to some organisms.
...one of the questions asks: what does the amount of oxygen in any body of water depend on? and the options were:

A: the amount of animals species diversity
B: the amount of plant species diversity
C: Water temperature, number of green plants, and sunlight
D: All of the above

I put C since the quality of water does not depend on species diversity, rather the species diversity represents the quality of the water. The answer on the answer key was D... can anyone clarify this?
Well, think of it this way - high species diversity means high water quality, right? And usually with high water quality, one sees a strong correlation with DO levels. I know the question sounds poorly worded, but it is clear that species diversity plays an important role in establishing these levels.
Well, the plant species diversification at least can affect DO levels - eutrophication and algal blooms are pretty good examples of this.
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Re: Water Quality B/C

Postby mnstrviola » April 15th, 2012, 2:15 pm

Okay I was thrown into this event at states 5 min. into the competition. There were 6 stations I believe. 2 were Dynamic Planet material, 1 was species ID, 1 was interpreting graphs based on pollution, 1 was random stuff I didn't understand and I forgot what happened on the last one. It seemed like an easy event, but we did pretty bad on the salinometer thing.

The test heavily emphasized on water treatment methods, also on coliform bacteria...

CORRECTION: it wasn't stations, but different colored papers that are part of the test. It should be *sections

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Re: Water Quality B/C

Postby 135scioly » April 15th, 2012, 7:53 pm

The problem we have found seems to be with the clay. It can dry out, change shape slightly, not seal correctly, absorb water. What I have found to be more accurate is to use different materials that are impermeable to water. I have had much more accuracy using a pipette or plastic syringe. The bulb part at the bottom I filled completely with sand (if you do not fill it completely, the air pocket will make the salinometer tip to the sides). Then, because my pipette was not long enough to keep the top above water, I plugged it with some clay and cut a straw in half and pushed the straw onto the pipette. I then taped over the edge of where the straw connects to the plastic pipette. I then started with my 0% solution and marked the line, then I mixed a 10% solution and marked the line. Then using my ruler I made a line that was 1/2 way in-between and then just experimented with eyeballing the other 4 lines in between 0 & 5 and 5 & 10 to make them equally spaced. I have tested this salinometer with other % solutions and it seems to be fairly accurate now. Here is a link of what the plastic pipette looks like (ask your science teacher if they have some!) and I used a larger straw that seemed to fit snugly. I cut the tip of the pipette somewhat to be able to pour the sand in. Hope this is helpful.
Thanks so much for this! I made my salinometer the night before using your way and although I didn't place in water quality at state(got thrown into the event last minute... Thats also why i was making my cheat sheet and salinometer the night before) im pretty sure i got the salinity right! :D
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Re: Water Quality B/C

Postby cngu23 » April 16th, 2012, 4:32 am

We took our state test today and it had mostly Dynamic Planet stuff with Base Levels, flow rate, stream gradients and sediment patterns etc.
Has anyone found this on any other test or was it just this weird test? The events are slightly related but I think it's slightly wild to expect us to know all about Dynamic Planet and general Water Quality...
I don't think the material for dynamic planet (flow rates, stream gradients, etc.) fits under the water quality rules.
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Re: Water Quality B/C

Postby ptkid » April 28th, 2012, 7:27 am

For nats how much is everyone studying?
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Re: Water Quality B/C

Postby hpfananu » April 28th, 2012, 11:15 am

Do you guys know if we are allowed to bring a graduated cylinder for our salinometer?
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Re: Water Quality B/C

Postby quizbowl » April 28th, 2012, 11:16 am

Do you guys know if we are allowed to bring a graduated cylinder for our salinometer?
At NY states this year, we were permitted to use a graduated cylinder, as long as we were the last ones to go in our time slot.
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