What Factors Influence Phytoplankton Growth?

[AngelShare]

I'm supposed to find the answer to this in a short video but no matter how many times I listened to it, I couldn't find the second answer (Got the first easy enough though.)...

What three things affect the growth of phytoplankton?

So, I decided to try to look the answer up myself. Is this right?

Light absorption, phosphate absorption, annndd...ah, I haven't found the third one yet so I'll guess. Nutrient absorption?

 

[DocToxyn]

If there a link to the video on the web? Perhaps a different ear would catch what you missed. Even if you can't produce the video, I think we can help you out. You said that availability of light and phosphorous are two of the three factors and then guessed at nutrients. I tend to agree, however phosphorous is considered a nutrient, much like nitrogen, iron, silicon, so you'd be better to just lump them all under "nutrient availability". So that's two, what's left... Think about what may affect other systems, what can speed up or slow down growth of organisms in general? Do some searches for growth of phytoplankton and see what you find. Here are a couple of sites I found: http://www.atmosphere.mpg.de/enid/1vg.html".

Come back to us with your thoughts and we'll see what you came up with.

 

[AngelShare]

I'm just now starting to read over the links you provided but, in the meantime, I decided to post the video I was given. Tell me if it doesn't work.

http://www.seaweb.org/ram/5.1.98.ram"

While waiting for the reply page to load (Yeah, it took that long... ), I scanned over the first link you gave me...my guesses, so far, are: temperature/season and salinity. Before even clicking on any of your links, pollution came to mind but I'm not sure if that effects the growth of phytoplankton as I haven't read about it during any of my searches...

 

[DocToxyn]

I got the audio from the link, but not the video. Just from that I'm surprised you got what you did (not a strike against you). The information seemed rather nonspecific, unless I missed some graphics or something.

Anyway, I think you're on the right track with temperature. However your other guesses could stand up as well. Both salinity and pollution would have an effect on phytoplankton growth, but I think that whoever formed the question was attemtping to set some bounds on it to keep you from going too far off the subject. If you can justify your answers with sound scientific evidence, you should be fine (but I can't guarantee anything ).

 

[AngelShare]

Ah, sorry, it isn't a video, it's an audio clip so that's all there was to it. As I'm still a bit behind and am using my vacation to catch up, I think I'll just give those three answers (Nutrient availability, light absorption, and temperature.) and see what he says. Otherwise, I'll just get a 0.

 

[AngelShare]

Alright, now I'm supposed to check my answers and tell the teacher how many I got right. However, I'm not sure exactly how many I did get right...

Questions:

1. What are phytoplankton and why are they important?

2. What three things affect the growth of phytoplankton?

3. How are diatoms and dinoflagellates alike?

4. How are diatoms and dinoflagellates different?

5. How do phytoplankton respond to weather patterns such as El Niño?

6. Which of the three groups is responsible for "Red Tide"?

7. How are cyanobacteria similar to other types of phytoplankton?

8. Why do many plants need cyanobacteria in their roots? Follow the link below and also the "Life History" link at the bottom of the site.

My Answers:

1. Phytoplankton are tiny ocean algae that produce oxygen and help to support life on land.
2. Light absorption, nutrient availability, and temperature all effect the growth of phytoplankton.
3. Diatoms and Dinoflagellates are both single-celled.
4. Diatoms usually lack flagella while dinoflagellates don’t.
5. El Nino causes the surface temperature of the ocean to rise by as much as 3 degrees Celsius which causes the upwelling of cold, nutrient-rich waters to stop. The phytoplankton then suffer.
6. Dinoflagellates are responsible for Red Tide.
7. Both use photosynthesis to create energy.
8. Cyanobacteria are one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia. It is these "fixed" forms of nitrogen which plants need for their growth, and must obtain from the soil.

Teacher's Answers:

1. Phytoplankton are microscopic plants that live in the ocean. They are important because they remove carbon dioxide from the atmosphere, provide food for organisms in the oceans, and produce oxygen from photosynthesis.
2. Three things that affect the growth of phytoplankton include sunlight, water, and nutrients.
3. Diatoms and dinoflagellates are alike because they are both single-celled organisms and use photosynthesis.
4. Diatoms are different from dinoflagellates because they have radial symmetry. Dinoflagellates are different from diatoms because they possesses two flagella that allow them to move.
5. The populations of phytoplankton may actually decrease during an El Niño because of the lack of cold, deeper water moving to the surface and bringing up nutrients from the bottom. El Niño causes warm water and stops the upwelling from the depths of the ocean.
6. Dinoflagellates are the main type of phytoplankton involved in the Red Tides.
7. Cyanobacteria are similar to other types of phytoplankton because they are photosynthetic, can live in all types of aquatic environments, and are a food source for organisms.
8. Phytoplankton may lower average temperatures by continually removing carbon dioxide, which is a greenhouse gas, from the atmosphere.

Some of his answers are rather confusing...first of all, it seems as though he added more for question number one than what I did but he never specified how much he wanted. Normally, he'd decide if what I put was enough but since I'm to check it, I don't know if I put enough by his standards. My answer is right though, I'm assuming, as I got it from that audio clip which is what we were to use. I had a hard time finding number two as you'll know and, as far as I know, my answers are, yet again, correct. Got number three...not sure about number four...pretty sure I got five and six...he added more for number seven but I got one of his reasons. Yet again, however, he never specified how much we were to put and his http://www.ucmp.berkeley.edu/bacteria/cyanolh.html" confused me a bit. I...don't even know what's going on in number eight.

 

[dumbadum]

I think in your answer for #1, instead of saying tiny, you should say microscopic, as said by your teacher, because tiny can be just very small, but still can be seen by the naked eye.
For #5, I think you should expand on how the suffer. Instead of just saying "they suffer", maybe describing the decrease in population would make the answer more complete.
For most of the answers, I think you just need to expand on your answers, they seem fine otherwise.
#8 is just weird.

 

[AngelShare]

How would I describe the decrease in their population? I already said, "which causes the upwelling of cold, nutrient-rich waters to stop"...they can't get the nutrients they need.

 

[iansmith]

1. Phytoplankton are tiny ocean algae that produce oxygen and help to support life on land.

The description is good but you used tiny instead of microscopic. I would give partial mark (0.5/1)

2. Light absorption, nutrient availability, and temperature all effect the growth of phytoplankton.

Partial marks again because light absorption is different than light availability (0.5/1)

3. Diatoms and Dinoflagellates are both single-celled.

The teacher did not specify the number of difference he wanted so your answer is good enough

4. Diatoms usually lack flagella while dinoflagellates don’t.

Again he did not specify. Full mark

5. El Nino causes the surface temperature of the ocean to rise by as much as 3 degrees Celsius which causes the upwelling of cold, nutrient-rich waters to stop. The phytoplankton then suffer.

Full mark

6. Dinoflagellates are responsible for Red Tide.

Full mark

7. Both use photosynthesis to create energy.

He did not specify so the answer is good enough

8. Cyanobacteria are one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia. It is these "fixed" forms of nitrogen which plants need for their growth, and must obtain from the soil.

Although you answer is different than the teacher, the answer is acceptable.

This is how I as TA I would correct the assignment, So you get 7 out of 8.

 

[DocToxyn]

I think the only thing you are missing in #1 is that phytoplankton are just as important for life in the oceans as they are for life on land. While iansmith is correct about #2, you might be able to argue that the ability of phytoplankton to absorb light is (at least partially) dependent on availability. I think your intention was obvious, it depends on how much of a stickler the prof is. Plus on that one, I had thought about water as one of the things that affects phytoplankton, but it seemed too obvious. Perhaps the question should have read - "What is required for phytoplanton growth?" rather than what affects growth.

The rest of your answers look fine, although as you point out not as lengthy as the teachers, but he/she didn't ask for an essay. As far a #8 yours looks much better, he/she didn't even discuss roots, I suspect this was an simple substitution error on the teachers part.